There are periods in history when we are tantalized by discoveries that are just outside our grasp. These are uncomfortable times. Imagine standing in France and looking out over the English Channel to see a mysterious, unexplored landscape just a short distance away, but you have yet to invent a boat.
I feel that impatience when I think about exploring the moons of the outer solar system, like Jupiter's moon Europa. You can look up into the sky with binoculars and see Europa; even Galileo saw the moon orbiting Jupiter more than 400 years ago. And today, we are highly optimistic that there may be life on that moon. There's nothing so difficult about getting there; most of the technology is in place. In fact, we've already sent preliminary probes, which returned spectacular images and data proving the existence of a vast, chemically interesting, liquid water ocean protected beneath miles of ice. This environment that might be incredibly welcoming to life; in fact, life might very well exist there today. We need to get out there and see what is under that ice!
But first we need to be patient. Technology must be developed, plans must be made, budgetary constraints must be dealt with. People like Kevin Hand and Tom Cwik (both at NASA JPL) deal with this tension every day of their lives. Kevin is an astrobiologist and planetary scientist who studies Europa. Tom manages the Space Technology Program at NASA’s Jet Propulsion Laboratory. Both men want to not only survey Europa's icy surface but ultimately find a way to get down into the water and search for life.
While NASA currently has plans to build an orbiting spacecraft to map Europa from above, a lander (and submersible probe) hasn't reached approval yet. There's a long journey ahead of these men to get to those precious oceans.
But that doesn’t mean scientists aren’t getting ready for the possibility. Even today, team members from JPL are testing robotic underwater rovers capable of operating beneath thick ice. Kevin and his collaborators are designing instruments and experiments to tease every last bit of information out of Europa’s surface and look for likely entrances to the water below. In our lifetime, we may well see a robotic submarine from Earth plying the oceans of a jovian moon, sampling its water, and perhaps even signaling the first encounter with actual alien life. (Sure, it's likely to be microbial, but in an ocean, maybe even more complex life is possible.)
For now, we’re still on that shore hoping to build a boat, but the journey begins now.