March 24, 2011
Into the purple dusk of twilight time: Stardust bids adieu
Stardust, a comet-hunting mission in which University of Washington astronomer Donald Brownlee played an integral role, officially came to an end Thursday.
Late Thursday afternoon, controllers at Lockheed Martin Aeronautics in Denver fired the engines one last time to burn the remaining fuel, then decommission the spacecraft, placing it in permanent “safe” mode with its transmitter turned off. Stardust’s last transmission to Earth ended at 4:33 p.m. PDT.
“Its been 12 years. Its sad to see it go, but having two successful flybys is more than we expected,” said Brownlee, in Denver to mark the end of the mission. “It is kind of a historic occasion and I wanted to be here.”
Stardust will continue to make huge loops around the sun, but without propulsion. After a million years the craft could crash into Earth or, more likely, be ejected from the solar system by Jupiters gravity, left to wander the universe beyond a time when Earth no longer exists.
Brownlee conceived the mission as a way to find out far more about comets. NASA approved Stardust in 1995, with Brownlee as the principal investigator, and the spacecraft was launched in February 1999. It flew past an asteroid named Annefrank in 2002 en route to its primary destination, a comet beyond Mars called Wild 2.
In January 2004, Stardust came within 150 miles of the comet and captured tiny grains of dust spewing from the comets surface, then in January 2006 it jettisoned its sample-return capsule to a landing in Utah. The comet particles have been under microscopic study ever since and have led to major scientific findings.
The return capsule itself is now in the Smithsonian Air and Space Museum in Washington, D.C.
With plenty of fuel left over, the spacecraft in 2007 was renamed StardustNExT and given a new mission, to fly past Temple 1 and capture images to show how that comet had changed since it was previously visited by another spacecraft. That mission was accomplished in February, with Brownlee along as a co-investigator.
In its travels, Stardust logged more than 3.5 billion miles on about 22 gallons of hydrazine fuel, the spacecraft motors firing more than 2 million times combined. The last maneuver, called a “burn to depletion,” will provide information on just how much fuel was left in the tank and how close that came to official estimates, which can help in planning other missions.
Stardust provided valuable data to the end.
See more information on Stardust.