Look: The surface of Mars

Dunes on Mars are almost free of their seasonal ice cover during early Martian summer, with pockets of ice still visible in areas protected by shade, as seen in this Mars Reconnaissance Orbiter image.

The surface of Mars after a meteoroid hit and exploded, creating an impact crater 5 meters across that triggered a one-kilometer-long slope streak, or avalanche. Image taken by NASA's Mars Reconnaissance Orbiter.

A view of the Ophir Chasma on the northern portion of the vast Mars canyon system, Vallles Marineris, taken by NASA's Mars Reconnaissance Orbiter.

Two geologically young craters on the surface of Mars.

A view of the Noctis Labyrinthus region of Mars, perched high on the Tharsis rise in the upper reaches of the Valles Marineris canyon system.

Part of the wall of Gale Crater. Here, a network of valleys believed to have formed by water erosion enters Gale Crater from the outside.

A gully in the sand dunes of Matara Crater on the surface of Mars, carved by seasonal dry ice that accumulates each year.

Rough spherical features in an area called Yellowknife Bay. These features are interpreted as concretions, implying they formed in water that percolated through pores in the sediment. Spherical concretions have previously been discovered in other rocks on Mars.

Cliffs of ancient ice on the surface of Mars, featuring brown dusty cliff walls and light blue ice.

The northern-most sand dunes are seen as they begin to emerge from their winter cover of seasonal carbon dioxide (dry) ice.

A field of barchan sand dunes appear turquoise blue on the surface of Mars in this enhanced image taken by the Mars Reconnaissance Orbiter.

A location on Mars associated with the best-selling novel and Hollywood movie, "The Martian" This area is in the Acidalia Planitia region and in the novel and the movie, it is the landing site of a crewed mission named Ares 3.

An impact crater on Mars is seen in an image taken by NASA's Mars Reconnaissance Orbiter.

A rock outcrop called Link pops out from a Martian surface. Rounded gravel fragments, or clasts, up to a couple inches in size are in a matrix of white material. The outcrop characteristics are consistent with a sedimentary conglomerate, or a rock that was formed by the deposition of water and is composed of many smaller rounded rocks cemented together. Scientists enhanced the color in this version to show the Martian scene as it would appear under the lighting conditions we have on Earth.

Nili Patera, one of the most active dune fields on the planet Mars. Image taken by NASA's Mars Reconnaissance Orbiter.