It’s been a busy time for NASA: Just before the first rover landed on Mars (page 10), the Stardust spacecraft achieved a dazzling double score, collecting pieces of comet Wild 2 (the first sample of a body beyond the moon) and sending back pictures of the comet’s 3.1-mile-wide icy core. The surface is pockmarked with lumps and strange depressions. Daniel Britt, a planetary scientist at the University of Central Florida, interprets the pits as impact craters that have been widened by eruptions of evaporating gas and dust. Compared with Borrelly, an older comet visited by the Deep Space 1 probe in 2001, Wild 2 appears to be a relative newcomer to the inner solar system, its surface far less chewed up by the sun’s heat. “It seems less evolved than Borrelly,” Britt says. If so, it may contain material that has changed little since the planets formed 4.6 billion years ago. More insights will undoubtedly come after January 15, 2006, when Stardust is scheduled to fly past Earth and drop its cache of comet dust. The package will parachute onto the salt flats of Utah and into the waiting arms of scientists.
Samples from Deep Space
NASA’s Genesis spacecraft has spent 3 1/2 years collecting particles from the solar wind. The payload will reach Earth on September 8 and be captured in midair by helicopter.
Japan’s Hayabusa probe will land on asteroid Itokawa in the summer of 2005, then lift off and return a sample to Earth two years later.
NASA plans sample-return missions to Mars, a comet, and the moon’s south pole. Dates are not yet set.
The European Space Agency plans a Mars sample-return mission, to be launched as early as 2011.