By 2030, the Europa Clipper and Juice missions will learn more about Europa, an icy moon of Jupiter. On this world, life could be found under a thick layer of ice. But how to pierce it to explore what is underneath? Researchers think they have found a solution!
In 2023 and 2024, two NASA and ESA missions will depart on Europe, an icy moon of Jupiter. They should arrive at their destination in 2030, with the aim of looking for life under the thick layer of ice on the satellite. A liquid ocean is found there, and clues on the surface of Europa suggest that it is heated and could therefore harbor various forms of life.
But, to be sure, NASA’s Europa Lander mission, which will follow on from the other two, should land on Europe and come and dig the ice to reach the liquid ocean. For that, it will have to be able to pierce the 15 to 25 km thick ice. To this end, several options have been proposed, based on a heating or nuclear-powered probe operating by radioactive decay. A team of NASA scientists has proposed another device this time: a hybrid nuclear reactor.
A hybrid reactor based on both fission and fusion
Currently, there are two methods for triggering the fusion reactions. Inertial confinement, which consists of compressing a target of deuterium and tritium to the extreme, using lasers, and magnetic confinement, which this time consists of heating a mixture of hydrogen isotopes to extreme temperatures. The proposed reactor is based on “fusion by lattice confinement”: a metallic lattice highly enriched in deuterium in which the atoms are accelerated by a source of neutrons, until causing collisions between deuterium atoms, then reactions of merger.
The reactions lead to the emission of energetic neutrons, which can then trigger reactions of nuclear fission, in a lithium blanket enriched in fissile elements. Due to the high energy of the neutrons emitted, depleted uranium or thorium could be sufficient to create the fission reactions.