Comet Dust Streaking Towards Earth

This illustration provided by NASA shows the Stardust spacecraft, left, encountering comet Wild 2. The Stardust's round-trip, interstellar rendezvous to comet Wild 2 draws to a close Jan. 15, 2006, when the spacecraft jettisons a canister containing comet grains through the Earth's fiery atmosphere to the high Utah desert.
The last time NASA scientists hunkered down at a remote desert Army base, they stared wide-eyed as a space probe hauling solar wind atoms crashed into the salt flats and split open like a giant clamshell.

Flash forward two years.

Nerves are on edge as scientists anxiously await the return of another space probe — this one named Stardust and bearing the first comet samples ever carried to Earth. Hovering 69,000 miles up, the spacecraft released the shuttlecock-shaped capsule late Saturday, putting it on course for a blazing re-entry at the Army's remote Dugway Proving Ground early Sunday.

During its mission, the Stardust captured comet dust, collecting a pay load that will barely fill a teaspoon – and yet the incredibly tiny samples were swirling about four and a half billion years ago, reports CBS News correspondent Jerry Bowen.

Scientists believe studying comets could shed light on how the solar system formed.

Memories of the ill-fated 2004 Genesis landing, in which the space probe's parachutes failed to open, are still vivid.

Scientists later found that gravity switches installed incorrectly caused the failure. Despite the mishap, they were able to salvage the tiny cosmic samples for study.

Afterward, engineers performed a thorough check on Stardust's systems and feel certain that it won't suffer the same fate as Genesis.

"They built this thing like a tank. They do believe that even if the parachute system failed, that they could still recover these samples," said CBS News space consultant Bill Harwood .

"I don't think you can ignore the Genesis situation. You just have to embrace it and apply the lessons learned from it," said Ed Hirst, mission system manager at NASA's Jet Propulsion Laboratory, which is managing the $212 million project.

Stardust left on a seven-year, 2.9 billion-mile journey that was highlighted by a flyby of comet Wild 2, a jet-black ball of ice and dust that was about 500 million miles away from Earth when the probe was launched in 1999.