A laser-powered probe might be the next step in seeing what's under the icy crust of Jupiter's moon Europa.
The idea was presented by inventor Bill Stone at NASA's Astrobiology Science Conference in Atlanta. His company Stone Aerospace has built robotic underwater vehicles for exploring under the Antarctic ice sheets. Stone's proposal is for a "cryobot" powered by a 5,000-watt laser. The laser light is transmitted via a fiber optic cable that unspools behind the robot as it drills through 250 meters of ice.
The robot, a 10-inch-wide, six-foot-long cylinder called VALKYRIE, would melt the ice ahead of it and leave the power plant on the surface. Stone Aerospace has tested a protoype of such a device and plans to try it out on an Alaskan glacier in June 2013.
Lasers are already transmitted through fiber optic cables in communications networks, so it wasn't a huge step to consider using them for power transmission.
Powering the probe with a laser on the surface does solve certain problems. A nuclear power plant of the kind used on space probes (called a radioisotope thermoelectric generator, or RTG) would be too big. Solar power is impractical as Europa is much further from the sun than Earth is, requiring gigantic panels.
While Stone has some experience building robots that go under the ice, there are important differences between the ones he's built and the kind that would work on Europa. One is melting through the ice. The previous robot built — ENDURANCE — explored an Antarctic sub-glacial lake. But it didn't have to bore through a layer of ice first.
Another issue is actually landing on Europa. While the Voyager and Galileo missions provided spectacular images of the surface, there aren't yet pictures with enough resolution to tell where a safe area to land is.
Last year Stone Aerospace got $4 million in funding for the VALKYRIE project. At least one mission proposal is under review, a mission designed to carry this kind of payload seems far in the future.
That said, getting through the Europan crust to study what's beneath it has excited scientists as various space probes have uncovered evidence of an ocean of water there — an ocean that might harbor life.
Credit: Stone Aerospace / National Geographic Television