On Feb. 20 the United States destroyed an out-of-control intelligence satellite with a three-stage missile fired from an Aegis cruiser in the Pacific Ocean. For the first time, the U.S. has used a missile from its missile-defense system to destroy a satellite. In January 2007, China destroyed an old weather satellite with a ground-based ballistic missile. In the 1980s, the U.S. and the Soviet Union carried out similar tests of antisatellite weapons. It is hoped that these developments do not encourage nations to accelerate an arms race in outer space.

The U.S. decided to use a ship-fired tactical Standard Missile-3 to shoot down the spy satellite because the satellite was loaded with a toxic fuel and was expected to begin uncontrolled re-entry into Earth's atmosphere on or about March 6. The U.S. held out the possibility that the satellite, which had become uncontrollable after it was launched in December 2006 and carried 450 kg of hydrazine, could leak toxic gas over a wide area if it survived the re-entry.

Experts say that although 50 to 200 "large" pieces of man-made space debris return to Earth every year, there are no reports of people being injured by such debris. That's because water comprises about 70 percent of Earth's surface. There is speculation that the U.S. destroyed the satellite to flaunt the power of its missile-defense system. The U.S. says the shootdown of the satellite does not represent a test of an antisatellite weapon. It should offer a full explanation.