Needle-in-a-haystack hunt underway

Stardust@home opens for volunteers to search for interstellar dust buried in spacecraft's payload.
By | Published: August 3, 2006
August 3, 2006
In January 2006, the University of California, Berkeley, launched a web site to recruit volunteers for its Stardust@home project — a chance for anyone with a computer to join the hunt for interstellar dust specks captured by NASA’s Stardust spacecraft. On August 1, participants began analysis.
Dust grains from Comet Wild 2
Dust grains from Comet Wild 2 plowed into Stardust’s aerogel collectors at more than 13,000 mph (22,000 km/h). The aerogel slowed the entering particles. Each grain appears at the end of a trail of melted glass. Some particles punched two-thirds of the way through the 1.2-inch-thick (3 cm) material.
Stardust encountered Comet Wild (pronounced “Vilt”) 2 in January 2004. During this meeting, the spacecraft used its racket-shape collector to gather less than an ounce (28 grams) of comet dust and a few interstellar dust specks. Aerogel, a substance attached to the collector in 132 panels, captured the particles. In January 2006, Stardust jettisoned the sample-return capsule, which landed in Utah.

When UC Berkeley announced Stardust@home, the program received nearly 115,000 volunteers. Participants use a web-based virtual microscope to search for the fewer than 50 grains of submicroscopic interstellar dust scientists expect are imbedded in the panels. The dust particles, made in supernova explosions as much as 10 million years ago, will provide insight to distant stars’ internal processes.

“The scanning, which is being done at Johnson Space Center in Houston, has been more challenging than we hoped,” explains Stardust@home Director Andrew Westphal. “The terrain of the aerogel surface is rougher than we expected, which makes it difficult to get the scanner in focus.”

While Stardust team members have extracted comet dust grains from the detectors and are analyzing them, it hasn’t been as easy to scan the aerogel for micron-size grains of interstellar dust.

“How we analyze these grains depends a lot on how big they are,” says Westphal. “These grains will be so precious that they will be studied for decades”

If the particles are as large as the comet dust, they could be studied with an X-ray microscope or probed with ion or electron beams.

On August 1, pre-registrants were notified about the initiation of Stardust@home. The program provided background information and tutorials for volunteers. After passinga practice test, they complete registration, and then begin searching for the miniscule particles. As of launch date, 40,000 views are ready for participant analysis. Those who find a confirmed dust grain will have the opportunity to name it.