preparation for their missions to the moon. >> they need to replicate what it is like on the south pole of the moon, where the sun is very low, right in your eyesight, but everywhere else is pitch black. >> nasa believes, there is water ice on the south pole. a possible source of drinking water, and rocket fuel. but, as colder, with less sunlight, lisa shore is the deputy chief of the pool lab. >> you will have this dusk lighting, and behind any large rock, or things like that, you will have a long shadow where we'll be pitch black. >> certainly, it's easier to drive when you are in the sunlight. >> absolutely. >> those shadows are so long. >> already, astronauts are using simulators to practice driving a rover on the moon. >> so, astronauts need to learn how to drive a rover, without going into one of these holes, and craters. >> exactly. you, very often, don't know how deep these creators are. it is difficult to tell how big these rocks are, with 18 inches