Space datacenters proposed by SpaceX, Jeff Bezos's Blue Origin and others would release staggering levels of pollution that would probably alter the Earth's atmosphere and be "catastrophic" for the planet, space industry experts and environmental groups warn in a new petition demanding a review of their impacts.

Tech companies have collectively proposed millions of "orbital datacenters" and are pressing forward with plans, which require Federal Communications Commission (FCC) approval. Among other issues, pollution from satellites and rockets burning up upon re-entry appears to be accumulating in the stratosphere at alarming levels. The spacecraft release black soot, rare metals, aluminum oxides and other pollutants with unknown effects.

Some scientists fear the pollution could destroy the ozone layer, potentially expose some people to higher levels of ultraviolet radiation, or help further destabilize the planet during the climate crisis. The pollution could also end up back on Earth, and millions of satellites would create a major source of light pollution.

The petition submitted to the FCC calls for a pause on new licenses for space data center projects, arguing that the plans "violate federal law".

The datacenter companies "describe their plans in grandiose, civilization-changing terms", the petition states. "But these same proponents have refused to embrace any inquiry into the impacts of their self-claimed epochal technology on the environment, science, economy, or other values."

The petition was filed by the Public Employees for Environmental Responsibility (Peer) non-profit, the Earthjustice legal non-profit, and the DarkSky International non-profit, which works to protect the sky from light pollution.

Several former federal US space officials told the Guardian they doubt the orbital datacenters are feasible. But putting millions of additional satellites into orbit would create a significant environmental risk, said Steve Volz, the former head of the National Oceanic and Atmospheric Administration (Noaa) satellite office.

"There is a lot of complex material in these things, and even if they do burn up, you do not want to be filling up the atmosphere with refuse from these any more than you would want it coming from a smoke stack," Volz said. Volz was with the agency until he was put on leave and eventually fired under the Trump administration.

Facing fierce public opposition from across the political spectrum to its datacenters on Earth, big tech last year began floating the idea of launching satellite datacenters into space. Some have begun seeking permits.

The number of active satellites in orbit has grown exponentially from about 1,400 in 2015 to about 15,000 currently. As many as 100,000 are expected to be in orbit within the decade, not including the datacenter networks. As of now, the bulk of the satellites' pollution is thought to come from Starlink and Amazon's "mega constellations" that provide broadband internet made up of about 10,000 satellites.

Spacecraft can cause problems on their way up and down. Launches emit a range of emissions like black carbon, nitrogen oxides, carbon monoxide, aluminum oxide, chlorine gases and, once in orbit, mercury. When satellites are decommissioned five to 15 years later, they release metals as they vaporize. That's injecting pollutants into previously pristine parts of the stratosphere, a highly sensitive system, and there's very little understanding of the consequences.