How Much Space Debris Is There? Russian Anti-Satellite Test Creates 1,500 Pieces of Junk

The detonation of a Russian anti-satellite missile created over 1,500 pieces of trackable space junk and thousands of smaller pieces of debris. U.S. authorities condemned the test, which is believed to have involved the destruction of a disused Russian satellite.

Experts say that it placed the crew of the International Space Station (ISS), including two Russians, at risk.

On Monday, the ISS Flight Control team, orbiting Earth at 260 miles above its surface, was notified of indications of a satellite breakup that might create sufficient debris to pose an impact threat to the station.

The crew, also including four Americans and a German, was forced to shelter as the cloud of debris passed the station.

"With its long and storied history in human spaceflight, it is unthinkable that Russia would endanger not only the American and international partner astronauts on the ISS but also their own cosmonauts. Their actions are reckless and dangerous, threatening as well the Chinese space station and the taikonauts on board," NASA administrator Bill Nelson said in a statement. "NASA will continue monitoring the debris in the coming days and beyond to ensure the safety of our crew in orbit."

The debris passed without incident, but it has brought into focus the risks associated with such space junk as well as the fact that debris is becoming increasingly common around our planet.

What Is Space Junk?

"Space junk" is the nickname that researchers and space agencies have given to debris in orbit around the Earth. The term can refer to any piece of human equipment that is no longer functional.

This can include fragmentation debris, as produced by this Russian test, mission-related debris, abandoned pieces of launch equipment, and even disused spacecraft.

A European Space Agency (ESA) simulation shows space debris in orbit around Earth.

As of May this year NASA had identified over 27,000 pieces of orbital debris large enough to track with the Department of Defense's global Space Surveillance Network (SSN) sensors. In addition, there is much more debris around the planet that is far too small to be tracked.

NASA says that of these pieces, at least 23,000 are larger than a softball and are traveling at speeds as high as 17,500 miles per hour.

Some of this debris is moving extremely fast in low-Earth orbit. Because spacecraft move at similar velocities, collisions can cause significant damage to valuable equipment.

When it comes to smaller pieces of debris, NASA estimates that there are up to half a million pieces of debris the size of a marble, around a centimeter, and 100 million pieces of debris around a millimeter in size.

Estimates say that there is even more micrometer-sized junk, which may sound harmless, but it still could cause significant damage. Even seemingly harmless flecks of paint have been shown to cause damage when traveling at orbital speeds.

What Damage Can Space Junk Do?

According to NASA, damage from orbiting paint flecks led to several space shuttle windows having to be replaced. Additionally, these tiny pieces of orbital debris pose the most significant risk to robotic space missions.

This risk is magnified when it comes to manned missions like the ISS and SpaceX's crewed Dragon missions, potentially endangering the lives of crew members.

In May, operators of the ISS's robotic arm, Canadarm2, noticed a hole in the equipment caused by an impact with space junk. The debris appeared to have struck the robotic arm and passed straight through it.

Canadarm2 Space Junk
An image showing damage to the robotic arm of the ISS caused by space junk earlier this year. Canadian Space Agency/NASA

More dramatic was a 2009 collision in which an inactive Russian communications satellite, Cosmos 2251, slammed in a commercial U.S. satellite operated by Iridium Satellite LLC.

The incident occurred around 500 miles above Serbia and itself produced around 2,000 pieces of debris at least 10 cm in diameter and thousands of smaller pieces of debris.

The collision inspired the development of evasive procedures that are now used by spacecraft and the ISS if a potential collision is flagged by SSN sensors.

But evasion isn't the only action that space agencies are taking to tackle the risk of space junk.

Clearing Up the Junk

Many space agencies are developing missions that will attempt to clear space junk from orbit around Earth. One such mission is the ESA's ClearSpace-1, set for launch in 2025.

This mission is just a small part of ESA's Active Debris Removal/ In-Orbit Servicing, or ADRIOS, mission. The project has two main goals; the removal of human-made objects in space and the development of in-orbit servicing, which can extend the lifetime of infrastructure in space.

Commenting on the need for such clean-up operations, ESA Director General Jan Wörner, remarked: "Imagine how dangerous sailing the high seas would be if all the ships ever lost in history were still drifting on top of the water.

"That is the current situation in orbit, and it cannot be allowed to continue."

space junk
A diagram of space junk in orbit around Earth. This debris can cause damage to space equipment and pose a risk to astronauts. A recent Russian missile detonation created over 1,500 pieces of trackable space junk. NASA