An article on the BBC by Jonathan Amos discusses the contenders for the two slots in ESA's Cosmic Visions program for 2017-2018 launches. Interestingly the article's focus is on the costs (see graph taken from article), but it also has a nice description of each mission (many of which I hadn't heard of).
The missions, and my shorter summary of their nature and aims, are:
- SPICA: Joint ESA/JAXA infrared space telescope (5 to 210 micron wavelength range) with a 3.5m primary mirror.
- Euclid: Map mass distributions using baryonic acoustic oscillations and weak lensing.
- PLATO: A planet hunter with a particular emphasis on finding Earth-like and super-earth terrestrial planets using milli-magnitude accuracy photometry.
- Solar Orbiter: Study the Sun and Solar wind from a relatively close-in orbit (as close as 48 Solar radii, it claims).
- Marco Polo: Joint ESA/JAXA sample return mission from a near-earth asteroid. Note the high cost!
- Cross-Scale: Study MHD plasma properties in the terrestrial magnetosphere and bow shock. 7 ESA spacecraft forming 2 nested tetrahedra with a shard corner. (International collaboration will produce the optimum fleet of 12 spacecraft in 3 nested tetrahedra.) High cost!