On Earth glaciers and ice shelves are often pock-marked with circular, near vertical shafts that puncture deep into the river of ice. Known as moulins, they are formed by meltwater and can plunge hundreds of meters from the surface right down to the bedrock or ocean below.
It is thought that if icy world’s such as Jupiter’s moon Europa can be shown to have moulins, they could offer an ideal and easy way to get beneath into the oceans thought to lie below. Researchers from NASA have been testing a robotic spelunker that could one day help us explore this distant world.
“To get under the surface of Europa or [Saturn's moon] Enceladus, we need to find the quickest way in,” said Andy Klesh from NASA's Jet Propulsion Laboratory, who is helping to develop the robots. “Can we map and navigate these subglacial lakes with robots? Are there accessible passageways hidden just beneath the surface? This first foray to Alaska tested the technology to begin answering these questions.”
The researchers have traveled to the Matanuska Glacier, the largest in Alaska, in order to test out a recently developed robotic spelunker, to see how well it holds up exploring the frigid watery crevasses and moulins. They hope that the labyrinth of caves will be a good proxy for what might be experienced on Europa.
The team sent a robotic submersible down into the tunnels, which are filled with water, going to depths of 46 meters (150 feet). While the robot could have gone deeper, the researchers say that the cloudy conditions of the water at these depths, and their reliance on its onboard camera, meant that they didn’t want to risk it.
The aim of the project was to use the cameras and laser scans to map the caves, channels, and crevasses in 3D. “The idea is to identify and map out these underwater channels,” Leichty said. “We want to know if they're correlated to surface features that we can identify using satellite or overhead images.”
It would mean that when NASA’s Europa Clipper mission is due to fly by Europa in the late 2020s snapping pictures as it goes, the surface features of the moon can be studied and compared to what is learned from these glaciers on Earth.
This is not the only piece of impressive robotic kit that NASA is developing to study the potential icy and watery depths of Europa. This August saw the deployment of a deep-ocean lander off the coast of Los Angeles. The platform sits at the bottom of the ocean, powering itself and sampling the waters that surround it, sending the information wirelessly back to a ship floating on the surface.