‘What goes up, must come down:’ Junk satellites are a looming hazard

What happens when thousands of old satellites are out of order?
SpaceX is seeking approval to expand its Starlink constellation to 40,000 satellites.
SpaceX is seeking approval to expand its Starlink constellation to 40,000 satellites. Credit: Paul Hennessy/NurPhoto via Getty Images

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Elon Musk’s SpaceX and its competitors are making reliable, and decently-fast satellite internet services a reality thanks to a growing armada of shimmering satellites orbiting overhead. Through its constellation of over 6,000, 500-pound satellites, SpaceX’s Starlink internet service already reportedly provides broadband to around three million global users, some in remote locations underserved by traditional internet providers. But what happens when all those aging satellites no longer serve their purpose? 

A new report from environmentally-focused advocacy group PIRG warns the current approach to decommissioning old satellites, which usually involves having them burn to a crisp when re-entering the atmosphere, lacks meaningful rules and regulation. That absence of oversight, they say, could lead to an increase in dangerous space junk affecting Earth, especially as competing satellite internet companies rush to build out and launch tens of thousands of new satellites into orbit. PIRG estimates SpaceX alone will have 29 tons of old material reentering Earth’s atmosphere every day if it is able to achieve its desired satellite constellation.  The organization estimates that comes out to roughly the weight of one Jeep Cherokee coming back down from space every hour. As of now, nobody really seems to have a firm grasp on the long-term consequence of all that fiery garbage.

“There’s too much that is unknown about the extent of environmental effects of rocket emissions, space junk, and satellite reentry on our atmosphere, Earth, and climate given the huge number of proposed satellites,” PIRG writes in its report. “With the scale of proposed satellite mega-constellations, and their disposability that requires constant replenishment, we can’t look away from the environmental harms of the space industry because we assume they’re science fiction. The science-reality of environmental harms is coming fast.”

LEO satellites are experiencing unprecedented growth 

Satellites capable of providing internet date back to the early 2000s but their numbers accelerated over the past five years thanks, primarily, to a flurry of launches by SpaceX in low-earth-orbit (LEO). Low earth orbit satellites operate at an altitude of around 1,200 miles or less, which is significantly lower than geospatial satellites responsible for services like GPS and older, gruesomely slow internet services. That relative closeness to the surface and their widespread coverage areas is what makes these types of satellites ideal for wireless internet connection. The International Space Station (ISS) is also maintained in LEO. 

SpaceX currently has around 6,000 satellites in LEO but has plans to increase that number to 40,000 over many years to build out its constellation. And Musk’s enterprise isn’t alone. Competitors, most notably Amazon’s Project Kuiper and OneWeb, are spending billions to launch their own constellations. China similarly plans to launch at least 15,000 satellites in the same area of space.. In theory, these denser webs of satellites should lead to wider-spread coverage which means faster internet for customers. It also radically increased the amount of materials hurling up towards space that will eventually need to make its way back down. 

Starting this year, companies granted license to operate in LEO by the Federal Communications Commission (FCC) are required to deorbit their satellites after five years. That ostensibly reduces the amount of clutter in the skies, but may also increase the amount of re-entry events. It also means satellite internet companies in particular will likely launch additional satellites to replace those they have decommissioned. 

Crowded satellite space could increase risks of debris or environmental damage 

Space junk does not always incinerate before reaching Earth’s surface. Just last year, a roughly .7 kilogram part of a pallet discarded from the ISS re-entered the planet’s atmosphere and violently pummeled its way through a Naples, Florida home. The homeowner fortunately wasn’t injured. More recently, a three-foot, ninety pound slab of debris reportedly connected to the SpaceX’s Dragon Crew-7 mission was also found by a Glamping Collective in the North Carolina mountaintops. These Chicken Little horror stories are rare, but PIRG and others worry they could become more common as the total number of satellites filling the night sky rapidly multiples. An increasingly congested LEO also ups the risk of collision between satellites and other objects which could create hazardous debris. 

SpaceX did not immediately respond to Popular Science’s request for comment. 

Chunks of red-hot satellite debris aren’t the only concerns. A recent preprint paper published by a researcher from the University of Iceland suggests even properly performed planned reentries could be creating a “conductive dust” of metals coating the Earth’s upper atmosphere. The researcher argues high levels of aluminum other conductive material emitted into the atmosphere from burning satellites may lead to “perturbations in the magnetosphere,” which could, theoretically, allow greater levels of cosmic radiation to reach the surface.  

Elsewhere, researchers from the University of Southern California writing in Geophysical Research Letters estimate airborne aluminum oxide pollution caused by a growing number of incinerated satellites may possess the potential to damage the Earth’s ozone layer. A diminished ozone layer allows s’more UV radiation to reach the Earth’s surface, which can lead to weaker immune systems and higher rates of some cancers in humans. 

“We shouldn’t rush forward with launching satellites at this scale without making sure the benefits justify the potential consequences of these new mega-constellations being launched, and then re-entering our atmosphere to burn up and or create debris,” PIRG writes.

Stricter environmental reviews could make satellite re-entry safer 

PIRG argues at least part of this uncertainty about just what happens to all those satellites once their ready for retirement stems from a lack of regulation. The Federal Communications Commission (FCC), which grants approval for US-based satellite internet projects, has given satellite operators an environmental review exemption. That practice, which started when space operations were mostly performed by NASA or other government agencies, has persisted in a space age marked by profit and privatization. Critics argue the lack of comprehensive environmental review in this domain may lead to pollution and habitat destruction at the launch level and may continue to environmental issues on reentry. A 2022 report from the Government Accountability Office (GOA) called on the FCC to remove that exception but it has yet to do so. 

”That launching 30,000 to 500,000 satellites into low earth orbit doesn’t even warrant an environmental review offends common sense,” PRIG wrote. 

The FCC did not immediately respond to Popular Science’s request for comment. 

In addition to calling on the PIRG to revise its rules around environmental reviews, the organization is calling on the FCC to immediately press pause all new LEO satellite launches and “look before leaping” into approving new projects. PRIG also advocated for an upper limit, or ceiling, on the total number of satellites deployed in orbit at any given time.

But much like it was with prominent technologists calling on tech firms to pause generative AI development, a meaningful slowdown in new satellites seems unlikely anytime soon. Some estimates suggest LEO could be filled with as many as 58,000 satellites by the end of the decade. More satellites may increase the performance of satellite internet services which could become attractive to the roughly 2.6 billion people worldwide who currently lack broadband access due to a combination of infrastructure and cost constraints. Stronger environmental safeguards and enforced standards around re-entry procedures, however, could help bolster confidence as the satellites become ever present.