Curiosity update, sols 2093-2162: Three tries to successful drill atop Vera Rubin Ridge-- E1

Heedless of the (now-dissipating) dust storm, Curiosity has achieved its first successful drill into rocks that form the Vera Rubin ridge, and is hopefully on the way to a second. It took three attempts for Curiosity to find a soft enough spot, with Voyageurs and Ailsa Craig being too tough, but Stoer proved obligingly soft on sol 2136. The rover delivered samples to both of its analytical laboratory instruments before driving away.


There have been lots and lots of images landing on Earth in the last several weeks, as Curiosity is ramping up data relay through MAVEN and ExoMars Trace Gas Orbiter. Once InSight lands, Curiosity will have to give up most of its Mars Reconnaissance Orbiter data relay to the lander -- InSight’s landing site is just a couple hundred kilometers north of Curiosity, so both missions want the same data relay passes as the polar-orbiting spacecraft passes overhead. For Curiosity, switching to MAVEN and ExoMars relay can replace the volume, but not the rhythmic repeatability, of Mars Reconnaissance Orbiter’s twice-a-day-like-clockwork relay sessions. Until InSight lands, though, Curiosity gets to hog all the data volume -- so the team is taking advantage of the bounty while it lasts.

Speaking of image bounty, I want to share this Mastcam self-portrait, taken at the Stoer drill site. Curiosity acquires most of its self-portraits with the MAHLI camera on the end of the arm, but the team is being cautious about using MAHLI much while the dust storm’s dust is still settling out of the sky. (More on this below.) Mission scientists wanted to document the accumulation of dust on the rover’s deck, so without MAHLI being available, that meant a Mastcam deck panorama. In Mastcam deck pans, we can see the arm but not the mast; the reverse is true in MAHLI self-portraits.

 Curiosity deck panorama at Stoer
NASA / JPL / MSSS

CURIOSITY DECK PANORAMA AT STOER
Curiosity used its Mastcam to take a 360-degree self-portrait from the top of Vera Rubin ridge, at the successful Stoer drill site, on sol 2136 (9 August 2018). The rover usually uses its arm-mounted MAHLI camera for self-portraits, but is constrained from using MAHLI much during the dust storm. Because it used its mast-mounted camera, we can see the MAHLI instrument on the turret in this view, but we can't see the rover's "head" or "neck" (the mast) on which the Mastcam is mounted.
No Joy at Voyageurs or Ailsa Craig
Spirits were high on the team as the rover departed the successful drill site at Duluth on sol 2084. They were ready to do a real drill campaign across the ridge, sampling its rocks in at least three places. In order to get to Duluth, Curiosity had driven down the relatively steep northern face of Vera Rubin ridge, so the next task was to drive uphill again. There were a few stalled drives as the rover encountered challenges in the climb, but the wheels were back on top of the ridge as of sol 2098.

Ten sols later, the rover pulled up to a site named Voyageurs. Roger Wiens nicknamed it “The Great Red Spot” because on an orbital map showing hematite mineral abundance on the ridge, Voyageurs lay within the brightest red pixel. Here’s a look at that map of hematite abundance from Mars Reconnaissance Orbiter’s CRISM instrument, which I’ve overlaid with Curiosity’s course. Voyageurs is one of the brown dots.

 Before & After: Vera Rubin Ridge HiRISE color and CRISM hematite band depthBefore & After: Vera Rubin Ridge HiRISE color and CRISM hematite band depth
NASA / JPL / UA / JHUAPL / CRISM map courtesy Valerie Fox, Ray Arvidson, and Abigail Fraeman

BEFORE & AFTER: VERA RUBIN RIDGE HIRISE COLOR AND CRISM HEMATITE BAND DEPTH
Curiosity explored Vera Rubin Ridge at the end of 2017 and through 2018. The ridge had long been a target for the rover because of its interesting geomorphology and because of a strong hematite signal in orbital spectroscopic images. Use the slider to compare HiRISE and CRISM views of the ridge. The yellow line shows the rover's path as of sol 2162 (5 Sep 2018).

The HiRISE image is ESP_042682_1755. Click here for an enlargement.

The CRISM map shows the strength of the 860 nm absorption seen by CRISM, which is diagnostic of the mineral hematite. Click here for an enlargement. Brighter reds correspond to deeper absorption. This parameter map was processed to 12 m/pixel using an along-track over-sampled CRISM image, FRT00021C92. Curiosity also observed hematite all along its traverse in the Murray formation leading up to the ridge, but these detections were more difficult to see from orbit due to sub-pixel mixing with sand and dust in the rocks below the ridge. CRISM data processing courtesy Valerie Fox and Raymond Arvidson, Washington University in St. Louis.
Spectroscopist Abigail Fraeman was especially excited to reach Voyageurs, because her Ph.D. thesis focused (in part) on high-resolution mapping of hematite along the ridge. Full of anticipation, the team drilled, and...womp, womp. (For those of you unfamiliar, that is the Internet’s approved transcription of the “sad trombone” sound.)

 Aborted drill attempt at Voyageurs