Tis the season for planetary missions! Mars is in the picture for Christmas and after New Years and Cassini is already sending back great images of Saturn in preparation for its upcoming encounter with the ringed planet. But, little pieces of the solar system like comets and interstellar dust grains are coming in for attention, too. Right after New Years’ Day the Stardust spacecraft will have its turn in the limelight as it encounters Comet Wild 2. The idea behind this mission is to capture tiny grains of interplanetary dust that are caught up in the coma and tail of the comet. Onboard the spacecraft is a tennis-racquet shaped collector with aerogel embedded inside — and this is the stuff that will “capture” the dust grains. While all this is going on, the spacecraft will send back close-up pictures of the comet. Ultimately, the spacecraft will return to Earth in January 2006 and send the collector (safely stored inside a capsule) back to scientists who will test the dust grains to understand their composition and age.
Actually, Stardust has been collecting particles throughout much of its mission, all in an effort to understand more about what’s populating interplanetary space. The comet particles will also tell us much about the conditions in the solar system at the time the comet formed — back when the Sun and planets were coalescing.
