5-Year LEO Deorbit Seen Becoming a Norm, but Regulatory Adoptions Less Certain

"My impression is that most other national regulators are deferring to the US and letting the FCC primarily handle this," emailed Brian Weeden, Secure World Foundation program planning director. He said the European Space Agency discussed moving toward a "zero debris" policy and standard, but for now it's unclear whether that would be strictly for government missions or commercial satellites as well, or what it would entail.

Other space-faring nations traditionally followed the nonbinding U.N. debris mitigation guidelines, which have a 25-year rule for deorbiting LEO satellites, emailed Christopher Newman, space law and policy professor, England's Northumbria University. The U.S. was the first to opt for five years, he said. The U.S. five-year rule is a way of trying to guide the international community to engage in more responsible LEO behavior, and other space-faring nations could adopt a similar protocol, he said.

China -- which also has ambitious mega-constellation plans -- takes "somewhat ad-hoc" approaches to deorbit and end-of-life procedures depending on the license being sought by the operator, Newman said. He said it's active in the U.N. Committee on the Peaceful Uses of Outer Space, "and it will not have escaped that committee’s attention that the US had put in place a specific and relatively short time limit for end-of-life purposes." Newman said the hope is that international pressure forces all users of space, including China, to consider implementing a similar five-year deorbit.

It's not surprising that other nations haven’t followed the FCC to adopt five-year deorbit rules of their own, satellite consultant Patricia Cooper told us. Satellite rules don’t generally get updated frequently, she said. The few nations that updated their rules in the past year haven't opted for shorter deorbit times, though that approach continues to be a part of broader discussions on orbital safety, she said. Many countries are also trying to gin up their own domestic commercial space sectors and may be reluctant to add further requirements that might deter new entrants, she said.

Getting any form of international agreement is a lengthy process, space experts said. "Others are working that direction for sure, but no one has jumped on board yet," emailed Darren McKnight, LeoLabs senior technical fellow. Organizations that need member consensus for approval, such as the U.N. and the international Inter-Agency Space Debris Coordination Committee (IADC) "always move more slowly," he said. U.S. policies don't always become de facto standards, he said, noting the U.S. one-in-10,000 chance threshold for casualties on the ground from orbital debris reentering the atmosphere isn't universally accepted.

Despite scientific research, policy efforts and attention given to orbital debris, the rate at which rocket bodies are being abandoned in LEO that will exceed the 25-year post-mission disposal guideline has been growing, McKnight said. "You would have thought that we, as a community, would have learned," he said.

When the FCC adopted the five-year rule, regulators around the world "were certainly talking about it," said Charity Weeden, Astroscale vice president-global space policy and government relations. Next step would be discussion at the IADC, she said. She said numerous best-practices groups have talked about encouraging five-year deorbits, even shorter time frames, or an "as-soon-as-possible" approach. One challenge is the five-year deorbit approach carries with it an unintended consequence of encouraging more crowding of orbital altitudes where atmospheric drag would result in deorbiting within five years, such as 550 km to 600 km, she said.

Astroscale -- which urged the FCC to adopt rules that would limit aggregate collision risk from nonoperating satellites in constellations -- presented an analysis of different space debris management risk metrics with FCC Space Bureau staff, per a docket 18-313 filing. Astroscale said its math reinforces that limiting aggregate collision probability "is the most effective and technologically agnostic way to limit the negative effects to LEO arising from derelict objects." Amazon's Kuiper recapped its own meeting with bureau staffers, at which it argued the aggregate risk approach "poses significant drawbacks [including] unnecessary and impossibly high standards on large constellations without providing meaningful benefits for space safety." Kuiper said Tuesday the aggregate approach also would artificially limit the size of constellations. It pushed instead for the satellite industry and government creating "a more scientifically-based collision risk standard for each individual satellite, regardless of whether it is a standalone spacecraft or part of a large constellation."