The robots that will one day be sent to the frozen moons of giant planets will have to be equipped to drill into great depths of ice, and autonomously. It’s less easy than it seems… But teams are working on it, in particular with the SLUSH prototype. Our best chance to explore these oceans?
“ All these worlds are yours, except Europe », wrote mischievously Arthur C. Clarke (in 2010, Odyssey two). The fact remains that one day, humanity will want to explore ice moons in depth, and Europa, the star of Jupiter’s moons, or Enceladus around Saturn, make ideal candidates. There have already been project proposals elsewhere, to send a robotic submarine or a lander onto the ice.
But to one day visit these oceans, we will first have to pass through their ice floes, the thickness of which undoubtedly reaches and exceeds several tens of kilometers. All in difficult conditions (very uneven surface, tidal effects, disturbances at depth). To tackle the problem, teams like that of the SLUSH project, for “Search for Life Using Submersible Heated”, are trying with their prototype to drill through our very terrestrial ice.
She drills, and it’s very strong
The principle of digging through a thick layer of ice is relatively simple. At the front (or rather at the end of the drilling head) is mechanical equipment for breaking the ice, on the principle of a percussion drill. When heated, these ice residues melt and are discharged through an upward auger, which causes the drill to descend while allowing the ice to reform behind it.
The biggest challenge, according to the team working with Honeybee Robotics on the prototype, is to communicate with the drilling head (the heating and power part can easily be maintained with a radioisotope generator) as it progresses. as it descends into the thick layer of ice. For this, there are several redundant means: wired connection, ejection of pucks which act as communication relays during the descent, and fibers which, if cut, can replace an antenna.
For the moment, she is not at the bottom of the hole
Are the tests conclusive? In a limited way, for now. In the laboratory, everything works very well. But the SLUSH team also tested several versions on Devon Island, Canada. The first very limited copy, “Salmon”, managed to reach 1.8 meters depth in 2022. In 2023, the “Dauphin” should have gone much deeper, but a logistical problem only allowed it to be tested up to ‘at a depth of 2 meters.
This is why there are more hopes for the new 2024 prototype, the Narval. On Devon Island there is normally enough ice to drill for at least 100 meters, which is still far from the layers of ice that line the entire surface of the frozen giants, but these are useful tests to avoid bad surprises.
Source : USRA
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