Newsbeat Technology Reporter
The missile launched by the US Navy to intercept the spy satellite
The United States is being accused of engaging in an arms race in space after it used a missile to shoot down one of its own spy satellites.
USA193 was descending out of control towards earth. American military sources said it posed a risk to people on the ground because of hazardous chemicals in its fuel tank.
However Russia has claimed that story is simply an excuse for the US to test its ground-to-space missile technology.
'Star Wars' nothing new
Others believe the exercise may have been a show of strength directed at Beijing.
In January 2007, China used a medium-range ballistic missile to destroy a weather satellite.
The idea of using space as a battleground is nothing new. It dates back to 1983 when US President Ronald Reagan proposed the Strategic Defence Initiative (SDI). The project later became known as 'Star Wars'.
In the event of attack by Soviet missiles, American submarines would launch X-Ray laser cannons into space.
Armed satellites planned
A nuclear explosion would power a high energy pulse beam which could destroy incoming nuclear warheads.
The SDI project also experimented with a number of other 'Directed Energy Weapons'. These included chemical lasers and particle beam systems.
Rail guns were also suggested. These use electrical charge to fire projectiles at ultra-high speed.
There were also plans to launch thousands of armed satellites into orbit. 'Brilliant Pebbles' would have shot down incoming missiles by targeting them with small projectiles, fired from space.
Much of the technology involved in SDI was still in development when the cold war ended. However the United States continued developing anti-missile systems.
Experiments with weapons
Under Bill Clinton, the organisation running SDI changed its name to the Ballistic Missiles Defence Organisation (BMDO) in 1993.
The new organisation abandoned the idea of covering the whole globe, and focussed on protecting specific areas.
In 2002 BMDO underwent another rebranding. The new Missile Defence Agency continues to experiment with high-tech intercept weapons.
Among them, airborne laser systems which are fitted to 747 airplanes. ABL beams are used to target incoming missiles, weakening their metal shells and causing them to break apart.
The system is currently in development. If successful, the US military is expected to commission seven ABL equipped planes for global patrol.