The buoyant robot will cruise on the surface of Europa’s ice – from below.
NASA’s Jet Propulsion Lab is testing a new rover under the ice in Antarctica, to find out if it can handle conditions on ice-covered moons like Jupiters’s Europa or Saturn’s Enceladus.
Ultimately, it would be used to explore these potential water worlds in the search for life. During these recent tests, Earth-based life certainly found the robot interesting.
“Fish would actually swim up to us, somewhat investigating,” lead engineer Andy Klesh told Quirks & Quarks host Bob McDonald.
“The Adélie penguins would come from all around to see what was going on, come and check out the rover, look at the wheels, try and figure out, ‘What is this beast?'”
The “beast” reffered to is a 40-inch (1-meter) wide robot called BRUIE, an acronym for Buoyant Rover for Under-Ice Exploration. It is an early prototype of a device NASA plans to send to explore Jupiter’s icy moon, Europa.
According to the plan, BRUIE will drill down through Europa’s ice to reach its ocean. From there on, its buoyancy would hold it up to the ice’s undersurface. The two wheels of the rover would then allow it to drive around ‘upside down’ on the undersurface of Europa’s icy shell.
NASA started developing BRUIE in 2012, and they are still in the early stages of building a robot that can withstand Europa’s extreme conditions, after surviving the long journey there and the descent down to the moon’s surface. It would then have to make it through the 20-kilometre thick ice sheet to start its mission.
“This is only an early precursor mission to what we might be able to do,” said Klesh.
Scientists assume Europa has liquid water under its icy shell and that it could hold three times as much liquid water as all of Earth’s oceans. And liquid water could signify at least the potential for life.
“It’s one of the most promising locations in our solar system for where we might find other signs of life,” said Klesh.
Even though a wheeled vehicle might seem like a weird choice for exploring an ocean, the best place to look for life is where ice and water meet. So using a submarine for that purpose would not necessarily work.
“We always tend to see life form on interfaces like the ice-water interface,” said Klesh. “With the rover, we can almost silently drive up to it, turn our cameras upwards and we’re looking right at that area with no power use to stay in place.”
With its buoyancy and spiked wheels, BRUIE is designed to stick to the underside of the ice sheet, keeping it safe from any currents that might otherwise knock it off its course. The rover can freely roam the unbdersurface of the ice to see what might be thriving there.
In Antarctica, aside from the fish and penguins, the research team was able to get a close-up look at the algae mats growing under the ice, and measure the amount of oxygen they were producing.
“Algae and microbes tend to use photosynthesis and actually anchor on that underside of the ice where they themselves can be protected from the currents that are around there in the air,” said Klesh. “Certainly there won’t be a lot of light [on Europa], but there will still be that anchoring point for many of the different microbes.
“So we’re still learning about what types of life forms, what are the signs of life that we might find on the underside of the ice.”
At the research location in Antarctica, the team tested the rover’s mobility to see if it could easily move around underneath the glaciers and ice sheets. They soon found that the undersurface of the ice is a lot more challenging than they’d expected.
“We thought at first, ‘Oh, it will be perfectly flat, will be very easy to drive a rover around,'” said Klesh. “But what we found is sometimes that we have craters similar to what you might find on the moon, crevasses that you can actually fall upwards into.”
So scientists are now focusing on designing ways to deal with those hazards.
“We’re looking at options for it to actually hop, to use thrusters to jump from one spot to another, and how to get it out of these fairly unfortunate spots that we still want to be able to traverse across,” Klesh said.
The next step will be to test BRUIE’s capabilities to explore for weeks and months under the ice from a remote location.
Building the rover may be the smaller part of the challenge of exploring Europa’s oceans though. NASA engineers are only just beginning to work out how how to drill down through Europa’s 20-kilometre thick ice sheet to get BRUIE in place for its mission.
The scientists are also working on making BRUIE much smaller to make that task easier.
“We’ve actually worked on one that can slim down, that the wheels can collapse and the tail can fold in, so we can fit into about a 20-centimetre diameter hole and be that much easier to get underneath the ice,” he said.
We can’t wait to see, and report on, the result.