More than half a century after the race to the moon, space is once again the venue for a rivalry. China is doing everything it can to become a superpower in space as well. Already, manned and unmanned Chinese missions have passed a number of milestones. But what does this mean for the rest of the world and the previously leading space nations?
The first landing of a space probe on the far side of the moon, a rover on Mars, and a manned space station in orbit: In recent years, China has caught up tremendously in space travel and is getting closer and closer to the previous leader, the USA. China’s government leaves no doubt that it is also striving for supremacy in space—whether in Earth orbit, on the moon, or on Mars.
At the same time, however, the political divide between China and Western countries seems to be widening, at least in terrestrial matters. As a result, a new competition for space may be brewing in spaceflight as well.
China as a new space nation
China has launched more probes and satellites in 2021 than any nation before.
Until just a few years ago, the U.S., Russia, and the EU were the undisputed pioneers in space travel. They launched the most rockets, sent space probes through the solar system, and carried the lion’s share of the International Space Station (ISS). But the skies have become more crowded in the meantime. More and more countries are launching their own satellite and space programs.
Enormous progress in a short time
At the forefront of this is China. President Xi Jinping is striving to make his country a superpower in space as well, and is well on his way to achieving this. After lagging behind the two major space nations, the United States and Russia, for a long time, China has now caught up. No other country has made so much technological progress in space in such a short time and in so many different areas. And no other country has such ambitious plans and such a good chance of implementing them.
“It’s becoming more and more clear how dominant China wants to be with regard to space and the space economy,” says Steve Kwast, a U.S. Air Force veteran and space strategist. “They see the profit margin, they see the economic revenue stream, and they see the national security implications.”
To achieve this, the Chinese government is investing huge amounts of money in the largely state-run space industry; more than 300,000 people are said to work for the Chinese space agency alone—far more than for NASA. In addition, there are semi-private companies working on behalf of the state.
From orbit to Mars
And the successes are impressive. Within a few years, China completed its own global satellite navigation system, Beidou, and set a new record for satellite launches in 2021. In one year, Chinese launchers put 55 satellites into orbit; the record previously held by the U.S. was 51 satellites in one year. The Chinese space agency is also already working on its own mega-constellation of some 13,000 Internet satellites.
China has also reached new milestones in the exploration of the moon and Mars. Chang’e 4 was the first space probe to land on the far side of the moon in 2019. In 2020, its successor, Chang’e 5 brought back to Earth the first lunar rock samples since the Apollo missions. In May 2021, China became the only country after the United States to successfully land a Mars rover on the Red Planet with its Tianwen-1 mission. The Zhurong rover has since been exploring an area in Utopia Planitia, a plain northeast of the landing area of NASA’s Perseverance rover.
China’s Mars probe Tianwen-1 with the Zhurong rover. (Image: China News Service)
China is now also competing with the U.S. and Russia in manned spaceflight. After launching its first astronaut in 2003, the country now operates a space station in low-Earth orbit, becoming the third nation after Russia and the U.S. to do so. In April 2021, the core module of the Tiangong station was launched into orbit, followed by the first laboratory module, Wentian, in July 2022. The second laboratory module, Mengtian, followed in October 2022. 14 Chinese astronauts have already spent time at the station as part of its construction and testing.
Just the beginning
For Xi Jinping and China’s space agency, however, this is just the beginning. They see an expanding space presence and space technology as an essential part of China’s development. “To explore the vast cosmos, develop the space industry, and build China into a space power is our eternal dream,” Xi stressed in a recent “white paper” on China’s space program. The space industry is a crucial element of the national strategy, he said.
Competition for space supremacy
For decades, things in space were largely cooperative and peaceful. Exploration of the solar system and research in Earth’s orbit were primarily characterized by cooperation rather than competition. Even old archenemies like Russia and the United States worked together on joint projects like the International Space Station (ISS).
However, this was not the case for China. Unlike Russia, which did maintain close relations with the Western space nations, the country remained relatively isolated even in space. For example, the U.S. blocked its participation in the ISS out of fear of industrial espionage by the Middle Kingdom or China. There was also little interest in cooperating on space probes.
Rival blocs
But the former pariah, China, has become a full-fledged rival. Thanks to its technological advances, China has also become a power in space that other spacefaring nations can no longer ignore. China’s undisguised striving for power, but also the Ukraine war and the associated conflicts between Russia and the West, have drawn new fronts—a new cold war is brewing.
As was the case a good 70 years ago, superpowers are vying for records, technologies, and resources in space. And as in the first “Space Race” in the 1950s and 1960s, two blocs with largely contrasting ideological and political views are facing each other. “One bloc includes more authoritarian states led by China and Russia, and the other is made up predominantly of democracies allied with the U.S. and “like-minded” countries,” Alanna Krolikowski of Missouri University tells The Guardian.
A new eastern alliance?
After decades in which Russia and China barely cooperated with each other in space, a new rapprochement between the two formerly communist states now seems to be on the horizon. There are declarations of intent for future joint projects on the moon and demonstrative mutual visits by Putin and Xi to their national spaceports. An alliance would bring advantages to both: China benefits from Russia’s greater space expertise and experience; Russia, in turn, could benefit from China’s greater financial strength and more advanced technology.
However, it remains to be seen how close this cooperation will actually be.
After all, Russia and China have another thing in common: Their governments are striving for global supremacy and a new old greatness for their empires. This also implies a more rivalrous than cooperative attitude with potential competitors. Some experts are therefore rather skeptical about the new “bromance” between Putin and Xi. The techno-nationalist attitudes of both states could stand in the way of genuine cooperation in space.
Return of the Sputnik trauma
For the U.S., long the undisputed leader in all areas of space, new rival China is a problem: “We are back to where we were in 1957. This is not a Sputnik moment in the strict sense, but it comes very close to its spirit,” U.S. intelligence expert Mike Rogers recently stated. “China is racing ahead in space, while we are unfortunately resting on our laurels, impressive as they may be.”
General David Thompson, vice chief of the U.S. Space Force, takes a similar view: “We are absolutely in a strategic competition with China, and space is a part of that,” he told in early 2022. China, he said, is expanding its space capabilities twice as fast as the United States. “If we don’t start accelerating our development and delivery capabilities, they will exceed us.”
The new space rivalry could become particularly problematic for the closest celestial body to us, the moon.
China’s plans for lunar missions
The lunar rover Yutu-2 and its mother probe Chang’e 4 completed the first landing of a man-made vehicle on the far side of the moon. (Image: CSNA/Siyu Zhang, Kevin M. Gill/CC-BY-SA 2.0)
Everyone wants to go to the moon. After a break of almost 50 years, the Earth’s satellite has once again become the focus of interest in space travel. The moon also has great strategic importance as a stopover to Mars, as a location for space telescopes, and as a lucrative destination for space tourists.
And here, too, China is playing a major role. China’s lunar program initially relies on unmanned probes to test and develop technologies and locations for later manned lunar missions. The first major success came in 2013 with Chang’e 3, the first landing of a Chinese space probe and small rover on Earth’s satellite. Chang’e 4 followed in 2019 with the first landing on the far side of the moon—the first space probe ever to do so. A satellite placed at lunar Lagrange Point 2 will serve as a relay for the radio signals; a second relay satellite is to be added in 2024.
Lunar South Pole as a priority target
This means that China is present even before the USA in a lunar region that is considered particularly suitable for future lunar stations. This is because data from orbital probes suggests that there could be 3-foot-thick layers of water ice in the deep shadows of some craters in the South Pole-Aitken depression located at the lunar south pole, an important resource for future lunar astronauts. Metals and other resources could also be found in the regolith of this region.
China plans to use the Chang’e 6 lunar probe to determine whether this is actually the case. It is scheduled to launch in 2024 and take samples from the South Pole basin and bring them back to Earth. The two follow-up missions, Chang’e 7 and 8, are also to land in this region and conduct geological investigations and technical tests there. Among other things, experiments are planned on the use of regolith as a building material.
But China also wants more than just robotic flying visits to the Earth’s satellite; its long-term goal is a manned lunar base. According to current plans, the unmanned construction phase for such a station is to begin around 2030, and the first Chinese astronauts could then land in 2036. According to the Chinese space agency, the lunar base will primarily serve research purposes and will also be open to other nations.
A joint lunar station between Russia and China
The first partner for this venture could be Russia. In the summer of 2021, the Chinese and Russian space agencies signed a memorandum of understanding for a joint International Lunar Research Station (ILRS). In July 2022, Roscosmos head Dmitry Rogozin told Russian broadcaster Russia-24: “We are now almost ready to sign the contract for a joint lunar base with China.”
In parallel, Russia has resumed its Luna program, which had been paused for nearly 50 years. In September 2022, the Luna-25 spacecraft was scheduled to initiate the Russian return to the moon, also landing in the lunar south polar region. The piquant thing about this is that the newly launched Russian Luna missions were originally planned in cooperation with the European Space Agency (ESA). However, the latter terminated the cooperation after the start of the Ukraine war. Luna 25 is scheduled to launch no earlier than 2023.
Dispute over the Artemis Accords
According to the report, lunar exploration is also seeing a new edition of the old space race, with the Chinese-Russian ILRS on the one side and the Artemis program of the U.S. and Europe on the other. The latter plan is to land astronauts on the Earth’s satellite again as early as 2025 and to launch a lunar space station into lunar orbit. This could threaten a conflict over lunar sites and resources, in part because space law has so far not contained any clear regulations for this scenario.
To change this, the U.S. has drawn up the so-called Artemis Accords, a set of agreements intended to regulate the dealings of various players on the moon. In the Accords, signatories agree to abide by the 1967 Outer Space Treaty, avoid mutual interference, share information, and use the most compatible technologies possible. “What we’re trying to do is make sure that there is a norm of behavior that says that resources can be extracted and that we’re doing it in a way that is in compliance with the Outer Space Treaty,” Bridenstine says. In addition to the U.S., 20 countries have signed the treaty so far.
But China’s government sees the Accords as an attempt by the U.S. to impose regulations on other space-faring nations, and China, in particular, that unilaterally benefit U.S. interests. “The Accords are an attempt to seize the moon for themselves and colonize it,” criticized Chinese military expert and commentator Song Zhongpin in the Global Times in 2020. Reports on Chinese state broadcaster CGTN were in a similar vein. However, there are also Chinese experts on space law who concede that international guidelines for lunar exploration and exploitation are needed and that the primarily bilateral accords could at least be a precursor to those.
In any case, one thing is clear: The next few years will see competition for lunar milestones, sites, and resources, and China will be at the forefront.
China’s new Tiangong space station
The Chinese space station Tiangong in July 2022, with the core module Tianhe in the center and the laboratory module Wentian on the left. Also docked outside are a freighter on the right and the manned Shenzhou space capsule below.
In parallel with the new race to the moon, the balance is also shifting in manned spaceflight in Earth orbit. After Russia and the USA as leading operators of space stations, China now also has its own space station in Earth orbit.
In principle, there was little else for the country to do because, in 2011, at NASA’s instigation, China was expressly excluded from participating in the International Space Station (ISS) because industrial espionage was feared.
Tiangong is modular and as big as Mir
Like the Russian Mir space station and the ISS, the Chinese Tiangong station has a modular design and is gradually being added to orbit. It orbits in low Earth orbit between 340 and 450 kilometers above the Earth, roughly the same range as the ISS. When it was completed in October 2022, the station consisted of a core module and two laboratory modules and weighed around 80 to 100 tons. In terms of size and weight, it is roughly equivalent to the former Russian Mir space station but has only one-fifth of the mass of the ISS.
The station’s core module, Tianhe, was successfully launched into orbit by a Long March 5B launch vehicle on April 29, 2021. The module, which is nearly 17 meters long, contains a service section with life support systems, a power supply, propulsion systems, and systems for position and navigation. The second part contains quarters for three astronauts, computer and control systems, and communications equipment. In addition, the Tianhe module has a docking system and a robotic arm.
The laboratory modules
On July 24, 2022, another mission brought the first of two laboratory modules to the station. This initially docked to the docking site located at the forward end of the core module so that the two modules are in line. However, subsequent transposition gave the approximately 20-ton laboratory module its final position transverse to the core module. Wentian contains quarters for three additional astronauts and space for scientific experiments, as well as a second robotic arm and backups for key core functions such as navigation, propulsion, and attitude control.
The Wentian laboratory module also contains the station’s future main airlock. Astronauts will disembark through it when they need to perform outboard missions. These will be necessary, for example, to maintain and service measuring instruments attached to the outside of the station in the future. The laboratory module has special holders for this purpose, into which large instruments can also be latched. These could include a small reflecting telescope from 2023 and, from 2027, a four-ton instrument for measuring cosmic radiation, which was developed with the participation of European scientists.
In October 2022, the basic structure of the space station was completed with the second Mengtian science module. This module contains additional space for experiments as well as an airlock for supplies and other payloads. Unmanned supply capsules of the Tianzhu type can dock with it. It is unclear to what extent the docking mechanism, which is based on the Russian system, is also compatible with the systems of the ISS and the space capsules of other countries, as, with many technical details, China’s space agency is keeping a low profile.
First ion propulsion system in manned space flight
Test of a Hall-effect ion thruster at NASA. Tiangong is the first manned space vehicle with ion propulsion. Image: NASA
The Tiangong station’s propulsion system is a major feature. In addition to classic thrusters, the Tianhe core module also has an ion propulsion system—the first manned space vehicle ever to do so. The four Hall-effect thrusters generate their thrust from a stream of positively charged particles, presumably xenon ions, accelerated by an electric field. A ring current of electrons controlled by a magnetic field provides additional thrust and neutralizes the ion current after it exits the propulsion nozzle.
The advantage of such ion drives is their small size and long operating life. They can generate less thrust than chemical thrusters, but a small amount of xenon gas is sufficient to propel them. On the Tiangong space station, the Hall thrusters are expected to operate for at least 15 years and maintain the station’s orbital altitude at a stable level. One disadvantage of ion propulsion, however, is the highly corrosive effect of the accelerated ions. To prevent them from damaging the thrusters and the space station’s hull, they are surrounded by an additional shielding magnetic field and a protective ceramic shell.
Other nations may also join in
At present, China’s new Tiangong space station is mankind’s second “outpost,” alongside the ISS, but it could soon be the only one. That’s because the ISS is already relatively old, and its funding is on the line. In the wake of the Ukraine war and increasing conflicts with Western countries, Russia has announced the end of its participation in 2024. Whether the International Space Station will continue to be operated then, and in what form, is still unclear.
In the future, however, Tiangong—the “Heavenly Palace”—could also become a place of international cooperation, the Chinese government emphasizes. Some of the scientific experiments currently installed on the space station are already being carried out in cooperation with other countries or were developed entirely by research institutions in Europe. Among others, Norway, Belgium, Switzerland, and Germany are involved. There is also particularly close cooperation between China and the Italian Space Agency. It is developing the cosmic ray measurement instrument, which is expected to be installed in 2027.
“After our space station is completed in the near future, we will see Chinese and foreign astronauts flying and working together,” Ji Qiming of China’s manned spaceflight agency said in a recent press conference. The participation of astronauts from other countries is guaranteed, he added. Whether and in what form this participation will take place, however, remains to be seen.
What also seems clear, however, is that if China’s rapid development in space travel continues at this rate, most other countries may have little choice but to join in. “The exploration of space will go ahead, whether we join in it or not,” said then-U.S. President John F. Kennedy in 1962 during his famous moon speech in Texas.
One of the main issues throughout the Cold War was the race to the Moon, which the Soviets and Americans clashed in a race that led one of them to the Moon in July 1969. From 1957 through 1969, the Cold War’s focus was mostly on the race to conquer space. It’s where the US and the USSR squared off in a heated technical duel, with both sides looking to prove their mettle. After the launch of Sputnik-1, the first artificial satellite, in 1957, the focus shifted to human missions and the goal of landing a man on the Moon.
Before the 1950s, interstellar travel was more science fiction than reality. The notion of transporting an item or a man beyond the atmosphere was not a priority for the Russian or American governments, even if Wernher von Braun collaborated with Walt Disney in the United States to publicize and propagate his ideas of space conquest. However, military engineers on both sides, particularly those specializing in ballistics, were giving this idea significant thought.
V2 missiles give the necessary boost
V2
During WWII, Nazi scientists created a brand-new kind of missile known as the V2. They were employed to bomb London towards the conclusion of the war, and their rocket propulsion made them particularly effective. This revolutionary technique allowed for the destruction of the enemy at a great distance (350 kilometers), at high speed (Mach 3.5), and without the need for airplanes.
The Cold War’s armaments competition prompted massive expenditures in research, including this promising new area. The V2s did get attention from both the East and the West. Wernher von Braun, the Nazi engineer who developed the V2, later joined the SS and the American army, and it was he who, together with Walt Disney, educated the American public about space.
The Sputnik 1 satellite, a world first
Despite some lag in the nuclear industry, it is the USSR that has made the greatest use of this innovation. In the 1950s, it began the development of an ICBM that could deliver an atomic weapon. The A-bomb is much larger than the H-bomb. They were dropped from an aircraft over Japan. That’s why it was such an ambitious project: to create a missile with an intercontinental range (a few thousand kilometers as opposed to the V2’s 350) and the ability to deliver a payload weighing several tons. The Ukrainian engineer Sergei Korolev, who was rescued from the gulag during World War II for his expertise in aeronautics, was given the task of leading the project.
He was granted permission to construct a tiny satellite and attempt to launch it into orbit after seeing the potential of such a rocket and sharing von Braun’s passion for space exploration. Korolev’s rocket design is a step in the right direction. While it had its share of problems during the first testing, it eventually worked well enough to launch Sputnik-1 into orbit on October 4, 1957. What started as a side project has become a significant technical and symbolic achievement, marking the crossing of a new boundary in the human environment. A little unit broadcasts a radio signal—just a beep—that anybody, anywhere may use to verify the Soviets’ claims.
The Sputnik 2 satellite and the dog Laika in space
This is a genuine embarrassment for the United States. This Soviet triumph has serious military implications, but it also severely undermines American faith in its technical dominance. The political power of the symbol is not to be underestimated, as the Soviet Union has always credited its success to the unique character of its own government. Therefore, in the United States, a crew has been assembled to be ready for the first launch. On the other hand, Sputnik-2 was launched by the Soviet Union on November 3, 1957. To further prove the Soviet Union’s progress, it carries a dog by the name of Laika. But unfortunately, the animal does not make it, and Russia is not quite ready to launch a human into orbit just yet.
Explorer-1, the first U.S. satellite
Despite the pressing need, the United States did not want to engage with former Nazi engineer Wernher von Braun, who was developing medium-range missiles, for obvious grounds of public perception. The official Vanguard project had initially failed, but on January 31, 1958, Braun’s crew was given the green light to attempt again with the Explorer-1 launch. It made the identification of the Van Allen radiation belt possible. Wernher von Braun, together with his rival Serguei Korolev, would thereafter play pivotal roles in the conquest of space. The USSR, on the other hand, decided to keep his identity a closely guarded state secret, so he would never get the same praise as his American counterpart.
The Luna to the Moon program
The U.S. eventually caught up and started investing in the long run. With this in mind, at the close of 1958, Eisenhower established NASA (the National Aeronautics and Space Administration). However, with the help of its Luna program, the Soviet Union goes on to become the undisputed leader in space exploration in the years that follow. Leaving Earth’s orbit and heading for the Moon, spacecraft Luna-1 took off on January 2, 1959. The Luna-2 spacecraft successfully landed on Earth’s satellite on September 13. After more than a month of searching, Luna-3 has finally revealed the Moon’s secret side to Earth.
It sends pictures with an uneven face superimposed on the real one. The Russians are encouraged by their accomplishments and decide to restart the Sputnik program, which aims to launch a man into space. Multiple launches occur, each time with a dog on board; unlike Laka, most of the dogs survive the trip back to Earth’s atmosphere. The United States is opposed to the Sputnik program and favors the Mercury program instead. Also in January 1961, thanks to these advancements, a chimpanzee named Ham was sent into space.
So the Americans go to the Russians and plot to get back at them by launching the first human into space. On April 12, 1961, however, the Soviet Union surpassed them with the launch of Yuri Gagarin on Vostok-1 from the Tyuratam spaceport. At an average height of 250 km, he flew in orbit around the Earth for 1 hour and 48 minutes. The Soviet Union continues to bolster its reputation for excellence in space exploration. As a response, on May 5, the Americans sent Alan Shepard into space, although at a far lower height and for a much shorter duration (15 minutes only).
The American Apollo program’s inception
This was the beginning of the Apollo project, which Kennedy first declared on May 25, 1961, when he said that an American would walk on the Moon by the end of the decade. The Gemini program ran concurrently, enabling a number of experiments in human spaceflight to be conducted in low Earth orbit. The Soviet Union kept working on the Luna project. In a nutshell, the race between the two nations to put a man on the Moon is the ultimate prize.
Therefore, all of 1960 was spent working towards this ultimate goal. There were as many phases to the programming as there were events. It took John Glenn about five hours and twenty minutes to complete three orbits of the Earth on February 20, 1962. In December of that year, thanks to the Mariner program, a U.S. satellite came within a few hundred miles of Venus. The Mariner-4 probe makes its way through Mars in July 1965. On March 18, 1965, the Soviet Union successfully completed its first spacewalk with Alexei Leonov. A few months later, in the context of the Gemini program, the Americans accomplished an identical feat.
The American Apollo program speeds things up significantly. There are three distinct stages of the curriculum. The first, which spanned 1960–1968, included equipment testing during pilotless flights. Since it was Wernher von Braun’s crew that created the Saturn V rocket, their contribution was crucial. During this time, Wernher von Braun oversaw the Mercury program, which allowed for piloted test flights.
Apollo 1 was the first mission of the second phase, but it was cut short on January 27, 1967, when a fire broke out during a mock launch, killing all seven men on board. Dramatically postponing the project, the mission’s failure adds more time to the process, since the capsule has to be redesigned. The first inhabited mission of the program, Apollo 7, did not take place until October 11, 1968. The testing lasted for 10 days, during which time the ship stayed in Earth’s orbit.
The Americans and the conquest of the Moon
When Apollo 8 successfully places a crew into lunar orbit in December 1968, the United States makes significant progress relative to the Soviet Union. Within the following six months, Apollo 9 and 10 successfully piloted mission scenarios for a potential lunar landing. On July 16, 1969, Apollo 11 lifts off from Cape Canaveral with astronauts Neil Armstrong, Michael Collins, and Edwin “Buzz” Aldrin on board, marking the beginning of the third phase.
His Eagle capsule touched down in the “Sea of Tranquility” on July 20. On July 21, 1969, Neil Armstrong and Edwin Aldrin made history by walking on the Moon for the first time. The astronaut would have subsequently made the now-famous statement, “That’s one small step for man, one giant leap for mankind,” after the successful landing. As a result, the United States now had the upper hand in its rivalry with the Soviet Union.
Moving toward Soviet-American collaboration
This was a decisive advantage, since Apollo 12 through 17 all accomplished the same thing (with the exception of Apollo 13, which was derailed by technical difficulties), but the Russians never stepped foot on the Moon. In addition, the setting of Détente (the thawing of relations between the superpowers) no longer justified such costly missions (the Apollo program cost the United States billions). They canceled the last four Apollo missions as a result of the economic crises in the 1970s. In truth, man’s historic moonwalk ended the Cold War-era rivalry between the United States and the Soviet Union in the race to space.
Everybody’s objectives were scaled down because of the new political reality and the high price tag that came with it. The Apollo-Soyuz collaboration represented détente despite the continued competition in unmanned exploration missions. This one began in 1972 and involved two spacecraft meeting in orbit around each other. In addition, human missions diminished in importance and were eventually confined to low-Earth orbit. The United States intended to enable frequent round trips, which was why new space shuttles had been built since 1976. The USSR, meanwhile, was placing its chances on orbital stations, as seen by Salyut, the world’s first permanently occupied space station, which was launched in 1971.
Space stations, from Mir to ISS
It was a Soviet space station that entered orbit in 1971. After their failed attempt to conquer the Moon, the Russians view this as an opportunity to reclaim space for themselves. They conduct a wide range of research and development, as well as military tests. Several space stations, including the MIR station, may be launched under the Salyut program and placed into orbit before 1986.
The Americans, not wanting to be outdone, developed Skylab. They employed parts from earlier Apollo flights to construct the station, but it suffered extensive damage when it was launched in 1973. It was inhabited for several years before facing unexpected solar activity. It decayed in the Earth’s atmosphere in 1979. In 1983, the United States planned to begin a new project; it would be the beginning of the International Space Station (ISS). In 1985, the Soviet Union launched the MIR station’s first module into space. Counting the optional ones, there would be seven. MIR was inhabited for twelve years. It was deorbited in 2001.
In the meantime, the International Space Station was launched in 1998. Countries like Russia and the United States, as well as many others, took turns working on the project. In 2011, work on the International Space Station was finally wrapped up. For their first space station, the Chinese picked this year, and they have given it the name Tiangong. For the time being, the International Space Station is still the biggest manmade object in Earth’s orbit. The facility is expected to remain operational until 2024.
Conquering Mars is the ultimate future project
The American space program has been a complete success. The American space program has not only caught up to the Soviet space program but has surpassed it. Numerous scientific and technical improvements have been made possible by the large human and financial resources used to transport men to the Moon. However, the lunar conquest was rapidly abandoned despite the economic gains and the impression this conquest had on the cultural imagination.
Although it made great strides in astronautics and expanded the bounds of possibility, the focus of the space conquest has shifted from the Moon to Mars. SpaceX fits this description; they are working on the Starship rocket to colonize Mars, but first, they want to conquer the Moon. Even though the United States hopes to train on the Moon before commencing its mission to transport humans to Mars, the details of the program are still quite hazy at this point.
Upcoming experiments: A lunar base
The Moon is currently of little interest to the world’s largest space missions. With the cancellation of the Constellation program in 2010 at Obama’s direction, even the United States has lost interest in the Moon. The main astronautical nations’ priorities have shifted in the wake of China’s successful landing of an autonomous probe on the far side of the Moon.
However, in order to be ready for a future Mars colony, the United States has planned a voyage to the Moon called “Moon to Mars,” which would enable the construction of a lunar facility in the year 2034. It is expected that the first lunar colony would be possible thanks to the Artemis program (scheduled to launch in 2022). So, after more than 50 years since the previous passage during the Apollo 17 mission, humanity might make its epic return to the Moon.
The industry of space travel is booming
A number of programs have been established since the turn of the millennium to make space flight possible for regular people without requiring them to undergo the rigorous training required of astronauts. The first flight was made in 2001 during the TM-32 mission aboard a Soyuz spacecraft.
Dennis Tito, an American multimillionaire, was the first space tourist. He paid a relatively modest $20 million to spend almost a week in Earth orbit. Many private enterprises have taken the lead in developing space tourism in recent years, and this has sparked a new race to the top. It seems that three firms have the necessary resources to take the crown.
First, Richard Branson’s Virgin Galactic (established in 2004) sells $250,000-per-person tickets for rides in space aircraft to an altitude of more than 80 kilometers. Then there’s Blue Origin, founded by Amazon’s founder Jeff Bezos, who takes things even farther by launching its New Shepard rocket over the Kármán line (100 km) for around 15 minutes.
Nonetheless, the price is substantially greater; $28 million was bid on the trip on July 20, 2021, with Jeff Bezos and his brother Mark. On September 15, 2021, tourists were finally able to ride SpaceX’s Falcon 9 rocket to the Crew Dragon spacecraft for the first time. Elon Musk, CEO and co-founder of SpaceX and Tesla, has made no secret of his fascination with space, as seen by his hopes for the colonization of Mars.
TIMELINE OF SPACE EXPLORATION
June 20th, 1944, and the V2 rockets had just been launched
In the Second World War, the Nazis developed the V2 rocket, marking the beginning of humankind’s conquest of space. It is possible to launch them over 100 km into the air.
On October 4, 1957, Sputnik was successfully launched
The first man-made satellite was launched into orbit by a Soviet R-7 rocket. Sputnik, whose name translates to “co-wayfarer” in Russian, is a 58-centimeter satellite that tips the scales at 83.6 kg. The satellite is then launched into a 900-kilometer orbit around the planet. We owe this technical achievement to Serguei Korolev, who is developing an ICBM. It’s based on the fact that the Germans were responsible for making V2 possible.
For the United States, this happened smack dab in the thick of the Cold War and was a direct provocation. There would be a “race to the stars” between the two superpowers, and it all started with the launch of the little spacecraft Sputnik 1. On January 4, 1958, Sputnik 1 disintegrated upon re-entry into Earth’s atmosphere.
On November 3rd, 1957, Sputnik 2 and the dog Laika were launched into space
Sputnik 2 was launched with Laika in a pressurized container one month after the first Sputnik satellite (Russian for “co-wayfarer”) was launched. The first live organism to be satellited is a little dog. Seven days later, the animal succumbs to oxygen deprivation.
First American satellite launched on January 31, 1958
It’s 10:48 p.m., and the Juno 1 rocket is finally ready to take off. The first American artificial satellite, Explorer I, weighing 14 kilograms, was launched into Earth orbit seven minutes later. America takes its turn in the conquest of space three months after the Soviet Union launched “Sputnik.”
On July 29, 1958, NASA was established
In order to beat the Soviet Union in the “space race,” President Eisenhower passed into law the creation of the National Aeronautics and Space Administration (NASA). NASA was in charge of coordinating the world’s aerospace and space exploration efforts. The United States was taken by surprise by the launch of Sputnik-1, and this organization was established in response. President Kennedy’s Moon program announcement in 1961 set the stage for NASA’s eventual success. In 1969, both parties honored the agreement to land a man on the Moon.
December 18, 1958, the world’s first communications satellite
This is the first experimental communications satellite launched by the United States, and the news came through a press release. The Atlas rocket launches the “SCORE” gadget into orbit for a 34-day test run. It sent seven transmissions to Earth, including a speech from President Eisenhower. In 1962, the first American television programs were sent via satellite to televisions throughout Europe.
The first space probe was launched on January 2, 1959
The Soviets are the first to successfully remove an artificial object from the pull of Earth’s gravity, after multiple failed efforts on both the Russian and American sides. The Lunik 1 spacecraft came within 6,000 kilometers of the Moon, but it ended up too far away from the Moon and instead entered a Sun-orbiting track a few months later. Even so, it sometimes broadcasted its scientific information. The American probe Pioneer made the same trip two months later.
A Soviet probe lands on the Moon on September 13, 1959
While the United States was still playing catch-up, the Soviets sent Luna II (or Lunik), the first lunar probe, to the Moon). This last one hits the Moon and leaves behind a Soviet flag shaped like a football. With this probe, scientists were also able to prove that solar winds do, in fact, exist.
October 7, 1959: First photos of the far side of the Moon
The first images of the far side of the Moon that cannot be seen from Earth were captured and sent back to Earth by the Soviet spacecraft Luna-3. Later, the world learned that it was far less uniform than the other side the Moon has always shown humans.
Yuri Gagarin launches into space for the first time on April 12, 1961
He was just 27 years old, yet his feat would live on in posterity. As the first human being to launch into space, Yuri Gagarin made history. He flew for 108 minutes on the rocket Vostok 1 (Orient in Russian), during which time he completed one orbit of the Earth. As a result, the Russians may rest certain that they are winning the space race against the United States.
May 5, 1961: Alan Shepard reaches space
Alan Shepard became the first American to circle the Earth a few weeks after Yuri Gagarin’s first voyage into space. This flight took just around 15 minutes and stayed at a low altitude (sub-orbital). John Glenn, on February 2, 1962, became the first true American astronaut.
On this day in 1961, man on the Moon by the end of the decade
The United States saw Yuri Gagarin’s orbital flight as a fresh insult; therefore, they made the strategic decision to strike back in the short term by achieving a goal that would demonstrate their technical dominance over the USSR. It was President Kennedy who made the public announcement that the Western powers wanted to put a man on the Moon by the end of the decade. Mankind would set foot on the Moon on July 21, 1969, proving that the Apollo program was successful and meeting its objectives.
September 12, 1961: Our destination is the Moon
In his now-famous “We chose to go to the Moon” address, President John F. Kennedy reaffirms the American goals first declared in May. As a result, the Apollo program is given more funding and attention at a time when its goals are most lofty. As the country that launched the first satellite and later the first man into space, the United States aims to beat the Soviet Union to this milestone.
February 20, 1962, John Glenn became the first American to orbit the Earth
The first American to take part in a human space voyage was astronaut John Herschel Glenn. It took him 4 hours and 56 minutes aboard the “Mercury Friendship 7” spacecraft to complete three orbits of Earth, covering a total distance of 129,000 kilometers. The ocean landing was successful 65 kilometers east of the Bahamas, close to the predicted target zone established by NASA scientists. Almost a year after Yuri Gagarin became the first man in space on April 12, 1961, the United States finally accomplished a human mission.
The satellite “Telstar” was launched on July 10, 1962
Florida’s Cape Canaveral was the site of the launch of the Telstar 1 communications satellite. It was created by the American telecom giant AT&T with the intention of keeping TV and phone lines open across the two continents. As a result of “Telstar,” the first transatlantic communications satellite, European viewers could tune in to a news conference held by President Kennedy, while American viewers could tune in to an entertainment show featuring Yves Montand.
Kennedy proposed space collaboration with the USSR on September 21, 1963
John F. Kennedy suggested to the United Nations that they organize a Soviet-American mission to the Moon as the United States and the Soviet Union entered a period of détente in the Cold War. The Soviet Union gave a neutral response. To the point where the Echo C satellite represents the culmination of their joint effort.
On March 18th, 1965, the first cosmonaut was launched into space
Alexei Leonov of Russia did a spacewalk for 15 minutes while still securely attached to his spaceship. The first human to ever float in space was him. On June 3, 1965, for around 20 minutes, American Edward White succeeded him.
The Space Race‘s first fatalities occurred on January 27th, 1967
Three astronauts perished in the burning capsule on Apollo 1, the first flight of the American space program. Spacemen Virgil Grissom, Edward White, and Roger Chaffee were all trapped aboard the burning spaceship on its first flight to Earth for preliminary ground testing. Initial plans called for launching the mission in February. According to the paper, the three astronauts died by breathing in a hazardous gas; however, the report did not specify what caused the fire. Before the Apollo program’s first human flight, several changes would be made.
October 18th, 1967: Venera 4’s mission was completed
Data on Venus’s atmospheric pressure and temperature are sent by the Russian space mission. There is a 94-minute window during which data is sent. The Soviet Union first sent a “Venera” probe to Venus in 1961. The first images of the surface of Venus were sent back by Venera 9 in 1975.
On December 24th, 1968, the first humans orbited the Moon
The Apollo 8 crew travels over the Moon three days after liftoff from Cape Canaveral. Frank Borman, James A. Lowell Jr., and William A. Anders make 10 times the turn of the star to conduct experiments for the future lunar landing, marking the first time that men have left Earth’s orbit to approach the Moon. On December 27th, after a successful six-day journey, they safely returned to Earth. The United States is getting ready to launch a mission to the Moon. For the first time, they made significant inroads against the Soviet Union.
Moon mission Apollo 11 lifted off on July 16, 1969
On July 16, 1969, on a mission to the Moon, astronauts Neil Armstrong, Edwin Aldrin, and Michael Collins took off. The Apollo 11 mission was a success on July 21, 1969, when astronauts Neil Armstrong and Buzz Aldrin became the first humans to set foot on the Moon.
The first human being landed on the Moon on July 20, 1969
At 02:56:15 GMT, Neil Armstrong stepped foot on the Moon at about 109 hours, 42 minutes after launch. He then said the thing that still remains engraved in our memories: “That’s one small step for man, one giant leap for mankind.” The world watched as Russia lost its space superiority in an event that was broadcasted across the globe.
Apollo 13’s “Houston, we have a problem” aired on April 13, 1970
When the Apollo 13 space shuttle is getting close to the Moon, an explosion occurs in the service module’s oxygen tank. The three astronauts on board are forced to immediately return to Earth once the program is terminated. During their rescue by the technical teams located in Houston, James Lovell, John Swigert, and Fred Haise took sanctuary in the LEM Aquarius. They make it to the South Pacific without any problems. Ron Howard’s 1995 film Apollo 13 dramatized the ill-fated mission of the crew of that spacecraft.
On April 17, 1970, the Apollo 13 crew successfully returned to Earth
Three American astronauts make it through the Apollo 13 mission unscathed, and they all touch down in the South Pacific without incident. Their dream journey into space was shattered four days before, 56 hours after departure, when an oxygen tank suddenly exploded at over 300,000 kilometers from Earth. The astronauts retreated to the Aquarius lunar module, which had dwindling supplies of oxygen and energy. There is a complete 180-degree turn from scientific goal failure to genuine human achievement.
On February 6, 1971, astronauts landed on the Moon and played golf
The first guy to play golf on the Moon was Alan Shepard. On January 31st, Shepard left the Apollo 14 spacecraft with Edgar D. Mitchell and Stuart A. Roosa and headed for the Moon. His “lunar walk” lasted 4 hours and 34 minutes, and he took Mitchell along for the ride. During his second walk (after 4 hours and 48 minutes), he indulges in his great enthusiasm for golf by hitting several balls near the Fra Mauro crater. In addition to Armstrong, Aldrin, Cernan, and Bean, Shepard is the fifth human to set foot on the Moon.
April 19, 1971: First manned space station
After failing to conquer the Moon, the USSR develops an orbiting station program and launches Salyut-1, the first station to host a human crew. In a pressurization disaster that occurred between June 7 and June 30, all three astronauts who inhabit the station perished. Humans occupied Salyut for a total of 813 days, and over 2,500 scientific experiments were conducted until the program was officially closed in 1986.
Mariner 9 went into orbit on November 14, 1971
After 167 days in space, the American spacecraft Mariner 9 was already in orbit around Mars. Its mission was to send back images of Earth’s surface and weather data. A catastrophic dust storm delayed the realization of photographs until January 1972, and the probe didn’t begin observing Mars’ satellites, Phobos and Deimos, until that month. Once the dusty mantle was removed, Mariner 9 would have until the end of its mission on October 27, 1972, to take over 7,000 photos. The spacecraft probably crashed into Mars’s atmosphere in 2022.
The United States sent its last lunar probe on December 11, 1972
Apollo 17 astronauts Gene Cernan and Harrison Schmitt, who set out on their mission on the 7th, finally landed on the Moon. A total of 74 hours, 59 minutes, and 30 seconds, or more than three days, were spent on the Moon by the crew. Apollo 17 was the final human trip to the Moon for the United States.
Pioneer 10 beginning its first orbit of Jupiter on December 3, 1973
The American Pioneer 10 probe was the first to provide data about Jupiter when it flew within 130,000 kilometers of the gas giant. The American interplanetary probe Pioneer 10 is the oldest of its kind, having been launched on March 3, 1973. In January of 1998, it vanished off the face of the Earth.
Apollo-Soyuz: a handshake in orbit, July 18, 1975
The United States and the Soviet Union hold hands in orbit to commemorate their historic first joint space mission. When the American Apollo and the Russian Soyuz spacecraft collide in orbit, astronaut Thomas Stafford and cosmonaut Alexis Leonov team up. In addition to the technological advancements, the actual revolution is political: after competing against one another for almost a decade in the race to space, the opposing forces finally came to an agreement. However, a more sophisticated level of collaboration between the United States and Russia can’t begin until the Mir orbital station is operational.
The Viking 2 probe set out toward Mars on September 9, 1975
NASA sent the Viking 2 spacecraft to Mars as part of an exploration initiative to take pictures of the Martian polar caps. The Viking 1 mission departed exactly one month before this one. The Viking project has returned hundreds of breathtaking images and other data about Mars and its moon Deimos. In 1978, the probes lost contact and were no longer transmitted.
On June 13, 1983, Pioneer 10 was launched into interplanetary space
The American probe “Pioneer 10” is the first terrestrial object to leave the solar system. Though it was only meant to operate for two years after its March 1972 launch, the probe was still sending out signals as late as January 2003. In 1973, it was the first to fly above the gas giant Jupiter; in 1983, it was the first to cross beyond Pluto’s orbit. The spacecraft was 82 times the distance from the Earth to the Sun away from us when it lost communication with us at a distance of 12.2 billion kilometers. The probe contains a gold plaque with a human description, Earth’s coordinates, and the mission’s launch date engraved on it.
February 7, 1984: Two astronauts spacewalk
To accomplish the first spacewalk without being tethered to a shuttle, two astronauts used the MMU (Manned Maneuvering Unit), essentially a rocket chair in 1984. For about five hours, astronauts Robert L. Stewart and Bruce McCandless floated in space roughly 100 meters from Challenger.
Voyager 2 passed by Uranus on January 24, 1986
The Voyager-II spacecraft stayed at a distance of 101,000 km (63,000 mi) from Uranus. Its studies shed light on the planet’s nine-ring system and its very diverse satellites, Miranda, Ariel, Umbriel, Titania, and Oberon. After leaving Earth in 1977, Voyager-II arrived at Saturn in August 1981 before continuing on to Uranus. They got to Neptune on August 25th, 1989. After that, it left the solar system and continued its orbit. As of now, communication is still going on.
The shuttle Challenger exploded on January 28th, 1986
The American space shuttle “Challenger” disintegrated into fragments 1 minute and 13 seconds after liftoff at 11:38 a.m. There were witnesses to the accident at Cape Canaveral, and millions more saw it on television. Sadly, the Challenger’s seven astronauts—including two women—were all killed in the blast. According to NASA’s study, the disaster was caused by the joint of one of the auxiliary thrusters breaking.
The Russian space station Mir was launched on February 20th, 1986
The core of the Russian space station Mir (which means “Peace”) was launched into orbit by a Proton rocket at a height of 350 kilometers. The 2.20-meter-diameter sphere weighed 21 tons. As of then, it was only waiting for modules to be connected to it. On March 13, 1986, humanity’s first mission to the “Mir” was launched. But the equipment obsolescence and the station’s prohibitive cost to maintain led to its demolition in 2001.
The planet Venus was discovered on May 4, 1989
The U.S. scientific exploration of Venus was assisted by the shuttle Atlantis, which propelled the American Magellan probe. Almost a year after it was sent into orbit, it was the first to provide a detailed map of Earth’s surface. After two years, it offered a map of 98% of the Earth using its radar to highlight the various volcanoes throughout the globe. Before it was destroyed in Venus’s atmosphere in 1994, the probe was used to explore the planet’s gravity. Learning about Venus’s geology and drawing parallels to our own planet was made possible by the Magellan expedition.
On April 24, 1990, the Hubble Space Telescope was sent into space
As a tribute to the late scientist Edwin Hubble, the space shuttle Discovery launched a telescope bearing his name into deep space. The first photographs that were sent to the scientists were a huge letdown. The primary mirror of the orbital telescope was flawed, resulting in very low picture quality.
In 1993, a crew of astronomers on the shuttle Endeavour were hopefully able to fix this flaw and make the system even better. There would be a series of subsequent missions to repair and upgrade this powerful orbiting observatory. Important findings made possible by these missions improve our understanding of how the cosmos works.
On August 28, 1993, Galileo discovered an asteroid with a moon orbiting it
On its approach to Jupiter, the American spacecraft Galileo found the first moon of an asteroid. A small satellite, just one kilometer in diameter, orbits the asteroid at a distance of around 100 kilometers from the surface. The asteroid measures 58 kilometers in length and 23 kilometers in width. Dactyl is a reference to a Greek god who ruled over Mount Ida.
On March 14, 1995, a Russian space shuttle carried an American astronaut
From Russia’s Baikonur spaceport first thing in the morning, astronaut Norman Earl Thagard takes off on the Soyuz TM-21 “Hurricane” rocket. For the first time ever, an American has flown on a Russian space mission. It is Thagart’s and his crewmates’ hope to make it to the Mir space station. Following 115 days in space, they have returned to Earth.
June 29, 1995: Assembly of Mir and Atlantis
Atlantis, a shuttle from the United States, arrived at the Russian space station Mir twenty years after Apollo and Soyuz first met. 395 kilometers above the ground, Vladimir Dezhurov and Robert Hoot Gibson did a handshake in a moment that went down in history. A total of ten astronauts share the spaceship until July 4 of the same year. The launch of international space cooperation and the building of a shared station called Alpha began with this gathering.
Incident at the Mir Space Station on June 25th, 1997
The Progress supply ship and the Russian space station Mir, whose core component was launched in February 1986, have been involved in a collision. Two Russians and an American astronaut work together to plug the leak and restore power. Due to the station’s many problems and the exorbitant expense of keeping it operational, the Russians made the decision to blow it up in March of 2001.
October 29, 1998: John Glenn returns to service
To begin a new mission aboard the shuttle Discovery, the 77-year-old man who was the first American in space in February 1962 prepared to lift off. He carried out experiments on the effects of ageing in space. After 9 days and 134 orbits around the Earth, John Glenn returned.
The Columbia space shuttle exploded on February 1, 2003
After 16 days in orbit, the shuttle Columbia was lost from NASA’s radar when it re-entered Earth’s atmosphere. Over Dallas, there are white streaks in the sky. There were seven fatalities; six Americans and an Israeli astronaut. A flaw in the heat shield has been discovered after extensive testing.
Launch of the Spitzer Space Telescope, 25 August 2003
NASA has launched its biggest infrared space telescope into orbit. The American astronomer who inspired its name is Albert Spitzer. Because of its superior sensitivity to infrared light, it can identify objects in the furthest reaches of the universe. Since infrared light cannot reach ground-based telescopes due to Earth’s atmosphere, it was crucial to launch such equipment into space.
The IRAS and ISO satellites were also able to examine star formation since they were launched before it. In fact, after stars are produced, they stay in a cloud state where they are completely hidden from view. Infrared radiation, however, may be used to pinpoint their location.
On October 15, 2003, China successfully launched its first cosmonaut
Yang Liwei, also known as a taikonaut, became the first Chinese cosmonaut after a 21-hour mission. After completing fourteen orbits of the planet, the Shenzhou V spacecraft returns to Earth and makes an emergency landing in a large Chinese plain. Forty years after the Soviet Union and the United States, China joins their ranks as the third nation with access to outer space.
July 1, 2004: Exploration of Saturn
Finally, the Cassini-Huygens spacecraft arrived at Saturn. Since its 1997 launch, it had traveled a long way to reach its current orbit, and during that time it had supplied some valuable data, especially on Jupiter. The probe’s objective was to learn more about Saturn and its surroundings by analyzing its rings, moons, and other features.
Cassini, which investigated Saturn and its moons, and Huygens, which examined Titan’s atmosphere, made up the spacecraft. Two modules broke apart in December 2004. On January 14, 2005, as scheduled, the Huygens module entered Titan’s atmosphere at a depth of 65,000 km as Cassini drew near. By the end of 2008, the mission was complete.
On July 4, 2005, the Deep Impact spacecraft collided with the Tempel 1 asteroid
A month after its launch in January, NASA’s Deep Impact space mission successfully impacted comet Tempel 1 at a speed of 37,000 kilometers per hour, as predicted. This results in a massive crater and a cloud of dust. The Deep Impact probe’s goal is to study the comet’s interior composition by analyzing the ejected debris, crater surface, and impact results. Researchers are hoping to fill in some gaps in their understanding of how our solar system came to be.
Titan was first seen by the Huygens spacecraft on January 14, 2005
In 1997, NASA launched the Cassini-Huygens spacecraft into space. The mission’s goal was to investigate Saturn and its moons. The Cassini orbiter has resumed its survey of Saturn’s moons while the Huygens probe has touched down on Titan. The mission, which had already been extended twice due to its overwhelming success, finally ended in 2017.
The last Space Shuttle launch occurred on July 8, 2011
The US’s Atlantis was the last space shuttle to launch to the ISS. Once the shuttles retired, conventional launchers were to take their place.
On November 12th, 2014, a probe touched down on the comet’s surface
Using the comet 67P/Churyumov-Gerasimenko as a target, the European space probe Rosetta deployed a miniature lander called Philae on the comet’s surface. It studied the comet’s structure and soil composition. The Ariane 5 rocket successfully launched Rosetta in 2004.
The New Horizons mission flew past Pluto on July 14, 2015
The American spacecraft New Horizons was launched in 2006 to investigate Pluto and its satellites. In 2015, it completed its mission and moved on to investigate other planets in our solar system.
The first lunar landing on the Moon’s dark side occurred on January 3, 2019
The Chinese spacecraft Chang’e 4, which was launched on December 7th, 2018, completed an orbit of the Moon on December 13th. The Chinese lander landed on the far side of the Moon on January 3, 2019. The Yutu 2 rover was dropped off to study this part of the Moon.
May 30, 2020: First manned space flight by a private company
Elon Musk’s SpaceX is the first private business to be contracted by NASA to transport humans to the International Space Station (ISS). Bob Behnken and Doug Hurley, the mission’s protagonists, used SpaceX’s Falcon 9 rocket to successfully lift off. The Dragon V2 (or Crew Dragon) capsule separated from the rocket’s first stage and continued on its way to the ISS. U.S. President Trump was there at the Kennedy Space Center in Florida to see the launch.
When oxygen was synthesized on Mars on April 20, 2021
As part of NASA’s Mars exploration program, the Perseverance rover successfully converted carbon dioxide into oxygen on April 20, 2021. This marks a first in the annals of space exploration: the creation of oxygen on a distant world.
The CO samples collected from Mars’s atmosphere, (which is 96% carbon dioxide) made this procedure feasible. Five grams of oxygen were produced during the reaction, which was enough for an average person to breathe for around ten minutes and make tiny amounts of rocket fuel.
The Ariane 5 rocket carrying the James Webb Space Telescope lifted off from Kourou. A space telescope of this magnitude has never been attempted before. It was a joint effort between NASA, the European Space Agency, and the Canadian Space Agency that resulted in the James Webb Space Telescope.
Every day, a fleet of satellites of every possible size and form completes numerous orbits around the Earth. The variety of duties they do mirrors the diversity of their appearances. Above the turbulent atmosphere, scientific satellites probe the depths of space, seeking answers to the astronomical community’s many unresolved problems. Television, long-distance telephone conversations, and global information exchange as we know them today would not exist if not for the fleet of communications satellites.
However, artificial celestial bodies employed for Earth monitoring are very crucial for living on Earth. They are able to see well even in the dark, and even through thick clouds. They aid in the mapping of the Earth, the forecasting of weather, the monitoring of volcanoes, and the packing of ice. To sum up, space explorers have emerged as crucial partners in mapping our home planet.
Keeping an eye on Earth
When in the right position, the naked eye may get a glimpse of a satellite even though it is very tiny and traveling at a great distance from Earth. This can only be done if their orbits are quite low, between 185 and 500 miles (300 and 800 kilometers) above the surface of the Earth; at these altitudes, they can complete an orbit of the Earth in around 90 minutes.
The optimum conditions for seeing satellites occur when the satellite is bathed in sunshine but the observer is located in Earth’s shadow, making it night for the observer. During the months of May, June, and July, when the days are long and the nights are short, this is particularly true. During this season, the sun dips just below the horizon at night. As a result, the nighttime elevation of Earth’s shadow is shallowest from north to south. In other words, at the height of the satellite, it is always daytime, even in the midst of the night. If the satellite is still receiving solar radiation, we on Earth will see it as a bright, swiftly moving object in the sky. If it travels too far south into the shadow of the Earth, where it is also dark, its light will suddenly go out.
These manmade stars shine brighter as their size and orbital height increase. The “satellite” ISS’s size and brightness are visible even to the unaided eye. The ISS is only visible because it reflects sunlight. You’ll need a telescope to see satellites that are either too small or too high in the sky.
It’s interesting to note that hardly any satellites can be seen crossing the sky from east to west. The ISS travels in a southwest-to-northeast direction. The rotational axis of the Earth explains why. The majority of satellites are positioned in a west-to-east pointing orbit, called a “corrected orbit”. It is not necessary to use maximum thrust in these orbits since the Earth’s rotation also adds to the speed. There would be no use in a satellite flying counter to the Earth’s rotational axis other than to use more fuel for acceleration.
So-called Iridium flares are magnificent celestial occurrences that are released by satellites. For the purpose of creating a mobile communications network that could be used all over the world, the defunct business Iridium launched 66 communications satellites into space. Years later, in 2022, 75 new Iridium satellites were launched into orbit on SpaceX Falcon 9 rockets to replace the old constellation. The satellites are still floating around up there, and they’re the ones making all those bright spots.
Flares are transient light phenomena characterized by a quick onset and rapid decay. Each satellite’s three enormous transmission panels are to blame for these phenomena. As the sun shines on the panels, some of the light is reflected back to Earth, where it quickly spreads into a 60-mile-wide (100-kilometer) light spot. The following may be seen by an observer who places themselves in the beam of this light: At first, we see a dim object whizz across the sky. In the next few seconds, it will brighten gradually at first, and then rapidly, until it practically blinds you. In the same rapid fashion, the brilliance will begin to fade once again until the satellite apparition is ended.
Satellites and their uses
According to the Union of Concerned Scientists (UCS), more than 5,500 man-made satellites performing a broad range of functions orbit the Earth today. And there are about 1,500 new satellites launched into orbit every year. Larger objects like the International Space Station (ISS) and the Space Shuttle also travel in orbit above Earth, although satellites are the most common. But what exactly are satellites anyway?
A “satellite” is the scientific term for any smaller entity in orbit around a bigger body. Therefore, the moon orbits around Earth, while Earth orbits around the sun. However, in a strict sense, we consider any artificial flying object that is in orbit around a celestial body to be a satellite. Manned and unmanned spacecraft exist, with the former more often referred to as space stations and the latter as space shuttles. There is also a great deal of space debris, such as retired satellites and spent rocket stages, orbiting among those artificial satellites. As of 2022, their number is around 27,000.
Satellites are launched into orbit for three major purposes: observing the Earth, communication, and space exploration. The latter investigates the solar system or space in different electromagnetic spectrum bands, including X-rays. Their primary function is to shield astronomers from the disruptive effects of the planet’s atmosphere.
A satellite designed for Earth observation performs a wide range of functions. They aid in weather prediction, volcano monitoring, Earth mapping, iceberg tracking, and a whole lot more. Without communications satellites, modern society would be a long way from its aim of globalization. They allow for global communication through the smartphone, global television broadcasting, and the transmission of scientific data from orbiting satellites to ground stations on Earth.
The development of satellite technology has substantially increased humanity’s knowledge of the planet and the cosmos. Quite a bit of the data satellites acquire reveals Earthly phenomena. The Landsat satellites (the newest Landsat 9 launched in 2021) provide such a detailed map of the Earth that it can be used to check the accuracy of older, less reliable maps. Scientists can even use them to check whether the vegetation in an area is healthy or has been harmed. The scouts in space can also assist in finding pollutants in the environment. Images from the Hubble Space Telescope, which is technically a satellite, have shed light on fundamental aspects of the cosmos. The James Webb Telescope has taken the flag now.
The specific orbits of satellites
The International Space Station orbits Earth once every 90 minutes.
Scientists use the term “orbit” to describe the specific route taken by each satellite as it circles the planet. All satellites must fly at heights above the tropopause (17 km/11 mi above the equator or 9 km/5.6 mi above the polar regions) to prevent speed reductions due to air friction. This is the case at altitudes above 185 miles (300 km), below which satellites cannot be put into permanent orbit.
An artificial celestial body’s orbit is determined primarily by two factors: its speed and the angle at which it orbits the Earth’s equator. A satellite’s speed is its circular orbital velocity, at which centrifugal force and Earth’s gravity cancel each other out, keeping the satellite in a stable orbit. This is conditional on the satellite’s height. It’s 5 miles per second (or 7.9 km ps) close to the surface and slows down with increasing altitude.
Depending on the satellite’s purpose, various orbits may be more or less appropriate. A polar orbit’s inclination angle is around 90 degrees with respect to the equator. Satellites in these orbits circle the Earth above the poles, providing a birds-eye view of the whole planet as it spins beneath them. In order to track storms, for instance, some weather satellites are placed in such orbits.
The geostationary orbit is used by other satellites. They need to be precisely 22,300 miles (35,888 km) above the equator to achieve this. At this height, a satellite travels around the Earth at a speed of 3.065 km/s, the same speed as a point on the earth’s surface when the earth rotates. Because of this, the celestial body always stays above the same point on the Earth’s surface.
Such orbits are often used by meteorological and broadcast satellites. Because otherwise, for example, the television satellite’s reception antenna would need to be continually adjusted with the satellite. Since the geostationary satellite’s transmitter is permanently fixed in the sky, the satellite dish only needs to be adjusted once to receive signals.
The equipment of the artificial satellites
Equipment for measuring and solar cells
The appearance of satellites, their size, and weight can be rather variable. The first satellite of the United States, Explorer 1, launched in 1958, was 6.5 feet (2 meters) in length and weighed 17.5 pounds (8 kilos). The Compton Gamma-Ray Observatory, built and launched by NASA in 1991, was 70 feet (21.3 meters) in length and weighed 17 tons. The largest artificial satellite is the International Space Station (ISS), weighing 444 tons or 980,000 lb with a diameter of 109 m or 357 ft in width.
Although satellites might vary widely in terms of size and mass, their core design features remain the same across the board. Large solar panels equipped with solar cells are the energy source for most satellites. The satellites are equipped with correction engines to counteract the effects of the Earth’s gravity and the very small amount of residual friction experienced during orbit. This enables the control center’s experts to reset the satellite’s orbit.
In addition to the measurement equipment that is essential for the satellite’s mission, they also carry additional instruments that are used for command and control. These tools can be used to identify power outages, temperature fluctuations, and pressure fluctuations, among other things. To keep the satellite on track, control sensors measure the spacecraft’s distance from Earth and its angle with respect to the horizon and the stars. The ground station can make course adjustments in response to erroneous readings from this equipment.
The vast majority of satellites are deployed in Earth observation roles. Primarily, weather monitoring satellites and other asteroids are crucial to human survival on Earth. But how do we make use of space-based observations?
Hurricanes, typhoons, floods, cyclones, tidal waves, and even wildfires can’t be predicted without the help of weather satellites. Understanding these occurrences allows for better catastrophe prediction and prevention.
It would be a mistake to discount the value of weather satellites in agriculture. They inform farmers of impending weather events like hail and snow, allowing them to better plan planting and harvesting. When a weather change is imminent, crops that are vulnerable to frost or wetness can be moved to a safe location with the aid of satellites. Planning large-scale projects like the building of bridges, roadways, and dams relies heavily on accurate weather predictions.
Television Infrared Observation Satellites (TIROS) were the first of their kind to study Earth from space. It was crucial in studying Earth’s cloud cover and proving the usefulness of satellites for meteorological reasons. The first in this series, TIROS 1, was launched in 1960, and its data has greatly improved our understanding of the Earth’s cloud cover ever since.
Nimbus is the name of a cloud formation that inspired NASA to create a program of the same name in 1964. To create the first-ever worldwide meteorological satellite system, these satellites were to be outfitted with both visible and infrared imaging sensors. The ozone spectrometer aboard Nimbus 7 was crucial to the investigation of the ozone hole over Antarctica and the worldwide distribution of ozone.
The newest weather satellites can be found in the GOES (Geostationary Operational Environmental Satellite) fleet. The first satellite in this series, GOES-1, ushered in a whole new era in weather monitoring. GOES-18 was launched on March 1, 2022, and GOES-U is scheduled for launch in April 2024. They are able to capture detailed photos throughout the visible and infrared spectrums and give maps of the Earth’s temperature and humidity.
Many more satellites than just those dedicated to weather monitoring circle the planet. The Global Positioning System (GPS) satellite fleet is one such example; it is used for satellite-based navigation. Within a few meters of accuracy, they allow for pinpoint earthly position determination. 24 satellites make up the GPS constellation, which circles the planet at varying distances from one another. And they allow up to 32.
All of Earth can receive satellite transmissions since their orbits span from 60 degrees north to 60 degrees south. Additionally, they serve a purpose regardless of the climate. Whenever a satellite communicates with Earth, it relays data about itself, its location, and the current time.
The GPS receiver uses the difference in time between when the signal was broadcast and when it was received to pinpoint its location. Scientists use the time difference to determine how far away the satellite is. The so-called 2D position, or geographical longitude and latitude, can be calculated if the receiver processes signals from three separate celestial bodies. A GPS device can determine the altitude value using information from four or more GPS satellites in orbit.
As of 2022, more than 140 million drivers in the United States alone rely on the GPS system to help them navigate unfamiliar places.
Satellites investigating space
The Upper Atmosphere Research Satellite (UARS), 1991, (Image credit: NASA Marshall Space Flight Center)
The first satellites in history were scientific satellites, which not only monitored the Earth but also looked out into the void of space. Scientists have learned a lot about the Earth and the cosmos from the data they have offered.
The Upper Atmosphere Research Satellite (UARS), which was launched in 1991, was the first research satellite to gather information about Earth from orbit. Its goal was to identify the systems in charge of the operations in the upper atmosphere. For instance, UARS created the first worldwide map of the atmospheric dispersion of chlorine monoxide. This demonstrated a clear correlation between the substance’s presence and the drop in ozone levels.
From orbits around the Earth, several additional satellites study the universe, the Sun, and other celestial bodies. For instance, Supernova 1987A was observed by the International Ultraviolet Explorer (IUE) in 1978, and it was discovered that the star explosion cooled surprisingly swiftly.
Both the Hubble Space Telescope (1990–today) and the Compton Gamma Ray Observatory (1991–2000) examined gamma rays in space, and produced important discoveries in the field of astronomy. The so-called gamma-ray bursts, one of the celestial phenomena that continue to confound scientists, were discovered by Compton to be far more intense than previously believed and to originate from regions well beyond the Milky Way. By that time, these gamma bursts had only recently been detected.
The United States launched a number of satellites in 1963 to keep an eye out for any nuclear weapon explosions in the atmosphere or in space during the Cold War. Instead of finding nuclear explosions on Earth, scientists were able to detect gamma bursts from space, a phenomenon that is still disputed among astrophysicists today.
We have discovered a great deal about the universe’s beginning thanks to these research satellites. A NASA satellite discovered slight temperature changes in cosmic background radiation in 1992. This radiation is a remnant of the Big Bang, the explosion that gave rise to the universe 13.8 billion years ago. The temperature changes that have been seen are consistent with the idea that the universe’s structure was formed when it was less than a trillionth of a second old.
A scientific satellite with equipment that goes far into outer space is the XMM-Newton built by ESA in 1999. It is equipped with the very sensitive X-ray telescope XMM (X-Ray Multi-Mirror), which hunts out and investigates undiscovered celestial bodies. It is accomplishing this by concentrating on countless stars in the Milky Way, extraterrestrial galaxies, galaxy clusters, and quasars, which are thought to contain black holes. One of the most powerful X-ray satellites in the world, XMM-Newton can detect minute amounts of X-ray radiation, penetrating the cosmos to depths never before reached.
The XMM-Newton travels in an elliptical orbit around the Earth at an altitude of between 5,700 (3,540 mi) and 113,000 kilometers (70,200 mi). It looks for X-ray sources in space outside the Earth’s atmosphere, which filters X-rays from space. These measurements may subsequently be used by researchers to make inferences about the physical and chemical data they hold. As of 2018, at least 5,600 papers have been published on the XMM-Newton and its scientific results.
Satellites simplify life
Today, the ability to connect to a phone anywhere on the globe and make calls is taken for granted, even in the most isolated areas. In a similar vein, the news can spread like wildfire around the world. Without the use of communications satellites, none of this would be feasible. This would otherwise only be possible via the time-consuming installation of cables in several parts of the globe; just like the first transatlantic cable.
The earliest commercial satellites were communications satellites. While some satellites are effectively administered by government entities, the majority are run by commercial businesses.
In 1960, aluminum-coated balloons were used as the first communications satellites. These were inactive satellites that only actively reflected radio signals in order to transfer them. Due to their restricted usefulness, they were quickly replaced by active satellites, which receive signals, amplify them, and then transfer them to another location on the Earth’s surface.
Telstar 1, which was run by the American telecommunications corporation AT&T, was the first privately launched communications satellite. It was the first satellite to carry both black-and-white and color television across two continents, and it was also capable of switching telephone calls between America and Europe.
The International Telecommunication Satellite Consortium (Intelsat), a global organization made up of 65 nations that significantly enlarged the commercial communications network, was created in response to the enormous need for new communication channels. Only two stations could connect at once with the first Intelsat satellite. Intelsat now runs one of the world’s biggest fleets of communications satellites, consisting of 52 satellites that provide service to 200 nations.
The NASA-developed Advanced Communications Technology Satellite (ACTS) was sent into orbit in 1993. This technology was far more cost-effective and affordable since it guaranteed three times the communications capacity at the same weight as other satellites. Additionally, it enabled quicker communication, enabling a business to use this upgraded technology. In fact, ACTS was the first high-speed, all-digital communications satellite.
Meteorologists need to be aware of the vertical distribution of temperature and water vapor in the Earth’s atmosphere in order to anticipate the weather. Weather balloons have often been used up to now to determine these. The gaps in our understanding of the vertical structure of the atmosphere are enormous since they are only ever installed at a few sites on Earth and at great intervals.
LANDSAT
Landsat 9 in orbit, NASA.
The LANDSAT series, launched in 1972, is one of NASA and the U.S. Geological Survey’s (USGS) most adaptable Earth observational tools. Earth’s surface has been observed by LANDSAT satellites for more than 50 years, which has aided in our understanding of the intricate interactions that cause many of the world’s changes.
In 1972, the first of the LANDSAT satellites were sent into orbit, paving the way for detailed, high-resolution monitoring of the planet’s land and sea surfaces ever since. The last of these heavenly bodies, called LANDSAT 9, entered Earth’s orbit in 2021 and is tasked with doing so for the next five years. LANDSAT is unlike any other Earth-observing satellite due to the breadth of its possible uses. From tracking the growth and shrinkage of glaciers to checking the cleanliness of lakes and coastlines to charting the distribution of pack ice and mapping out forest coverage, the Earth satellites’ imagery has been used for a wide variety of uses.
LANDSAT is used by researchers to keep an eye on the land surface and nearshore water regions and analyze the effects of climate change on various ecosystems. Important natural processes and human-induced changes, including deforestation, agricultural usage, erosion, and water levels in drinking water reservoirs, are all documented by LANDSAT. Repeated observations of the same spot over the course of a year can reveal seasonal variations.
The repeated eruptions of Hawaii’s Kilauea have been studied in part via the use of LANDSAT imagery. Mapping active lava flows is critical so that locals may be warned in a timely manner. The delicate equipment on LANDSAT is capable of distinguishing between fresh lava flows and those that have previously cooled.
In recent years, forest fires have played a significant role in the degradation of ecosystems across the world. Knowledge of the volume and wetness of biomass on the ground, which supplies fuel for the flames, is crucial in preventing and putting out these types of natural catastrophes. For safer firefighting, this data may be used to identify potentially hazardous places and minimize dry biomass there.
Methods for recognizing various kinds of dry biomass have been developed with the use of LANDSAT images. Scientists may use spectral analysis to tell whether the flora they’re studying consists of lush meadows or dry trees that might spark the next forest fire.
Radar satellites
Tracing the surface of the planet
Scientists utilize radar satellites for the specific purpose of surveying the Earth’s surface. In the course of their development, radar systems have become the most potent remote sensing tools available today.
Radar waves, which have a wavelength in the centimeter range, are simply radio waves that are reflected by solid objects and liquids. These systems are versatile in their use, since they may be used not only to find things but also to investigate surfaces through their unique reflecting qualities. Radar systems excel due to their ability to function in low-light conditions and see-through cloud cover.
The military first used radar as a means of surveillance in order to locate and track hostile aircraft and ships. After the war, the technology was adopted by the general public. It was rapidly recognized for its use in cartography, oceanography, and land-use research.
Radar systems need to be elevated above the reach of airplanes if they are to be used for mapping out bigger regions. NASA began conducting experiments with radar systems in orbit as early as 1962; in 1972, Apollo 17 sent an upgraded version of this device to the moon for a detailed study of the lunar surface and underlying geological features. These findings prompted the addition of a radar system to the SEASAT satellite for ocean monitoring. As a result of SEASAT’s efforts, more data was collected in 100 days about the ocean floor than in the previous 100 years of ship-based research combined.
The use of radar equipment on space shuttles became commonplace in the 1980s. During this trial run, new information on how to scan geological features was gleaned from radar pictures. Meanwhile, there are a plethora of radar satellites in Earth’s orbit. They were used to learn more about the planet’s surface in novel ways and to keep tabs on noteworthy occurrences. In the past, for instance, after its replacement, ERS-2, had taken up its duties, the ERS-1 satellite was reactivated so that it could watch the eruption of the Icelandic volcano Vatnajökull.
ERS satellites (European Remote-Sensing Satellites) have a dual capability for observation. The first setting is utilized for land surveys, while the second is for ocean research. Applications for satellite radar data are expanding in the field of environmental monitoring. To better understand oceanic phenomena like wavefronts and sea conditions, for instance, researchers can monitor oil spills, track sediment intake from rivers, and track the movement of ice sheets. The satellites collect information on human activities on the ground, such as farming and logging, as well as natural phenomena, such as earthquake hotspots and geological formations.
Radar satellites can also be used to investigate mineral, oil, and gas deposits as well as underground water supplies. Archaeology, for example, has benefited greatly from the use of radar technology. In the past, scientists were able to measure the whole Angkor temple complex in Cambodia. In addition, barely visible from the ground, vestiges of an even earlier wall complex were uncovered close to the modern Great Wall of China.
These days, instruments like sextants and measuring rods aren’t necessary for “measuring the globe.” When it comes to measuring global phenomena like sea levels, massive ice sheets, or the water cycle, geodesy is increasingly dependent on satellites. But what are the mechanics and techniques of surveying the Earth from space?
Due to its many benefits, satellite geodesy has become an integral part of modern Earth systems and climate studies. Taking a look at Earth from orbit using a geodetic instrument provides a comprehensive overview of our planet and its interconnected systems. However, the satellites can still take quantitative readings of a number of different factors. Both satellite gravimetry (the measurement of gravity from space) and satellite altimetry (the use of radar to examine the topography of water, ice, or land) are widely used nowadays.
History of Measuring the Earth
From Triangulation to Satellite
Carl Friedrich Gauss and Alexander von Humboldt were two of the most famous geodesists. Common knowledge recognizes the two gentlemen for their work in mathematics and the natural sciences, respectively. The central goal of geodesy is the process of measuring and charting the Earth’s surface. As a matter of fact, Gauss and von Humboldt accomplished just that in the 18th century.
Gauss is famous for his involvement in surveying. His work in practical measurement informed many of his mathematical innovations, including the least squares estimate approach and his statistics. The latter is represented by Gauss’s normal distribution. On all of his explorations, Alexander von Humboldt carried surveying instruments, proving that he was also a dedicated geodesist.
The Dream of Surveying the Earth
One of the ultimate goals of geodesy is to take a global measurement of the Earth. The groundwork for this was created 150 years ago, in 1862, when Prussian General Johann Jacob Baeyer called delegates from Prussia, Austria, and Saxony to Berlin to examine his plan for a Central European linear measurement. The International Association of Geodesy (IAG) was officially founded when more European nations joined the proposal.
But it wasn’t until the era of satellites that the hope of conducting a truly worldwide survey of Earth came to fruition. Only from space is it possible to conduct a global survey with consistent precision and in a reasonable amount of time. Earlier and more accurately than any previous terrestrial measurements, the flattening of the Earth was able to be calculated from observations made during the first Sputnik orbit. After that point, satellite geodesy progressed quickly. Think of the potential social and economic benefits of global satellite-based navigation systems like the United States’ Global Positioning System (GPS) and Europe’s Galileo.
The Principle of Satellite Altimetry
Satellite altimetry monitors geometry, including depressions and elevations of the terrain, water, or ice, while satellite gravimetry records the distribution of big masses on Earth. The basic premise of the measurement is straightforward: a satellite emits a radar pulse to the ground, which is then reflected by an object like the ocean’s surface and sent back to the satellite. With accurate knowledge of the satellite’s orbit and, more importantly, its altitude (as provided by GPS data, for instance), the height of the ocean’s surface can be calculated from the duration of the radar waves’ journey. In this technique, the ground track right below the satellite’s orbit is scanned, providing a profile of the Earth’s surface.
Tides, El Niño and Other Fluctuations
Four decades have passed since the first use of satellite altimetry. American and French scientists worked together to create a new generation of altimeter flights. Such measurements are often taken by satellites operated by NASA and the European Space Agency (ESA). In 2016, the European Union deployed Sentinel-3, the successor to the unsuccessful Envisat satellite, into orbit as part of the GMES Earth surveillance program.
The primary purpose of satellite altimetry is ocean monitoring. Because of this, oceanography has made enormous strides forward, allowing for more precise tidal models, continuous monitoring of global ocean circulation and its variations, the recording of smaller-scale structures like eddies and tsunamis, and a deeper understanding of the El Niño phenomena.
The Rise in Sea Levels
However, sea level is also a crucial factor in studying climate. Long-term, precise, and spatially consistent monitoring of ocean surfaces is now possible because of satellite altimetry. This is the only method to accurately predict the increase, and it plays a vital role in many studies, including those of the Intergovernmental Panel on Climate Change (IPCC). Because of altimeter readings, it is feasible to pinpoint areas experiencing increasing and declining sea levels, for instance.
There are so-called interannual influences, such as the El Niño phenomenon, that may produce localized sea level fluctuations over the course of many years. Despite some variances, a coherent picture emerges from the data collected by the numerous altimetry satellites.
How Satellite Altimetry Can Also Help in Hydrology
However, it is only via the integration of gravimetric and geometric techniques that satellite geodesy begins to show any signs of genuine promise. By correlating changes in an ice sheet or river mass as measured by the gravity field with changes in sea level as recorded by altimeters, researchers can isolate the contributions of ice melt and thermal expansion to sea level rise, among other factors. Such independent measurements are crucial for supporting the viewpoints in the IPCC reports since the values can be calculated without the use of modeling or climatic assumptions.
Surveying the Earth for Climate Research
Possible tipping elements in the climate system. Image: Wikimedia.
The ongoing discussion about climate change highlights the necessity for constant Earth monitoring. Sea levels are increasing, as is often reported in the news. When compared to the size of waves and tides, which may be many orders of magnitude greater, measuring changes of just approximately three millimeters (0.11 inches) each year can be a challenge. And where does the water come from?
The average amount of water expands as its temperature increases; this phenomenon helps to explain the rise in sea levels. However, the most compelling explanation for sea level rise is a massive redistribution of water and ice in the Earth’s hydrological cycle.
Researchers at the Potsdam Institute for Climate Impact Research (PIK) first used the phrase “tipping points” to describe a critical turning point in the climate change debate. These metrics are crucial for understanding the state of the global climate. For some years now, geodetic satellites have seen the rapid retreat of the Greenland Ice Sheet. At around half of the “tipping points”, satellite geodesy performs an essential observing role. The critical parameters are determined with the aid of two distinct geodetic satellite systems.
How Does Satellite Gravimetry Work?
The Gravitational Field Is a Dead Giveaway
How can we “weigh” the changes in mass on Earth on a global scale from outer space, like Greenland’s melting? The key to this is taking an indirect route. As mass is redistributed on a global scale, the Earth’s gravitational field shifts. The Earth’s gravitational field is “just” a representation of the distribution of all masses inside and on the planet. These changes in time can be measured, even to the sixth or seventh digit.
Dissimilarity as a Clue
Like an astronaut on the International Space Station, a satellite seems to float in space, unattracted to the planet Earth. But the force of gravity does, nevertheless, operate upon them; and the orbital motion counteracts this effect. Although the strength of this pull cannot be determined directly, it can be inferred from the relative positions of two satellites. Due to their relative locations in Earth’s gravitational field, they experience various levels of attraction. And due to their free-falling nature, the distances between satellites vary.
The GRACE satellite project (2002–2017), a joint effort between the United States and Germany, put this concept, known as “low-low satellite-to-satellite tracking,” into practice. Two identical satellites have been orbiting the Earth at around 280 miles (450 kilometers) in the polar region for the last decade. Both satellites were in geosynchronous orbit, but one was roughly 125 miles (200 kilometers) ahead of the other, so they pursued each other at nearly 30-second intervals. K-band ranging can measure distance changes between satellites to within around 32 ft (10 m). Geodesists created a gravity field map of Earth almost monthly using these precise observations.
Changes Over Time Are Important for Climate Research
However, such findings are only relevant to climate science when the monthly gravity fields are arranged sequentially, as in a film. The end result was a 10-year time series of gravity field shifts, or mass changes in the Earth’s system. However, satellite gravimetry can only discern such changes on spatial scales bigger than around 250 miles (400 kilometers) owing to the height of the satellites and the relatively low sensitivity, notwithstanding the accuracy of the readings.
While hydrologists, ice scientists, and geophysicists had never observed the Earth in this way previously, the time series of mass changes gave them a more complete picture. But if you’re interested in learning more about our planet but want to go beyond the traditional methods of satellite remote sensing, satellite gravimetry will give you a whole new perspective. In this method, gravitational interaction is used instead of electromagnetic waves.
Observing Earth’s Water Masses From Space
How Satellite Measurements Provide Information About Water Distribution
The equivalent water height is a common way of expressing mass displacements on the Earth, since many of these movements are tied to the water cycle. It represents the deviation from a reference height of the gravitational field caused by the presence of water masses. But not every satellite’s gravitational signal can tell the difference between water on the surface of the Earth, water in the soil, water in the ground, or water in the biosphere. Thus, vertical separation is not possible. However, this has the benefit of providing a standardized measurement and international perspective.
Gravity Field Reflects Water and Ice Distribution
Annual cycle of hydrological mass changes, expressed in equivalent water height in centimetres.
Global variations in comparable water height are seen on this map. While other timescales have a role, it is the yearly cycle that is of most interest here. Each color on this map represents the amplitude of a yearly sine wave, which can be determined by looking at the associated pixel.
The water level in the Amazon basin reservoir, for instance, fluctuates yearly by as much as 8 inches (20 cm). It’s also clear that the Amazon and the Orinoco Basin are geographically distinct from one another. Other places with significant hydrologic activity include the confluence of the Ganges and the Brahmaputra rivers, as well as the tropical regions of Africa and northern Australia.
Bright colors can draw attention to the more hydrologically inactive continental regions, such as deserts and Antarctica. Current satellite gravimetry’s limits are also shown on the map. The spatial resolution is inadequate for several regions, including the islands of Indonesia.
It’s commonly known that the desert experiences relatively little in the way of hydrological activity, whereas the tropics are home to a flurry of activity. The novelty of satellite gravimetry is that it allows metrological and worldwide quantification of mass turnover with consistent precision and homogenous, although coarse, spatial resolution.
Because of the long-term fall in the number of terrestrial hydrological and meteorological monitoring stations, this is of critical importance. Maintaining infrastructure like river gauge stations over extended periods of time is today an expensive endeavor for many nations.
Thawing Glaciers and Trembling Earth
Use of Gravity Field Measurements for Climate Research and More
Long-term shifts in the global distribution of water and ice can also be gleaned from satellite measurements of the Earth’s gravitational field. They reveal locations where the Earth’s crust seems to be rising, such as in Scandinavia and North America. This is because, after the previous ice age, the land masses rose due to postglacial uplift. The Earth’s crust was pushed inward by the then-existing, one-kilometer-thick (0.60 mile) ice sheets; since their melting, the crust has been slowly springing back out again, at rates of up to one centimeter (0.40 inch) per year, which can be detected using other geodetic measurement techniques like GPS or from geological analyses.
Melting Hotspots
The data for Greenland and West Antarctica are the most worrisome. They prove that something more than a simple rebound of the Earth’s crust is happening there, namely, changes in the gravitational field. The Greenland ice sheet is losing around 300 gigatons of ice every year, more than it gains from snowfall, and this is the reason.
Its mass is equivalent to that of a cube of water having a length of one kilometer on each of its sides, or one gigaton. The average annual increase in sea level caused by the melting of 300 such ice cubes is around 0.85 millimeters (0.03 inches). As a whole, this may not seem like much. Still, Greenland is responsible for approximately a centimeter (0.04 inches) of the ocean’s overall average increase in only a few years. There has been a recent speedup in the melting process in recent years.
Ice Masses Also Have an Attraction
This method of measuring sea level rise can only ever provide an average figure for the whole ocean. However, in actuality, the meltwater is not uniformly dispersed over the world’s seas. Massive masses like Greenland’s ice sheet have their own gravitational influence, raising sea levels locally. When Greenland’s ice sheets melt, their gravitational pull weakens, and the seawater in the area is attracted to them to a lower degree. As a consequence, local sea levels may fall even further. Since this is the case, melting Greenland need not negatively impact other continents, at least not in terms of sea level rise.
Antarctica is experiencing a significant ice loss, most notably in West Antarctica. The average annual increase in sea level is 0.5 mm (0.02 inches), which is about equivalent to the size of the problem (approximately 180 Gt/year). Nonetheless, studies of the gravitational field show that inland glaciers like those in Alaska and Patagonia are also shrinking. As a matter of scale, this may not be as important as Greenland or West Antarctica. However, melting is unmistakable evidence of global warming.
Rivers, Groundwater, and Earthquakes Leave Traces of Gravity
Satellite gravimetry can detect even minute variations in water distribution, such as the volume of water in river basins. As seen by these measurements, the Amazon and the Zambezi both seem to be growing heavier or wetter. However, the findings suggest groundwater exploitation for agricultural reasons in California, the Middle East, and northern India. The gravity decreases when the water evaporates after being pushed out.
For instance, the shift in the Earth’s gravitational field due to the massive earthquake that struck Sumatra and the Andaman Islands in 2004 was quite intriguing. It was a sudden shift in the gravitational pull. This jump was reflected on the map because of the magnitude of the mass shift. It demonstrated that satellite-based gravity field changes are of interest to geophysicists in addition to hydrologists and ice scientists.
Networks of thousands of mini-satellites are presently being placed in earth orbit, which allow for broadband Internet access even in the remotest corners of the planet, data linkages for autonomous cars or drones, and communications everywhere. There are pros and drawbacks to these mega-constellations, which promise nothing less than a new era in global communications.
Competition in the satellite Internet industry has begun. SpaceX with Starlink, Amazon with the Kuiper project, and OneWeb, a corporation formed particularly for this purpose, are the three private firms now in direct rivalry. However, both China and the EU have stated their ambition to launch their own satellite networks into space in the near future. Big bucks and total control of the digital communications market are in sight.
However, some people have a negative opinion about putting tens of thousands of satellites into Earth’s orbit. Astronomers are concerned that this may cause light pollution and interference with their telescope observations. The increased risk of accidents and space debris is a major concern for space organizations.
What does satellite internet bring?
The issue is not new: although individuals in major cities and urban regions benefit from continual connectivity and relatively fast data transfer rates made possible by broadband Internet and extensive cellular coverage, those living in rural areas are left in the digital darkness. Fiber optic connections are the stuff of fantasy for those living in rural areas of even highly developed nations like Germany.
Almost half of the world’s population is still offline
Distribution of ping-accessible Internet connections in 2012. Cody Hofstetter/CC-BY-SA 4.0
And on a worldwide basis, this digital divide is much more severe: Approximately half of the world’s population uses the Internet, with estimates putting the number of users at slightly under four billion. When it comes to network availability, developing nations and sparsely populated areas like Asia’s steppes do the worst. According to the International Telecommunications Union (ITU), a full 72% of Africa and slightly more than half of Asia lacked access to the internet in 2020.
This is because installing data connections, whether fiber optic or even copper cables, is a difficult and costly process. The same is true for the construction and installation of cell towers. This is profitable for commercial network providers only if a sufficient number of users are present in the region. Despite claims to the contrary, if this is not the case, laying the cables or constructing the antennas is a loss-making business and has thus simply not been done to date.
Satellite network instead of cable
At this point, the mega-constellations become relevant: Through orbiting networks of communications satellites, we hope to speed up Internet and cell phone service in regions where they were previously unavailable or painfully slow. These constellations provide continuous service because their hundreds to thousands of mini-satellites are evenly spaced over the world. One thousand kilometers is the extent of the coverage area that can be provided by a single satellite in SpaceX’s Starlink constellation.
The satellites used for telecommunications and broadcasting are located in geostationary orbit at an altitude of 36,000 kilometers; the mini-satellites of the mega-constellations, in contrast, travel in low earth orbit (LEO) at an altitude of 500 to 1,500 kilometers. In these constellations, many satellites should be able to cover any given area, resulting in a reliable connection. One satellite’s loss of communication won’t affect the operation of the system as a whole.
Each satellite weighs around 250 kilograms and is equipped with little, making them far cheaper to manufacture than traditional communications satellites. Constellation mini-satellites are minimally equipped with a radio antenna and transmitter, a couple of tiny solar sails, a computer, a star and sun tracker for navigation, and an ion propulsion engine. Because they are cheap to construct in bulk, these satellites may be launched in batches of 60–75 at a time.
Increased data transfer speed and lower latency
The new mega-constellations’ increased capacity and transmission speeds are the main benefits over earlier satellite broadcasts. The Ka and Ku bands of the microwave spectrum are used by satellites in low Earth orbit, and their frequencies range from around 12 to 40 gigahertz. Providers of the new satellite Internet have made claims that the short-wave Ka band is capable of very high data transfer speeds, rivaling or even surpassing those of terrestrial broadband services.
The latency of up to 700 milliseconds experienced by a signal sent by a typical communications satellite renders real-time remote control of equipment, video telephony, and other real-time applications impractical over such links. In low Earth orbit, communications travel a fraction of the distance, bringing latency down to 20 to 40 ms, which is practically on par with fiber-optic and DSL speeds.
New application possibilities
The Internet via satellite gains a wealth of new uses because of these characteristics. The mega-constellations may be useful for a variety of emerging technologies, as well as the possibility of bringing high-speed Internet to previously unconnected locations. One potential use of this lightning-fast satellite link is the remote operation of automobiles, aerial vehicles, and other robotic companions in real-time. This might make remote monitoring of pipelines, disaster zones, or even agricultural fields and plantations simpler than ever before. In the future, satellite transmissions may potentially be useful for autonomous cars.
Improvements might also be made to the Internet connectivity of ships, planes, and moving vehicles. They had to rely on mobile phones or wired links to older types of satellite communications before this. However, mega-constellations may be able to provide broadband connectivity to even moving targets like ships at sea or aircraft in the sky. For its Starlink system, SpaceX has already submitted license applications to the U.S. Federal Communications Commission for use of such mobile apps began in the spring of 2021.
However, only those who can afford the monthly fees and the price of the satellite dish and router will be able to take advantage of this exciting new world of the Internet. The cost of using Starlink’s beta version is $99 per month plus an initial equipment cost of $499. Despite the fact that Starlink is making a profit on these basic bundles at the moment, they are still likely to be out of reach for many in developing nations.
Starlink – the pioneer
What is the purpose of SpaceX’s constellation?
In September 2022, SpaceX launched 52 Starlink satellites into space.
Three privately held corporations owned by some of the world’s wealthiest individuals own the most technologically sophisticated mega-constellations. Elon Musk, the creator of Tesla and CEO of SpaceX, is at the helm of the Starlink project. The only satellite network that is up and operating at the moment is his, and it is still in beta.
There are now around 2,200 operational satellites
In 2018, SpaceX tested only two prototype satellites; in May of this year, the company started constructing its orbital network. The startup has gotten off to a sluggish start, but now every two weeks it sends a Falcon 9 rocket carrying between 50 and 70 miniature satellites into orbit. In September of 2021, there were around 1,800 Starlink satellites in orbit, and that number is steadily increasing. Today it is around 2,200.
Most of the 1,440 Starlink satellites already in orbit are part of the “first dish” of the mega-constellation, which is located at a height of 550 kilometers and has orbits inclined at 53 degrees to the Earth’s equator. There are also more shells with tens of thousands of satellites, orbiting at varying inclinations and altitudes between 540 and 570 kilometers. The current approval status indicates that 4,408 satellites will make up the Starlink constellation.
Future plans call for around 7,000 more Starlink satellites to be placed in an even lower orbit, between 335 and 345 kilometers above the earth. They will make use of the unused portion of the communications spectrum that lies between 40 and 52 gigahertz. All systems are expected to be finished by 2027.
Currently, 40 countries have access
Starlink’s network beta shows that it’s possible to go online through satellite and how successfully it does so. Access to Starlink was initially restricted to users in the United States, Canada, and the United Kingdom; but, beginning in the spring of 2021, certain European nations, notably Germany, have been granted restricted access. In 2022, Starlink went live in Japan and India. More than 100,000 users and 500,000 pre-orders have been reported for the satellite network’s beta edition.
Initial tests conducted in the USA demonstrate how reliable the satellite connections are. These claim that Starlink has reached peak download rates of 168 Mbit/s and average download speeds of 97 Mbit/s. This indicates that orbital data transfer already approaches the 115 Mbit/s baseline US broadband Internet bandwidth and even significantly outperforms it locally. In the UK, Starlink has a download speed that is almost nearly twice as fast as the typical broadband connection, at 108 Mbit/s. In terms of uploads, Starlink is reportedly only slightly slower than wired internet speeds.
However, while Starlink works to enhance the system’s hardware and software, beta customers are still forced to deal with sporadic satellite connection failures. Transmission rates are anticipated to rise even more as the number of satellites in orbit rises: “Data rates, latency, and network availability will improve considerably as we launch more satellites, deploy more ground stations, and upgrade our network software,” according to a Starlink announcement.
Data congestion in metropolitan areas
There is a caveat, though: satellite Internet becomes slower the more people use it from a single area. Elon Musk, chief executive officer of SpaceX, said in a tweet that “Starlink is built for low to medium population densities.” That implies that in certain regions, we might quickly exceed our maximum user capacity. This essentially implies that sparsely inhabited areas are where satellite constellations may best use their benefits. On the other hand, fiber optics companies may continue to lead in urban regions.
The rivals
In addition to promising faster Internet and improved data transfer, mega-constellations in Earth orbit might end up being a true money mine for their operators. Whoever wins here might have a significant lead over their rivals. Currently, there is a tremendous race for who can expand orbital Internet capacity quickly. State participants like China and the European Union are getting ready to join the competition.
OneWeb: Getting closer
To get at least some of its remaining low-Earth orbit (LEO) broadband satellites into orbit, OneWeb has contracted with India’s biggest launch vehicle.
With its Starlink constellation, SpaceX is the first to launch, but two rivals are right behind it. The closest is OneWeb, a business created especially for satellite broadcasting. It launched its first six test satellites into orbit in February 2019, using a Soyuz rocket as a payload. However, OneWeb only just avoided a pandemic-related bankruptcy in the summer of 2020. The corporation didn’t have the requisite cash once again until Bharti Airtel and the British government entered the picture. The satellite gear is also being co-manufactured by the European airline Airbus.
358 OneWeb spacecraft, or almost half of the 648 constellations intended for the first expansion stage, are already in orbit above the Earth. In 2022, it’s expected to be finished and put into use. The OneWeb constellation covered the whole planet by May or June 2022, according to billionaire businessman and CEO of Bharti Enterprises Sunil Mittal. OneWeb has submitted applications for permission to launch 6,372 satellites, and there are already plans for further mega-constellation expansion phases.
Yet a different target audience
Unlike Starlink, the OneWeb satellites orbit at a height of 1,200 kilometers and have an inclination to the equator of a respectable 98 degrees. Because of this, they need fewer satellites for comprehensive coverage and can even reach high latitudes. There were enough satellites in orbit by the end of 2021 to provide orbital Internet service north of 50 degrees latitude.
OneWeb partner Airbus said in July 2021 that “this will allow coverage of Northern Europe, the UK, Canada, Alaska, Greenland, Iceland, and the Arctic Ocean.” This would be beneficial for the region’s ships and planes, in addition to the nations there. However, since the signals must go a little farther than with Starlink satellites, which soar just half as high, latency may be a little greater.
OneWeb is not designed to give direct access to individual users; rather, it targets organizations such as enterprises, telecommunications companies, governmental bodies, or whole towns as clients.
Amazon is the third but currently least developed commercial satellite Internet rival. The business intends to place a mega-constellation of 3,236 satellites in Earth orbit as part of “Project Kuiper.” By 2026, half of these spacecraft should be in orbit. Similar to Starlink, the constellation will be spread out among three dishes at a height of 560 to 630 kilometers and will transmit data mostly in the Ka-band.
However, Amazon is now far behind its rivals. While Amazon is currently hiring experts for the project, Starlink already has the beta version of their satellite Internet up and running. Additionally, according to reports, the business allegedly collaborated with Facebook to borrow certain staff for this project, which was made public in July 2021.
Better synergy effects
However, the Amazon constellation has a certain benefit that might compensate for this weakness: Amazon can seamlessly combine Project Kuiper’s transmission services with its current Internet offerings, most notably Amazon Web Services (AWS) cloud storage, unlike its rivals. “Data may be sent from point A to point B by SpaceX. However, Amazon is able to provide data to customers and its cloud services through the satellite network” Zac Manchester of Stanford University says.
This would provide many Amazon cloud service users with the benefit of being able to access their data quickly and anywhere they are using fast broadband connections, in addition to being able to outsource computationally intensive applications that require a lot of storage space to the cloud as they have done in the past.
Government initiatives
Even while commercial businesses are the most advanced in mega-constellations, state players have also woken up in the meantime. They don’t want to take the chance of being excluded from the lucrative and maybe crucial satellite Internet market in the future.
China: 13,000 satellites requested
Launched in China in August 2021, this Long March 2 launcher had two test satellites on board for a future Chinese mega-constellation in addition to additional payloads. China Aerospace Science and Technology Corporation (CASC)
The first state participant to begin is China. Several reports claim that the nation started working on creating its own satellite constellation in 2018. According to Bai Weimin of China’s State Space Administration (CASC), among others, the first prototypes have already been constructed and put through orbital testing. “We are planning and developing Internet satellites and have already launched test satellites,” he said in an interview with Shanghai Security News. Officially included in the five-year plan for 2021 to 2026 that President Xi Jinping and his administration have established is a satellite Internet.
According to a proposal made to the International Telecommunication Union (ITU) in September 2020, the Chinese mega-constellation would include up to 13,000 satellites spread out in a variety of orbits between 500 and 1,145 kilometers in height. According to reports, a national network firm was founded expressly to build these satellites. By 2022 at the latest, the first wave of 60 test satellites will be sent into orbit.
It is not yet known whether the Chinese satellite Internet will be available worldwide or if it will solely serve Chinese citizens. “The domestic market seems to be the present emphasis. However, similar to previous technologies, such as high-speed rail, it is also plausible that China would first work out any flaws domestically before marketing the service internationally.” In October, American analyst Bhavya Lal stated.
EU: A feasibility study is in progress
The European Union arrived relatively late to the party. It has only asked a group of aerospace, telecommunications, and satellite manufacturing businesses to research the viability and need for an orbital communications system in 2020. According to consortium member Airbus, the project “will examine how a space-based system may complement and link essential infrastructures.” Additionally, the advantages of using cloud services will be examined. By the end of 2021, the review’s preliminary findings are anticipated.
“We can observe that certain constellations are still in the process of formation. However, they are not European, which might present a problem for European member states as we consider safe connection inside and beyond the continent,” said Dominic Hayes of the Space and Defense Division of the EU Commission. The goal is to prevent future reliance on commercial suppliers by European governments, agencies, and even military users.
Hoping to benefit from a “late birth”
Hayes admits, “We don’t have the benefit of being first to market.” However, the fact that certain parts and technologies are developed by commercial pioneers and can later be manufactured more affordably might be advantageous for Europe. The EU expert uses the Starlink system’s receivers as an illustration: Up until this point, SpaceX had been making theoretical losses by selling the antennas and routers below their market value. But in the future, mass manufacturing might make such receivers substantially less expensive.
Who will be engaged in building and developing a European satellite constellation if that option is chosen? This is a valid concern. Along with the businesses already participating in the feasibility study, another potential applicant would have been the French satellite operator Eutelsat. But in April 2021, the latter made a $550 million investment in OneWeb, making it a direct rival to a proposed European constellation.
EU Internal Market Commissioner Thierry Breton said, “I don’t understand how one participant can be participating in two rival initiatives.” According to him, the new EU structure is critically necessary for the bloc’s autonomy, sovereignty, and future. Breton said, “We won’t give up on this.”
Space debris and collisions
The drawback of massive constellations
Earth’s orbit is becoming increasingly crowded: If all the mega-constellations planned so far come to pass, there may eventually be as many as 100,000 satellites orbiting the planet, which is significantly more than the roughly 2,500 “normal” military and civilian satellites that have been in place up to this point. Astronomers and space agencies alike have serious worries about this in a number of ways.
Near-collision averted
ESA’s Aeolus satellite had to dodge a Starlink satellite in 2019. ESA
The European Space Agency (ESA) had to conduct an evasive maneuver with its Aeolus Earth observation satellite because a collision with a Starlink mini-satellite was about to occur on September 2, 2019, proving how legitimate such worries are. The Aeolus launched its thrusters, lifting its orbit by 350 meters, barely averting the collision.
The Starlink satellites are really designed to automatically avoid other flying objects, but a flaw prevented this from happening in this instance. ESA has to respond as a result. It’s true that this prevented damage to both satellites and further space junk and collision debris from entering Earth’s orbit. However, such evasive actions are fuel-intensive and only effective when the threat is identified in time. Each ESA satellite in low Earth orbit already receives two collision warning signals each week.
The topic of when a costly and time-consuming evasive maneuver becomes essential is also raised by such warnings: “Such actions would be routine if you already respond at a collision probability of 1:10,000. But with a risk of being struck off at 1 in 50, it’s quite likely,” Hugh Lewis from Southampton University recently explained the problem. Monitoring systems are currently not accurate enough to tell the difference between a collision and a barely missed one in advance.
Who has to dodge?
ESA satellite Aeolus and a Starlink satellite on a collision course on September 2nd, 2019. ESA
Another issue is that there are now no defined traffic regulations in orbit: It is not immediately evident who has to be avoided and there are no automatic communication procedures between the operators involved. Holger Krag, director of the ESA’s Space Safety Program, adds that there is a pressing need to catch up in this area. After all, as Earth’s orbit becomes more congested, the danger of collision increases, and each impact causes an avalanche of new debris to race around the world.
Future satellite launches and space mission launches would also benefit from this collaboration. After all, the more rockets there are in orbit, the greater the chance that one of them may launch and strike a satellite. The ESA specialist said that “the spacecraft operators need to come together to develop automated maneuver coordination.”
In the legal gray area
A ring of debris from the Chinese satellite Fengyun-1C a month after it was shot down by a Chinese missile. NASA Orbital Debris Program Office
The issue of how satellite constellation operators should handle imperfect or totally failing satellites in orbit is also still up for legal debate. According to Corinne Baudouin and her colleagues at the University of Paris-Saclay, there is simply no internationally enforceable law that currently mandates the mandatory regulation of waste disposal in orbit. “SpaceX is not doing anything that violates the rules, because there simply aren’t any yet,” the researchers say.
True, several nations and space agencies have previously decided on non-binding principles. These allow for the sharing of data on satellite locations, potential collision hazards, and approaching accidents, among other things. Such agreements also provide for the disposal of inoperative satellites beyond low Earth orbit by allowing them to burn up by impacting the atmosphere within a certain time frame.
Simple politeness is unlikely to be enough, however, as Baudouin and her colleagues note in their explanation of the problem. “Even if an operator does not abide by the regulations, there is a possibility of producing new space debris,” they write. The most egregious example of this contempt for all regulations came from China in 2007, when it used a medium-range rocket to launch a defunct weather satellite. About 40,000 additional bits of junk are now in orbit as a consequence.
What is the rate of failure?
So far, only the satellite failure rate has been specified in terms of the mega-constellation standards. For instance, the U.S. Federal Communications Commission (FCC) mandates that operators provide reports on the number of satellite failures, near flybys, and evasive maneuvers that have occurred every six months. A supplemental report is also necessary if there are more than three or four satellite failures in a calendar year.
However, there is conflicting information on how high the Starlink satellite failure rate is. For instance, SpaceX now estimates it at a maximum of 1.45 percent, yet five percent of the constellation’s first generation is already damaged. The FCC is reportedly already debating stronger requirements, with a limiting of the failure risk to a maximum of 0.1 percent being under consideration, in light of the heightened danger of collision caused by failed mini-satellites. However, it is still unclear what this implies for the satellites that are already in orbit.
Light pollution and large constellations
Streaks of light from 19 Starlink satellites captured by the four-meter telescope at the Cerro Tololo Inter-American Observatory.
Astronomy may see dramatic changes in the future if thousands of mini-satellites are in low Earth orbit. This is due to the fact that, in telescopic photos, the satellite reflections look like unsettlingly brilliant points of light. Additionally, the night is already becoming noticeably brighter due to flare or stray light from artificial Earth satellites.
Luminous spots in the sky
As chains of dazzling points of light, the first 60 Starlink satellites from SpaceX that were launched in May 2019 immediately generated a sensation around the globe. Due to their low height, sunlight reflected off of their flat, glossy metal surfaces was easily seen. When the Earth’s surface is already completely black but the satellites are still being lighted by the sun, the brilliant reflections mostly happen soon before dawn and immediately after sunset.
Astronomers were concerned about the following: It’s anticipated that there will be tens of thousands of these satellites in the next few years. This increases the risk of possible negative effects on astronomy conducted both on Earth and in space. The American Astronomical Society (AAS) issued a warning on this.
Under bad circumstances, even the reflections of regular satellites may obstruct or even make telescope photos useless, and the danger rises proportionately for constellations.
Up to 40 percent unusable recordings
Olivier Hainaut and his colleagues at the European Southern Observatory explain that a strong satellite reflection “might overwhelm the detector and destroy the whole picture with a big, powerful telescope” (ESO). The researchers predict that reflections from satellite constellations might make 30 to 40% of the wide-angle photographs obtained in the first and final hours of the night from such a telescope useless.
The failure rate, however, is estimated to be less than 1% for telescopes with limited fields of view or for spectroscopic studies in the visible and near-infrared. However, they consider it essential that satellite operators, astronomers, and governmental organizations reach a consensus on how to reduce the possibility of unintended consequences in astronomy.
Avoiding glossy surfaces on satellites is one precaution that may be taken, as SpaceX is now experimenting with a number of its Starlink satellites. According to astronomers, the positioning and direction of the satellites should be managed to reduce light flashes that are directed at Earth, such as those produced by solar sails.
More orbital flare
Around 90 minutes before dawn, the night sky above the European Southern Observatory’s (ESO) Very Large Telescope in Chile. Future constellation satellites that might be observable as interfering objects in astronomical observations are indicated by the green dots. ESO/ Y. Beletsky, L. Calçada
This is crucial because, as recently discovered by Miroslav Kocifaj of Comenius University in Bratislava and his colleagues, satellite constellations may affect nighttime light pollution and astronomical imagery in ways other than the direct interference effects of bright light spots. They used a model to determine how much diffuse dispersed light is already produced by reflections from the tens of thousands of bigger space debris objects in orbit and the almost 3,400 operational satellites.
As a consequence, the night is illuminated by the orbital debris and active satellites alone to the tune of 16 to 20 microcandela per square meter. The researchers explain that this amount of light is above the critical threshold that the International Astronomical Union has designated as an acceptable upper limit for light pollution at astronomical sites. This amount of light corresponds to about 10% of the natural brightness of the night.
In other words, even at far locations, orbital flare already brightens the night. This might become worse if tens of thousands more satellites and their solar sails are deployed later.
It’s been decades since humans last visited the Moon, but that could change soon. That’s because several space organizations have recently announced plans to send humans to the Moon, and unlike previous trips, they want to really settle there. The plan is to set up bases on the Moon’s surface and in orbit around it. However, what may these lunar outposts really resemble? Where will they acquire the supplies they need?
Apollo 11‘s first lunar landing was 50 years ago, marking a major milestone in human spaceflight. The next logical step would be to begin lunar colonization. Due to the fact that the Moon still contains valuable resources like helium-3 and rare metals, it also serves as a crucial staging area for missions to Mars and beyond.
Thus, there has been a resurgence in the Moon Race. This time around, material economic and geopolitical objectives are at the forefront, rather than political considerations. Major space powers and private enterprises are developing ideas and technology for future lunar orbits and surface stations.
The long-fictionalized “Moon Base Alpha” is therefore taking on more concrete shape, and may become a reality within the next 20 to 30 years.
Why do we want to go back to the Moon?
Eugene Cernan, Apollo 17 astronaut, with lunar rover – he and Harrison Schmitt were the last men on the Moon in 1972.
New beginnings on the Moon
Humans have only ever stepped foot on the Moon, yet it is the first and only extraterrestrial celestial body we have ever explored. When Apollo 11 landed on the Moon for the first time in July 1969, people all across the globe applauded in response. At the time, many people thought that we would soon have outposts on the Moon and possibly colonies on Mars.
The Moon takes a back seat
But the excitement didn’t last long, and in 1972 the United States government abruptly scrapped the Apollo program once again, after only six landings and a total of twelve astronauts. All three remaining missions were scrapped. After the United States and the Soviet Union won the historic and politically significant race to the Moon, many American leaders, including President Richard Nixon, decided that further space exploration was no longer a priority.
The Moon and its exploration have been put on the back burner since then. Few orbiter probes remain in Earth’s satellite orbit, but the information they provide from afar is invaluable. However, landings have not occurred for decades, not even with unmanned probes. That all changed in 2013 when the Chinese spacecraft Chang’e 3 and the lunar rover Hutu touched down on the Moon for the first time in four decades. The first two unmanned missions to the far side of the Moon—Chang’e 4 and Hutu 2—landed in January 2019. Even still, no one has set foot on the Moon since 1972.
Alluring raw materials
However, in the meanwhile, there is activity once again in terms of lunar missions, as many space agencies and commercial organizations have revealed plans to send people to the Moon in the near future. However, the current objective is a lengthier, and probably even permanent, human presence aboard Earth’s satellite, in contrast to the flying visits of the Apollo missions.
Another deviation from the Apollo period is that the stakes are now material, economic, and technological benefits rather than a race of political systems. One reason to go to the Moon is all the precious metals and minerals it contains, including iridium. Due mostly to meteorite impacts, they have collected in the lunar regolith. Desire may also be sparked by helium-3, an exceptionally uncommon isotope of the noble gas helium. We’ll need it for things like coolants, measuring devices, and potential fusion reactor coolants, and the Moon has just what we need. Several corporations have declared their future plans for “Moon mining.”
The significance of Moon
In addition, the Moon’s strategic value lies in the fact that it might be used as a launching pad for human trips to Mars and beyond due to the much reduced rocket fuel needs afforded by the Moon’s low gravity. Telescopes and other observatories might potentially help boost space exploration efforts from the Moon. This is because, in particular, the far side of the Moon provides complete protection from any terrestrial disturbance.
Finally, the potential for profit from well-heeled space travelers is exciting. Elon Musk, the creator of SpaceX, revealed his company’s first lunar tourist in 2018: Japanese tycoon Yusaku Maezawa, who paid millions of dollars for passage for himself and a large group of friends on SpaceX’s first voyage to the Moon in 2017. In 2023, we want to achieve lunar orbit.
Thus, the Moon is now again a very appealing vacation spot.
Moon Village and Lunar Gateway
The European Space Agency (ESA) is preparing to build a full-scale lunar village that will serve as a research and business hub. Image: ESA
New Moon missions are in the works
When will the world learn the truth about the space countries’ bold new Moon programs? It seemed to be getting serious after 10 years of lofty intentions that never materialized. The United States, the European Union, China, and Russia are all planning missions over the next several years to be ready for the eventual return of humans to the Moon and the eventual establishment of a lunar outpost.
Everyone living in their own “Moon Village”
Jan Wörner, the head of the European Space Agency, proposed the idea of a Moon Village in 2016. This would be a multi-national outpost on Earth’s satellite, available for any and all uses. Her goal is to set up shop on the Moon permanently. Science and fundamental research, economic operations like raw material extraction, and even tourism might all be conducted by participants at this permanent lunar outpost.
Robots and autonomous rovers might launch the first phases of construction for this lunar outpost, with human astronauts joining in later. One major benefit of this plan is that it may be launched with very few resources. A number of nations are currently making preparations to send modest land missions, so that’s where we can begin. Afterwards, bigger initiatives might be built upon that foundation and include worldwide collaboration. As such, the lunar town has the potential to serve as the ISS’s successor, although one that is located on the Moon rather than in Earth’s orbit.
America: We’re here to stay this time
In December 2017, the United States issued a directive making a trip back to the Moon and subsequent trips to Mars a top priority for the American space program. Rather than just leaving our mark this time, we want to lay the groundwork for future exploration of Mars and beyond.
We are taking cutting-edge technology and systems to the Moon in order to study previously inaccessible regions, said NASA Administrator Jim Bridenstine. We want to settle on the Moon this time, unlike Apollo. Our next giant step into space will be taken after that.
Lunar Gateway
In the 2020s, NASA hopes to realize its goal of constructing a lunar “gateway,” or space station in lunar orbit. Because of this gateway, we will be able to establish a strong foothold in cislunar space and more effectively investigate the Moon and its potential benefits. From there, we want to launch manned missions to the lunar surface.
In the same way that the ISS was built in increments, this next orbiting outpost will also be composed of modular components. The parts will be sent into orbit by NASA’s Space Launch System (SLS) and carried there aboard the Orion spacecraft. The core propulsion and supply portion of the station might be placed in lunar orbit really soon. In 2024, astronauts will have access to the first module that doubles as a home and lab. Once that happens, personnel may stay at the station for 30 or 60 days at a time to do their jobs.
Assisted landing by a private party
NASA is hoping to recruit commercial enterprises to help with the trip from the ISS to the Moon’s surface. Six businesses are competing in a tender announced at the end of 2018 under the NextSTEP initiative. The objective is to design a method that can transport, land, and return to the space station from the lunar surface.
In terms of requirements for future landing modules, durability and reusability are high on the list. In contrast to the Apollo lander modules, whose whole underpinnings were left on the Moon and are still there today, future landers will be entirely reusable. After that, they’ll be refueled either on the ground or in space. According to NASA Administrator Jim Bridenstine, we aim to return humans to the lunar surface within the next decade, but this time we want to do it sustainably.
How would a Moon base look like?
The European Space Agency’s (ESA) vision for a Moon base.
Lunar selters made of lava rock and regolith igloos
Those who choose to settle on the Moon in the future will be met with a harsh and perhaps lethal environment. As a matter of fact, the Moon is not exactly a warm and fuzzy location to spend some time. There is no magnetic field, no atmosphere to shield you from the elements, and no oxygen. Those who choose to remain on Earth’s surface are unprotected from the Sun’s radiation, the solar wind, and the meteorite showers. Simultaneously, there are dramatic shifts in temperature: If the Sun is out, everything will get to be around 120 degrees. Temperatures, on the other hand, dip to a chilly minus 170 degrees in the shadow and on starry evenings.
Therefore, the primary function of a lunar base is to offer shelter from these dangerous conditions. I mean, how? Obviously, an inflatable dome like the one seen in “The Martian,” a science fiction novel and film, would not be sufficient for a lunar outpost. A shield from radiation or meteors could not be created with this. Astronauts need sturdy walls in their lunar habitat if they are going to be able to stay there for an extended period of time.
Living and working in lunar lava caves
Lava caverns, which are found naturally on the Moon, might be used as a safe haven. Underground craters and tubes were formed by the Moon’s early volcanic activity. In 2017, scientists found a massive lava tunnel in the lunar Ocean of Storms (Oceanus Procellarum). It stretches for 31 miles (50 km) and is up to 3300 feet in height and width, providing enough room for an entire lunar metropolis. A hole with a diameter of around 165 feet (50 m) provides access to the surface.
Lava caverns near the Moon’s polar area, though, might be an even better fit. This is due to the presence of water ice, which may be used to provide both potable water and fuel for the astronauts. Philolaus crater, an impact crater of 44 miles (70 km) in size at 72 degrees north latitude, has been mapped and explored by scientists, and many spots inside it have been identified as promising candidates. Multiple shadowy crevices on the crater floor suggest the presence of lava caverns.
Moon bricks from the solar oven
We may also use Moon dust to construct the requisite defensive fortifications. DLR (German Aerospace Center) scientists in Cologne are already hard at work on a plan to fire regolith into a Moon block. They are focusing sunlight into a powerful beam using curved mirrors. The thin layer of volcanic grains used as a regolith mimic is heated to temperatures of over 1,000 degrees using this method.
Extreme heat causes the material to sinter, which means the granules adhere together and create a solid layer. Layer by layer, like a 3D printer, solid components may be created from regolith. Already, with today’s technology, we have access to a substance approximately as stable as gypsum. However, with more improvement, lunar regolith might be made into a construction material with the strength of concrete.
However, even with their solar 3D printer, it still takes the team around five hours to manufacture a single regolith building block. It would take around 10,000 of these bricks to create a protective shell around a lunar igloo. Months would pass before it could be accomplished. However, if many sintering plants were to be run in parallel on the lunar surface, the process may be sped up.
3D printing with regolith sludge
Together with the British firm Monolite, ESA researchers are researching an alternative method. First, a slurry is made by combining the regolith mimic with a magnesium oxide solution. This allows the document to be printed out. The business uses a binding salt to turn the substance into a stone-like solid, turning it from a liquid into “ink” for solid creations.
With this technique, the team can print and complete 6.5 feet (2 m) of material in an hour. If the next-generation design can achieve 11.5 feet (3.50 m) per hour, a whole skyscraper might be constructed in one week. Regolith material is used to make each block, which results in each one weighing 1.5 metric tons and featuring many holes throughout. It has not yet been determined, however, whether the building method would hold up in the lunar vacuum and dramatic temperature swings.
Catenary arch igloo design
A plan for the next ESA lunar outpost already exists, even though the building material has not been agreed upon. British superstar architect Norman Foster and his team designed it. The mathematical-physical theory of the catenary arch was adhered to in order to make the lunar dwellings as stable as possible. Arches are very stable because their shape, a parabola, takes the route of least energy.
In this way, the homes on the Moon seem more like igloos than like regular residences. They too are a hybrid of tube and dome shapes. The inflated inner shell serves as the structural base for these Moon igloos. This is the outline, which the robots are currently covering with regolith bricks from the outside. Each habitation module on the Moon will have enough room for four people and shield them from cosmic rays, meteorites, and temperature swings.
Water and oxygen
Both the Moon’s South Pole (left) and North Pole (right) have ice deposits (turquoise) in craters. Credit: NASA
Raw material sources: crater ice and regolith
Assuming the lunar base is complete and ready for its first residents. Then, at the very least, there’s the issue of getting fuel, water, oxygen, and food to the astronauts. It would be impractical and prohibitively costly to transport all of these materials from the Earth. Therefore, it is evident that a lunar colony, in order to exist, must make use of on-site resources.
Ice from the lunar craters
The most straightforward answer concerns the provision of water: if future lunar outposts are constructed in the polar regions of Earth’s satellite, sufficient water ice will be found there. In 2010, data from India’s Chandrayaan-1 lunar spacecraft indicated that there are ice layers a 3.2 ft (1 m) deep in the craters near the lunar north pole. Present evidence suggests there may be roughly 10 billion metric tons of water at each pole.
However, the exact amount and composition of the ice found in the lunar dust have not been determined. To this end, the possibility of obtaining potable water from ice remains open. In the next several years, this will be answered by a number of robotic lunar missions. To be fair, the needs of a lunar outpost wouldn’t be very high at first: NASA suggests that a crew of four may get by on just a few dozens of metric tons of water each year.
Water from the crater ice might be collected using solar energy. Using parabolic reflectors, the radiation may be focused and directed to evaporate the ice only in the parts that were shielded by the foil. In the event that this water vapor is dispersed and cooled once again, it condenses into potable water. Alternatively, robotic excavators may harvest ice, which could subsequently be melted or evaporated in stationary solar furnaces.
Regolith as a raw material supplier
Water could be retrieved from the regolith on the Moon even if there were no ice formations. This is because, as was recently discovered by spectrometer data from the Lunar Reconnaissance Orbiter, water is bonded to the rock as hydroxyl (OH) practically everywhere on the lunar surface. This trapped water is also located away from the lunar poles, making it a more accommodating site for a lunar outpost than the polar craters.
NASA’s Goddard Space Flight Center scientist William Farrell says that after being blasted by the solar wind, every rock on the Moon has the potential to generate water. According to the findings of his group, this bound water is produced by a chemical process in the regolith. Oxygen-containing minerals in lunar rock have their connections broken by the solar wind’s intense energy. Since reactive oxygen radicals are created, they may “grab” hydrogen from their surroundings to form hydroxyl.
Oxygen and water from the lunar soil
How, therefore, might this potentially hydrous rock be mined for potable water? Again, researchers showed that solar heat was crucial on a mock journey to Hawaii. At temperatures of around 900 degrees Fahrenheit, the regolith-like volcanic dust began to shine. Furthermore, passing hydrogen or methane across it causes it to react with the oxygen in the regolith to produce water. NASA estimates that 119 grams of water may be recovered from one kilogram of the most abundant lunar mineral, ilmenite (FeTiO3).
As a useful byproduct, the astronauts’ breathing air’s oxygen may be extracted from the regolith using this method. When water vapor is produced during heating, it must be separated back into its original hydrogen and oxygen components. One kilogram of ilmenite could provide enough oxygen for 106 grams of breathing space, at least in principle. However, studies are currently being conducted to ascertain which approach is most appropriate and how oxygen and water may be created using the fewest resources and the least amount of energy.
Electricity and fuel
The Moon’s 14 days long nights might hamper solar power generation. Credit: NASA’s Scientific Visualization Studio.
Generating power on the Moon
A lunar outpost needs its own power plant if its inhabitants are to survive. Electricity is essential for astronauts because it powers their heaters, lights, and other electronic gear. They should be able to use local resources to produce fuel for the landing shuttles and lunar vehicles.
Electricity from the Sun
Sunlight is a simple and effective way to get energy. Photovoltaic systems have a long history of usage in space exploration, and the Moon is a suitable location for them. The catch is, however: Since one lunar day is equivalent to 29 Earth days, the Moon is always in the dark for two weeks when the Sun isn’t available to provide energy. Aside from that, the Earth sometimes shuts out the Sun for a few hours during solar eclipses, which happen several times a year.
Scientists, however, have come up with answers for this as well: Aidan Cowley of the European Space Agency says that throughout the day, there is sufficient solar energy to split water into its component parts of hydrogen and oxygen. We could convert these gases back into water and use them to generate energy when the Moon was asleep. In theory, this might work by having fuel cells soak up sunlight throughout the day and then churn out power after the Sun goes down.
In a perfect world, hydrogen, oxygen, and the resultant water would all be recycled indefinitely inside this system, forming a closed cycle. The only other component needed is sunshine. According to David Bents of the Glenn Research Center, who studied these regenerative fuel cells for NASA a few years ago, if nothing breaks or wears out, this may operate indefinitely without having to be recharged.
Moon as a gas station
Among the many resources needed for space flight, fuel is one of the heaviest and most vital. As of now, it constitutes the vast majority of the total launch mass of a rocket, and thus, a significant proportion of the associated launch expenses. A lunar outpost would have to generate its own fuel to be cost-effective.
In addition, a lunar outpost is seen as crucial by space organizations as preparation for Mars and beyond. For this reason, NASA’s lunar orbiting station Lunar Gateway will, in the long run, serve as a refueling station for space trips. After all, space probes won’t have to struggle against Earth’s gravity to lift their entire fuel load into space if they only do it in lunar orbit. Concepts for such “refueling stations” in lunar orbit are already being developed by a number of academic organizations and businesses.
Even if these filling stations are built, the issue of where to get gasoline for them remains. Once again, the regolith of the Moon is being seen as the best option. It contains the ingredients for a standard rocket fuel, hydrogen, and oxygen, and can be extracted using the Sun’s heat. The upper burn stage of the Saturn V, the Atlas 5, and the engines of the space shuttles have all employed liquid oxygen and hydrogen. However, this fuel combination is also used by cutting-edge rockets like the European Ariane 5 rocket.
What is the source of the food on the Moon?
A Mars greenhouse is seen in this artist concept. Using a hydroponic method, plants are being grown with the aid of red, blue, and green LED light strips. Image credit: SAIC
Plants grown in the Moon
That remains the issue of sustenance for the lunar colonists of the future. For a long time, astronauts (including those living on the ISS) have needed to rely on supplies sent all the way from Earth. But the logistics and prices of a lunar colony would not allow for something that is currently difficult and costly in Earth orbit. Because of this, it is essential that the lunar station’s personnel generate as much as possible inside the facility itself.
Vegetables cultivated on lunar soil
Vegetables and fruits, at least, could make this simpler than previously believed. Plants were successfully grown by Dutch researchers in 2016 using lunar and Martian soil replicas. The difficulty is that the regolith has almost no nutrition since it lacks organic components due to the absence of life on the Moon. However, the astronauts’ own waste products, like urine or leftover food, might make up for the lack of these organic ingredients.
To secure the success of their culture experiment, Wieger Wamelink and his colleagues sent in soil microorganisms from Earth to further enrich their synthetic lunar regolith with such organic material. They then planted a variety of vegetables and grains including tomatoes, peas, rye, radishes, leeks, spinach, lettuce, cress, quinoa, and chives. The end result was that plant life flourished in the artificial lunar soil. About half as much biomass was created as on Earth, but there was still plenty to harvest.
Orbit and Antarctica are being used for test crops
On the International Space Station, astronauts are attempting a new approach. Since 2015, the station has included a miniature greenhouse. Plants are nourished by a nutrient solution and grown in a calcareous mineral mass. Bright red, blue, and green LEDs light up the entire object. The ISS crew has already gotten their hands on fresh lettuce thanks to this “veggie” technology. A completely autonomous automated plant-growing system is the next step. More than 180 sensors monitor the soil, air, and water supplies separately and adjust the flow as needed.
Plant growth on the Moon is being tested again in the Antarctic. The EDEN-ISS greenhouse container has been stationed in the Antarctic since the beginning of 2018, around 1300 feet (400 m) from the German Neumayer III research station. Plants like lettuce, radishes, and cucumbers thrive here because the system is comparable to the one used on the space station. Scientists working in the Arctic have already harvested their first crop, which they have consumed with great gusto.
Gioia Massa, a NASA researcher, notes that the farther and longer people go from Earth, the more important it is to be able to produce plants for food, for processing the atmosphere, and for psychology. So, plant life is crucial to any future extended space missions.
It’s a matter of compromises
The people of the future lunar outpost, however, will need more than just lettuce and cucumbers to sustain themselves. Unfortunately, supplies of food will still need to be sent in from Earth. Therefore, a trip back to the Moon and the construction of a lunar station will not be a cheap luxury. What ultimately matters is whether or not the benefits and insights acquired are worth these expenses.
Tonight, the DART spacecraft from NASA ended its mission and successfully hit an asteroid. The 540-foot (165-meter) wide asteroid moon Dimorphos was the intended target of the DART probe’s autonomous navigation system. The force of the collision should have been enough to decrease the fragment’s orbital period around Didymos by around 1 percent. As of this moment, only telescope observations can confirm or deny this theory.
This is only a practice run before the big thing: If an asteroid ever threatened Earth, the most promising solution would be a kinetic deflector, which would involve deflecting the asteroid with a massive unmanned space probe. However, it has to strike its target early enough, fast enough, and at the appropriate angle for its impact pulse to send the asteroid far enough out of its orbit for it to miss Earth.
DART’s approach and successful impact
The DART probe collides with the asteroid moon Dimorphos, altering its course.
NASA’s DART mission has now demonstrated that this is possible, even when the asteroid in question is 6.8 million miles (11 million kilometers) from Earth and cannot be seen with ground telescopes. DART arrived Friday night at the 2560-foot (780-meter) asteroid Didymos and its 540-foot (165-meter) moon Dimorphos after a ten-month journey. When the spacecraft was 56,000 miles (90,000 kilometers) from its target, the photos taken by DART’s onboard camera were analyzed by the probe’s autonomous navigation system, which distinguished the two asteroids from each other and headed for the actual target, Dimorphos.
Just after midnight, the moment had come: The DART spacecraft sped at an estimated 14,000 miles (22,500 kilometers) per hour toward its target asteroid and slammed into it. The navigation camera captured the last moments before the DART crashed into Dimorphos, revealing a close-up picture of the asteroid’s surface littered with gritty rubble. NASA scientists now know that they can successfully bring a spacecraft to collide with a rather minor celestial body with precision.
Dimorphos was deflected by how much?
The final photo of the Dimorphos asteroid from the DART camera before the probe collided with the asteroid. (Image: NASA/Johns Hopkins APL)
Even though the DART spacecraft is only around 1,260 pounds (570 kilograms) in weight and the asteroid Dimorphos weighs roughly five billion kilograms, the velocity of the collision and the rebound of the ejected rock should be enough to nudge the asteroid slightly off of its orbit. An asteroid’s course can be drastically altered with even a little increase or decrease in its speed.
Telescopic studies over the next several weeks will indicate whether or not the collision of DART altered the course of the asteroid Dimorphos. The orbital period of Dimorphos can be tracked from Earth by observing the pair’s brightness as Dimorphos passes in front of its bigger parent asteroid. Based on the simulations, the collision between Dimorphos and DART should have shortened its orbit by 1%, which would have shortened its orbital period by 10 minutes.
Compact chunk or porous pile of rubble
The degree to which the rammed asteroid’s trajectory was altered is an important indicator of both the efficacy of kinetic deflection and the composition of the target asteroid. But, the stability and compactness of the target object have a significant impact on the outcome of a deflection operation. Too much porosity allows impact energy to evaporate without an influence, rendering the deflection useless, which would be critical in a crisis situation.
The LICIACube mini-satellite will provide valuable data about the DART-Dimorphos collision. LICIACube is part of the DART mission and positioned itself 15 days before the impact to photograph the crash and its immediate aftermath. This is because the asteroid’s interior may be revealed by factors like the crater’s size and composition and the kind of material that was ejected. However, it will take many weeks to receive all of the photographs due to the tiny CubeSat’s (LICIACube) restricted communication capabilities.
The European space probe HERA will revisit the asteroids in four years to investigate them further.
Validation for the actual test
The critical part of the DART mission has been accomplished with the successful “ramming test” of the asteroid Dimorphos. According to NASA’s first-ever Planetary Defense Officer Lindley Johnson, “DART’s success provides a significant addition to the essential toolbox we must have to protect Earth from a devastating impact by an asteroid.” DART has demonstrated that “we are no longer powerless to prevent this type of natural disaster.”
What is the DART mission? Here is everything there is to know about it. Thousands upon thousands of asteroids speed through space with many of them routinely passing within Earth’s orbit. A regional or perhaps worldwide disaster could be triggered if one of them were to arrive on a collision track with Earth. With its DART mission, NASA is exploring whether or not this may be avoided; for the first time, humankind will seek to alter an asteroid’s course by use of a ram probe.
What could be done if an asteroid is headed in the direction of Earth? According to NASA, a more effective defense would be to use an unmanned spacecraft to deflect the asteroid. On September 26, 2022, NASA’s DART mission will put this kinetic deflector approach to the test.
How do you avoid an asteroid collision?
The risk is real: Earth has been bombarded by space debris several times during its existence. The impact of the 6.2-mile (10-kilometer) wide Chicxulub asteroid 66 million years ago terminated the Cretaceous epoch and wiped out the dinosaurs, while other impacts have created worldwide disasters and monumental mass extinctions. The Tunguska event of 1908 and the Chelyabinsk meteor explosion in February 2013 proved, however, that even tiny fragments may wreak devastating harm.
About 25,000 asteroids, each about 500 feet (150 meters) in size, orbit in the neighborhood of the Earth and often pass through the Earth’s orbit. Although many incidents still go unreported.
It’s just a matter of time
Small chunks up to 3.3 feet (1 meter) in size continue to impact Earth practically daily but are burned up in the atmosphere before reaching the surface. Asteroids up to 1,000 feet (300 meters) in size are expected to strike every few thousand years, and asteroids the size of the Chelyabinsk meteor are seen on average once every 50 years. They are big enough to obliterate a whole city of millions. It’s not a matter of if, but rather when, the next major impact on Earth will occur.
What could be done if an oncoming asteroid is noticed in time? Whether humanity still has time to adopt countermeasures for an approaching asteroid depends on the size of the asteroid and the time left before the impact. When the threat is known decades in advance, the “gentle” “Gravity Tractor” defense could be all that’s needed: Using the gravitational pull of a large probe brought in close proximity to the asteroid, you can divert the asteroid off an Earth collision trajectory.
The kinetic deflector
A spacecraft smashes the asteroid and attempts to divert it off its crash route in an asteroid defense via a kinetic deflector. (Image: INASA/Johns Hopkins University APL)
But in reality, it is more probable that the asteroid will go undetected until it is too late. Because many possible Earth-orbiting asteroids are hard to spot in advance due to their dimness and their orbital distance to the Sun. The 330-foot (100-meter) asteroid called “2019 OK,” for example, was only discovered 12 hours before its closest approach in 2019. Thankfully, it was passing Earth at a distance of barely one-fifth that of the moon. After that point, no amount of protective measures will be able to prevent an impact.
However, there is still hope for an asteroid deflection if an asteroid on a crash track is discovered months or perhaps years in advance. The kinetic deflector approach is generally thought to be the best in such a scenario. As part of the strategy, the heaviest feasible spacecraft is sent in the direction of the asteroid to smash it at a specific angle. If the collision happens early enough, the force of the impact can deviate the fragment off its trajectory, and a deviation of only a few millimeters or a modest slowing is enough to prevent a collision with Earth.
But there is more to it
However, such a deflection is notoriously difficult in reality. The asteroid probe has to make a perfectly timed and hard collision with the asteroid. Too much of an off-angle impact will just alter the asteroid’s spin and not its course. The deflecting impact will be insufficient if the momentum is too low. This method requires the most precise data available regarding the asteroid’s course, spin, and size in order to precisely plan the collision.
If the asteroid is porous, most of the impactor’s energy might be absorbed instead of dissipated. The spacecraft’s collision might cause the asteroid to fracture if it is fragile or made of debris that is only weakly held together. Multiple, potentially catastrophic chunks can still head toward Earth in this case.
Given these challenges, NASA is conducting its first practical tests of kinetic deflection, called the DART Project, as a means of asteroid deflection, serving as a kind of “dress rehearsal” for the real deal.
Target object of the DART
A double asteroid as the impactor
Dimorphos’ new orbit after the collision of the DART satellite. The LICIACube will track the collision and broadcast pictures of the impact back to Earth. (Image: NASA/DART)
This is no easy feat since the whole collision must take place millions of miles from Earth to redirect an asteroid off its crash course with Earth. However, if the asteroid is so far away, the scientists may not be able to determine its exact nature, rotation, or mass before sending out the defensive probe since it will be beyond the precision of current Earth-based telescopes.
The selection of the test asteroid for DART
With the “Double Asteroid Redirection Test,” or DART, NASA is exploring the limits of an asteroid defense mission’s success and the hazards it faces. If an asteroid were to be headed toward Earth, a kinetic deflector, like the one shown by DART, would be the only way to stop it. DART’s mission is to change an asteroid’s orbit, so it can not collide with Earth.
The primary stipulation for the DART is that the experiment must not endanger Earth in any way. Even after an unsuccessful deflection, the target asteroid must follow a course that moves it as far away from Earth as feasible. However, in order to accurately assess the ramming’s effects, the candidate asteroid must be rather near. Thus, it has to be visible with large telescopes.
Didymos and its moon Dimorphos
Size comparisons of DART, Dimorphos, and Didymos. (Image: NASA/Johns Hopkins University APL)
The 1996-discovered twin asteroid Didymos satisfies these requirements for the DART mission. Didymos, the 2560-foot (780-meter) asteroid, and Dimorphos, its moon, measure around 525 feet (160 meters) in diameter. Because of their eccentric orbits, they both swing from the furthest distance from the Sun outside of Mars’ orbit to the closest distance to the Sun within Earth’s orbit. Accordingly, both are circling the Earth and are part of the class of asteroids that, although not immediately dangerous, may one day approach Earth.
This is also why the DART mission isn’t actually aimed at the asteroid Didymos itself. Because there’s too much of a chance that the asteroid may be redirected in such a manner that it would eventually crash on Earth. The moon of the asteroid Dimorphos (Greek for “two forms”) is the actual target of the DART. Due to the stability of its orbit around Didymos, any deviation will only alter the minor-planet moon’s path relative to Didymos.
Observing Dimorphos with transits
When Dimorphos passes in front of his parent asteroid Didymos, the change in brightness allows scientists to calculate its orbital period. (Image: NASA/Johns Hopkins University APL)
While in orbit around Didymos, the asteroid moon also travels directly in front of it. Due to this predictable transit, astronomers have been able to estimate Dimorphos’ orbit and size using just Earth-based telescopes. This tiny moon takes 11 hours and 55 minutes to complete one orbit around its parent asteroid. During this time, the distance between them stays at just approximately 0.73 miles (1.18 kilometers).
The DART mission’s before-and-after planning requires a high level of foreknowledge about the asteroid system. Dimorphos’ orbit around its parent asteroid may be significantly altered if the DART probe collides with the moon at just the proper location and velocity. This deflection, at least in the model predictions, is expected to become apparent during the transit phase. As a result of the impact made by DART on the smaller asteroid in the Didymos system, its orbital period will be altered by at least 73 seconds.
The Didymos-Dimorphos binary asteroids will be within observing distance of Earth at the time of the DART’s collision on September 26, 2022, at a distance of just around 6.85 million miles (11 million kilometers).
Almost indistinguishable from the actual threat
However, there is a second reason why the Didymos system is well suited as a test case for the DART: its two components are illustrative of prospective asteroid impactors on Earth’s course. Dimorphos, with a diameter of around 540 feet (165 meters), is huge enough to cause widespread destruction in the case of an impact on Earth. While its size is comparable to that of probable next-catastrophic-impact asteroids, it is not one of them.
The composition of the target asteroid of the DART mission is also quite similar to that of the asteroids that are flying close to Earth. Didymos’s composition matches that of an “L/LL chondrite” meteorite class according to the analysis of its visible and near-infrared spectra. And this is the composition of most meteorites that strike Earth. The experimental findings of the DART collision will be used for a wide variety of planetary defense research.
Order of events of the DART mission
Specifications of the DART spacecraft
The DART probe places itself at the ideal impact point by autonomously navigating its course. (Image: NASA/Johns Hopkins University APL)
The DART spacecraft has been traveling toward the asteroid Dimorphos since it was launched on November 24, 2021. The asteroid moon Dimorphos will be rammed by the spacecraft on September 26, 2022, at 23:14 UTC, in an attempt to knock it out of orbit. This will be the first-ever test of a technology designed to protect Earth from asteroids. The DART mission is outfitted with various high-tech enhancements that allow this to happen.
The impactor probe used in the DART mission seems plain at first glance: The dimensions of its hull are 3.9 by 4.3 feet (1.2 by 1.3 meters), making it about the size of a soda machine. During the roughly 10-month approach, the DART probe has been powered by two solar panels, each of which is a good 26 feet (8 meters) in length. An experimental ion drive generates thrust by electrostatically accelerating and ejecting xenon ions in a magnetic field. DART has 12 hydrazine-fueled classical maneuvering thrusters for course corrections and fine-tuning of the final approach to Dimorphos.
DART’s autonomous target acquisition and approach
The DART spacecraft from two perspectives. (NASA)
The DART probe has a navigation system that is considerably sophisticated. This is due to DART’s ability to fine-tune its trajectory on its own. The data from the DRACO camera, a tiny telescope with a focal length of around 8.3 inches (21 cm), and a high-resolution digital image sensor are placed on DART for this purpose. High-resolution photos captured by the camera will reveal the precise location and shape of Didymos and Dimorphos.
The spacecraft’s autonomous navigation system records these photos with location and attitude data. About 4 hours before the crash with Dimorphos, at a distance of 56,000 miles (90,000 kilometers) from the target, this SMART Nav system will assume complete control of the DART probe. The navigation system will initially perform an evaluation of the data in order to pinpoint the precise locations of Didymos and its moon Dimorphos using custom algorithms. An hour before impact, Dimorphos will appear as a small 1.5-pixel light point.
The navigation system will then be able to make autonomous decisions about whether or not trajectory modifications are required, and the DART probe’s correction jets will receive new commands. When there are only 930 miles (1,500 kilometers) left between Dimorphos and DART, the asteroid in DRACO images will be around 22 pixels in size and it will be too late for DART to make any changes at this point. When DART is around 460 miles (740 kilometers) away from the target, it will be on a collision track with Dimorphos in two minutes. The probe will now just cover the rest of the distance.
The impact
The DART probe will crash on the surface of Dimorphos at a speed of around 14,000 miles (22,000 kilometers) per hour. DART weighs only 1,260 pounds (570 kilos), whereas the asteroid moon Dimorphos is predicted to weigh over 11 billion pounds (5 billion kilograms). Therefore their collision is more like a bug landing on an elephant. The impact’s relatively small impulse might not seem like it would accomplish anything.
This, however, is not true. The 540 feet (165-meter) rock will receive a little push from the high velocity of the DART collision. In addition to blasting between ten thousand and a hundred thousand pounds of debris into space, the impact will also create a hole in the asteroid’s surface. The force exerted on Dimorphos will be greater than that of the hit alone because of the rebound of this ejection. The combination of this amplified ramming action and the collision is enough to cause a little shift in the asteroid moon’s kinetic energy and knock it off of its orbit.
After DART crashed onto Dimorphos, the spacecraft will be destroyed but the scientific investigation will only be getting started.
Consequences of the DART Impact Event
What will happen to the massive Dimorphos-moon once the tiny DART spacecraft crashes into it? Will the massive asteroid be able to be steered out of orbit by kinetic deflection? How did scientists successfully predict the collision characteristics of the DART-Dimorphos event essential for a deflection?
LICIACube as the direct observer
The Italian Space Agency constructed LICIACube for the impact between DART and Dimorphos to send the collision images to Earth. (Image: (NASA/Johns Hopkins APL/Ed Whitman)
The LICIACube mini-satellite will report back the first data on the DART’s impact results and its effects on Dimorphos’s surface. This mini-satellite will ride behind the DART probe before it collides with the Didymos double asteroid, and its mission is to check out the impact area. Self-propelled with its maneuvering thrusters, it’s programmed to move into an observation point 15 days before the collision, which has already been initiated on September 11th.
LICIACube stands for Light Italian CubeSat for Imaging Asteroids. And the observations and documentation from this courageous little reporter will provide insights scientists couldn’t gain any other way. Using two optical cameras, LICIACube will capture the moment the DART spacecraft crashes on the surface of Dimorphos. Three minutes after the impact, LICIACube will adjust its course to fly near the DART’s crash location.
Images of the crater, the ejected material, and the type of debris of the DART impact are to be provided by this mini-probe. These photographs, together with the last close-ups captured by DART’s DRACO camera before the collision, will provide crucial details regarding the Dimorphos’ make-up, nature, and reaction.
A view of the Dimorphos orbit
Around the same time of the collision, a dozen or more very powerful telescopes on Earth will be aiming toward the Didymos system. The pair of asteroids are 6.85 million miles (11 million kilometers) away from Earth and are only a tiny speck of light even with the best telescopes. But we will be able to see from Earth the periodic variations in brightness of this light, which are set off by the transit of the moon Dimorphos in front of its parent asteroid.
A little shift in transit timing would indicate that the DART probe’s collision deflected the asteroid moon. Astronomers may roughly infer the strength of Dimorphos’ kinetic momentum and the extent to which its trajectory shifted in magnitude to find out whether the asteroid was successfully deflected and the DART mission was a success.
The essentials for the “genuine deal”
The events of DART’s mission definitely won’t be the basis for a Hollywood blockbuster, but the future of Earth’s safety is equally at stake. The ultimate goal of the DART mission is to demonstrate that human beings can deflect an approaching asteroid. If a similar-sized rock is ever found on a collision path with Earth, the knowledge and expertise gained from the DART test in the Didymos system will be invaluable.
Where to watch DART’s collision live
On Monday, September 26, at 4:14 p.m. PT / 7:14 p.m. ET, the spacecraft DART will crash with Dimorphos. Live coverage will start on NASA’s YouTube channel, and the NASA TV at 3 p.m. PT / 6 p.m. ET.
You can also see DART’s position live in the official NASA webpage.
Aftermath of DART
HERA, a spacecraft bound towards the Didymos system
This deflection mission won’t be completed right away despite the DART spacecraft’s collision with the asteroid moon Dimorphos and subsequent studies of the immediate repercussions.
HERA, a European spacecraft, will be launched in 2024 toward the Didymos system and arrive in 2026. For the first time, it will use on-site scientific instrumentation to explore the effects of this kinetic deflection. The HERA spacecraft will scan Dimorphos’s surface topography to an accuracy of within 33 feet (10 meters) using its LIDAR measuring system, camera, and mid-infrared scanner in order to examine the impact crater and any other changes to the surface that may have resulted from the collision.
More crucially, HERA will finally provide us with more accurate information on how far the DART probe steered away from its intended target. The rotation, mass, and orbit of Dimorphos and Didymos will be directly measured, unlike with terrestrial observatories. One way HERA will achieve this is by pointing its laser towards the parent asteroid and picking up the minute wobble caused by the small moon’s gravity. Additionally, HERA will do many near flybys of Dimorphos, transmitting data back to Earth each time. Scientists on the ground will be able to determine whether the asteroid moon’s gravity has altered the signals and, if so, by how much.
Milani: What are Didymos and Dimorphos made of?
The asteroids’ surface will be mapped by the CubeSat Milani, which will also examine the expelled dust. (Image: ESA/Science Office)
However, HERA isn’t traveling alone; it’s accompanied by two smaller satellites (CubeSats) that carry their own sets of equipment and will take readings that supplement those taken by HERA. The Milani minisatellite will use a hyperspectral camera and spectrometer to determine the elemental make-up of Dimorphos and Didymos.
This will also enable scientists to compare the composition of its surface to that of known meteorites and minerals, such as that of the DART crater and its ejecta. Milani also has an onboard analyzer calibrated to detect dust particles between 200 and 400 microinches (5 to 10 micrometers) in diameter. Scientists can use it to learn more about Dimorphos’ composition by studying the dust thrown up by the collision.
Juventas: First radar view into the interior of an asteroid
For the first time, radar will be used by the CubeSat Juventas to illuminate an asteroid’s interior. (Image: ESA/Science Office)
HERA’s companion CubeSat, Juventas, will be investigating the asteroids’ composition and dynamics up close. It is equipped with a miniature replica of the radar sensor used by ESA’s Rosetta comet mission to survey 67P/Churyumov–Gerasimenko, making it the smallest radar system ever sent into orbit. The Juventas radar system will carry out the same task at Didymos and Dimorphos. To do this, it will set up 4 radar antennas, each measuring 5 feet (1.5 meters) in length, and radiating radar waves with circular polarization. The incoming and outgoing signals from Dimorphos’ interior will be recorded and decoded simultaneously.
In order to get accurate readings, the tiny radar satellite Juventas will fly within 1.85 miles (3 kilometers) of Dimorphos at a slow enough speed to get high-resolution data despite the radar’s low power. The radar scan of an asteroid by Juventas will be the first of its kind which will greatly expand the understanding of asteroids. The reason for this mission is that the outside of an asteroid does not actually portray its interior accurately.
Determining whether Dimorphos is made of solid, compact rock or a loosely formed “pile of debris” will be crucial for future asteroid defense. This data, together with measurements of the DART deflection experiment will aid scientists in improving and adjusting the models and calculations used to plan such defensive operations to protect Earth from asteroids in the future.
On Saturday, September 10th, the enormous satellite named BlueWalker 3 was launched, and today it was put into orbit. When its antenna is fully extended, BlueWalker 3 has the potential to far outshine the constellations that are visible in the night sky and to become the second brightest object in the sky after the Moon. BlueWalker 3 will be used to test a new kind of satellite Internet.
693 square feet behemoth
Credit: Nokia / AST SpaceMobile
AST SpaceMobile, a mobile communications company based in Texas, reportedly launched a massive satellite into Earth orbit over the weekend and gave it the name “BlueWalker 3.” Astronomers have expressed their displeasure with this incident in multiple sources. When the satellite’s antenna array, which is 693 square feet (64 square meters) in size, is fully extended, the reflected illumination from the satellite has the potential to match the brightest stars, completely obscuring the night sky—with the exception of the Moon, of course.
At dusk, the BlueWalker satellite will be just as visible as the brilliant star Vega, according to an astronomer who was quoted in the technology magazine Gizmodo. Her argument was that astronomical observations would be affected by the introduction of future communications satellites like the large BlueWalker 3.
Aim of the project
BlueWalker 3’s Falcon 9 launch.
The “BlueWalker” spacecraft was successfully delivered to a low Earth orbit by a “Falcon 9” rocket that was built by SpaceX and launched from Florida on Saturday. Along with the new satellite, SpaceX launched dozens of its own Starlink satellites. There, the U.S. company AST SpaceMobile plans to conduct a test to determine how successfully mobile Internet can be delivered to mobile devices from space.
AST SpaceMobile is “building the first and only space-based cellular broadband network to be accessible by standard smartphones.” BlueWalker 3 is the biggest commercial communications satellite ever launched into low-Earth orbit. Its true brightness will only be seen once it has been fully unfolded.
As part of the project “BlueBirds”, those satellites are intended to pair seamlessly with regular cellphones to provide a high-speed Internet connection. Compared to Apple’s demonstration of the technology only last week and SpaceX’s plans with T-Mobile, this new system has substantially more capacity than just making satellite emergency calls. They both want to provide a means of contact in case of an emergency when regular mobile phone service is unavailable but their connections won’t be fast enough for video conversations or web browsing, unlike the aim of Internet satellites like BlueBirds.
There are plans for 100 giant satellites
That’s how large the satellites will be one day. (Image: AST SpaceMobile)
If everything goes according to plan during the test phase, the company plans to put 100 more giant satellites into orbit before the end of 2024 in order to establish a global data network. The satellites are referred to as “BlueBirds,” and it is anticipated that they will have a size that will allow them to reflect the same quantity of light as “BlueWalker 3.”
Whether or not it will flicker or shine steadily is still unknown at this point. AST SpaceMobile still intends to launch satellites that are twice as large. As of right now, no international laws prohibit this, and very bright objects are not prohibited anywhere around the globe.
Already, astronomers all over the world are becoming concerned about the ever-increasing levels of light pollution in the sky.
Elon Musk’s private space company, SpaceX, has ambitious plans to blanket the entire planet with high-speed Internet service by deploying 42,000 satellites into low Earth orbit. The company has requested clearance to operate tens of thousands of satellites, but they have only been granted permission to operate 12,000 so far.
There are plenty of companies besides SpaceX and AST SpaceMobile that have aspirations of putting hundreds of satellites into orbit. The emerging Internet service providers planning to operate out of space are competing head-to-head with companies such as OneWeb and Amazon.
