'Stardust' sweeps up space dust, snaps rare comet pics
Particles could unlock secrets of the universe
By Jeordan Legon
The Stardust spacecraft captured rare pictures of the nucleus of a comet.
(CNN) -- After traveling five years and 2.3 billion miles, a speeding NASA space probe pounced on the shimmering tail of a comet Friday, trapping tiny space dust to bring back to Earth and snapping rare, closeup pictures of a celestial body.
Shortly after 2:45 p.m. ET today, the Stardust spacecraft reached its closest point with the massive chunk of ice and rock known as the Wild 2 Comet, getting within 200 miles at a relative speed of 13,645 mph, the National Aeronautics and Space Administration said.
At that point, the craft made a turn, pointing a camera at the nucleus of the comet and snapping pictures that began arriving on Earth an hour later. The probe also reported that its robotic arm trapped comet dust in a tennis-racket-shaped catcher filled with a material called aerogel.
"We have successfully collected samples from the comet and we're bringing them home for analysis in laboratories all over the world," said Don Brownlee of the University of Washington, principal investigator for the $200 million Stardust mission.
While the space particles will take two years to travel back to Earth, scientists say a dust counter began signaling Stardust mission control almost immediately with the size and number of particles gathered. Another gadget is expected to analyze and report the composition of the matter. And researchers hope to receive many more black-and-white pictures of the comet's frozen core in the coming days.
But the biggest promise lies with the dust aboard the spacecraft. If it makes it back, the mission would be the first robotic retrieval of extraterrestrial material since 1976, when the Soviet Luna 24 returned soil and rock from the moon.
The hope is that the comet's dust, which has been lingering in the cold of space for billions of years, could provide clues to how the solar system formed, including the sun and planets, and perhaps other stars and the universe.
"In recent decades, spacecraft have passed fairly close to comets and provided us with excellent data," Brownlee said. "Stardust, however, marks the first time that we have ever collected samples from a comet and brought them back to Earth for study."
Surviving the close encounter 242 million miles from Earth with the Wild 2 -- pronounced Vilt 2 -- wasn't easy. Scientists prepared the refrigerator-sized craft to be pelted with rocks and other debris traveling six times faster than a speeding bullet. The Stardust was protected by two bumpers in the front, guarding its solar panels, and another shield on the probe's body.
"We've flown through the worst of it and we're still in contact with our spacecraft," said Tom Duxbury, Stardust program manager.
"We can breathe easy," he said, shaking hands with fellow scientists in NASA's Jet Propulsion Lab in Pasadena, California.
An artist rendering of Stardust's encounter with Comet Wild 2.
After gathering the particles, the collector was expected to fold down into a capsule, programmed to close like a clamshell and make its return trip to Earth.
In January of 2006, the capsule is scheduled to detach from the craft and make a soft landing in the Utah desert, while the Stardust mother ship remains in space. The capsule could also bring back particles that it collected from February through May 2000, when Stardust passed through a region where interstellar particles flow through the solar system.
"The science that's going to come out of this, that's going to tell us about the early formation of our solar system, the role that comets have played in the formation of Earth and ourselves, that will unfold over the next few years," Duxbury said. "The science that this project is returning will be unprecedented."
Researchers hope the unique chemical and physical information locked within the comet's dust samples, which collectively could fit in a thimble, will teach them whether comets or interstellar dust provided the water or 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. Interstellar particles, also gathered by the Stardust mission, consist of most of the known elements and include complex carbon structures. Their exact origin remains a mystery but scientists think they are linked to young stars.
"We're collecting things that are very ancient and even older than our solar system," Brownlee said. "We are literally reaching for the stars."