The HST Deep Impact Campaign

Paul D. Feldman

NASA's Deep Impact mission successfully placed a 362 kg impactor onto the surface of comet 9/P Tempel 1 at a relative velocity of 10.2 km/s on 2005 July 4 at 05:52:02 UT. The event was observed by cameras aboard the mother spacecraft and by a large number of Earth-based telescopes as part of an extensive campaign to study the comet prior to, during, and in the course of several days following the impact. The Hubble Space Telescope (HST) was a major player in this campaign as the High Resolution Camera (HRC) of the Advanced Camera for Surveys (ACS) provided the highest spatial resolution images from Earth (36 km). The ACS Solar Blind Channel (SBC) was also used with a filter sensitive primarily to the ultraviolet emission from the CO Fourth Positive system to determine the amount of this volatile liberated by the impact. All of the evidence points to an event in which the impact excavated a measureable piece of the comet's nucleus, but did not penetrate into the frozen primordial interior of the comet.