For years, astrobiologists, planetologists, space scientists, and anyone who's ever wondered, "Are we alone?"have pondered the mysteries of Jupiter's moon, Europa - a world containing twice as much water as all of Earth under its icy surface.

Since liquid water is a necessary ingredient for life as we know it, many researchers consider Europa the best possibility of a habitable world, other than Earth, within our solar system. With several Europa missions on the drawing board, it seems inevitable that we will one day be operating hydrobots beneath its water-ice surface.