Last night (Feb. 14), a NASA spacecraft zipped close by the comet Tempel 1, keeping a cosmic date that wrapped up an out-of-this-world Valentine's Day. The Stardust-NExT probe flew to within 124 miles (200 kilometers) of the comet at 11:37 p.m. EST (0437 GMT today), snapping photos and making measurements all the while.
It took mission scientists until midnight EST to confirm the successful encounter, because of the communications time lag between the probe and Earth. The first of the comet images should arrive on scientists' computers around 3 a.m. EST (0800 GMT) today.
"Some people have asked me where I will be when those first images come down," said Steve Chesley, Stardust-NExT co-investigator from NASA's Jet Propulsion Laboratory in Pasadena, Calif., in a statement. "I know exactly where I will be. I'll be on the edge of my seat."
Comet Tempel 1 is no stranger to robotic visitors from Earth.In July 2005, another NASA probe, known as Deep Impact, smashed an 800-pound (364-kilogram) impactor into Tempel 1 to study the comet's composition.The 3.7-mile-wide (6 km) Tempel 1 has an orbital period of 5 1/2 years, so it had made one trip around the sun since Deep Impact's visit. Stardust-NExT's main mission is to help scientists learn how much the comet has changed during this time.
Researchers also hope to get a good look at the crater Deep Impact pounded out of the surface; the Deep Impact probe was not able to see it well through the huge cloud of debris ejected from the blow. Another aim of the Stardust-NExT mission is to extend geologic mapping of Tempel 1's surface, adding to the work done by Deep Impact.
Stardust-NExT principal investigator Joe Veverka, of Cornell University, said in a recent NASA video. "We want to see more of the surface, and we also want to see what changes have occurred since Deep Impact was there five years ago". Through these and other observations, Stardust-NExT can contribute to scientists' understanding of how comets formed at the solar system's birth 4.6 billion years ago and how they have evolved, researchers have said.