On Jan. 11, 2007, a Chinese missile intercept of the defunct Fengyun-IC weather satellite led to the creation of over 2,300 new trackable elements of orbital debris in low Earth orbit. On Feb. 10, 2009, the collision of the Iridium 33 and Russian Kosmos-2251 satellites created over 2,000 new trackable elements of orbital debris. Today there are over 22,000 elements of orbital debris being tracked - mosdy in low Earth orbit But there are also over 500,000 elements of orbital debris the size of a marble, plus millions the size of a grain. Even these small elements have enough kinetic energy to damage a spacecraft or pierce a spacesuit. Donald Kessler, the NASA scientist who first warned of orbital debris build-up, has now projected that without any more collisions we may still see a significant collision once every 10 years.
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