Simplify a mission to Europa by investigating only the surface, where fossils and/or frozen life may be present
Sunday, June 20, 2010
One of the most exciting proposed missions is the Europa Jupiter System Mission, one that would involve cooperation between NASA, the ESA, JAXA and Russia, in order to send some four probes to the Jupiter system. One would orbit Europa, one would orbit Ganymede, a third would orbit Jupiter itself and measure the magnetosphere, and the Russian probe would land on the surface of Europa and carry out measurements there.
Exactly what to do on the surface of Europa is unknown, as some of the most ambitious plans propose a melt probe (cryobot) that would sink into the ice, melting it as it goes down, and then release a hydrobot that would explore the ocean below after reaching water.
That seems like a bit too complex a mission for us now though, even a decade from now. Europa's ice is likely 100 kilometres thick, which to be honest is way beyond us. Luckily if life is present on the moon there should be no reason why it doesn't occasionally find itself encased in the ice, after which it would eventually make its way to the surface in a frozen form, so if it exists we should be able to find it on the surface.
So for the surface mission portion of a Europa probe the design is probably not that difficult to envisage: a probe that is able to scoop up and analyze ice samples on its own, and given how little we know about the surface so far it should also be able to move on its own to other locations; we don't want to send a probe all the way to Europa and realize that it has landed in one of the least scientifically interesting parts of the whole moon and not be able to move it anywhere else.
Europa is somewhat smaller than the Moon and has a slightly lower surface gravity (80% that of the Moon):
and when you reach a low enough surface gravity you eventually reach the point where driving around from one location to another is not as efficient an option as simply hopping instead. A hopping probe has been proposed before for the Moon, so if the terrain makes driving around difficult then it could be a good idea for Europa as well.