potential – adj. possible
deposit – n. a layer of a substance that has developed from a natural or chemical process
frontier – n. the limits of what is known or what has been done before in an area of knowledge or activity
subsurface – n. the area below Earth's surface
polar – adj. relating to the north or south pole regions
plain – n. a large area of flat land
glacier – n. a very large area of ice that moves slowly down a slope or valley or over a wide area of land
mission – n. the flight of a spacecraft to perform a certain task or job