NASA is sending two decorated veterans out to collect more scientific data. After already having traveled 3.2 billion kilometers to pick up 1 microgram of dust from comet Wild 2 and having dropped it back to Earth for analysis, NASA's Stardust spacecraft will be visiting comet Tempel 1 in 2011. NASA's Deep Impact spacecraft fired a massive copper projectile at the comet on 4 July 2005, and researchers want Stardust to image the resulting impact crater to learn about the structure and porosity of the comet's nucleus. "A revisit is always a good idea," says Gerhard Schwehm, head of solar system science at the European Space Agency, although he warns that "Stardust's hardware was designed for a different purpose."
Meanwhile, Deep Impact also has been given a new assignment. It plans to fly past comet Boethin on 5 December 2008 after looking for transiting planets around other stars. NASA science chief Alan Stern says the new missions get "more from our budget."
