Program: GS-2007B-DD-2

We propose to recover comet 85P/Boethin using GMOS-S on Gemini South. This comet is the unique target for the NASA Deep Impact (DI) extended mission, DIXI, and it must be recovered by mid-September 2007 because the latest that mission operation planning can get underway for targeting for the December Earth gravity assist is October 1, and this requires the new orbit (determined immediately after recovery). This is time critical and essential for the scientific success of the spacecraft flyby mission. The comet has been only observed at 2 apparitions in 1975 and 1986 and consequently has a large ephemeris error. Furthermore the comet is very faint, with an expected V mag fainter than 26.5, and is passing through a low galactic latitude. This Gemini request is part of a concerted international effort for recovery. The high resolution images DI provided provided information which changed our paradigm of comet physics in terms of the thermal properties and surface geology. DIXI will be the next mission to provide high resolution images and equally exciting science that will help inform the ESA Rosetta mission.