Stardust Mission Successfully Flies Through Comet Cloud
In the first of what is hoped will be a series of spectacular space missions in 2004, the Jet Propulsion Laboratory flew the Stardust spacecraft today on a wild ride right into the dusty coma of comet Wild-2 (pronounced Vilt-2). Though the dust storm would have killed an astronaut at that range, the craft emerged on the other side unscathed, with possibly millions of dust particles embedded in its aerogel collector. The first sample return mission since Apollo 17 in 1972, Stardust will parachute its capsule loaded with the precious cargo into the Utah desert in January, 2006. During the encounter today, the mass spectrometer also worked well, and so did the camera. About six dozen images were snapped of the comet’s nucleus from about 250 km (150 mi).
Elated by their picture-perfect enounter, the spacecraft team proudly displayed two detailed images of the nucleus at the press conference this afternoon, just 3 hours from the time they were taken. They expect additional images still being processed may be even better. The photos reveal a rough surface mottled by pits, with about five jets visible. The pits, rather than being impact craters, may be sinkholes from collapse of underlying volatiles. If this comet is like Halley and Borrelly visited earlier by Giotto and Deep Space 1, respectively, the surface is probably as black as asphalt, but data will have to be analyzed to nail down the actual reflectivity. Principal investigator Donald Brownlee (Univ. of Washington) said that the jetting of volatiles and dust only comes from a few percent of the surface.
Project Manager Tom Duxbury explained that the spacecraft was named Stardust because comet dust is assumed to be pristine material from our star, the Sun, left over from its formation (although this assumption has been questioned recently: see 08/12/2003 entry). Brownlee, co-author of Rare Earth (12/19/2000), a book that asserts intelligent life is rare in the universe, stressed that photographs and actual physical samples that can be examined in the lab are worth much more than mere ideas. These first images were surprising, and more surprises are anticipated once the samples are returned to Earth. Nevertheless, he reiterated the evolutionary theme Carl Sagan made famous, that humans, like comets, are also made of star dust.
Upcoming comet rendezvous missions include the European Space Agency Rosetta, launching (after previous delays) in February (01/13/2003), and NASA’s Deep Impact, launching in December.
As expressed in similar headlines in the past, we congratulate those who succeed in risky missions to gather data, and we can hardly wait to see what the particles in the collector show, but the public should be “taught the controversy” when there is one. If not all scientists agree that comets are made of pristine material, that should be mentioned, rather than making matter-of-fact statements to the press that comet material has been unprocessed for 4.6 billion years.
The phrase “we are made of starstuff” is a misleading half-truth. Yes, our bodies have carbon, hydrogen, oxygen and other elements found in stars, but we know what Sagan and Brownlee mean. They want us to believe that stardust aggregated into the Earth, and from the atoms on Earth, life arose and evolved upward into human beings by unguided, purposeless, undirected natural processes. Such myths should be distinguished from science. They would not get smiling nods at press conferences if scientists were expected to use disclaimers when preaching naturalistic philosophy: “According to my atheistic, naturalistic opinion, and according to the teachings of my tradition’s creation myth, we are all made of stardust. Won’t you please join me in singing my favorite hymn, Godless Philosophy.”