In February this year, ESA selected four candidates for the third
medium-class mission (M3) that will launch in the period 2020-22. The
mission concepts cover very different areas of scientific research,
ranging from investigations of black holes and general relativity to
near-Earth asteroid sample return and studies of planets orbiting
distant stars. The four proposals chosen to proceed for assessment are
called EChO, LOFT, MarcoPolo-R and STE-QUEST.
To read the full article:
http://bit.ly/oJfRPG