By Jim Allen
The long-running NASA spacecraft Stardust finally completed its 5.7 billion km, 12-year mission last week. At 7.33pm EDT (23.33 GMT) on 24 March the probe finished its remaining fuel in one final 146 second blast, 312 million km from the Earth.
Launched on 7 February 1999, Stardust was the first NASA mission entirely dedicated to the observation of a comet and the first designed to retrieve material from outside the orbit of the Moon. In 2002 Stardust passed by and imaged asteroid Annefrank en route to its main mission, collecting particle samples from comet Wild 2.
In 2004 the spacecraft passed through the comet’s coma, catching particle samples and sending images back to Earth. The spacecraft passed close to Earth in 2006, where it jettisoned the first ever comet samples back to waiting scientists on the ground.
After being renamed Stardust-NExT, the craft was then sent on a final mission to pass by comet Tempel 1 and examine the scene of the 2005 Deep Impact mission. This final fly-by was completed in February this year, bringing the probe’s data gathering to an end.
"This is the end of the spacecraft's operations, but really just the beginnings of what this spacecraft's accomplishments will give to planetary science," said Lindley Johnson, Stardust-NExT and Discovery scientist.
Useful to the end, Stardust still had one final mission before ending transmission. Due to the weightlessness in space, there is no accurate way to gauge how much fuel a rocket has used during its mission – remaining fuel is predicted from the history of the vehicle’s flight. As Stardust’s rockets fired for the final time, invaluable information was returned on how much fuel the spacecraft had remaining.
"We'll crunch the numbers and see how close the reality matches up with our projections. That will be a great data set to have in our back pocket when we plan for future missions," said Allan Cheuvront, an engineer at Lockheed Martin Space Systems.
