If we could remove the 50 most concerning pieces of space debris in low-Earth orbit, there'd be a 50% reduction in the overall debris-generating potential,
reports Ars Technica. That's according to Darren McKnight, lead author of a paper presented Friday
at the International Astronautical Congress in Sydney, which calculated the objects most likely to collide with other fragments and create more debris. (Russia and the Soviet Union lead with 34 objects, followed by China with 10, the U.S. with three, Europe with two, and Japan with one.) Even just the top 10 were removed, the debris-generating potential drops by 30%.
"The things left before 2000 are still the majority of the problem," he points out, and "76% of the objects in the top 50 were deposited last century." 88% of the objects are post-mission rocket bodies left behind to hurtle through space.
"The bad news is, since January 1, 2024, we've had 26 rocket bodies abandoned in low-Earth orbit that will stay in orbit for more than 25 years," McKnight told Ars... China launched 21 of the 26 hazardous new rocket bodies over the last 21 months, each averaging more than 4 metric tons (8,800 pounds). Two more came from US launchers, one from Russia, one from India, and one from Iran. This trend is likely to continue as China steps up deployment of two megaconstellations — Guowang and Thousand Sails — with thousands of communications satellites in low-Earth orbit.
Launches of these constellations began last year. The Guowang and Thousand Sails satellites are relatively small and likely capable of maneuvering out of the way of space debris, although China has not disclosed their exact capabilities. However, most of the rockets used for Guowang and Thousand Sails launches have left their upper stages in orbit. McKnight said nine upper stages China has abandoned after launching Guowang and Thousand Sails satellites will stay in orbit for more than 25 years, violating the international guidelines.
It will take hundreds of rockets to fully populate China's two major megaconstellations. The prospect of so much new space debris is worrisome, McKnight said. "In the next few years, if they continue the same trend, they're going to leave well over 100 rocket bodies over the 25-year rule if they continue to deploy these constellations," he said. "So, the trend is not good...." Since 2000, China has accumulated more dead rocket mass in long-lived orbits than the rest of the world combined, according to McKnight. "But now we're at a point where it's actually kind of accelerating in the last two years as these constellations are getting deployed."
A deputy head of China's national space agency recently said China is "currently researching" how to remove space debris from orbit, according to the article. ("One of the missions China claims is testing space debris mitigation techniques has
docked with multiple spacecraft in orbit, but U.S. officials see it as a military threat. The same basic technologies needed for space debris cleanup — rendezvous and docking systems, robotic arms, and onboard automation — could be used to latch on to an adversary's satellite.")
