NASA's Curiosity Mars Rover

Mosaic of 10 overlapping images (MastCam)

Returning to the path towards the large boxwork structures

NASA’s Mars rover Curiosity used its Mast Camera (Mastcam) to acquire this image showing a part of Volcán Peña Blanca from about 10 meters away (about 33 feet). It is already possible to see the different layers and make out that some of them are parallel, while others are at an angle. Curiosity acquired this image on July 6, 2025 — Sol 4591, or Martian day 4,591 of the Mars Science Laboratory mission — at 10:13:13 UTC. NASA/JPL-Caltech/MSSS

Written by Susanne P. Schwenzer, Professor of Planetary Mineralogy at The Open University, UK

Earth planning date: Monday, July 7, 2025

A few planning sols ago, we spotted a small ridge in the landscape ahead of us. Ridges and structures that are prominently raised above the landscape are our main target along this part of Curiosity’s traverse. There are many hypotheses on how they formed, and water is one of the likely culprits involved. That is because water reacts with the original minerals, moves the compounds around and some precipitate as minerals in the pore spaces, which is called “cement” by sedimentologists, and generally known as one mechanism to make a rock harder. It’s not the only one, so the Curiosity science team is after all the details at this time to assess whether water indeed was responsible for the more resistant nature of the ridges. Spotting one that is so clearly raised prominently above the landscape — and in easy reach of the rover, both from the distance but also from the path that leads up to it — was therefore very exciting. In addition, the fact that we get a side view of the structure as well as a top view adds to the team’s ability to read the geologic record of this area. “Outcrops,” as we call those places, are one of the most important tools for any field geologist, including Curiosity and team!

Therefore, the penultimate drive stopped about 10 meters away (about 33 feet) from the structure to get a good assessment of where exactly to direct the rover (see the blog post by my colleague Abby). You can see an example of the images Curiosity took with its Mast Camera above; if you want to see them all, they are on the raw images page (and by the time you go, there may be even more images that we took in today’s plan.

With all the information from the last parking spot, the rover drivers parked Curiosity in perfect operating distance for all instruments. In direct view of the rover was a part of Volcán Peña Blanca that shows several units; this blogger counts at least three — but I am a mineralogist, not a sedimentologist! I am really looking forward to the chemical data we will get in this plan. My sedimentologist colleagues found the different angles of smaller layers in the three bigger layers especially interesting, and will look at the high-resolution images from the MAHLI instrument very closely.

With all that in front of us, Curiosity has a very full plan. APXS will get two measurements, the target “Parinacota” is on the upper part of the outcrop and we can even clean it from the dust with the brush, aka DRT. MAHLI will get close-up images to see finer structures and maybe even individual grains. The second APXS target, called “Wila Willki,” is located in the middle part of the outcrop and will also be documented by MAHLI. The third activity of MAHLI will be a so-called dog’s-eye view of the outcrop. For this, the arm reaches very low down to align MAHLI to directly face the outcrop, to get a view of the structures and even a peek underneath some of the protruding ledges. The team is excitedly anticipating the arrival of those images. Stay tuned; you can also find them in the raw images section as soon as we have them!

ChemCam is joining in with two LIBS targets — the target “Pichu Pichu” is on the upper part of the outcrop, and the target “Tacume” is on the middle part. After this much of close up looks, ChemCam is pointing the RMI to the mid-field to look at another of the raised features in more detail and into the far distance to see the upper contact of the boxwork unit with the next unit above it. Mastcam will first join the close up looks and take a large mosaic to document all the details of Volcán Peña Blanca, and to document the LIBS targets, before looking into the distance at two places where we see small troughs around exposed bedrock.

Of course, there are also atmospheric observations in the plan; it’s aphelion cloud season and dust is always of interest. The latter is regularly monitored by atmosphere opacity experiments, and we keep searching for dust devils to understand where, how and why they form and how they move. Curiosity will be busy, and we are very much looking forward to understanding this interesting feature, which is one piece of the puzzle to understand this area we call the boxwork area.

Curiosity Rover - Focus Stacked MAHLI images form Sol 4594 (July 9, 2025)

Cross Bedding at Volcán Peña Blanca

Credits NASA/JPL-Caltech/MSSS

Mosaic assembled from 15 Bayer reconstructed left mast camera images. The ridge of sedimentary rock is called 'Volcán Peña Blanca'

published July 7

Published July 7, 2025

This image sees the sensor head of the Alpha-Particle X-ray Spectrometer (APXS) instrument placed on a target to acquire data. The image was taken by one of the Front Hazard Avoidance Cameras (Front HazCam) onboard NASA's Mars rover Curiosity on Sol 4590 July 5, 2025 at 11:24:54 UTC. Credits: NASA/JPL-Caltech

The APXS for MSL is an improved version of the APXS that flew successfully on Pathfinder and the Mars Exploration Rovers Spirit and Opportunity. The MSL APXS takes advantage of a combination of the terrestrial standard methods Particle-Induced X-ray Emission (PIXE) and X-ray Fluorescence (XRF) to determine elemental chemistry. It uses curium-244 sources for X-ray spectroscopy to determine the abundance of major elements down to trace elements from sodium to bromine and beyond.

The instrument consists of a main electronics unit in the rover's body and a sensor head mounted on the robotic arm. Measurements are taken by deploying the sensor head towards a desired sample, placing the sensor head in contact or hovering typically less than 2 cm away, and measuring the emitted X-ray spectrum for 15 minutes to 3 hours without the need of further interaction by the rover. At the end of the measurement, the rover retrieves the science data of 32 kilobytes, containing up to 13 consecutively taken spectra and engineering data. The internal APXS software splits the total measurement into equal time slots with an adjustable cycle time parameter. This allows us to check for repeatability and to select spectra with sufficient spectral quality.

The MSL APXS can activate an internal Peltier cooler for the X-ray detector chip. This results in a sufficient spectral resolution (FWHM) of below 200 eV at 6.4 keV below ~ -5 deg C and best FWHM of < 150 eV below ~ -15 deg C environmental temperature. Compared to the APXS on MER, where the best FWHM was reached at temperatures below ~ -45 deg C, this allows a significantly larger operational time window for APXS analysis.

The MSL APXS has approximately 3 times the sensitivity for low Z (atomic number) elements and approximately 6 times for higher Z elements than the MER APXS. A full analysis with detection limits of 100 ppm for Ni and ~ 20 ppm for Br now requires 3 hours, while quick look analysis for major and minor elements at ~ 0.5% abundance, such as Na, Mg, Al, Si, Ca, Fe, or S, can be done in 10 minutes or less.

On MER, the elements detected by the APXS in rock and soil samples are typically Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Zn, and Br. Elevated levels of Ge, Ga, Pb, and Rb were found in some of the MER samples.

The sampled area is about 1.7 cm in diameter when the instrument is in contact with the sample. A standoff results in gradually lower intensity and an increased diameter of the measured spot. Low Z element X-rays stem from the topmost 5 microns of the sample, higher Z elements like Fe are detected from the upper ~50 microns. Sample preparation is not needed; the APXS results average the composition over the sampled area and the oxide abundances measured are renormalized to 100%. However, on MSL, a dust removal tool (brush) is available to remove loose material from a rock surface before making an APXS measurement.

15 overlapping images

View full screen to see the diverse rock types [5506x1012px]

The mosaic is assembled from 10 overlapping RMI images from the CHEMCAM instrument, the images were acquired on Sol 4589 (July 4, 2025) and assembled in MS-ICE. Image Credits: NASA/JPL-Caltech/LANL

This image was taken by the Front Hazard Avoidance Camera (Front HazCam) onboard Curiosity rover on Sol 4588 (2025-07-03 09:15:59 UTC). Credits: NASA/JPL-Caltech

It shows a lighter toned rock close to the rover.

The rover is pointing Southwest after the drive to the down-slope drive of 23.4 meters (76.8 ft) towards the Northwest

NavCam mosaic (partial)

Nothing of interest to the team here as they drove away the next morning

The yellow line shows the path of the drive on sol 4587

post drive data from JPL

Mosaic of overlapping post-drive L-NavCam images - NASA/JPL-Caltech

The drive path is highlighted in yellow.

Credits: NASA/JPL-Caltech/MSSS/UofA

Credits: NASA/JPL-Caltech

Assembled from 15 overlapping Bayer reconstructed L-MastCam images. Credits: NASA/JPL-Caltech/MSSS/fredk