Some space rubble is natural micrometeoroids, like the fragment that struck the starboard payload bay radiator of the STS-115 flight in 2006.

Even tiny, untrackable micro-debris can become a problem. A paint fragment chipped off a spacecraft can move at nearly ten times the speed of a bullet and puncture an astronaut's suit, crack a window of a Space Station, and potentially destroy satellites.

A problem NASA scientist Donald J. Kessler outlined in 1978: As space becomes more packed with spacecraft and debris, collisions become more likely, creating more debris that could trigger a chain reaction of collisions. There is a possibility that near-Earth space can become a shrapnel field.

The first known case of damage happened in 1996 when a piece of European Ariane rocket struck the French spy satellite, Cerise. Many similar incidents have occurred since then.

China and companies like SpaceX, OneWeb, and Amazon aim to launch thousands of satellites into lower Earth orbits to reduce the time it takes for a signal to travel from the satellite to the user.

But some space experts are concerned that satellite mega-constellations could create more space debris. A 2017 study found that the deployment of satellite mega-constellations into low Earth orbit could increase catastrophic collisions by 50 percent.

At this point, no international rules are governing the deployment and management of satellite mega-constellations.

The Inter-Agency Space Debris Coordination Committee comprises 13 of the world's space agencies. It aims to prevent on-orbit break-ups and to remove old spacecraft from the densely populated orbit regions. But, while space debris is everyone's problem, no entity is obligated to solve it.

Cleaning up space will be complex and expensive and requires a coordinated, international effort. The most agreed on strategy among space organizations are to get rid of the big stuff first.

To clean up low Earth orbit, space organizations have proposed multiple solutions. The most promising is the ClearSpace-1 that will try to capture the junk with a robotic arm.