HiRISE Updates Week of 2018 Feb 19

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HiRISE Updates Week of 2018 Feb 19

Post by bystander » Sun Feb 25, 2018 7:07 pm

Shane Byrne wrote:

Icy Layers in Craters (ESP_053642_2225) (HiClip)

Scientists now realize that ice is very common on the Martian surface. It often fills up craters and valleys in the mid-latitudes in older climates, although when it’s covered in dust it can be hard to recognize. Today the climate on Mars makes this ice unstable and some of it has evaporated away.

In this image we can see the edge of a mound of ice in one of these mid-latitude craters. Some of it has already been removed, so we can see layering that used to be in the crater’s interior. Scientists use ice deposits like these to figure out how the climate has changed on Mars. Another upside of recognizing this ice is that future astronauts will have plenty of drinking water.
Alfred McEwen wrote:

The Phoenix Landing Site, 5 Mars Years Later (ESP_053451_2485) (HiClip)

This image is a close match in the viewing and illumination geometry to an earlier observation (PSP_009290_2485) that we acquired on 20 July 2008, about five Mars years ago.

An animation comparing the two images shows a number of changes. The lander (top) appears darker, and is now covered by dust. The dark spot created by the heat shield impact (right) is brighter, again due to dust deposition. The backshell and parachute (bottom) shows a darker parachute and brighter area of impact disturbance, thanks again to deposits of dust. We also see that the parachute has shifted in the wind, moving to the east.

See our Phoenix Lander greatest hits images here.
Cathy Weitz wrote:

A Layered Mound in Juventae Chasma (ESP_016712_1760) (HiClip)

Many of the chasmata (the plural of “chasma”) in Valles Marineris contain light-toned mounds that are distinct from the darker rocks that define the walls. The light-toned mounds, like this one in Juventae Chasma, generally contain sulfates, which are salts of sulfuric acid that form when water is evaporating.

The darker material that we see is collecting near the base of the light-toned mound, and likely represents wind-blown debris.
Chris Okubo wrote:

Wrinkles in Rock (PSP_003418_1865) (HiClip)

The bedrock in this region of Arabia Terra has been worn away by the wind, revealing their internal structure and geologic history.

The wavy lines are individual layers of sand and dust, originally laid down as the bedrock was forming. These patterns indicate that the bedrock formed as layers of sand and dust lost their confrontation with the relentless Martian wind in a desert-like environment.

NB: The cutout is rotated so that north is to the right.

This is a stereo pair with PSP_002574_1865.

Credit: NASA/JPL-Caltech/University of Arizona

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