Thousands of pieces of "space junk" orbit our planet.
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Image courtesy of ESA.
Whether on Earth or in Space, human activity creates waste. Like the Earth's environment, the space environment is getting more and more cluttered. There are currently millions of man-made orbital ruins that make up "space junk". Unfortunately, the past 45 years of space exploration have generated a lot of junk. Orbital debris includes things such as hatches blown off space modules, paint fragments from the space shuttle, or satellites that are no longer in use.
Most space junk is very small (for example, paint flecks). But there are thousands of objects orbiting Earth that are bigger than a baseball. These objects are tracked by ground-based radars.
Human-made debris orbits at a speed of roughly 28,000 km/hr (17,500 miles/hour)! Think of the damage even a small speck of paint could do if it hit a spacecraft at such a high speed! Even an object as small as small as a grape has enough kinetic energy to permanently hurt a medium-sized spacecraft!
Some spacecraft have shielding to protect from damage caused by space junk. It is also sometimes possible for a spacecraft to move out of the way to avoid getting hit by debris. The Center for Orbital and Reentry Debris Studies (CORDS) helps space mission controllers plan so as to avoid impacts between their spacecraft and space junk.
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