if there are lava tubes on mars, there could be life in there, too. next, daniel is keen to show me another terrestrial analogue a couple of hours�* drive from the lava tube, and this one is even more extreme. we're going under the ice to an environment of very different challenges. we think about the lava tube that we visited earlier — that's a ready—made structure perfect for potential habitat. whereas the analogue we're currently in, here in the ice tunnel, this is a wonderful place to do isolated confined extreme environments to test various challenges that have to do with cold weather and isolation. how important is it that we find and use water ice on the moon and mars? finding frozen water