space.com:
NASA has narrowed the choices for its next unmanned space
mission down to three potential expeditions: one aimed at Venus
and the others promising to return samples of an asteroid or
the Moon.But only one of those contenders will get the green
light for $650 million in funding (which excludes rocket costs)
and a launch sometime before 30 December 2018. The competition
is part of
NASA's New Frontiers
program to develop medium-class missions to explore the
solar system.
