February 14, 2008
Posted: 04:05 PM ET
The Pentagon announced today that sometime in the next few weeks a U.S. Navy ship will shoot down a failed National Reconnaisance Office spy satellite.
We don't know much about the satellite in question except that it launched on December 14, 2006 and it failed several hours after entering orbit.
It was apparently designed with the ability for a controlled de-orbit, but since command and control has been lost, that's now out.
Expert analysis indicates about half of the 5000-pound satellite would survive atmospheric reentry. It has a full tank of noxious hydrazine rocket fuel aboard, which would vent if the tank survived and hit the ground. Anyone within two football field's distance would be sickened by the fumes.
The U.S. Navy will fire one SM-3 missile from a ship in an effort to hit the satellite just as it grazes the atmosphere. By waiting until it is just about to re-enter before blasting it, they intend for most of the debris to quickly fall out of orbit and burn up ... most of it within hours, almost all of it within days or weeks.
This is not the first time a government has shot down a satellite. A decision to shoot down the satellite is sure to cause controversy in the aerospace community, as it would result in a massive amount of additional space junk in low earth orbit.
In January 2007, China used a land-based missile to destroy a 2,200-pound weather satellite called Fengyun-1C that was orbiting 528 miles above Earth.
That impact left more than 150,000 pieces of debris floating around he Earth, the NASA Orbital Debris Program Office estimates. The space agency characterizes nearly 2,600 pieces s "large," meaning greater than 10 cm (4 inches) across.
China is responsible for 42 percent of all satellite debris in orbit as of January 1, most of it from that Fengyun-1C satellite. NASA has called it the worst satellite breakup in history.
-Kate Tobin, Senior Producer, CNN Science & Technology
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