The Stardust spacecraft's Valentine's Day flyby of the Tempel 1 comet has delivered pictures of the comet that clearly show the effects of its last encounter with a spacecraft in 2005.
They show a scar resulting from the 2005 Deep Impact mission, and also indicate that the comet has a fragile and weak nucleus.
The spacecraft made its closest approach to Tempel 1 on Monday, Feb. 14, at 8:40 pm PST, getting to within 111 miles of the comet. Stardust took 72 high-resolution images of the comet, and also accumulated 468 kilobytes of data about the dust in the comet's 'coma' - its surrounding cloud of dust.
"This mission is 100 percent successful," says Joe Veverka, Stardust-NExT principal investigator from Cornell University. "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."
Several of the images show the effects of the Deep Impact mission's collision with Tempel 1.
"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," says Pete Schultz of Brown University. "This tells us this cometary nucleus is fragile and weak, based on how subdued the crater is we see today."
Engineering telemetry downlinked after closest approach indicates that the spacecraft flew through waves of disintegrating cometary particles. These were caused by about a dozen impacts that penetrated more than one layer of its protective shielding.
"The data indicate Stardust went through something similar to a B-17 bomber flying through flak in World War II," says Don Brownlee, Stardust-NExT co-investigator from the University of Washington. "Instead of having a little stream of uniform particles coming out, they apparently came out in chunks and crumbled."
While the spacecraft is now speeding away from Tempel 1, it will carry on imaging the comet as long as the science team can gain useful information, says NASA.