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NASA is developing swimming robots to search for extraterrestrial life

One day in the future, a swarm of robots the size of mobile phones could swim through the water under the icy shell several kilometers thick of Europa, the moon of Jupiter, or Enceladus, the moon of Saturn, in search of extraterrestrial life. These robots could be encased in narrow ice-melt probes that cut through the frozen crust to free the tiny robots underwater, which can then swim far and deep to discover new worlds.

Or at least that’s the vision of Ethan Schaler, a robotic mechanical engineer at NASA’s Jet Propulsion Laboratory (JPL) in Southern California. Schaler’s Sensing With Independent Micro-Swimmers (SWIM) concept recently received $600,000 in Phase II funding from NASA’s Innovative Advanced Concepts (NIAC) program. Schaler and his team will use the funding to manufacture and test 3D-printed prototypes over the next two years.

SWIM’s initial concept envisions wedge-shaped robots, each about 12 centimeters long and 60 to 75 cubic centimeters in volume. They are designed so that about four dozen of them can fit in a cryobot (ice-penetrating probe) 25 centimeters in diameter, occupying only 15% of the volume of the science payload. This would leave more room for more powerful but less mobile scientific instruments that could gather data through stationary ocean measurements.

Each robot would have its own propulsion system, on-board computer and ultrasonic communication system, as well as temperature, salinity, acidity and pressure sensors. Phase II of the study will also add chemical sensors to monitor biomarkers.

NASA’s Europa Clipper mission, scheduled for launch in 2024, will conduct multiple flybys of Jupiter’s moon to collect detailed data with a large suite of instruments when it arrives there in 2030. Cryobot concepts to study these ocean worlds are being developed through NASA’s underground scientific exploration. Access Mechanism for Europa (SESAME), as well as through other NASA technology development programs.

The cryobot that deploys the swimming robots would be connected to the lander on the surface via a communication tether. The surface lander, in turn, would be the point of contact with mission controllers on Earth. This tethered approach means the cryobot would likely be unable to venture much beyond the point where the ice meets the ocean.

“What if, after all those years it took to enter an ocean, you cross the ice shell in the wrong place? What if there are signs of life there but not where you entered the ocean? By bringing these swarms of robots with us, we could look ‘over there’ to explore much more of our environment than a single cryobot would allow,” said SWIM team scientist Samuel Howell of JPL. in a press release.

The cryobot that deploys the swimming robots would be connected to the lander on the surface via a communication tether. (Illustration credit: NASA/JPL)

Howell compares swimming robots to NASA’s Ingenuity Mars helicopter, the airborne companion to the Perseverance rover on Mars. The helicopter extends the rover’s range and returns images, helping the rover understand how to explore its surroundings. In this case, the multiple swimming robots can be considered as several helicopters exploring the areas around the cryobot to return data.

Additionally, the cryobot will have a nuclear battery, which it will rely on to melt a downward path through the ice. Once in the ocean, this heat could create a thermal bubble, slowly melting the ice above and causing reactions that could change the chemistry of the water. SWIM would allow data collection far from it.

Additionally, SWIM robots could mimic fish and birds to “join” and take overlapping actions to reduce errors in data. These group data could also show gradients: temperature or salinity. For example, the swarm’s collective sensors could be used to identify the source of a change in temperature or salinity and point in that direction for further exploration.

“If there are energy gradients or chemical gradients, that’s how life can start to appear. We would need to go upstream of the cryobot to detect them,” Schaler said in a press release.