Not all rovers are designed to roam around on the surface of other worlds like Mars. One rover, at least, is aquatic; a necessary development if we’re going to explore Enceladus, Europa, and the Solar System’s other watery worlds. This rover is called the Buoyant Rover for Under-Ice Exploration, or BRUIE.
This is not a swimming, submarine type of vehicle. It’s a wheeled vehicle designed to drive upside down on ice sheets.
BRUIE is buoyant, which keeps it pressed against the ice ceiling.
BRUIE is currently in the Antarctic, at Australia’s Casey Research Station. During the next month, operators will put it through its paces, testing its endurance in anticipation of a future mission to an icy ocean world, likely Europa. The testing will focus on interface areas, where the ice sheet meets water.
Ice-water interface areas are important because on worlds like Europa, they can have very dynamic chemistry, partly because dissolved impurities are rejected from an advancing ice front.
On living worlds like Earth, there are also higher concentrations of life forms in these types of interfaces. Scientists can also learn a lot from the topography of the underside of the ice, including how the ice forms. And the ice can act as a trap for gases, either from biological or geological processes.
Kevin Hand is the JPL lead scientist on the BRUIE project. Hand, and many others in the scientific community, think that lunar oceans in our Solar System – Europa, Enceladus, and others – are likely the best place to look for life. Submersible robots will have to play a role in exploring them.
“The ice shells covering these distant oceans serve as a window into the oceans below, and the chemistry of the ice could help feed life within those oceans. Here on Earth, the ice covering our polar oceans serves a similar role, and our team is particularly interested in what is happening where the water meets the ice,” said Hand.
But the interface area can be difficult to explore. Submersibles aren’t practical.
“We’ve found that life often lives at interfaces, both the sea bottom and the ice-water interface at the top. Most submersibles have a challenging time investigating this area, as ocean currents might cause them to crash, or they would waste too much power maintaining position,” said lead engineer Andy Klesh.