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NASA Stardust Mission Capsule Brings Comet Dust to Earth

15 January 2006

Cargo will help answer questions about comets, solar system origins

By Cheryl Pellerin
Washington File Staff Writer

Washington -- After spending nearly seven years in space and traveling more than 4.6 billion kilometers, the National Aeronautics and Space Administration's (NASA’s) Stardust capsule returned to Earth in the early morning hours of January 15, carrying precious samples of cometary and interstellar dust.

Scientists believe the cargo will help answer basic questions about comets and the origins of the solar system.

The capsule entered the atmosphere at 46,670 kilometers per hour -- faster than any human-made object on record. A drogue parachute (a small parachute used to pull a main parachute from its storage pack) was supposed to deploy at about 32 kilometers above the Earth but did not appear to do so.

At three kilometers, the main parachute deployed after being packed away for seven years, eventually slowing the capsule to about 16 kilometers per hour to make a soft landing in the desert at the U.S. Air Force Utah Test and Training Range, southwest of Salt Lake City.

The capsule is 81 centimeters in diameter and 53 centimeters high, and weighs 43 kilograms.

"All stations, we have touchdown," Stardust Project Manager Tom Duxbury of NASA’s Jet Propulsion Laboratory announced at 5:12 a.m. EST (10:12 a.m. GMT), after which NASA scientists at Mission Control broke into applause and cheers.

Helicopters quickly found the capsule, which was examined and packed up for a trip to the Michael Army Air Field at the U.S. Army Dugway Proving Ground in Utah for initial processing.

Later, the samples will be moved to a special laboratory at NASA's Johnson Space Center in Texas, where they will be preserved and studied.

"With the information we gathered during our encounter with comet Wild 2 in January 2004, Stardust has already provided us with some remarkable science," said Don Brownlee, Stardust principal investigator at the University of Washington in Seattle.

"With the return of cometary samples," he added, "we'll be able to work with the actual building materials of the solar system as they were when the solar system was formed. It will be a great day for science."

The $168.4 million mission (not including the Delta 7426 launch vehicle) was launched from Cape Canaveral Air Force Station in Florida in February 1999. Stardust has circled the sun three times in nearly seven years.

SPACECRAFT CAPTURED OTHERWORDLY SAMPLES, IMAGES

On the way to its comet encounter, the spacecraft collected interstellar dust on two different solar orbits.

On January 2, 2004, after traveling 3.41 billion kilometers across the solar system, Stardust made its closest approach of comet Wild 2 at a distance of 240 kilometers.

During this flyby, a special collector captured particles of the comet as the spacecraft flew through the coma -- or cloud of dust and debris -- surrounding Wild 2.

Aerogel, a silica-based material contained in a tennis-racket-shaped grid, was developed specially to help capture the comet material without damaging it.

Along with this cosmic sampling, the spacecraft also took remarkable images of comet Wild 2’s nucleus.

The otherworldly landscape included such features as steep near-vertical cliffs, house-size boulders, pinnacles, flat-floored craters with near-vertical walls, overhangs and materials of varying brightness.

The images showed a complex rugged surface that is quite different from those of other comets, asteroids and moons that have been imaged.

Deep depressions on the comet suggest that regions of the surface have eroded to depths of 100 meters or more. One of the most spectacular findings was that the comet had more than 20 active jets -- localized hotspots -- spewing gas and dust into space.

Six hours after the comet encounter, the spacecraft carried out a half-hour process of retracting and stowing the sample collector with its cometary pickings. From that point on, the sample canister has been sealed.

In the hours and days following the encounter, images and other science and engineering data recorded onboard during the event were transmitted to Earth.

SAMPLES FROM DEEP SPACE

Stardust is the first spacecraft with the ability to retrieve samples obtained in deep space and to return them to Earth for research.

NASA expects most of the collected particles to be no more than a third of a millimeter across. Scientists will slice the particle samples into even smaller pieces for study.

The mission is a joint effort among NASA, several universities and industry partners. It is the fourth in a series of NASA Discovery missions that are economical and use high-performance technology.

"Our mission is called Stardust in part because we believe some of the particles in the comet will be older than the sun and planets that formed around other stars," said Stardust principle investigator Don Brownlee at a December 21 NASA briefing. "We call them stardust."

More information about the Stardust mission is available on NASA’s Web site.

(The Washington File is a product of the Bureau of International Information Programs, U.S. Department of State. Web site: http://usinfo.state.gov)