Photos of NASA’s ruined Genesis probe were a depressing sight, crushed metal shards left half-buried in the Utah desert last September after a recovery mishap. Plans for helicopters to intercept the solar probe in midair went amiss because its parachute failed to open. This should never be the way expensive scientific missions end! Well, hardly ever. Sometimes a crashing finish is the definition of success.
The Ranger probes, 1961-1965, were designed to take close-up images of the moon while hurtling into the lunar surface. Although the first six Ranger spacecraft either missed the moon or failed to transmit their pictures, finally, Rangers 7, 8 and 9 successfully flew into the Moon, sending back images from six cameras until the moment of impact.
A similar notion inspires the Deep Impact cometary study mission NASA launched on January 12. A probe will gather data as it smashes into its subject, Comet Tempel 1 — a bit of Independence Day fireworks for astronomers if it hits when scheduled, July 4, 2005.
The Deep Impact mission will be carried out by a pair of spacecraft – the “Impactor” payload will be released to slam into Comet Tempel 1 at 23,000 mph while the “Flyby” mothership looks on. “Impactor” carries its own camera and (in the tradition of Ranger!) will return the closest images ever taken of a comet nucleus.
Studying the comet will hopefully reveal something about our origins. “Only the internal material of a comet is unchanged from the beginning of the solar system,” said Deep Impact principal investigator Michael A’Hearn, of the University of Maryland. Much the same was said when underappreciated Comet Shoemaker-Levy met its demise, causing David Bofinger to laugh, “Funny how you don’t learn how ancient and valuable something is until you watch it drop into the red spot of Jupiter.”
For comet researchers the early 21st century is an exciting time. After “Impactor” is sacrificed, “Flyby” will swing past the comet and may be used again to study a couple of other comets in an extended mission. Last year, NASA’s Stardust spacecraft flew through Comet 81P/Wild 2, taking pictures and collecting samples that will be returned to Earth for study in 2006. The European Space Agency (ESA) also launched its comet probe Rosetta
on March 2, 2005 to visit Comet 67P/Churyumov-Gerasimenko, where it is expected to drop its lander, Philae, on the comet’s surface in 2014.
Comets: SF’s Beginning and End
Science fiction writers have long used their imaginations to probe comets, a favorite part of the science fictional repertoire, especially if they are on the verge of smashing into something important like our home planet (every writer’s favorite target.) For example, in Niven and Pournelle’s Lucifer’s Hammer (1977) a giant asteroid or comet collides with the earth and ends middle-class life as we know it. Their bestseller has been called “among the first of the scientifically reasonable impact stories.”
Other writers give an old phrase a new twist – they would start life as we know it by crashing water-bearing comets onto Mars to start life, like Bruce Sterling (“Cicada Queen”). And ultra-scientific Greg Benford says to heck with Mars, let’s use those comets to terraform the moon! (Read how, here.)
Writers have a particular fondness for Halley’s Comet because its 1910 appearance seared a legend into American popular culture and everyone knew the rerun was coming, never imagining it would prove a disappointment. Greg Benford and David Brin in Heart of the Comet
(1986) whet our appetites for a manned expedition to Halley when it comes back in 2061 – if you like redheads, this book’s for you….
Fellow writer Mark Twain was born in a year Halley’s Comet appeared, 1835, and hoped he would go out with it in 1910 – a wish that was granted. Well, some claim otherwise, but close enough for skiffy….