Dealing with the many thousands of pieces of space debris generated by more than 60 years of rocket launches could be done at a relevantly low cost and fast speed if operators focus on removing the smallest pieces or pushing larger satellites out of the way of collision, 10. March report (opens in new tab) states.
Removing space debris would have positive implications for missions to the International Space Station, which has had to maneuver out of the way of space debris twice in the past week alone. Low Earth orbit satellites like SpaceX’s Starlink are also responsible for numerous close encounters in space.
While space junk removal plans are in their infancy, the report emphasizes that there is a path to success as long as the space community works together and is clear about where to prioritize solving the problem. There is hope, however: The report says that “some mitigation approaches can achieve net benefits in less than a decade” once a viable method is in place.
Related: How often does the International Space Station have to dodge space debris?
Although the risk of space debris is difficult to quantify (since not all pieces are traceable), humanity has launched more than 15,000 satellites since the first launch in 1957 of the Soviet Union’s Sputnik, and only about 7,200 of that number are operational, according to the European space agency (opens in new tab)figures for December 2022. A recent article in the journal Science calling for an international treaty to deal with space debris says there could be 100 trillion pieces of junk floating around out there.
Some of these satellites have broken up due to accidental collision or deliberate destruction. A notable recent incident was a Russian anti-satellite debris test in 2021 that created so much debris that it disrupted both the ISS and Starlink operations.
NASA’s 147-page report assesses several options for removing debris in orbit, mostly targeting the smallest pieces (4 inches/10 cm and smaller) or entire satellites. Lasers appear to be one of the leading options, although the report calls for no specific action; this method is discussed twice (for ground-based and space-based lasers) in three separate options for removing small debris, and once among five options for removing large debris.
Lasers appear to be particularly useful when trying to remove large numbers of small debris, as both space-based and ground-based lasers are expected to provide a net cost advantage. But other options such as space tugs or manually moving pieces out of the way are also being considered.
Laser nudging of the top 50 objects of concern would also be helpful, the report says, although higher-cost ones such as rocket nudges could work more quickly. The authors emphasized that their discussion should, however, be taken as a start to solving the problem in the near future.
“Instead of relying on proxies for risk such as the number or mass of debris, this report aims to encourage the space community to take a holistic approach to framing the risks of space debris in dollar terms and how debris can affect satellite operators for decades to come,” the authors said.
Some early-stage projects are showing promise, such as the ELSA-d spacecraft from Japanese startup Astroscale, which captured a simulated piece of space junk in 2021, and an effort by the European Space Agency with ClearSpace-1 to test debris removal as soon as 2025. NASA also announced this week that it will seek a $1 billion space tug to safely remove the ISS when the orbiting complex ends operations in 2030 or so.
Elizabeth Howell is the co-author of “Why am I taller? (opens in new tab)?” (ECW Press, 2022; with Canadian astronaut Dave Williams), a book about space medicine. Follow her on Twitter @howellspace (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) or Facebook (opens in new tab).