Scientists Sound the Alarm Over a Growing Trash Problem in Space

Sixty-six years ago, there was just a single human-built object in Earth orbit. It was Sputnik, the Soviet Union’s—and the world’s—first satellite, launched on Oct. 4, 1957. Now take a moment and try to guess how many objects—including active satellites, defunct satellites, and bits of debris from all of that space traffic—are currently circling the planet. Have you made your guess? Good.

Your answer is wrong. Or let’s put it this way: it’s wrong unless the figure you guessed is 100 trillion. That’s the jaw-dropping number cited by an international team of researchers writing an open letter in last week’s issue of Science, calling for a global treaty to curb the amount of satellites and rubbish that have been forming an ever-growing debris belt in low-Earth orbit for more than three generations now.

The researchers report that there are currently 9,000 active satellites in orbit—a number expected to grow to over 60,000 by 2030. The 100 trillion figure includes everything from spent boosters and stray bolts, to metal flecks and floating paint chips that went along with launching all of that hardware. And don’t think something as small as a paint chip is harmless. Orbiting the Earth at 28,200 km/hr (17,500 mph), so small a piece of rubbish can strike a spacecraft or other orbiting object like a bullet. Astronauts spacewalking outside the International Space Station report that the skin of the 25-year-old orbiting lab looks in some spots as if it has been hit by buckshot. The astronauts routinely have to shelter in place in one of the attached Soyuz or SpaceX spacecraft to wait out a passing swarm of space debris in case the station gets catastrophically struck and they have to bail out in a hurry. Ultimately, all of this debris will fall back to Earth and incinerate in the atmosphere, but we’re replacing the junk at a faster pace than its orbit can decay.

Each of the seven researchers writing in Science are experts in one of two fields: satellite technology and ocean plastic pollution. Why the latter? Because, as they write, the mess we’ve made of the oceans—witness the great Pacific garbage patch, a mass of floating junk that measures twice the area of Texas—mirrors the mess we’re in the process of making in space. The difference: we’ve had centuries to foul the oceans and only decades to do the same in space, and yet we’re not wasting time.

More from TIME

“As a marine biologist I never imagined writing a paper on space,” said Heather Koldewey, a senior marine technical adviser at the Zoological Society of London and a coauthor of the letter, in a statement that accompanied its release. “But through this collaborative research [we] identified so many parallels with the challenges of tackling environmental issues in the ocean. We just need to get better at the uptake of science into management and policy.”

The researchers see hope for space in the progress that has been made so far in cleaning up the oceans—or at least in nations agreeing to try. In March 2022, world leaders representing 170 nations signed a global plastics treaty at the United Nations Environment Assembly, in an attempt to curb continued dumping of plastics in the oceans and eliminate what is already there. Other negotiations are already underway on a more ambitious Global Plastics Treaty.

Similar initiative should be taken now, the authors write, to implement treaties that hold both government and commercial space launch services liable for minimizing the amount of debris their launches create, deorbiting satellites after they’ve reached the end of their functional life, and developing technologies to clean up at least some of the 100-trillion-strong rubbish swarm.

“Most nation states have neglected to implement the necessary local space regulations that could promote long-term equitable and sustainable use of Earth’s orbit,” the authors of the letter write. “There is no international treaty that seeks to minimize orbital debris.”

That must change—and fast. “To avoid repeating the mistakes that have left the high seas—and all who depend on them—vulnerable, we need collective cooperation, informed by science, to develop a timely, legally binding treaty to protect Earth’s orbit.”

A species that is smart enough to have gotten itself to space—an order of magnitude more difficult than initially learning to sail (and foul) the oceans—should be smart enough not to make a mess of things once it gets there. As Moriba Jah, coauthor and associate professor of aerospace engineering at The University of Texas at Austin, put it in a statement, “Marine debris and space debris are both an anthropogenic detriment that is avoidable.”