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Curiosity Blog, Sols 4798-4803: Back for More Science

Curiosity Blog, Sols 4798-4803: Back for More Science

  • The NASA Mars rover Curiosity has returned to the “Nevado Sajama” drill location on Mars, where it conducted a series of scientific experiments using its Sample Analysis at Mars (SAM) instrument suite.
  • During this visit, Curiosity used a chemical reagent called tetramethylammonium hydroxide (TMAH) to analyze the minerals and compounds locked in the rock sample, which was collected from a drill hole.
  • The rover also conducted additional science observations, including targeting the interior of another drill hole, analyzing rocks exposed by the wheels, and measuring the chemistry of the Martian atmosphere.
  • Curiosity’s instruments, such as the Mast Camera (Mastcam), Navcam, RAD, and REMS, made various measurements and observations to complement the SAM analysis and provide a more comprehensive understanding of the Martian environment.
  • The rover is now awaiting results from the first part of the SAM analysis and plans to run the second part over the weekend, with additional science experiments scheduled for future visits to the “Nevado Sajama” drill location.

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Curiosity Blog, Sols 4798-4803: Back for More Science

An overhead color photo of the Martian surface shows pale orange-tan, flat, rocky terrain, with the surface a mixture of jagged-edged slabs with fine soil leveling the gaps between them, and small rocks of various sizes scattered around the surface. Near the image center and at lower-right are two drill holes in the rock, each with mounded soil around the opening that had been extracted from the holes during drilling.
NASA’s Mars rover Curiosity acquired this image showing the side-by-side drill holes “Nevado Sajama” (right) and “Nevado Sajama2” (left). Curiosity used its Mast Camera (Mastcam) to capture the image on Jan. 31, 2026 — Sol 4795, or Martian day 4,795 of the Mars Science Laboratory mission — at 22:55:27 UTC.
NASA/JPL-Caltech/MSSS

Written by Michelle Minitti, MAHLI Deputy Principal Investigator

Earth planning date: Friday, Feb. 6, 2026

The results from our first visit to the “Nevado Sajama” drill location were intriguing enough to motivate our return to do a deeper dive into the minerals and compounds locked in this rock with SAM (the Sample Analysis at Mars instrument suite). As explained in the last blog, that deeper dive involves using the second of two vials of a chemical reagent, tetramethylammonium hydroxide (TMAH), that helps makes molecules detectable to SAM that would otherwise be undetectable. This week was focused on completing the many carefully-coordinated steps to apply the TMAH reagent to the rock powder from a drill hole and then analyze the treated sample. As you can see in the image above, we know the drilling necessary to collect the sample was successful, as was delivery of the sample to SAM. We are awaiting word about the first part of the SAM analysis, and are running the second part in the weekend plan. 

As you can imagine, running a mass spectrometer and chemistry experiment remotely on another planet takes a lot of energy, but throughout the week, the team took advantage of whatever spare power there was to include additional science observations. ChemCam planned two attempts at targeting the Nevado Sajama2 drill-hole interior, analyzed “Tiquipaya,” one of the family of rocks broken by the rover wheels that expose bright white material, and measured the chemistry of the atmosphere with a passive sky observation. They also planned an RMI mosaic of layers near the base of the “Mishe Mokwa” butte to our east. MAHLI and APXS paired up to image and analyze the ground-up tailings around the drill hole for the most direct measure of chemistry of what SAM analyzes. As Mastcam acquired a full 360-degree mosaic the first time we were at Nevado Sajama, they did not have many rock observations to plan. Instead, they turned their eyes toward the sky to measure the amount of dust in the atmosphere. Navcam made complementary measurements of atmospheric dust and planned movies and imaging surveys of clouds and dust devils. Ever watchful, RAD and REMS made their regular measurements of the Martian environment while DAN regularly monitored the Martian subsurface. 

A rover sits on the hilly, orange Martian surface beneath a flat grey sky, surrounded by chunks of rock.
NASA’s Mars rover Curiosity at the base of Mount Sharp
NASA/JPL-Caltech/MSSS

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Last Updated

Feb 10, 2026

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Q. What is the name of the Mars rover that acquired an image showing the side-by-side drill holes “Nevado Sajama” and “Nevado Sajama2”?
A. Curiosity

Q. When was the image taken by the Mast Camera (Mastcam) on Sol 4795, or Martian day 4,795 of the Mars Science Laboratory mission?
A. January 31, 2026, at 22:55:27 UTC.

Q. What is the purpose of using tetramethylammonium hydroxide (TMAH) in the SAM instrument suite on Curiosity?
A. To make molecules detectable to SAM that would otherwise be undetectable.

Q. What was the focus of the team’s activities during Sol 4798-4803, after their first visit to the “Nevado Sajama” drill location?
A. Completing the many carefully-coordinated steps to apply TMAH reagent to the rock powder from a drill hole and then analyze the treated sample.

Q. What was one of the additional science observations planned by ChemCam during Sol 4798-4803?
A. Targeting the Nevado Sajama2 drill-hole interior.

Q. What is the name of the instrument that measured the chemistry of the atmosphere with a passive sky observation?
A. Navcam.

Q. What was one of the complementary measurements made by DAN during Sol 4798-4803?
A. Monitoring the Martian subsurface.

Q. What is the purpose of the RAD and REMS instruments on Curiosity?
A. To make regular measurements of the Martian environment.

Q. When did the team plan to run the second part of the SAM analysis, which involves using TMAH reagent?
A. During the weekend plan.

Q. What was one of the planned activities by Mastcam during Sol 4798-4803?
A. Acquiring a full 360-degree mosaic of the “Mishe Mokwa” butte to our east.