Space Trash

Background

Space trash, or space junk, refers to human-made debris orbiting Earth. Millions of pieces of space trash exist in low Earth orbit—roughly 100 to 1,250 miles above the ground—most of which are incredibly small.

Traveling at more than 15,000 miles per hour, even tiny pieces of space trash pose a threat to satellites and the International Space Station, and some larger pieces occasionally fall back to Earth.

Where Space Trash Comes From

Space trash consists of pieces of satellites, rockets, and other spacecraft, and comes in many sizes. The vast majority of the debris is tiny—estimates suggest there are more than 100 million pieces of space trash larger than one millimeter but smaller than one centimeter, such as flecks of paint that have chipped off a spacecraft.

There are also roughly 1 million objects between one and 10 centimeters and more than 35,000 items larger than 10 centimeters. See a visualization of the problem here.

The amount of space trash is also increasing. NASA estimates that the destruction of a Chinese spacecraft in 2007 and the collision of an American and Russian spacecraft in 2009 increased the amount of large orbital debris in LEO by approximately 70%.

Virtually all of the trash is in LEO, which means it is traveling approximately 17,500 miles per hour. If it travels much faster, it reaches escape velocity and leaves orbit. If it travels much slower, gravity pulls it back down to Earth.

Critically, most satellites—as well as the ISS—also operate in this orbital range. That means space trash poses a significant threat, because even small objects can punch a hole in spacecraft when they’re traveling so fast.

Is Space Trash Really a Problem?

While scientists knew space exploration was creating space trash, it only reached theoretical consideration in 1978, when NASA scientists predicted space trash would eventually come more from unplanned collisions than from new objects being launched into space.

And all that space trash has created real problems. In June 2024, astronauts on the ISS had to go into lockdown due to concerns that debris from a disintegrating satellite might damage the space station.

Thousands of pieces of space trash also fall out of orbit each year. While much of that debris burns up in the atmosphere, sometimes it makes a crash landing. In 2024 alone, space debris from various sources landed in North Carolina and Saskatchewan and punched through the roof of a home in Florida.

Who Will Clean Up Space Trash?

There is no international agreement regarding who is responsible for cleaning up space trash. But that doesn’t mean nobody is thinking about it.

In 2022, the US imposed regulations for the first time requiring satellite operators to deorbit satellites in LEO within five years of completing their designated missions. And US legislators have proposed legislation to have NASA create an orbital debris removal program. However, efforts outside the US are mixed, and the United Nations has only issued general guidelines on the subject.

In 2023, NASA released a cost-benefit analysis on addressing space debris, which looked at approaches ranging from recycling debris to nudging it out of orbit to burn up in the atmosphere. While these approaches were expensive, the analysis found the benefits often outweighed the initial costs within a decade.

There is some optimism that the private sector will develop cost-effective solutions to remove space debris, but the question remains: Who pays for it? Some argue nations responsible for the trash should pay for cleanup efforts, which would mean the US, Russia, and China foot most of the bill—with China being the biggest contributor of space trash in recent decades. As of late 2024, no nation has yet stepped forward to take the lead.