- The Washington Times - Monday, January 9, 2006

LOS ANGELES (AP) — Comets have long lighted up the sky and the imaginations of scientists. Now these icy bodies from the beginnings of the solar system are ready for their close-up.

Six months after NASA scientists first peeked inside one comet from afar, they are bringing pieces of another to Earth for study under the microscope.

This weekend, the Stardust spacecraft will jettison a 100-pound capsule holding comet dust. It will nose-dive through the Earth’s atmosphere and, if all goes well, make a soft landing in the Utah desert.

The searing plunge is expected to generate a pinkish glow as bright as Venus that should be visible without a telescope across much of the West.

Astronomers consider comets among the solar system’s leftover building blocks. The heavenly bodies have been scrutinized for centuries, but only in recent years have scientists had the technology to learn firsthand their ingredients.

In July, the Deep Impact spacecraft released a probe that carved a crater in a comet, exposing its interior to NASA telescopes. The Stardust mission went a step further by retrieving the first samples from a comet named Wild 2, which was about 500 million miles from Earth when Stardust launched in 1999.

Comets are bodies of ice and dust that circle the sun. About 4.5 billion years ago, a cloud of gas and dust collapsed to create the sun and planets. Comets formed from what was left over, and scientists hope that studying them will shed light on the solar system’s birth.

“This is a true treasure,” principal investigator Don Brownlee of the University of Washington said of the Stardust capsule.

For the capsule to come home, it faces a blistering descent, piercing the atmosphere at a record-breaking 29,000 mph — the fastest re-entry of any man-made probe.

Its target is Dugway Proving Ground, a Rhode Island-sized Army base southwest of Salt Lake City where in 2004 the ill-fated Genesis probe crashed on live television after its parachute failed to open. Despite that crash, scientists recovered enough solar wind atoms for study.

To avoid another embarrassment, engineers checked Stardust’s systems and think they will work, said Ed Hirst, a mission system manager at NASA’s Jet Propulsion Laboratory in Pasadena, which is managing the $212 million mission.

Comet particles from Stardust would represent the second robotic retrieval of extraterrestrial material since 1976, when the unmanned Soviet Luna 24 mission brought back moon samples.

If all goes as planned, the main spacecraft will free the shuttlecock-shaped capsule about 69,000 miles from Earth late Saturday. Then the mother ship will fire its thrusters and go into a perpetual orbit around the sun.

Scientists think thousands of particles of comet and interstellar dust, most smaller than the width of a human hair, are locked inside the capsule. To determine the makeup of the particles, scientists will slice the samples into even smaller chunks and probe them under powerful microscopes, Mr. Brownlee said.

“We are literally bringing back samples of the solar system as they were billions of years ago,” he said.

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