Rosetta: evaluating the possibility of using Ptolemy for pre-landing scientific investigations

Launched in 2004, the Rosetta spacecraft, which is en-route to rendezvous with, and land on, comet 67P/Churyumov-Gerasimenko, will awake from its current deep space hibernation on January 20 th , 2014 (i.e. by the time of the conference it will be known whether this was successfully completed or not). Our abstract for the 44 th LPSC describes some of the operations that will hopefully accompany the phase of the mission where the lander element, Philae , is ejected from the main spacecraft, directed towards the comet, and ultimately anchored to its nuclear surface. The Ptolemy instrument, which is designed to undertake elemental and isotopic analyses of surface materials, will be operational during on-comet investigations; indeed, this is its raison d'etre. However, as was witnessed during the fly-by of asteroid 21 Lutetia, Ptolemy can also be operated in a remote, stand-alone capacity, i.e. in space, as opposed to being on the surface of any particular body. Based on this experience we have been evaluating the possibilities of using Ptolemy for scientific investigations of the cometary coma prior to the separation of Philae from the orbiter craft.