Debris Making Particular Orbital Altitudes Hairier: LeoLabs' McKnight

Some orbital altitudes are becoming increasingly dangerous because of growing amounts of orbital debris, Darren McKnight, senior technical fellow for orbital debris monitoring company LeoLabs, said Thursday in a University of Washington webinar. He said 780 km to 850 km is becoming a hotbed of debris generated by the U.S., China and Russia. He said 1400 km is also becoming problematic, compounded by atmospheric drag helping clear lower altitudes over time, but at 1400 km "it's there for centuries." The U.S. is "woefully behind the rest of the world" on the need for active debris remediation, with French, Japanese and European space agencies "way ahead," he said. "It's been seen as something we can worry about decades later. We need to worry about it now." Mega constellations "are really the victim" rather than the causes of increasing orbital debris concerns, McKnight said. He said operators like SpaceX and OneWeb are "operating very responsibly" and going beyond government regulatory requirements, though they still will likely face difficulties because of debris from old payloads and rocket bodies. Russia's anti-satellite missile demonstration in November (see 2111160063) raised the likelihood of a collision in some orbits by a factor of two, generating 500 to 2,000 trackable pieces of debris and probably ten times that in untraceable debris, he said. Technology has changed notably since 1997, when the 25-year guideline that's now become an international norm was established, he said. Electric propulsion systems would accommodate requiring satellites be deorbited one or five years after end of mission, though no nations have gone that route, he said. He said along with technical solutions to remediate debris, more preemptive efforts are needed to prevent debris generation, such as increased information sharing by satellite operators and inter-government trust.