After three previous attempts to launch, the space shuttle Discovery lifted off into outer space in what was the last scheduled nighttime launch remaining for the shuttle fleet. NASA only has six more shuttle missions planned before the fleet is retired either in 2010 or 2011. The 37th flight for Discovery started with a brilliant nighttime launch into orbit at 11:59 pm ET Friday night.

In the first test of planetary protection technology, astronauts on the International Space Station (ISS) swabbed their space-walking gear for microbes, using the "Lab-On-A-Chip Application Development Portable Test System" (LOCAD-PTS), a compact biological laboratory designed for use in space. Such tools will be further developed and refined to prevent humanity from contaminating other planets.

The crew of the U.S. space shuttle Atlantis is making final preparations for Thursday's scheduled return to Earth. The shuttle will have two opportunities to land at NASA's Kennedy Space Center in the southern U.S. state of Florida. But a possibility of thunderstorms and low clouds over the landing site could postpone the shuttle's return until Friday.

Russian specialists monitoring the current Atlantis mission to the International Space Station said the U.S. space shuttle's crew were preparing for their first spacewalk Monday, a day after docking with the orbital station, run jointly by Russia's Federal Space Agency and NASA.

NASA will try to launch Atlantis on the first space shuttle mission of the year in early June, almost three months later than originally planned, so that technicians can finish repairing its hail-damaged fuel tank, officials said.