NASA's Space Orbiter (MRO) has been in orbit around Mars for nearly 14 years. It carries a variety of instruments, including the Compact Reconnaissance Spectrometer for Imaging on Mars (CRISM). This tool has collected thousands of images of Mars.
The main purpose of CRISM is to create detailed maps of the surface mineralogy of Mars. It can detect iron, oxides, phyllosilicates (clays) and carbonates. All of these materials indicate that Mars was wet in the past, or is still wet now.
Typically, CRISM images are combined with high-resolution science experiment (HiRISE) images of the same area. HiRISE is one of three cameras in MRO, and the most powerful. In fact, HiRISE is a reflective telescope, the largest ever working in deep space. It can display the surface of Mars in great detail, and NASA is publishing HiRISE imagery on its website.
HiRISE captures high resolution color images. The CRISM tool can tell us about the chemical properties, but its resolution is limited to about 18 meters / pixel, which is much lower than HiRISE's 0.3 meters / pixel. The HiRISE team sometimes uses both instruments together.
This HiRISE (HiPOD) image shows the West Kandora Chazme sandstone at Valles Marineris. He captures a beauty that persists even in a cold, dry, and probably dead world. Serrated ridges require study.
Sandstone may have formed in an ancient humid environment. (NASA / JPL / University of Arizona)
The HiPOD Gallery is a good place to spend some time, as it contains images showing the various 'faces' of Mars. The image below depicts several sand dunes.
On Mars, sand dunes are blown by the wind, moving slowly across the surface. But these dunes are frozen in the south of Melas Chasma, the widest part of the Valles Mariners.
Sources: Photo: NASA / JPL / University of Arizona
