Deep Impact hits its target

by Chris Bergin

NASA’s Deep Impact mission has been a success, as images come through from the tiny spaceship of its projectile impacter striking comet Temple 1 over 83 million miles from Earth, causing a huge flash on impact. (See below for impact images)

One hundred and seventy-one days into its 172-day journey to comet Tempel 1, NASA’s Deep Impact spacecraft successfully released its impactor at 11:07 p.m. Saturday, Pacific Daylight Time (2:07 a.m. Sunday, Eastern Daylight Time).

At release, the impactor was about 880,000 kilometers (547,000 miles) away from its quarry. The
separation of flyby spacecraft and the washing-machine-sized, copper-fortified impactor is one in a series of important mission milestones that will cap off with a planned encounter with the comet at 10:52 p.m. Sunday, PDT (1:52 a.m. on July 4, EDT).

Six hours prior to impactor release, the Deep Impact spacecraft successfully performed its fourth trajectory correction maneuver. The 30-second burn changed the spacecraft’s velocity by about one kilometer per hour (less than one mile per hour). The goal of the burn is to place the impactor as close as possible to the direct path of onrushing comet Tempel 1.


The first images of the impact were obscured by dust and sand-blasting of the spacecraft’s cameras, but once high resolution images came in on the fly-by, the sequence showed a bright flash on the bottom right of the comet – producing a spectactular explosion as the projectile impacter struck the comet.

“We hit it just exactly where we wanted to,” co-investigator Don Yeomans said.


After the impact, as a cloud of ice and dust explodes into space, the mother ship, having staked out a front-row seat 5,000 miles from the collision, began recording the crash and resulting crater with its high-resolution telescope. About 15 minutes later, Deep Impact made its closest fly-by of the comet nucleus, approaching within 310 miles.

The climax of the $333 million (£188 million) mission was also be watched by Nasa’s space-based Hubble, Chandra and Spitzer telescopes. The European Space Agency’s Rosetta spacecraft, on its way to a 2014 rendezvous with a comet, also watched, as did professional astronomers from dozens of observatories in 20 countries.

More pictures:

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