It is widely accepted that comets contain the most primordial material accessible in the solar system and that they provide major constraints on the conditions in the protoplanetary disk. However, it is also widely accepted that the outer layers of a comet are highly evolved, as discussed in other papers at this meeting. We will highlight in this poster the major gaps in our understanding of cometary nuclei, showing that the only way to address these gaps is to probe to depths of tens of meters.
Crater counts are widely used for determining the surface ages of many bodies in the solar system, from small objects the size of Dactyl to the Galilean satellites and Mars. This age dating depends among other things on relating the crater sizes to the sizes of impactors. The physical laws on which this relation is based is known only for high-gravity cases and must be extrapolated by several orders of magnitude for use on small bodies such as asteroids and comets.
We will describe in this poster a proposed mission to probe a cometary nucleus to depths of tens of meters by creating a large impact crater. We will discuss both the mission scenario and the scientific returns to be expected.