Comet probe regains eyesight before Earth flyby

Artist's conception of Stardust

By Richard Stenger
CNN.com Writer

(CNN) -- A comet-chasing probe experienced a marked improvement in its vision this week, shortly before it was scheduled to swing around Earth, NASA scientists said.

The navigation camera aboard NASA's Stardust spacecraft had malfunctioned for months after unknown contaminants fouled up its optical surfaces.

But Stardust engineers managed to clear up the robot ship's blurry sight by ordering it to heat up its camera parts, which boiled off the blinding goo.

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Tests last year revealed a problem with the onboard camera, which takes pictures of stars to navigate the craft on a mission to visit a comet. And photographic images beamed back to Earth turned out much fuzzier than expected.

"The contamination might have been released with gases escaping from the spacecraft after its launch," concluded the Stardust team in a statement Thursday.

After heating the optical components of the camera, the team re-tested the camera and received much clearer pictures.

The correction should allow the spacecraft to perform its final navigation maneuvers when it approaches the comet, said the Stardust engineers, who work at NASA's Jet Propulsion Laboratory in Pasadena, California.

Stardust regained its vision just in time for a close encounter with its home planet, from which it was launched in February 1999.

The refrigerator-sized probe should fly to within 3,700 miles (6,000 km) of Earth on Monday, giving it a gravitational slingshot boost on its way to its final destination, Comet Wild- 2. Traveling at about 6.2 miles per second (10 km per second), the probe should reach the ice chunk in 2004.

The $200 million Discovery mission is the first designed to collect and return material from beyond the moon. The probe should drop a payload of comet and interstellar dust particles in a Utah desert in 2006.

By studying what Stardust returns, scientists think they could learn if comets provided the water and organic material necessary to form life.

Comets, possibly the oldest bodies in the solar system, could contain a record of the original material that formed the sun and planets 4.5 billion years ago.

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NASA Jet Propulsion Laboratory

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