...Or it might be completely prohibitive, depending on what sort of radiation is present.  High fluxes of low energy radiation are much easier to shield against than low fluxes of high energy radiation.  This is incidentally why there is at present no realistic plan to deal with GCR&#x27;s in interplanetary travel.<p>Getting beneath Europa is a perfectly workable plan only if you assume that you can get <i>to</i> the Europan surface safely.  It may be that just approaching it for landing gives too much dose for short-term survival.<p>Absent good reason, though, Europa makes little sense for a manned mission relative to Ganymede or Callisto, which likely also have oceans, or Titan, which has an atmosphere to boot.