Europa is hard vacuum on the surface, so this is not actually intuitively obvious: i.e. if you built up a gaseous steam interface between the bore hole walls, t

Europa is hard vacuum on the surface, so this is not actually intuitively obvious: i.e. if you built up a gaseous steam interface between the bore hole walls, then you might have quite a bit of trouble losing heat back into the surrounding ice. In fact you could just boil the water to steam and vent it out the top via a surface valve assembly - the interior would act like a vacuum thermace flask.