Science and Space

space and astronomy articles.

Stardust coming

Comets have been scrutinized for centuries. But only in recent years have scientists had the technology to learn firsthand their ingredients.

Last July, the Deep Impact spacecraft released a probe that carved a crater in a comet, exposing its interior to NASA telescopes.

The $212 million 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. Stardust traveled nearly 3 billion miles halfway to Jupiter and back, looping around the sun three times. Along the way, it also captured interstellar dust — tiny particles thought to be ancient stars that exploded and died.

After five years, the 850-pound spacecraft finally reached Wild 2. During a historic 2004 flyby, Stardust sped through the comet’s coma to collect the microscopic samples. The particles were trapped by a catcher the size of a tennis racket, which has since been clammed up inside the capsule for the trip home.

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

Early Sunday, the 100-pound capsule will penetrate the atmosphere. Traveling at supersonic speed, the capsule will release its first parachute at 100,000 feet, followed minutes later by a larger chute, which will guide it to a landing.

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.

posted by: kyawoo at 02:38 | link | comments |
unmanned missions, comets

« first

‹ previous

1 2