Until a few years ago, objects that were launched into space were not designed to return to Earth orbit and roamed through space when their useful life ended. Something similar happened with the spacecraft that took off on April 28 with the aim of putting the future Chinese space station into orbit. Once the mission was completed, it fell uncontrollably over the Indian Ocean, prompting NASA to accuse the Asian giant of behaving irresponsibly. "It is clear that China is not meeting responsible standards with respect to its space debris," said then Bill Nelson, the agency's chief executive officer. In May 2020, Beijing staged an almost identical incident, although this time the remains fell on the Ivory Coast. In early June, the International Space Station,detected significant damage to its external structure, without its astronauts knowing when or how it had occurred. These events, although they seem distant, have the same protagonist: the space debris that accumulates around the Earth and that is becoming a real problem for the different actors in the cosmos.
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This waste comes from the explosion of batteries or fuel tanks of abandoned satellites or rockets, and that multiplies when colliding with other bodies.
According to estimates by the European Space Agency (ESA), there are about 7,200 satellites in Earth orbit, although only about 4,300 are working.
Another estimate, based on statistical models, puts the number of objects smaller than 10 centimeters at about 130 million.
The mass of all these bodies is around 9,400 tons, almost like the Eiffel Tower (10,100 tons).
An estimate based on statistical models puts the number of objects smaller than 10 centimeters at about 130 million.
The mass of all these bodies is around 9,400 tons, almost like the Eiffel Tower
The different agencies pledged to remove the waste within 25 years after it ceases to be useful, as stated in the regulations of the UN Office of Outer Space. The problem, according to David Galadí, of the Spanish Astronomy Society (SEA), is that these deadlines are never met. "The good thing would be if these types of maneuvers were mandatory," he says. According to the Annual Report on the Space Environment prepared by the European agency, "more than half of the space agents whose missions do not fall back to Earth and disintegrate at the end of their useful life do not try to dispose of their missions in a sustainable way" . The numbers are improving, but not fast enough. Tim Flohrer, director of ESA's Office of Space Debris, believes they are on the right track:“Everyone is concerned and takes it seriously. I think we should keep that attitude. "
However, according to Galadí, the role played by space agencies "begins to be a minority". The also coordinator of ICOSAEDRO, a SEA working group that studies the impact of satellite constellations, considers that the leading voice is currently carried by private companies: “The entity that has the most active satellites today is the company by Elon Musk. And the second is OneWeb [another corporation] ”. In 2020, satellite launches increased threefold over the previous year, according to ESA. This increase is explained by the exponential growth of satellites for commercial purposes. Starlink, Musk's company, plans to launch 12,000 satellites with which to offer internet to almost the entire planet, of which more than 1,500 are already in orbit. Amazon owner Jeff Bezos wants to send 3 more.200 for the same purpose. For its part, the Chinese space agency announced 40 launches for 2020. Meanwhile, India announced that it would carry out 36 missions between 2020 and 2021.
Both Musk's company and OneWeb promote the removal of objects once they stop working.
"So far they are complying with it and they make them descend in a matter of weeks or months", Galadí tells about Starlink.
Miquel Sureda, doctor in aerospace engineering and researcher at the Polytechnic University of Catalonia, assures that these companies comply with the rules, but the underlying problem is the law.
"At the moment when you do not have one satellite, but thousands, the law has to look at the constellation as a whole," says the scientific popularizer.
"What for a satellite seems common sense and is possible, for a mega constellation there are new risks and new challenges that must be taken into account," he says.
Location of the constellation of satellites Starlink according to the study of the Spanish Society of Astronomy.SEA / SEA
The researcher highlights another reason why current legislation is not effective in the face of mega-constellations. “When a satellite disintegrates in the atmosphere, nothing happens. The material volatilizes and its particles remain in suspension. But when you have thousands of satellites reentering, you have to ask what effect disintegrating thousands of satellites a year into sensitive orbits has, ”says Sureda. Something similar happens with the light pollution that thousands of satellites generate when reflecting light and that is another of the main criticisms of scientists. In this case, Elon Musk announced that he would redesign his satellites to make them less bright.
Sureda considers that international legislation "has become obsolete" in this regard, although he believes that even updating it, it would be insufficient.
"Active policies are needed, like sending missions that can clear part of the orbit," he says.
In 2019, ESA announced by 2025 the launching of a satellite capable of collecting this waste into orbit.
The ClearSpace-1 mission aims to seize the remains of the Vega rocket, launched in 2013, and which is about 700 kilometers high.
For NASA, launching a cleanup mission remains "a technical and economic challenge."
"What for a satellite seems common sense and is possible, for a mega constellation there are new risks and new challenges that must be taken into account
Miquel Sureda, researcher at the UPC
If measures are not taken, what is known as Kessler syndrome can occur, whereby objects in the same orbit constantly collide, creating a domino effect that will leave some areas totally unusable. “As individuals, the risk of suffering the consequences of this pollution is negligible, but if we think about our dependence on space infrastructure for our daily lives (navigation, global communication, etc.), these essential services have a huge impact on our lives. daily. There is a risk that space infrastructures will no longer be available to everyone, ”says Flohrer.
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