How Does NASA Track Space Debris?

Space, the final frontier… - James Tiberius Kirk

In the sixty and half decades since Sputnik 1 first orbited the Earth, we’ve left a lot of debris up in space. And each and every chunk of junk that we’ve casually abandoned in our race to go higher, further, and faster than we’ve ever been, has to be carefully tracked to make sure that it doesn’t collide with any of the satellites that are currently in orbit or any spacecraft that are launched in the future.

Any collision with even the smallest piece of space debris, whether man-made or a meteoroid could have catastrophic consequences for a satellite or rocket. In order to try and ensure that doesn’t happen, NASA constantly tracks all of the debris in low, medium, and geostationary Earth orbit.

However, it isn’t just NASA that tracks space debris, as the SSN (Space Surveillance Network) sensor array that makes it possible to track all of the debris in all three previously orbital planes is owned and operated by the Department of Defense.

The DoD and NASA work together and using the SSN track the estimated twenty-seven thousand pieces of junk and debris in orbit around the Earth to ensure that none of it collides with the satellite network, the ISS (International Space Station), and the spacecraft that resupply it, satellite launches and increasing number of private space endeavors that have already, or are scheduled to launch in the near future.

How Does NASA Monitor The Amount Of Space Debris?

NASA monitors the amount of space debris around the Earth using the already mentioned SSN sensor array, and jointly shares the responsibility with the Department of Defense.

There are currently twenty-three thousand items of debris that are larger than the size of a softball (the easiest way to measure an item larger than ten centimeters in diameter is by comparing it to a familiar everyday object, in this case, a softball) traveling around our planet at speeds of up seventeen thousand miles per hour, or more than twelve times the speed of a bullet.

If any of these objects were to hit a spacecraft at those kinds of speeds, the impact would be disastrous for any vehicle struck by space debris.

In the last fifteen years two major collisions in Earth orbit, the first involving an old Russian spacecraft and an American satellite and the second in which China attempted to destroy a decommissioned weather satellite, added nearly five thousand seven hundred pieces of trackable space debris to the minefield that was already being monitored by NASA and the Department of Defense.

To put that in context, two collisions in the last fifteen years are responsible for a quarter of the man-made debris orbiting Earth.

Does The ISS Get Hit By Space Debris?

The ISS (International Space Station) gets hit all the time by small pieces of space debris and meteoroids, but the Whipple shielding (the same type of shielding used by satellites and rockets) that the ISS is built from protects it, and the astronauts aboard it from any danger that the debris might otherwise pose.

Sometimes however it is necessary for the ISS to move out of the way of any larger chunks of debris that could pose a serious threat to it, and those maneuvers are guided by the international space agencies responsible for the safety of the station and the personnel onboard.

Thanks to NASA constantly tracking and monitoring the debris in orbit, it’s possible to work out and plan those maneuvers in advance and to return the ISS to its original orbit once they‘ve been completed and the threat of any potential collision has passed.

Can Space Debris Be Cleaned Up?

Technically, it is possible although it is incredibly challenging and difficult to do. The main problem lies with identifying what can and can’t be cleaned up, and which countries are ultimately responsible for cleaning up the “trash” in space.

While NASA is on record as saying that it is actively tracking more than twenty-seven thousand items of space debris, the United Nations estimates that there are up to nine hundred thousand pieces of debris that could potentially threaten manned and unmanned missions in the next two decades.

It was this estimate that was partially responsible for the first real attempt to prove that it was and is physically possible to clean up some of the smaller items of space junk and debris.

In 2018, a satellite called RemoveDEBRIS was launched to test various methods of debris removal and retrieval. The two experimental forms of debris removal and retrieval that the satellite tested involved using a net and a harpoon, both of which were relatively successful and could potentially be used in possible future clean-up operations.

While it’s incredibly difficult to capture and clean up smaller items of debris, due to the speed at which they’re traveling and the costs of actually launching more spacecraft to clean up the debris left by other spacecraft, one of the more tried and tested methods for clearing older, decommissioned debris (or satellites) that are still under some sort of control deliberately brings them back to Earth by forced re-entry into the atmosphere. In other words, they’re brought down in a “controlled” crash.

How Many Rocket Bodies Are Floating In Space?

So what happens to the satellites and rocket stages that can’t be returned to Earth because they‘re “dead” (a term used when all communication and control with a satellite has been lost) or can’t get back because they’re caught in orbit?

The truth is, these satellites and rocket stages are locked in an orbital plane, and without direct interference from a mission launched to either retrieve them or attempt to alter their orbital trajectory to force them to reenter the atmosphere, they’re going to remain in orbit forever.

And three thousand of the twenty-three thousand items of space debris larger than a softball that are currently being tracked and monitored by NASA are either “dead” satellites or abandoned rocket bodies and “stages” of manned and unmanned space missions. 

Gordon Watts