Sorry, our comet is missing.

Astronomers at the University of Hawaii recently had to make a strange correction to the Deep Impact mission. The ship, which thrilled scientists in 2005 by successfully firing a metal probe into the nucleus of a comet, was slated to do it all again with a new target in 2008 – but, well, um, the target has vanished:

The decision was made after an international consortium of astronomers led by the University of Hawaii’s Dr. Karen Meech, a co-investigator on the mission, announced that the first-choice target, called comet 85P/Boethin, has apparently disappeared.

“We were confident we could find the comet, and we were astonished when it wasn’t there,” said Meech.

Comet Boethin had been selected as a target because its orbit takes it to a region of the solar system that the Deep Impact spacecraft could have been directed to in 2008. Boethin has an 11.8-year orbit, but can be seen from Earth only during the six months when it is closest to the sun.

They’ve chosen another target, Comet Hartley 2, to whack with their big metal stick.

More on the lost comet at the Honolulu Star Bulletin.