In this artist’s concept, a SPARROW robot uses steam propulsion to get away from its landing base and explore the surface of an icy moon. Credit: NASA / JPL-Caltech
SPARROW, a steam powered robotic concept, could one day make giant leaps over some of the most dangerous (and unknown) terrain in the solar system.
Steam locomotion may sound like an outdated way of getting around, but it could be getting a science fiction makeover as we expand our reach in the solar system.
A new robotic concept being investigated in POTThe Jet Propulsion Laboratory in Southern California would use steam propulsion to jump over the type of icy terrain found in JupiterEurope’s moon and SaturnEnceladus’ moon. Both are believed to harbor vast underground saltwater oceans under a thick crust of ice. But while that makes them fascinating destinations for scientific study, the little we know about their surfaces could also make navigating them especially challenging.
That’s where the steam powered autonomous recovery robot for Ocean Worlds, or SPARROW, comes into play. Approximately the size of a soccer ball, the robot consists of a system of propellers, avionics, and instruments enclosed in a protective spherical cage. To maintain the pristine environment for the study, SPARROW would not run on rocket fuel but rather steam produced from the melted ice, traveling primarily through the air through short thrusts. In the kind of low-gravity environment found on those distant icy moons, there would be no atmospheric drag to slow it down, allowing leaps of many miles over landscapes that other robots would have difficulty navigating.
NASA is investigating a jumping robot that can easily navigate harsh glacial terrain on icy worlds in our solar system. And that’s just the tip of the iceberg. NASA 360 takes a look at NASA’s Advanced Innovative Concept (NIAC) called SPARROW, a revolutionary approach to exploring frozen ocean worlds. Credit: NASA 360
“The terrain in Europe is very complex,” said Gareth Meirion-Griffith, JPL robotist and principal investigator of the concept. “It could be porous, it could be riddled with cracks, there could be penitents six feet high,” long sheets of ice that form in Earth’s high latitudes, “that would stop most robots.” But SPARROW has total terrain agnosticism; You have complete freedom to travel through inhospitable terrain. “
The concept relies on a lander to serve as SPARROW’s base of operations. It would extract the ice and melt it before loading the water into the jumping robot. SPARROW would then heat the water inside its engines, creating bursts of steam to propel the surface. When it is low on fuel, the jump robot would return to the lander to get more, and would also leave the scientific samples for further analysis.
To maximize the scientific research that could be done, many SPARROWs could be dispatched together, swarming around a specific location or dividing to explore as much alien terrain as possible.
This computer simulation shows a group of SPARROW robots exploring the surface of an icy moon. The results of such simulations help scientists determine the most efficient jump distance. Credit: NASA / JPL-Caltech
In 2018, SPARROW received funding from Phase I of NASA’s Innovative Advanced Concepts (NIAC) program, which nurtures visionary ideas that could one day be used in future space missions. Phase I studies explore general feasibility and advance the Technological Readiness Level (TRL). Eligible recipients of Phase I awards can propose a follow-up Phase II study.
For SPARROW, the NIAC Phase I funds enabled the development and testing of different water-based thruster systems that could be used to produce steam in the most efficient way. Furthermore, the SPARROW team was able to better understand how the spherical robot could fall when landing on icy and chaotic terrain using computer simulations, thus identifying the most efficient launch angle and jump speed.
“From this, and related propulsion calculations, we were able to determine that a single long jump would be more efficient than several smaller jumps,” added Meirion-Griffith.
NIAC is funded by NASA’s Space Technology Mission Directorate, which is responsible for developing the new technologies and cross-cutting capabilities that the agency needs.
