Submersible robot helps scientists measure ice melt in Antarctica

NASA engineers who specialize in building spacecraft to explore distant planets are now working on another project. The plan is to develop a fleet of underwater robotic probes that will help measure how quickly climate change is melting the vast ice sheets around Antarctica and calculate what that would mean for sea level rise.

A prototype of the submersible vehicles, which is being developed by NASA’s Jet Propulsion Laboratory (JPL), was tested at a U.S. Navy research site in the Arctic, where it was deployed under the ice of the Beaufort Sea north of Alaska in March.

“These robots are used as a platform to deliver scientific instruments to the hardest-to-reach places on Earth,” explains Paul Glick, a robotics engineer at JPL and principal investigator on the IceNode project, in a summary published on NASA’s website.

The probes are intended to provide more accurate data to measure the rate at which the continent’s coastal ice is melting into seawater around Antarctica, allowing scientists to improve computer models that predict future sea level rise.

A JPL analysis published in 2022 found that the thinning and collapse of the Antarctic ice sheet has reduced its mass by about 12 trillion tons since 1997, double previous estimates.

If melted completely, according to NASA, the loss of the continent’s ice sheet would raise sea levels by about 200 feet.

Ice shelves – floating sheets of frozen freshwater that extend for miles out to sea – take thousands of years to form and act as huge buttresses, holding back glaciers that would otherwise easily slide into the ocean.

Satellite images have shown that the outer shell of icebergs is calving off at a faster rate than nature can replace the lost ice. At the same time, rising ocean temperatures are eroding the shelves from below, a phenomenon that scientists hope to examine more closely with the IceNode submersible probes.

Although they would not have any form of propulsion, the robotic probes would be carried by ocean currents, using special guidance software, to reach “grounding zones” where the ice shelf meets salty seawater and land. These cavities are impenetrable even to satellite signals.

“The goal is to get data directly at the melting ice-ocean interface,” said Ian Fenty, a climate scientist at JPL. Upon reaching the target, each spacecraft would drop its ballast and float upward, attaching itself to the underside of the ice shelf by deploying a three-pronged “landing gear” that unfolds from one end of the vehicle.

From there, the IceNodes would record data from beneath the ice for up to a year (including seasonal fluctuations) before breaking free to drift back into the open ocean and transmit the readings via satellite. Previously, ice shelf thinning was documented by satellite altimeters that measured the changing height of the ice.

During the field test, a prototype IceNode was lowered 100 meters below the sea surface to collect salinity, temperature and flow data. Previous tests have been conducted in Monterey Bay, California, and below the frozen surface of Lake Superior on the U.S.-Canada border.

Scientists believe that 10 probes would be ideal for collecting data from a single ice shelf cavity. But Glick said more testing is needed before a timeline can be set for large-scale deployment.

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