The Caves of Mars Project was a program funded through Phase II by the NASA Institute for Advanced Concepts

NASA Institute for Advanced Concepts

right|200pxNASA Institute for Advanced Concepts was a NASA-funded program that was operated by the Universities Space Research Association for NASA from 1998 until its closure on 31 August 2007. NIAC sought proposals for revolutionary aeronautics and space concepts that could dramatically impact...

to assess the best place to situate the research and habitation modules that a manned mission to Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 would require.

Caves and other underground structures, including lava tubes, canyon

Canyon

A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...

 overhangs, and other Martian cavities would be potentially useful for manned missions, for they would provide considerable shielding from both the elements and intense solar radiation that a Mars mission would expose astronauts to. They might also offer access to minerals, gases, ices, and any subterranean life that the crew of such a mission would probably be searching for.

The program also studied designs for inflatable modules and other such structures that would aid the astronauts.