Return of Stardust space probe is eagerly awaited

DUGWAY PROVING GROUND — The comet dust is coming.

A NASA spacecraft carrying the first comet dust samples to Earth is on course to land in the Utah desert this weekend.

"We are nearing the end of quite a fantastic voyage," said Don Brownlee, principal investigator for the Stardust project.

Late Friday, the spacecraft adjusted its flight path for the third and final time. Then late today, it is scheduled to release the shuttlecock-shaped capsule that will plunge through the atmosphere for a parachute landing early Sunday.

The mothership will enter perpetual orbit around the sun.

The best place to watch the Stardust space probe burn through the atmosphere prior to its landing at Dugway Proving Ground may be along a line from Elko, Nev., to Wendover. People there may also hear its sonic boom, said Patrick Wiggins, NASA solar system ambassador to Utah and Nevada.

"Assuming good weather, the problem is that it's simply going to be so low from the sky that, say, from the Salt Lake Valley, the Oquirrhs will probably stick up higher than the spacecraft will be," Wiggins said.

Stardust's homecoming will mark the end of a seven-year, $212 million journey in which the spacecraft swooped past comet Wild 2 to collect microscopic dust. Along the way, it also captured interstellar dust, storing all the samples inside the capsule for the trip home.

Scientists believe about a million dust particles will be returned, including some older than the sun.

Comets are icy bodies that formed in the outer fringes of the solar system. Studying comets could yield important clues to the origins of the solar system, scientists say. The Stardust capsule is set to land at a remote Army base — the same site where NASA's Genesis probe carrying solar wind atoms crashed in 2004 after its parachutes failed to open.

If Stardust makes a hard landing, scientists say they should be able to recover most of the samples because they are locked in a capsule that was built to withstand more impact than the Genesis probe.

The mission is managed by the Jet Propulsion Laboratory in Pasadena, Calif.