Space shuttle Discovery made a rare middle-of-the-night landing today after its crew members accomplished their last orbital job -- releasing Starshine, a glittery, educational satellite.

Discovery touched down at 2:03 a.m. on Kennedy Space Center's floodlighted runway, ending a journey of nearly 4 million miles. NASA's space shuttles have landed in darkness only 10 times before.

Commander Kent Rominger and his crew spent six of their 10 days in orbit at the new international space station. They left 2 tons of tools, water, clothes and other supplies for the first permanent crew, scheduled to arrive next spring.

Before departing Thursday, the astronauts also fixed a broken radio, replaced flawed battery packs and made the station quieter by installing mufflers over noisy fans.

This was only the second crew to visit the orbiting outpost. The first crew connected the station's two components in December.

It will be this December before shuttle astronauts arrive with more supplies. But, first, Russia must launch its long-delayed service module; that is scheduled for November.

Discovery's astronauts briefly set aside their packing for the release of Starshine, a 19-inch sphere covered with 878 small, circular mirrors that were polished by schoolchildren.

In the educational project, more than 25,000 students around the world will track the satellite over the next seven to eight months and, in doing so, determine the atmosphere's density.

Reminiscent of a 1970s disco ball, the $1 million Starshine twinkled as it popped out of a canister in the shuttle's cargo bay and floated away. Observers on the ground could spot it easily with the naked eye.

"It was a fantastic sight," said Canadian astronaut Julie Payette, who pushed the ejection button. "The first thing we all saw was the flickering of the mirrors. . . . We could track it with our cameras for the longest time because it's now and then getting a flash. It's beautiful."

The project's director, Gil Moore of Utah State University, said the satellite should remain in orbit until January before it plunges through the atmosphere and burns up.