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BBC News Online: Sci/Tech

Wednesday, 23 February, 2000, 11:53 GMT

Spacecraft collects stardust

Stardust will collect material from a comet and bring it back to Earth

By BBC News Online science editor Dr David Whitehouse

The Stardust spaceprobe has begun sweeping-up particles of interstellar dust that stream into our Solar System from distant stars. In a few years, the space dust will be brought back to Earth. Aerogel: Almost nothing at all

"This will be the first sample-return mission ever beyond the Moon," said Don Brownlee, the mission's principal investigator.

Stardust will keep its dust collector extended until May and again during much of 2002. During that time, scientists hope the metre-square collector will sweep-up as many as 100 of the particles.

Along with bits of comet dust that the other side of the collector will trap in 2004, Stardust will then return the samples to Earth in 2006, jettisoning them to a soft landing in Utah, US.

Butterfly net

The interstellar dust grains, about a thousandth of a millimetre in size, will be trapped in any one of 130 blocks of glass foam. The Aerogel collector on Stardust

"This is our butterfly net, if you will," says Kenneth Atkins, Stardust's project manager at Nasa's Jet Propulsion Laboratory.

The dust particles are captured in a very light substance called Aerogel which slows the particles down without harming them.

When they strike the Aerogel, they are travelling at a speed relative to Stardust of between 10 and 26 km per second (6 to 16 miles per second).

Other suns

Astronomers believe that the dust particles come from stars elsewhere in our galaxy, where they are formed by condensation around those other suns.

"The Milky Way is awash with the stuff - just peer upward on a clear night," Brownlee said.

"You see this dark band running along the middle of it?" Brownlee adds, "That is interstellar dust, blocking the light of some stars."

Once the sample capsule is back on Earth, scientists will use an arsenal of instruments including electron microscopes, ion microprobes, atomic force microscopes, synchrotron microprobes, and laser probe mass spectrometers, to coax the interstellar grains to give up their secrets.

Related to this story:
Eyes up for the Leonids (15 Nov 99 | Sci/Tech)
Voyage through a comet's trail (17 Nov 99 | Sci/Tech)
Balloon bags space dust (12 Apr 99 | Sci/Tech)
Caught a falling star (14 Apr 99 | Sci/Tech)
Space probe on comet quest (09 Feb 99 | Sci/Tech)

Internet Links: Stardust (Nasa)
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