Spacecraft gets close to comet — but not too close

A NASA spacecraft has caught up with a comet for the second time — but confusingly only the first trip was a suicide mission.

EPOXI came within 435 miles of Hartley 2 this morning (US time), the planned close-point of its approach. At the time of writing, NASA was awaiting images from an on-board camera: the image above is an artist’s impression of the encounter.

In proof that recycling can work even outside our own atmosphere, EPOXI is in fact the left over section of a previous comet-chasing missioncraft, Deep Impact. In 2005, an 800 pound “impactor” section was fired into the Tempel 1 comet, officially to produce a spray of dust and ice for scientific analysis into the formation of the solar system, though I can’t help thinking everyone involved secretly admitted it was just fun to do anyway.

The remaining section still had plenty of life in it, so it was assigned two new missions, Extrasolar Planet Observation and Characterization (using a camera to examine known planets outside our solar system) and Deep Impact Extended Investigation (more comet hunting.) The two acronyms, Epoch and Dixi, combined to produce EPOXI.

(And yes, technically it should be Nasa’s Epoxi rather than NASA’s EPOXI, but we at GeeksAreSexy believe you are allowed exemptions from traditional style-guides only if and when you blow up a comet.)

EPOXI then began a three-year journey to intersect the Boethin comet. Unfortunately a few months before the scheduled intersection, NASA was unable to locate the comet and concluded it had broken up into pieces too small to detect. Instead officials rerouted EPOXI to Hartley 2, a further three year journey.

This marks the fifth comet to get a close visit from a spacecraft. Prior to the Tempel collision, Deep Impact flew close to Borrelly in 2001. Another NASA craft, Stardust, set the record for the closest fly-by (not including the Tempel collision) in 2004, coming within 186 miles of Wild 2. And the first such journey came from the European Space Agency’s Giotto probe, which was the closest of five craft to visit Halley in 1986.