In the icy caves of Mount Erebus in Antarctica, volcanic gases swirl through shimmering tunnels. These tunnels could hold a clue to the earliest forms of life, preserved in the DNA of microbes clinging to their walls. But researchers haven’t been able to explore the caves in detail because of one big problem: Levels of carbon dioxide in the tunnels can be so high that humans would pass out from respiratory distress in as little as a minute.
That may all change soon, however, thanks to a new piece of technology: an ice-climbing robot called IceWorm. The robot is the first of its kind designed to scale up icy cliffs; someday, the robot may take samples in places that scientists have never reached before. The details of how IceWorm works will be presented in a poster on Wednesday afternoon at AGU’s Fall Meeting 2018.
Aaron Curtis, the lead designer behind IceWorm and a postdoctoral scholar at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., thinks that IceWorm could be the ticket to exploring not only Mount Erebus but also some of Earth’s most frigid frontiers. Curtis hopes to speak with glaciologists at the Fall Meeting who may find IceWorm’s skill at climbing on icebergs at sea or squeezing down melting channels in glaciers useful.
Inch by Inch
One foot at a time: That’s how IceWorm scales a slippery frozen precipice. The 1.4-meter robot, made of hollow aluminum tubes and rotary joints, holds on to the icy wall by nesting its two feet into the ice with steel alpinist screws.
To climb, the robot simply unscrews one foot, curls its body until the two feet are near each other, and refastens its free foot to the wall. It then unscrews the second foot, lengthens its body forward toward its destination, and screws back into the wall. It repeats the dance over and over, said Curtis, so that the robot “inchworms up the wall.”
“It’s a whole new way to move around,” Curtis told Eos. “It hasn’t really been tried before.”
Curtis and his colleagues in the Extreme Environments Robotics Group at JPL first started developing IceWorm in 2016, when Curtis joined NASA. His inspiration arose from his doctoral work studying tunnels in Mount Erebus, where he wished he could venture into the many passageways with dangerous carbon dioxide levels.
“It seemed really clear to me that we needed robots that could go in there. So I started looking around to see if anyone had made a robot who could get around on ice,” Curtis said. Finding no such robot, Curtis pitched the idea to JPL. Two years later, Curtis took IceWorm on its first real expedition: to scale the walls of a volcanic ice cave in the crater of Mount St. Helens.
Beneath the Ice of a Volcano
IceWorm dug its feet into its first real-world ice wall on a summer morning in Mount St. Helens’ Mothra Cave earlier this year.
After the researchers assembled the robot’s body on sleeping pads laid out on the floor of the ice cave, they held IceWorm up to the wall while it dug its first footholds into the glacial ice. Once the robot was secured, the scientists stepped back and let it climb while directing its next moves using a laptop nearby.
The key to IceWorm’s success lies in its dexterous feet. Each foot contains ice screws equipped with a pressure sensor that directs how hard to drill into the ice, striving for the right balance between rotation and forward thrust. A 3-D rendering on the researchers’ computers shows IceWorm’s body position in real time and lets researchers drag its free foot to the next stop on the wall.
IceWorm’s steps are also part of retrieving samples. While the robot bores into the ice to lock a new foothold, it simultaneously collects material in its legs. Someday, the system may be able to store these samples for later analysis, testing for salinity concentrations or microbial life.
But for now, the scientists are focusing on enhancing each component of the robot to make it as nimble as possible. After 8 hours of testing at Mount St. Helens, Curtis called it IceWorm’s first “successful test,” and he looks ahead to future development.
“We’re still playing with a lot of different options. We’re mostly just focusing on the mobility at the moment,” Curtis explained. “It’s at the extremely early stages of this technology.”
Where to Next?
Where will IceWorm climb next? Curtis said that’s still under discussion.
NASA hopes to develop the robot to explore icy worlds in our solar system, perhaps traveling to the frozen plains of Enceladus, Pluto, or Europa. IceWorm could dart off a lander to retrieve samples deep in ice fissures and bring them back for scientific analysis.
On Earth, glaciologist Kiya Riverman at the University of Oregon in Eugene said that IceWorm could help her get to areas she’s been studying that lie just out of reach.
“I’m particularly interested in how this little robot would do within a waterfall,” she said. Riverman crawls around the insides of glaciers to predict how fast they’re melting from warming temperatures, and taking measurements of waterfalls poses a continuing challenge for her work.
She also noted how IceWorm could make her own ice climbing safer by setting up rope holds for her. “It would be great if this little guy could climb channel walls and set anchors for me. That would dramatically speed the process of mapping channels,” Riverman added. She is not involved in the IceWorm project.
Curtis hopes that IceWorm will someday climb in the caves that inspired it. “I would be really interested to see a trip go back to Mount Erebus and explore a pristine cave where no one’s entered,” Curtis said.
“The caves that have higher levels of volcanic gases might be the ones that are more fertile for microbial life,” he added. “I would be very fascinated to see what lives in them.”