Six years ago, NASA visited the comet Tempel 1 with a fury: Its Deep Impact mission launched a projectile into the comet that kicked up dust and ice for the spacecraft to capture as a sample. Tonight, NASA is taking another pass by the comet—but a little more gently this time. The hardy Stardust explorer, which has passed by other comets and brought samples back to Earth, will pass by Tempel 1 tonight to try to get a good look at what NASA's blast did to the comet. Last time around, Deep Impact's projectile was actually too effective. It blasted so much debris off the comet that it blinded itself.
Now, Stardust will be able to obtain images of that crater up close for the first time. Moreover, in the nearly six years since that initial encounter, the comet has completed an orbit around the solar system, passing close to the sun. "For the first time, we'll go back to see what happens to a comet" after it passes close to the sun, said Pete Schultz of Brown University, a scientist for the new mission, which has been dubbed Stardust-NExT. [Los Angeles Times]
Stardust's pass presents an opportunity not just to see what's changed in the last five to six years of the comet's life, but also to peel back more of Tempel 1
's ancient history.
“Here’s a chance where we can see what has changed, how much has changed,” said Joseph Veverka, a professor of astronomy at Cornell and the mission’s principal investigator, “so we’ll start unraveling the history of a comet’s surface." For example, photographs taken by Deep Impact in 2005 showed areas that looked old and others that seemed much younger. But the snapshots did not tell the ages of any of them. “We have no idea whether we’re talking about things that have been there for a hundred years, a thousand years, a million years,” Dr. Veverka said. [The New York Times]
The flyby is scheduled to begin at about 11:30 p.m. Eastern tonight (Monday). Stardust should pass within about 125 miles of the comet, taking snapshots of the cosmic traveler and also catching some of the particles flying off it. The approach will mark the first time two spacecraft have studied the same comet up close, and probably mark the last hurrah for Stardust: After returning with samples from the comet Wild 2 in 2004, the craft was still running fine and got the OK from NASA to go on this second comet chase. But after a dozen years in space logging billions of millions, Stardust will soon be, simply, out of fuel. Related Content: 80beats: Photo: Comet Hartley 2 Travels With a Posse of Snowballs
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(photo gallery) Image: NASA