For the last several weeks, Curiosity has been hopping between areas of blue-ish toned rocks on the Vera Rubin Ridge and the results from these locations continue to become more compelling. Our next blue-toned destination has informally been called "Stop E" (the light-colored bedrock material in the depression near the top of the image) and today we had made a unanimous decision to get there as quickly as possible on the second sol of our plan, Sol 1930.

That's not to say we will be ignoring the current location en route! We planned contact science for Sol 1929 with APXS and MAHLI on a bedrock target termed "Banff" as well as an associated ChemCam LIBS raster and Mastcam images. We also targeted ChemCam and Mastcam on targets "Bass Rock" and "Barraclough". In addition to the drive on Sol 1930, ENV also planned three Mastcam tau observations during the day to help study how the amount of dust and clouds in the sky vary throughout the day.

Today's image is a color version of part of the workspace image from the Sol 1925-1926 blog, which shows in greater detail the numerous layers and color variations that kept us at this spot for another round of science observations. Exploring more of the steps in our staircase-like workspace was the name of the game today. The MAHLI mosaics acquired on Sol 1925 from the targets "Jura" and "Crinan," near the bottom of the workspace, were intriguing enough to lead ChemCam to analyze both of them with rasters that crossed over multiple layers exposed in these targets. Also near the bottom of the workspace, the target "Craighead," a gray rock cut by criss-crossing sulfate veins, will first be brushed by the Dust Removal Tool (DRT), and then imaged by MAHLI and analyzed by APXS. In between the targets Crinan and "Assynt" (another Sol 1925 target), ChemCam will shoot the target "Brodick" to add to our chemical survey of the outcrop. MAHLI will follow up on a ChemCam target from Sol 1925, "Barra," taking advantage of the dust-removing capability of ChemCam's laser to get a closer, cleaner look at this target near the top of the workspace.

We took a few brief breaks from the rocks in front of us to image and analyze other objects of interest. ChemCam will shoot the sand target "Boreray" to compare its chemistry to those of sands Curiosity has encountered throughout the mission. ChemCam and Mastcam will both image the Peace Vallis fan, far north of us on the Gale crater rim, as our vantage point on top of the "Vera Rubin Ridge" gives us a clear view of it. MAHLI will image the REMS UV sensor to monitor dust accumulation on the zenith-pointing sensor. REMS itself along with RAD will make regular measurements of the environment, and DAN will ping the ground below the rover both before and after we drive to seek signs of subsurface hydrogen. Early morning Navcam and Mastcam observations of clouds and the amount of dust in the atmosphere will complement a similar suite of observations made mid-day on Sol 1925.

On the second sol of the plan, we will drive away to a new patch of bedrock that, at least from orbit, shares characteristics with the bedrock we have spent the past few sols investigating. By comparing what we find there to our recent measurements, we can continue to put together a story for how the Vera Rubin Ridge came to be.

Curiosity's hard work over the holiday break paid off, giving the science team a rich collection of new data to assess and a new workspace to explore. The science team certainly got the year off to a bang with a very full plan at our new parking spot!

The layered rocks in the workspace extend away from the rover like a staircase, and our observations were aimed at "walking" up the staircase to survey similarities and differences in the layers on our journey. We started near the bottom of the workspace, acquiring MAHLI mosaics on layers in the targets "Jura" (the triangular-shaped target immediately in front of the rover) and "Crinan." About halfway up the staircase, we stopped at the target "Assynt" for MAHLI imaging and chemistry measurements with ChemCam and APXS. A few more steps up brought us to the target "Barra," which we analyzed with ChemCam. Finally, at the farthest point where the arm could reach (the upper right edge of the above image) we acquired MAHLI images and ChemCam data from the target "Elgin." We acquired Mastcam multispectral observations, which tell us something about the iron-bearing minerals in the rock, in a continuous swath from Crinan to Elgin, and tracked the layers from in front of us to the right of the rover using a 5x2 Mastcam stereo mosaic.

While mostly busy looking at the rocks in front of us, we paused to take an afternoon glance skyward to look for clouds and dust devils, and measure the amount of dust in the atmosphere. The bountiful workspace meant that we did not drive, so we will remain here to start our weekend plan, allowing the science team to follow up on the observations made today.

There's no real rest for the rover. We planned sols 1921-1924 on December 22 and 29. Earlier, the team had planned a minimal set of activities for the rover to carry out over Sols 1913-1920, letting the science and engineering teams spend a bit of time away from work. However, this doesn't mean Curiosity was sitting idle. There were still plenty of things to do on Mars, including some automated ChemCam AEGIS observations. These activities automatically pick out targets of interest and measure their chemistry at our current parking spot.

On New Year's Eve, the rover started carrying out the four-sol activity plan we completed Dec. 29. This site was so interesting that we backtracked to get to where the rover was parked for this plan. In the workspace in front of the rover, we have some very peculiar targets that warranted some additional interrogation. From orbit, this location has a very interesting appearance, with bluer hues being observed in High Resolution Imaging Science Experiment camera data onboard the Mars Reconnaissance Orbiter. On the ground, we are making Alpha Particle X-ray Spectrometer measurements on two targets, Haroldswick (the dark toned "stick"-like features observed in this Mastcam image from sol 1905) and the Raasay target. We are using these observations to help characterize the interesting compositional variability observed at this location even further. We also planned several ChemCam activities to aid in understanding this ever-evolving compositional story Curiosity is unraveling. In all, while the science and engineering teams took some time off over the holiday season, Curiosity was hard at work on Mars.

This morning we found ourselves back on familiar ground, near the targets "Lismore" and "Leadhills" that we imaged back on sol 1905. We drove here to take a closer look at the transition between the blue-gray and red rocks in order to understand the geologic processes that may be responsible for this color change. Since we pulled up right alongside this transition, we were able to plan a monster, 180 frame Mastcam stereo mosaic that will cover the entire area with very high-resolution color information. Downlinking all of these frames from Mars to Earth may take some time, but fortunately we'll have some great opportunities to get big data downlinks during the upcoming holiday. I'm very much looking forward to spending the break unwrapping the data bundles and seeing what's there!

In addition to the awesome mosaic, we will also have some environmental science observations including an atmospheric tau measurement to monitor dust in the atmosphere, a Mastcam crater rim extinction observation, and a dust devil survey. We'll collect ChemCam, Mastcam, APXS, and MAHLI closed cover data from targets named "Ben Loyal" and "Ben More." Because we're coming up on a long holiday plan, we want to be extra careful that the MAHLI dust cover doesn't unintentionally get left open during the long command uploading break, so we're not opening it in today's plan. After all this wraps up, we will drive back towards the target "Laphroaig" that we imaged on sol 1905 to do additional follow-up investigations of some interesting, small scale features.

A final note, we got some terrific news from SAM this morning that their first wet chemistry experiment on Mars ran successfully! Over the last few sols, the SAM team mixed some of the sample we've been carrying around since our investigation at Ogunquit Beach with special chemicals called "derivatization agents" that are designed to make certain molecules easier to detect. I'm looking forward to hearing the results of their experiment once they complete their analyses!

Local area today:
https://mars.nasa.gov/msl/multimedia/raw/?rawid=NRB_567057006EDR_F0671714NCAM00269M_&s=1910

Similar area from sol 1905 Mastcam:
https://mars.jpl.nasa.gov/msl-raw-images/msss/01905/mcam/1905MR0099970000900125C00_DXXX.jpg

Today's planning session kicked off with an important decision about where to drive and how that will set us up for exciting science over the holidays. After much discussion, the team decided to return to some familiar yet intriguing rocks that we explored last week, visible in the above Navcam image. These rocks show a lot of color variations and alteration features (as seen in the above Mastcam image), and we're curious how they fit in the overall stratigraphy at Vera Rubin Ridge. The other main event in today's plan is a SAM wet chemistry experiment on the Ogunquit Beach sample. This is a very power hungry activity, so we had to keep our other remote sensing activities in check. The team planned two Mastcam mosaics to document the context of the site we're driving back to, and to investigate similar color variations in an outcrop to the southeast. After a busy night of SAM activities, Curiosity will spend the second sol driving back toward an area named "Lismore." During the drive we'll take a bunch of MARDI images to document the terrain beneath the rover, and then we'll take our typical post-drive Navcam and Mastcam mosaics to prepare for targeting on Wednesday. In the afternoon, Curiosity will acquire two Navcam movies to monitor the atmosphere and search for clouds. I'll be on duty on Wednesday, so I'm looking forward to seeing some familiar rocks and preparing for the long holiday plan!

Only two days ago, Curiosity was exploring a region of the Vera Rubin Ridge that appears more "blue" than its surroundings, and consists of patches of sand and clean bedrock. Curiosity spent several days at this location, trying to understand the diversity within this interesting geologic region, taking pictures, and making geochemical measurements.

After a ~14 meter drive to the east out of this "blue" region, we're in a completely different type of landscape - lots of smaller rocks and bedrock exposures that appear more "red" or "purple" than the previous "blue" terrain. The original plan was to try to brush a rock surface and to perform a suite of geochemical analyses over the weekend, but the lack of large blocks will prohibit our ability to brush a rock clean (see image). Instead, the team is going to use the ChemCam LIBS analyses to both measure the chemistry of two rock targets ("Haddo House" and "Holyrood") as well as blast away surface dust, which will allow for the APXS instrument to have a clear view of "clean" bedrock material for its analyses over the weekend. A third ChemCam target named "Old Man of Storr" is a bright clast that is very different from the other rocks in the scene. Lastly, Mastcam will be used to investigate local color and spectral variability, and to also image the region ahead of the rover to help plan for future traverses.

The team also decided not to drive this weekend, instead giving the team more opportunity to interpret the data acquired over the past few days and leaving the option in place to potentially continue our exploration of this area of the Vera Rubin Ridge before getting too far away. This decision will also prevent Curiosity from using too much power, in case the team decides next week to plan some power-intensive analysis using the Sample Analysis at Mars (SAM) instrument.

I was on downlink for ChemCam on Wednesday, so I was busy analyzing the latest data while the uplink team decided what to do for sols 1904 and 1905. We had some nice data, including a gorgeous image of a finely-layered rock named "Trotternish" (shown above).

The sol 1904 plan started with some Mastcam and Navcam atmospheric observations, followed by ChemCam on the targets "Oban", "Talisker", and "Laphroaig". That is followed by a MAHLI "goniometer" observation of Oban. A goniometer measures the amount of light scattered from a surface at different angles, so when we say we have a MAHLI goniometer measurement, it means lots and lots of images of the same target from precisely spaced intervals. It gives Curiosity's arm a workout and delivers a nice data set that can be used for detailed photometry and to create a 3D reconstruction of the target. In addition to the goniometer observation, MAHLI also did normal observations of Oban and Talisker. APXS then did overnight observations on both targets.

On Sol 1905, Mastcam had a documentation image of Talisker, and a full multispectral observation of Oban. Mastcam also had a couple of mosaics of targets "Leadhills" and "Lismore" followed by a MARDI image to document the terrain before we move on.

The majority of the time on the "Vera Rubin Ridge," Curiosity focuses on the rocks that make up the ridge, measuring their chemistry and imaging their structure to try and understand the origin of this prominent feature in Gale crater. Today, however, sand was the focus of Curiosity's attention. Small depressions gather sand as the wind blows along the ridge, and the team wanted to measure the chemistry and grain size of such a Vera Rubin Ridge sand deposit to understand their similarities (or differences) to those of the Bagnold dune sands. MAHLI and APXS were deployed on two targets, "Goatfell" and "Eilean Dubh." The former is along the crest of a sand ripple, and the latter avoids ripple crests to provide the largest contrast to Goatfell. ChemCam will raster across another ripple crest at "Stonehaven," and Mastcam will acquire a multispectral observation at "Corrie" that covers the ripple crests targeted by ChemCam, MAHLI and APXS.

The Vera Rubin Ridge rocks did not go without attention despite the comprehensive sand observations. ChemCam will measure bedrock chemistry at "Arran," and the chemistry of one of the gray cobbles scattered throughout the workspace at "Trotternish." Targets "Coll" and "Yell" mark a contact between two different rock types on the ridge; Mastcam mosaics across these targets will provide detailed insight into the nature of the contact. Mastcam will also image "Hoy," a small, bumpy rock that shares similarities with the target "Moffat" imaged at our last stop. All of the plan's targets will be recorded for posterity in one of our systematic Mastcam 360 degree mosaics, including Curiosity's drive target, a stretch of bedrock ~5 m away with unique color characteristics as viewed from orbit.

Environmental observations include dust measurements at three different times of day, early morning searches for clouds looking above the rover and across the horizon, DAN passive and active measurements spaced throughout the plan, and regular REMS and RAD measurements.

The plan for this weekend is to finish up the investigation of Vera Rubin Ridge stop #9 and drive toward the next stop. On Sol 1899, Mastcam will acquire multispectral observations of possibly hematite-rich outcrops at "Farr" and the Sol 1897 contact science target "Wick." Both ChemCam and the Right Mastcam will observe "Muck," another Sol 1897 contact science target, and new rock targets named "Gala" and "Lagavulin." Mastcam will also take standard color images of interesting blocks named "Moffat" and "Cape Wrath." Then more of the Ogunquit Beach sample will be dropped into SAM for an overnight evolved gas analysis on Sols 1900 and 1901. The goal is to measure the amounts of various noble gases in the sample in order to determine when the minerals in the sand were formed.

Just before sunrise on Sol 1900, ChemCam will again attempt to detect frost on the "Sandwick" soil target that was observed during the day on Sol 1898. Navcam will search for clouds above the rover just after sunrise, then only REMS measurements and a few engineering activities are planned before the SAM solid sample analysis, which requires a significant amount of power.

The drive is scheduled for Sol 1901, followed by the usual post-drive imaging to enable more contact science in the next plan. Finally, the AEGIS software will be used to autonomously select an outcrop target and observe it with ChemCam.