In article ,
Tony Sivori wrote:

Stephen Souter wrote:
"The White House plan, detailed in internal documents, also
mentions the possibility of sending humans to asteroids or moons of
Jupiter."
--http://www.space.com/news/bush_science_040114.html

Europa! By robot or by manned mission, we really need to find out if
anything lives in that sea.

Probably not Europa (unless they could burrow in under the ice). At
least at first. Or Io or Ganymede. But Callisto, as I understand it, is
far enough outside the Jovian radiation belts for humans to survive; and
it could be used as a forward base.

--
Stephen Souter

http://www.edfac.usyd.edu.au/staff/souters/