Increasing Satellite Reentries Raise Concerns About Orbital Debris and Atmospheric Impact
Recent analysis highlights growing concerns surrounding the increasing number of satellites reentering Earth’s atmosphere, particularly in the context of large constellations like SpaceX’s Starlink. Astronomer Jonathan McDowell warns that even a small failure rate within these massive deployments could significantly exacerbate the risk of Kessler Syndrome – a cascading collision scenario in low Earth orbit.
McDowell explained that if just one percent of the planned 30,000 Starlink satellites were to become non-functional while in orbit, that would still represent 300 satellites. ”Three hundred big satellites could tip low Earth orbit into Kessler,” he stated.
While Starlink’s operations pose a risk, McDowell identifies China’s satellite plans as a more notable worry. The 600 to 1,000 kilometer altitude range is already congested with debris from old Soviet rocket stages, increasing the likelihood of kessler Syndrome. Many of China’s proposed constellations will operate at similar altitudes to Starlink, but a portion are planned for altitudes above 1,000 kilometers. McDowell cautioned that a failure in that higher orbit would be particularly problematic, stating, “we’re probably screwed.” He noted that the higher altitude means these satellites would remain in orbit for centuries, and he has not seen any demonstrated plans for their eventual decommissioning.
Beyond the risk of collisions, the increasing frequency of satellite reentries is raising concerns about the impact on Earth’s atmosphere. McDowell emphasized that “using the upper atmosphere as an incinerator” has largely unknown effects, representing a “hazardous blind spot.”
Data from the US National Oceanic and Atmospheric Administration (NOAA) indicates that approximately 10 percent of aerosol particles in the stratosphere currently contain aluminum and other exotic metals believed to originate from burning-up rockets and satellites. NOAA projects this figure could rise to 50 percent as launch and reentry rates increase.
Research into the effects of this atmospheric influx has yielded inconclusive results, ranging from assessments that the impact is negligible to warnings that damage is already occurring. “So far answers have ranged from ‘this is too small to be a problem’ to ‘we’re already screwed,'” McDowell said. “But the uncertainty is large enough that there’s already a possibility we’re damaging the upper atmosphere.”
Several groups are currently investigating the potential for these reentries to contribute to climate change or other catastrophic effects. McDowell concluded,”There are indications that things are already getting bad…But it’s murky right now,and that scares me.”
