I definitely missed this a couple of months ago:
The Geophysical Monitoring Station (GEMS) will perform for the first time an in-situ investigation of the interior of Mars.
The Titan Mare Explorer (TiME) [...] proposes to determine the composition and depth of the seas of Titan their variation over time and their relation with meteorology and the geography of their surroundings.
The Comet Hopper (Chopper) mission proposes to study in detail a comet over its full revolution around the sun. The spacecraft will “hop” on the small comet nucleus and collect data about its surface composition and properties. Taking advantage of the weak gravity of the comet nucleus, it will be able to go back in orbit (a “sortie” as shown in the figure above) and remains around the nucleus to study as well the cometary coma to understand the link between the surface activity and the cometary activity.
All three sound like fascinating missions. Unfortunately, only one will be selected for funding.
The NASA Discovery program is a low-cost mission ($425 million FY2010) program aimed at developing and supporting a well-defined and narrow-range science mission in the field of planetary exploration.