The USA 193 Spy Satellite

A 24-story Delta IV-Heavy rocket is poised for launch on Cape Canaveral's Complex 37B in July 2012. The payload? A classified spy satellite for the National Reconnaissance Office dubbed NROL-15.

© Ben Cooper/SuperStock/Corbis

On Dec. 14, 2006, Vandenberg Air Force Base launched a rocket carrying a satellite called USA 193. The satellite was part of the National Reconnaissance Office's (NRO) intelligence program. In other words, it was a spy satellite. T­he satellite had trouble maintaining orbit, and by late 2007 the Air Force determined that it would soon crash to Earth. The U.S. government announced in January 2008 that it intended to shoot the satellite down with a missile.

Why shoot down the satellite? The government said it was because the satellite's fuel tank contained hydrazine, which is toxic. If the fuel tank survived re-entry, it could land on a populated area. On Feb. 20, 2008, the U.S. fired a missile and struck USA 193. Some people believe the government didn't tell the entire story. They say that the government also wanted to prevent the satellite from falling into another country's possession. Others go even further and suggest the United States only wanted to show the world that it's capable of shooting down a satellite with a missile. In 2007, China destroyed a weather satellite with a missile, calling it a test. That test spread debris in an area around the Earth filled with other satellites, endangering those machines. By contrast, the United States' approach was to fire on USA 193 when it reached a low enough orbit to minimize danger to other satellites. Was the U.S. government using USA 193 as an excuse to respond to China's test missile? Some people think so.