NASA has a plan to clean up space junk—but is going green enough?

NASA is taking environmentalism to orbit. The space agency’s deputy administrator, Pam Melroy, recently unveiled the first phase of NASA’s new Space Sustainability Strategy. In the coming months, NASA will roll out additional  parts of the strategy, which together are designed to ensure that the space around Earth gets cleaned up—and that resources in space are shared equitably and sustainably.

“This was a long time coming,” Melroy says. Different parts of the agency have been embracing sustainability on their own and using their own approaches—now, NASA is going to make an agency-wide effort, she says.

The first phase of NASA’s sustainability strategy focuses on junk in orbit around Earth. In fact, the orbital trash problem is arguably the most pressing space issue today. Nearly 10,000 functioning satellites encircle the globe, but there are also many, many more defunct spacecraft, derelict rocket bodies, and millions of pieces of other garbage hurtling around our planet at some 17,000 miles per hour. 

Astronomers who have sounded the alarm about the increasingly crowded space around Earth have praised the new plan, but many say that the U.S. space agency is lagging behind other countries, and it needs more urgency to address this pressing issue of pollution in orbit.

“I’m very happy to see that NASA’s doing this. But I think it’s very important to see whether Congress gives them the budget to actually do anything differently,” says Darren McKnight, senior technical fellow at LeoLabs, a spacecraft and debris-tracking company based in Menlo Park, California. 

Growing pains

What is true is that any satellite orbiting in a crowded area is at increasing risk of getting smashed by an errant chunk of metal careening into it, and thus becoming trash itself. 

Melroy and her colleagues at NASA are particularly concerned about the risks to the International Space Station and the astronauts aboard it—risks that were dramatized by the 2013 movie Gravity, where Sandra Bullock had to flee the orbiting outpost. In such a worst-case-scenario, the space station’s critical modules would be compromised, and any astronaut who couldn’t board a spacecraft and escape would die.

The more satellites there are, the more dangers there are, too. If there were a collision in orbit, say, between an abandoned rocket body and a dead satellite, that would beget yet more debris, risking more collisions, rendering that orbit unusable for years or decades. It’s akin to a car crash pileup on a highway lane, except there are no emergency vehicles in space and no way to clean it all up without spending millions if not billions of dollars on a years-long process.

In the new report, NASA lays out the first part of the sustainability strategy. It cites the rapidly growing satellite population and the increasingly congested space that is low Earth orbit, as well as all those hazardous bits of space junk, large and small. The report also points to the recent expansion of artificial constellations in the sky made up of thousands of satellites apiece. The largest one by far is SpaceX’s Starlink, which could eventually amass more than 40,000 spacecraft in its ranks. Amazon’s Project Kuiper plans to be not far behind.

Great garbage patch

NASA’s long-term models are useful, says McKnight, as they show how debris could continue accumulating over decades. But the agency is missing the fact that bad things are already happening now—and they need solutions now, too, he says. 

For example, on February 28, NASA’s TIMED spacecraft, which studies solar radiation in the upper atmosphere, had a close call with a 32-year-old defunct Russian satellite. The satellite was dead and so couldn’t possibly have maneuvered out of the way. If they’d been on a collision course, no one could’ve prevented it.

The stakes are higher for the International Space Station, which houses astronauts. The station has been threatened several times by orbiting garbage over the past couple years—once by a piece of an old Russian rocket and another time by shrapnel from a Russian anti-satellite missile test that took place in 2021, which delayed a planned NASA spacewalk, since debris could easily penetrate a spacesuit. 

The United States, China and India have all tested anti-satellite missiles, too, by blowing up their own satellites, creating space junk in the process. The problem was so acute that in 2022 U.S. Vice President Kamala Harris called for an international moratorium on these space-polluting weapons tests.

National Geographic Explorer Moriba Jah, who is also a University of Texas aerospace engineer and the cofounder of Privateer Space with Apple’s Steve Wozniak, says that, ultimately, NASA and other space agencies and companies need to face the fact that “the fate of everything we launch is to become trash, and that needs to change.” 

Taking action

Some agencies are already trying to do as Jah suggests—and NASA is playing catch up. The European Space Agency released its zero debris approach more than a year ago. It has specific targets the agency plans to meet by 2030 to reduce risks of satellite-trash collisions in orbit. The United Kingdom’s Space Agency, meanwhile, announced it would put a premium on space sustainability in 2023, and Japan has started to invest in private space companies dedicated to addressing space debris, too. Japan is also working with the United Nations to raise awareness of the problem worldwide. 

While NASA has been lagging, some American regulatory agencies like the Federal Communications Commission have their own space junk rules. In 2022 the FCC imposed new rules designed to force telecom companies to dispose of their old spacecraft rather than letting them drift in orbit for decades. The Federal Aviation Administration also has proposed a rule to make space companies dispose of upper-stage rocket bodies left in orbit. 

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But NASA’s strategy could be a significant step forward, Jah says. Yet it’s also a missed opportunity to link to waste management principles already developed for land, ocean, and air pollution, he says. 

“The space community is trying to reinvent the wheel,” Jah says. Unlike its European counterpart, NASA also currently lacks a concrete plan to develop a circular space economy, which means redesigning spacecraft, experimenting with new materials and fuels, and reusing and recycling satellites rather than deploying so many single-use ones. 

Cleanup time

NASA is late to the debris cleanup party, too. A mission called Active Debris Removal by Astroscale-Japan, or ADRAS-J, launched in February and is now attempting to safely approach an old rocket body left in orbit 15 years ago. The team’s aim is to image the giant hunk of space garbage, characterize its condition and movements, and synchronize the ADRAS-J spacecraft’s spin with that of the rocket body—all precursors to removing it from orbit, which a future mission could accomplish. 

Meanwhile, in 2026, the European Space Agency and a private company called Clearspace plan to launch a spacecraft that will use robotic arms to capture a 250-pound rocket part and safely tug it down into the atmosphere, where it and the spacecraft will both safely burn up. According to the U.S. Space Force, the rocket part they’re targeting appears to have itself been hit by smaller debris last summer, further demonstrating the problem and the need for action.

America will certainly lead its own space junk disposal missions, NASA’s Melroy says, but the agency still has to flesh out its space sustainability plan before it makes any major decisions. She’s already familiar with myriad concepts for decluttering orbit, having previously served at DARPA, an agency that explores far-out ideas, including concepts for using harpoons, nets, or an orbital catcher’s mitt to grab litter in space. 

NASA’s annual budgets ultimately depend on Congress, which cut the agency’s fiscal year 2024 budget by 2 percent, with the Mars sample return mission and other programs losing some funding. A debris disposal mission would be a major new investment.

NASA’s cost-benefit analysis demonstrates that removing the top 50 most concerning objects in low Earth orbit—mostly derelict rocket bodies and other objects orbiting near critical satellites—would be expensive but worthwhile in the long run. It would also make financial sense to develop lasers and other technologies that could be used to nudge debris out of harm’s way to prevent imminent collisions, according to that analysis.

But designing and deploying such garbage-hauling tech will take years, and scaling it up will take longer than that.

Next steps

Ultimately, getting rid of space trash now is important, but “active debris removal cannot be used as a panacea,” says Aaron Boley, a planetary scientist at the University of British Columbia and cofounder of the Outer Space Institute, a network of space experts. 

“I’m pleased they put out this strategy on space sustainability. There’s a lot of work to be done,” he says. It’s also necessary to change behavior, for example, since it’s impossible to clean up the mess if people keep polluting and leaving more junk up in orbit. 

And he argues that the reflectivity of spacecraft altering the night sky should be considered part of space sustainability, too. Boley and his colleagues wrote a paper in March about satellite visibility during 2024's April 8 total solar eclipse that was viewed by millions of people in North America. 

Earth’s orbit marks the cusp of outer space—and sustainability will have to extend beyond that. 

To the moon

The rest of NASA’s strategy will include long-term plans for the moon and its orbit and for deep space, which includes Mars and asteroids. 

Through the Artemis moon program, NASA’s racing to develop a lunar outpost and a space station, while China, Russia, and the commercial space industry have their own designs for the moon, too. 

But there’s limited resources on the moon. That means NASA's use of any water ice there has to take others' needs, including those of future generations, into account. Such considerations will play into NASA’s sustainability efforts, Melroy says. “I think these things will evolve with time as we learn, but we’re going to be focused on preserving areas of scientific significance and areas of historic significance and great natural beauty.”

Melroy likens NASA’s approach to space sustainability to its work on climate change, as the space agency has for decades been studying the Earth’s climate as a holistic system and promoting sustainability on our own planet. 

The climate analogy is apt for the space junk crisis in another way too, McKnight says. “This is like global warming in the sense that we see it coming. But no one wants to act until it’s really a problem,” he says. 

“We’re kind of waiting for something bad to happen so that we’ll respond, but it’s better to deter or deny a threat than recover from it. I applaud NASA taking this step, but I hope it’s with the right level of urgency.”