Atlantis' astronauts blasted an electron beam gun at the Earth on Thursday to create artificial auroras in the heavens and tried to communicate with Russian cosmonauts aboard the Mir space station.
Although astronaut David Leestma received sound from Mir around 5:40 a.m. EST, his signal was not acknowledged. The Atlantis crew shuttle had three more time periods Thursday morning to try to contact the Russian station, but there was no immediate word on whether contact was made.The only time a U.S. and Russian spacecraft have talked ship-to-ship was in 1975 during the Apollo-Soyuz mission. Astronauts tuned in to Mir last April, but it was uncertain whether the cosmonauts could hear them and so they could not have a conversation.
The paths of the two space crafts crisscross during two 90-minute orbits. On the first pass, the ships came within about 540 miles of each other over Eastern Europe and the former Soviet Union as Mir passed below Atlantis' tail.
Atlantis' seven-member crew is on the third day of an eight-day mission to study Earth's delicate ozone layer and other aspects of the atmosphere.
The electron beam gun - one of 13 scientific instruments in the cargo bay - was fired Thursday in an attempt to create an artificial aurora in the Southern Hemisphere.
Astronaut Byron Lichtenberg explained that the beam's particles travel down through the atmosphere along one of Earth's magnetic field lines, then collide with and energize atoms of nitrogen and oxygen. As the atoms lose their charge, "they emit energy in particular colors, whether it's green or blue or red or whatever."