NASA's Stardust braves cometary flak
Survives photographic close encounter with Tempel 1
NASA's Stardust spacecraft has survived a close encounter with comet Tempel 1, during which it took a few substantial hits from cometary flak.
The craft passed within 111 miles of the comet at 20:40 p.m. PST on 14 February (04:40 GMT on 15 February), and has returned some impressive photos of the distant body.
As well as 72 high resolution snaps of Tempel 1, Stardust collected data on the comet's tail, and engineering telemetry revealing it "flew through waves of disintegrating cometary particles including a dozen impacts that penetrated more than one layer of its protective shielding".
Don Brownlee, Stardust co-investigator from the University of Washington, said: "The data indicate Stardust went through something similar to a B-17 bomber flying through flak in World War II. Instead of having a little stream of uniform particles coming out, they apparently came out in chunks and crumbled."
Despite the rough ride, principal investigator Joe Veverka confirmed the mission had been "100 per cent successful". He added: "We saw a lot of new things that we didn't expect, and we'll be working hard to figure out what Tempel 1 is trying to tell us."
Of particular interest to scientists is the result of the whack Tempel 1 took from the Deep Impact spacecraft impactor back in July 2005. It's released a before-and-after comparison of the impact site:
NASA explains: "The left-hand image is a composite made from images obtained by Deep Impact in July 2005. The right-hand image shows arrows identifying the rim of the crater caused by the impactor. The crater is estimated to be 150 meters (500 feet) in diameter."
Pete Schultz of Brown University elaborated: "We see a crater with a small mound in the center, and it appears that some of the ejecta went up and came right back down. This tells us this cometary nucleus is fragile and weak based on how subdued the crater is we see today."
Stardust launched back in February 1999, on its primary mission to "collect dust and carbon-based samples during its closest encounter with Comet Wild 2" in January 2004.
These samples, plus interstellar dust, returned to Earth in January 2006 aboard a capsule which parachuted to earth in Utah
NASA then sent the spacecraft on its final mission - officially dubbed Stardust-NExT ("New Exploration of Tempel") - although it's not quite ready for retirement.
Tim Larson, Stardust-NExT project manager at the Jet Propulsion Laboratory, said: "This spacecraft has logged over 3.5 billion miles since launch, and while its last close encounter is complete, its mission of discovery is not. We'll continue imaging the comet as long as the science team can gain useful information, and then Stardust will get its well-deserved rest." ®