At those speeds, impacts involving even the smallest of those items can damage satellites and spawn chain reactions of collisions, increasing the amount of orbital flotsam and creating "minefields" in space that can remain unpassable for centuries.
Tracking debris is thus essential-not just to protect existing commercial and government satellites but also to ensure that paths to critical locations in low Earth orbit (LEO), geosynchronous orbit, and orbits in between stay clear and safe for future space assets," DARPA stated.
NASA weighs in
In March, NASA updated its top 10 space junk missions. NASA' s Orbital Debris Program Office said that by far the source of the greatest amount of orbital debris remains the Fengyun-1C spacecraft, which was the target of a People's Republic of China anti-satellite test in January 2007.
"This satellite alone now accounts for 3,428 cataloged fragments or almost 20% of the entire population of cataloged manmade objects in orbit about the planet. Additional debris from this test and other events are currently being tracked by the U.S. Space Surveillance Network (SSN) and are officially cataloged on a routine basis," NASA stated. In 2010 there were 2,841 pieces of junk from this spacecraft.
Orbital debris can include all manner of space system parts from derelict spacecraft and upper stages of launch vehicles to debris intentionally released during spacecraft separation from its launch vehicle or during mission operations and even tiny flecks of paint from small particle hits on existing spacecraft, NASA said.
The space agency says that 10 missions out of the 5,160 space missions that have launched since 1957 account for approximately one-third of all cataloged objects now in Earth orbit.
NASA said that the second and fourth most significant satellite breakups are Cosmos 2251 and Iridium 33 spacecraft, which were involved in the first ever accidental satellite collision February 2009.
"While over 68% of the Cosmos debris cloud remains on orbit, only 58% of the Iridium cloud is on orbit, due in part to the higher area-to-mass ratio bias of the latter cloud. Because of their relatively high altitude, these clouds will continue to present a hazard for decades to come, NASA said.
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