Space debris, also known as space junk, is a collection of inactive human-made objects floating in space. Most of this debris is found orbiting Earth. This includes out-of-service spacecraft, remnants of rocket launches, and fragments resulting from the disintegration or collision of these objects. Examples range from large defunct satellites to tiny particles like paint flecks.
A significant issue with space debris is that it’s an unintended consequence of space exploration. The costs associated with this debris, such as potential damage to active spacecraft, are often not considered by those who launch or operate these objects. Space debris poses a real risk to both crewed and uncrewed spacecraft, and there have been instances of damage caused by it.
As of late 2022, over 25,000 large artificial objects were reported to be in Earth’s orbit, including operational satellites. However, this is just a fraction of the debris, as millions of smaller pieces exist but are too tiny to be tracked. These small fragments, when combined with micrometeoroids, create a significant hazard for spacecraft, similar to sandblasting effects on sensitive equipment.
Most space debris is found below 2,000 km from Earth. Here, the density of debris exceeds that of natural meteoroids, consisting mostly of particles from rocket motors, paint flakes, and remnants from old satellites. The International Space Station (ISS), orbiting at a lower altitude, employs special shielding to protect against small debris. However, for larger, trackable debris posing significant collision risks, the ISS often maneuvers to avoid impact.
Overall, space debris is an ongoing concern in space exploration, with efforts focused on monitoring, mitigating, and potentially removing this debris to ensure the safety and sustainability of future space activities.