“Water and related chemistry in the Solar System” is a Herschel Space Observatory
Guaranteed-Time Key Programme. This project, approved by the European Space Agency,
aims at determining the distribution, the evolution and the origin of water in Mars, the outer
planets, Titan, Enceladus and the comets. It addresses the broad topic of water and its
isotopologues in planetary and cometary atmospheres. The nature of cometary activity and
the thermodynamics of cometary comae will be investigated by studying water excitation in a …