Mars

'Raw,' 'Natural', and 'White-Balanced' views of Martian terrain. These three versions of the same image taken by the Mast Camera (Mastcam) on NASA's Mars rover Curiosity illustrate different choices that scientists can make in presenting the colors recorded by the camera. The left image is the raw, unprocessed color, as it is received directly from Mars. The center rendering was produced after calibration of the image to show an estimate of "natural" color, or approximately what the colors would look like if we were to view the scene ourselves on Mars. The right image shows the result of then applying a processing method called white-balancing, which shows an estimate of the colors of the terrain as if illuminated under Earth-like, rather than Martian, lighting.

The first image from the surface of Mars was obtained by the Viking 1 probe just minutes after the spacecraft landed successfully on 20 July 1976.

This is the original description provided by NASA with this historic image:

The center of the image is about 1.4 meters (five feet) from Viking Lander camera #2. We see both rocks and finely granulated material - sand or dust. Many of the small foreground rocks are flat with angular facets. Several larger rocks exhibit irregular surfaces with pits and the large rock at top left shows intersecting linear cracks. Extending from that rock toward the camera is a vertical linear dark band which may be due to a one-minute partial obscuration of the landscape due to clouds or dust intervening between the Sun and the surface. Associated with several of the rocks are apparent signs of wind transport of granular material. The large rock in the center is about 10 centimeters (4 inches) across and shows three rough facets. To its lower right is a rock near a smooth portion of the Martian surface probably composed of very fine-grained material. It is possible that the rock was moved during Viking 1 descent maneuvers, revealing the finer-grained basement substratum; or that the fine-grained material has accumulated adjacent to the rock. There are a number of other furrows and depressions and places with fine-grained material elsewhere in the picture. At right is a portion of footpad #2. Small quantities of fine grained sand and dust are seen at the center of the footpad near the strut and were deposited at landing. The shadow to the left of the footpad clearly exhibits detail, due to scattering of light either from the Martian atmosphere or from the spacecraft, observable because the Martian sky scatters light into shadowed areas.

Two spacecraft engineers join a grouping of vehicles providing a comparison of three generations of Mars rovers developed at NASA's Jet Propulsion Laboratory (JPL), located in Pasadena, California. The setting is JPL's Mars Yard testing area.

Front and center is the flight spare for the first Mars rover, Sojourner, which landed on Mars in 1997 as part of the Mars Pathfinder Project. On the left is a Mars Exploration Rover Project test rover that is a working sibling to Spirit and Opportunity, which landed on Mars in 2004. On the right is a Mars Science Laboratory test rover the size of that project's Mars rover, Curiosity, which is on course for landing on Mars in August 2012.

Sojourner and its flight spare, named Marie Curie, are 2 feet (65 centimeters) long. The Mars Exploration Rover Project's rover, including the "Surface System Test Bed" rover in this photo, are 5.2 feet (1.6 meters) long. The Mars Science Laboratory Project's Curiosity rover and the "Vehicle System Test Bed" rover, on the right in this photo, are 10 feet (3 meters) long.

The team operating NASA's Curiosity Mars rover uses the Mars Hand Lens Imager (MAHLI) camera on the rover's arm to check the condition of the wheels at routine intervals. This image of Curiosity's left-middle and left-rear wheels is part of an inspection set taken on April 18, 2016, during the 1,315th Martian day, or sol, of the rover's work on Mars.

Holes and tears in the wheels worsened significantly during 2013 as Curiosity was crossing terrain studded with sharp rocks on its route from near its 2012 landing site to the base of Mount Sharp. Team members are keeping a close eye for when any of the zig-zag shaped treads, call grousers, begin to break. Longevity testing with identical wheels on Earth indicates that when three grousers on a given wheel have broken, that wheel has reached about 60 percent of its useful mileage.

The rectangular openings visible in the backs of the wheel treads in this image create a unique, repeating pattern in the sandy Martian surface, which the rover can use as a visual reference to drive more accurately in barren terrain. Incidentally, the pattern is Morse code for the letters JPL. [link]

This set of three images shows views three seconds apart as the larger of Mars' two moons, Phobos, passed directly in front of the Sun as seen by NASA's Mars rover Curiosity. Curiosity photographed this annular, or ring, eclipse with the telephoto-lens camera of the rover's Mast Camera pair (right Mastcam) on 20 August 2013, the 369th Martian day, or sol, of Curiosity's work on Mars.

The rover's observations of Phobos help researchers to make measurements of the moon's orbit even more precise. Because this eclipse occurred near mid-day at Curiosity's location on Mars, Phobos was nearly overhead, closer to the rover than it would have been earlier in the morning or later in the afternoon. This timing made Phobos' silhouette larger against the Sun - as close to a total eclipse of the Sun as is possible from Mars.

The Mars Orbiter Laser Altimeter (MOLA) aboard the Mars Global Surveyor produced the first global map of the topography of Mars. MOLA operated by shining a laser at the planet and timing its reflection. The most obvious feature of this map is the major contrast in elevation between the southern highlands (mostly orange) and northern lowlands (blue). The highest elevations are found in the Tharsis volcanic province at about 250°E, while the lowest elevations are in the Hellas basin at about 60°E.

This contrast between the hemispheres is probably the result of a giant impact of a Pluto-sized object near the north pole of Mars early in its history. There are fewer craters in the north hemisphere, indicating that the terrain was "repaved" by melting or being covered with sub-surface lava as a result of the impact. This event might have contributed to the rapid shut-off of Mars’ global magnetic field.

Olympus Mons is so massive that it is slowly collapsing under its own weight, even in the comparatively low gravity of Mars (40% of Earth's gravity). The steep cliffs visible along the right side of the volcano's base in this side-view image constructed from Viking data were caused by collapse. Heights in this image are exaggerated by a scale of 10:1.

Comparison of large mountains on Earth and Mars. Mauna Kea is shown starting from the sea floor; the part that is underwater is shaded blue.

The Ophir Chasma region of Valles Marineris, the northernmost of the connected valleys. For scale, the large impact crater in the lower right corner is about 30 km (18.5 miles) wide. Ophir Chasma itself is a large west-northwest-trending trough about 100 km (62 miles) wide. The Chasma is bordered by high-walled cliffs, most likely tectonic faults, showing the effect of numerous past landslides.