Sols 2119-20, July 23-24, 2018. Above is a Sol 2119 Mastcam view of the ridge’s rolling terrain to the rear of the rover. Below is a Sol 2119 Mastcam composite showing the workspace and the Sgurr of Eigg site, with the target area circled. At right is a Sol 2120 MAHLI closeup of Sgurr of Eigg. The images are to check for dust accumulation since Curiosity was here last on Sol 1999.
All images enlarge when clicked.
Sol 2119 raw images (from all cameras).
Auroras appear on Earth as ghostly displays of colorful light in the night sky, usually near the poles. Our rocky neighbor Mars has auroras too, and NASA’s MAVEN spacecraft just found a new type of Martian aurora that occurs over much of the day side of the Red Planet, where auroras are very hard to see. (…)
The MAVEN team was studying Mars’ atmosphere with the Imaging UltraViolet Spectrograph (IUVS), and observed that on occasion, the ultraviolet light coming from hydrogen gas in Mars’ upper atmosphere would mysteriously brighten for a few hours. They then noticed that the brightening events occurred when another MAVEN instrument, the Solar Wind Ion Analyzer (SWIA), measured enhanced solar wind protons.
But two puzzles make this type of aurora seem impossible at first glance: how did these protons get past the planet’s “bow shock,” a magnetic obstacle which normally diverts the solar wind’s charged particles around the planet? And how could the protons give off light, since atoms need electrons to do so?
“The answer was thievery,” said Justin Deighan, of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, lead author of a paper on this research appearing July 23 in Nature Astronomy. “As they approach Mars, the protons coming in with the solar wind transform into neutral atoms by stealing electrons from the outer edge of the huge cloud of hydrogen surrounding the planet. The bow shock can only divert charged particles, so these neutral atoms continue right on through.” [More at links]
Alluvial fans are found on Earth, Mars, and even Saturn’s moon, Titan. Roddy Crater on Mars is home to several large alluvial fans, which formed as water moved sediment from the mountainous crater rim and deposited it onto the flatter crater floor.
The fans built up over time during intense rain storms or from melting snow. Due to the strong winds on Mars, the river channels that once carried water and sediment on the fan surfaces are now standing as raised ridges and platforms. A thin blanket of ejecta (upper right) from a small crater on Roddy’s eastern rim protected underlying fan surfaces from modification by the wind compared to nearby, unprotected fans (left). The scarp beneath the thin ejecta surface exposes beautiful… [More at link]
Sol 2120, July 23, 2018, update by MSL scientist Abigail Fraeman: Our weekend drive completed successfully and we have our next intended drill target attempt in the rover workspace. Unfortunately, the combination of the rover’s pitch and roll would make future delivery of drilled sample to SAM via the new feed extended sample transfer (FEST) method impossible in our current orientation, so tosol we are going to scooch the rover over slightly to put it in a more favorable position for drill sample delivery activities.
The main activity for tosol is the small bump to get us into a good drill position. We also managed to get some science in before the bump. We will take a MAHLI image of “Sgurr of Eigg,” a contact science target from almost 120 sols ago, to see how much dust has deposited on it since we DRTed it. We will also take some… [More at link]
THEMIS Image of the Day, July 24, 2018. This VIS image is located at the northern end of Gordii Dorsum, where the surface slopes down into southern Amazonis Planitia. Within this image are several different surfaces and textures.
At the top left of the image (ignoring the very tip) moving down towards the larger depression there are three different surfaces. There are two small, discontinuous ridges that parallel the depression that divide the three surfaces from each other.
At the top the surface is uniformly wavelike, in the middle, there is a region of shallow depressions, and in the third region the shallow lineations are more complex and a higher density of features. The lineations are largely parallel and radial to the large depression.
The cliff face between the top of the image and the lower right consists of two levels. The upper cliff slopes gently to the edge of the lower cliff face, where the change in elevation is dramatic.
Dark slope streaks are visible on the lower cliff face, and on both cliffs on the far right side. The floor of the large depression has a rough surface, with a general linear trend from the bottom right of the image to the uppper left corner.
Along the bottom edge of the depression are a series of small intersecting ridges. These features typically represent fracture fill that is more resistant then the surrounding material, which are left as ridges when the surrounding materials are eroded away.
At the base of the cliffs at the bottom of the image is a region of uniform texture, probably from erosion of the cliff forming material.
A smaller crater on the floor of Gale Crater. This crater likely exposes Gale Crater bedrock beneath the floor units and may allow mapping of floor units in the south of Gale.
Beautiful Mars series. [More at links]
The dunes, they are coming for you! These dunes are next to a central peak in a crater.
Beautiful Mars series. [More at links]
THEMIS Image of the Day, July 23, 2018. This VIS image shows an unnamed crater in Noachis Terra. The crater is relatively young, with several different structures on the floor and rim still visible.
The inner rim of the crater has series of concentric benches, formed by collapse of the impacted surface into the bowl shaped interior. The crater floor is not flat, with several mounds created by rebound of melted material inside the crater.
One of the more interesting features is that the crater is not round, as would be expected. The straight rims likely mean the there was a pre-existing tectonic fracture system, where the forces of the blast aligned with the fractures.
Sols 2117-19, July 20, 2018, update by MSL scientist Michelle Minitti: Curiosity made great progress yesterday across the “Vera Rubin Ridge” toward the site of our next drilling attempt at “Sgurr of Eigg”. In this weekend plan, we will collect more data about the ridge materials around us, and the sky above us, before embarking on a ~12 m drive to Sgurr of Eigg. We drove back into the Torridon quadrangle, so the target names once again have Scottish flavor. ChemCam shot three targets, each with a different characteristic. “Ben Stack” is a representative laminated bedrock target, “Ben Avon” is bedrock with small nodular features throughout it, and “Ben Lawers” includes a thin, resistant layer jutting out above the laminated bedrock surrounding it. APXS will also analyze a… [More at link]
