The Nation : Shuttle Tests Ionosphere

In a study important to the “Star Wars” defense program, the space shuttle Challenger’s astronauts fired its rocket engines while scientists using telescopes in Australia attempted to analyze the exhaust’s effect on charged gas particles, called plasma, that make up the ionosphere. Scientists “saw the burn” as Challenger passed over the Reber Observatory in Hobart, Tasmania, a National Aeronautics and Space Administration spokesman said. A shorter rocket firing was done over observatories in Massachusetts. The Strategic Defense Initiative space-based missile defense system will use lasers or particle beams in the ionospheric plasma to track and destroy attacking missiles.