"His predecessor but six or eight or 10 - Nye Bevan - said he wanted a bedpan falling in Tredegar to be heard in the corridors of Whitehall, " Mr Miliband said.
"You're going to actually get a chance to actually drive flight hardware on another planet, " said Bill Nye, a children's science show host on U.S. public television and a member of Planetary Society's board, who was also present for the announcement.