For a long time, science has known that several of the moons of the outer planets probably have oceans. Now technology is under development that will allow a spacecraft to explore them. One of the perennial problems with space exploration is that rockets can only accelerate so much to the outer planets, so spacecraft cannot be too big. This limits the amount of science that can be done.

A new idea from NASA’s JPL is to use lots of very small robots, which will be delivered through the ice of an ocean world to explore it in detail. The robots will also allow studying the likely gradients in the ocean by flying in formation, taking slightly different data depending on their position. Such gradients are possible signs of life, according to the engineer in charge of the proposal, Ethan Shaler.

The advantage of small robots is that they will maximize the amount of area covered under the ocean. If a single stationary robot lands where there’s nothing interesting in range, the mission will have returned nothing. Also, the under-ice probe uses a radioisotope thermoelectric generator (RTG) to melt the ice, and that could change the possible results, so getting away from the probe is best.

The idea of the robot swarm is fairly risky, but some of that risk is reduced by the sheer number of robots – four dozen twelve-centimeter robots. Some of them could fail, but since each can function independently, science could still be done despite any individual failures. The small volume lets other instruments fit in the under-ice probe as well, maximizing science.

Shaler first developed this concept under a Phase 1 NASA Innovative Advanced Concepts grant. He received a Phase 2 grant this year to further advance the concept and create a few prototypes. In the 2030s, a lander may visit Europa’s surface, after the Europa Clipper orbiter visits it earlier in the decade. Europa Clipper is currently scheduled for a 2024 launch, arriving in 2030.

More Information

NASA JPL press release