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Space debris or space junk is basically discarded material from launch vehicles like rockets or parts of spacecraft that are left to around in space. Since this junk material floats around space, it can often come in contact with satellites or space stations collision. Space debris can also come from explosions in space or through missile tests to destroy satellites. Since space debris floats in low Earth orbit and at speeds of around 15,700 miles per hour, this makes it highly possible for satellites or a spacecraft to with the materials. According to the US Department of Defense’s global Space Surveillance Network (SSN) more than 15,000 pieces of space debris larger than 4 inches have been tracked. It is also estimated that there are around 200,000 pieces between 0.4 and 4 inches, and millions of pieces smaller than 1cm.