Space Probes Add Side Trips

摘要

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."