In making use of the technologies around us, NASA have now gone and created a rover in Second Life, which mimics the real world Phoenix.
Explorer Island, in Second Life has been around for a while and hosts a variety of space exhibitions. Ranging from a virtual copy of a space shuttle to a replica of the desert weather on the Martian surface.
See: http://news.cnet.com/8301-10784_3-9960846-7.html
See: http://news.cnet.com/8301-10784_3-9960846-7.html