Spacecraft Goes AWOL, but Leaves “Deep Impact”

Eight years after Deep Impact was launched into deep space, NASA in August lost contact with the spacecraft.

But over its longer-than-expected life, the probe, conceived and managed by University of Maryland astronomers, left a long trail of discoveries about comets and other celestial bodies.

Deep Impact is most famous for its first mission in 2005, when it sent a washing machine-size “impactor” into the path of the comet 9P/Tempel. The crash left a crater on the comet the size of a football field, and gave scientists a wealth of new data about comet structure and content.

“It dramatically changed the way we look at comets,” said Maryland astronomy Professor Michael A’Hearn, who led the mission. Data from Deep Impact proved, for instance, that many comets are mostly porous, as fluffy as a bank of powdered snow.

After the first mission ended, Maryland scientists convinced NASA to keep using Deep Impact rather than let it spin off into space. Its later missions led to discoveries about comets’ chemical makeup, formation locations and surface changes.

For the UMD team, the loss of the spacecraft was an emotional blow. “When something is taken away for good, you suddenly realize how much it’s been there,” says Professor Jessica Sunshine, who along with A’Hearn helped write the 1998 proposal that led to the mission, and worked on the project to the end. “We had a helluva run.”

See Deep Impact’s Greatest Hits: A slideshow for photos of the mission: