The importance of studying water and organic molecules is related to their biological relevance.
The origin of water oceans and pre-biotic organic molecules on Earth, and the origin of an ancient ocean on Mars, is unsolved.
Even today the bulk Earth is cosmically dry (poor in hydrogen, relative to the protoplanetary disk). About 60 Ma after Earth-accretion, the moon-forming impact probably removed any water that may have outgassed after core formation, leaving the Hadean Earth water-poor at its surface.
How did terrestrial planets acquire their water? Bombardments of Earth and Mars by icy and rocky planetesimals (represented today by comet nuclei and asteroids) were common from their formation through the Late Heavy Bombardment. Because water is the most abundant native ice in cometary nuclei, with the aggregate of organic ices comprising a close seconds, we want to understand the role primitive bodies played in delivering water and pre-biotic organics to the young inner planets.