Europa, one of the four Galilean satellites of Jupiter is one of the most intriguing locations in the Solar System to search for life. However, its subsurface oceans are buried beneath thick layers of ice making exploration difficult. To explore its oceans, scientists have suggested using small swimming robots capable of penetrating the icy shell. Recently, NASA engineers tested prototypes designed to operate as a swarm, enabling them to explore the mysterious sub-ice oceans on Europa and other icy worlds in the Solar System.
Along with the other three Galilean satellites orbing Jupiter, Europa was discovered just over 400 years ago by Galileo. It is the smallest of the four measuring just 3,120 km across. It orbits Jupiter at a distance of 671,000 km in an almost circular orbit. In comparison to our own Moon, Europa is a little smaller but that is where the similarities end. Europa is made of a silicate rock and has a thick water ice crust below which is thought to be a liquid water ocean and it is this which has captured the interest of scientists.
The deep oceans of Europa may well harbour forms of aquatic life. Consider the deepest parts of the oceans of Earth where whole eco-systems thrive off thermal vents. At these depths, no light from the Sun penetrates so the organisms and creatures living at these depths take all their energy from the heat escaping from inside the planet. It is this which tantalisingly suggests that maybe such life could have evolved in the oceans of Europa too.
The exploration of Europa is already underway with NASA’s Europa Clipper expected to arrive in 2030. It will explore Europa with a powerful set of scientific instruments over a total of 49 flybys. Each pass will see the instruments search for signs that the ocean under the thick icy crust could sustain life. This will just be a flyby mission with Europa being probed from high above its surface. NASA are already shaping up their next mission to include even more complex robots that could survey the depths of the sub-surface oceans of Europa.
This is where NASA’s new mission called SWIM ‘Sensing With Independent Micro-swimmers’ comes in. The concept at least, is simple…a swarm of self-propelled robots that can swim around in the underground oceans having been deployed by the ice piercing cryobot. Once underway, the swimming robots, which are about the size of a mobile phone, would hunt for chemical and temperature signals that might indicate life.
The swimming robots are not just on the drawing board. Engineers have already used 3D printers to create prototypes that have already been tested in a 23 metre pool. The devices which are propelled along by two propellers, with flaps for steering were able to stay on course. These prototypes however were a little larger than those destined to make it into space measuring about three times larger.
The results of the test were very promising but much more work is needed before they are ready for launch. Meanwhile the robots are likely to be trialled here on Earth to support oceanographic research before being sent on their way to Europa.
Source : NASA Ocean World Explorers Have to Swim Before They Can Fly