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Stardust Sees Stellar Ending

A seven-year journey to gather comet particles concludes with a capsule landing in Utah. JPL considers the mission a major success.

January 16, 2006|John Johnson Jr. | Times Staff Writer

NASA's audacious Stardust mission, a seven-year effort to learn more about the origins of the solar system by capturing particles from the tail of a comet and returning them to Earth, ended successfully Sunday when the spacecraft's scorched capsule parachuted into the Utah desert, its cargo intact.

The desk-sized capsule glowed red as it streaked across the sky over the northwest United States on its way to a 2:10 a.m. soft landing at the Air Force Test and Training Range in Dugway, Utah.

The mission was a major accomplishment for NASA's Jet Propulsion Laboratory in La Canada Flintridge and Lockheed Martin Space Systems in Denver, which jointly oversaw the spacecraft on its 2.88-billion-mile journey to snatch pieces of a speeding comet and bring them back to Earth.

"This is really a great day for NASA and the exploration of our solar system," said Andrew Dantzler, head of NASA's solar system division.

Tom Duxbury, project manager at JPL, said: "This thing went like clockwork."

Launched Feb. 7, 1999, Stardust made two loops around the sun before meeting up with comet Wild 2 between Mars and Jupiter in January 2004. The craft flew as close as 147 miles to the hamburger-shaped comet, passing through its tail of dust and exotic gases.

The spacecraft deployed a tennis racket-shaped collector, packed with a material called aerogel, to capture comet particles, which are thought to be the building blocks of the solar system.

Scientists won't know for a few days how many comet particles were collected, but they said early evidence pointed to a successful mission.

As Stardust neared Earth, it released a capsule containing the captured samples just before 10 p.m. Saturday. The capsule, protected by a thick heat shield, entered the atmosphere about 2 a.m., while the main spacecraft remained in orbit. High winds in the mountains of Utah pushed the capsule slightly off course during its descent.

NASA program managers still called it a "bull's-eye" landing on a surface muddied by recent rain.

Controllers were especially pleased to see the parachute open after 2004's near-disastrous end to NASA's Genesis mission. Like Stardust, Genesis was a difficult sample-return mission, the first U.S. attempt since Apollo 17 brought back moon rocks in 1972.

Genesis was returning with microscopic evidence of solar wind, the energy particles that flow out from the sun, when its parachute failed to open and the capsule "pancaked" in the Utah desert. Scientists have spent months trying to reassemble its delicate collector array. Like Genesis, Stardust was built by Lockheed Martin.

In contrast, everything seemed to go near perfectly for Stardust.

The only apparent damage was the loss of small bits of the heat shield due to the tremendous temperatures the capsule experienced on its return trip. Because of the complicated geometry of the journey, Stardust reentered the Earth's atmosphere at a higher speed than any spacecraft in history -- 29,000 mph.

On Sunday, technicians at Dugway removed the science materials, including the aerogel collector in which the particles bury themselves like a baseball going into a mitt, for shipment to the Johnson Space Center in Houston.

Mission scientists hope they captured thousands of particles. The largest they expect to find are about one-fifth of an inch in diameter. Most are likely to be in the range of microns, thinner than a human hair.

"The real touchdown will be when we open it up Tuesday ... and figure out how many particles we did capture," said Joe Vellinga, Lockheed Martin's Stardust manager.

The dust and ice particles captured by Stardust will help scientists understand the complex chemical and physical processes that lead to the formation of planets around stars.

Comets are some of the oldest and least tainted objects in the solar system.

"The most interesting thing about comets is they are libraries with the stored records of our formation," said Donald Brownlee of the University of Washington, the mission's principal investigator.

"All the atoms on Earth and in our bodies were in stardust before the solar system formed."

Originally thought to be dirty ice balls, evidence collected from last summer's Deep Impact mission -- which sent a probe into comet Tempel 1 -- showed they would be more accurately characterized as icy dirt balls, composed of what Brownlee called an "organic goo."

The dirt of a comet is not like dirt on Earth. However, scientists theorize that comets could have seeded an early Earth with some of the molecular building blocks of life. Lending weight to this idea was the 1979 discovery of a meteorite in Australia containing amino acids.

Looking at the components of a comet such as Wild 2 is like looking back in time billions of years.

Unlike the loosely-arranged, oblong-shaped Tempel 1, Wild 2 is rounder, with rugged features that include craters and cliffs 300 feet tall. "It's very bizarre," Brownlee said.

Both comets are about a mile across.

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