Curiosity's 48th drill: prospecting for minerals at Basque Lakes in the new Cache Creek quad

The 48th drill hole on Mars

Retrospective note: the original event described here, the Earth planning date for this week of Curiosity operations, was Friday, Sept. 25, 2026, and the drill itself was imaged by the rover on Sept. 23, 2026 (Sol 5023). This article is explicit retrospective coverage of that completed week of Mars science, written from the mission blog NASA published later, on Oct. 4, 2026. It is not breaking news, and the publication date gap between the event and the source document is stated here up front.

NASA's Curiosity rover has drilled its 48th rock sample inside Gale crater, a bedrock target unofficially named "Basque Lakes," and the mission team is now waiting on the rover's onboard mineralogy lab to say what the powder is made of. The details come from the mission blog "Curiosity Blog, Sols 5022-5028: Cashing in at Cache Creek," written by Lucy Thompson, a senior research scientist at the University of New Brunswick who served as an APXS uplink lead and strategic planner for the week, with an Earth planning date of Friday, Sept. 25, 2026, and publication on the NASA science site on Oct. 4, 2026.

The blog post describes an observation, not yet a result: the drill hole exists, the pre-drill chemistry and imaging were completed, and the powdered sample has been handed to instruments inside the rover. What the analysis will show remains an open question that the team is framing in deliberately optimistic terms.

Why the map is named Cache Creek

While we may not literally strike gold, we are all eagerly anticipating the outcome of the CheMin X-ray diffraction analysis of our drilled sample that will take place in this weekend plan.

Attribution: Lucy Thompson, senior research scientist at the University of New Brunswick and APXS uplink lead for the week, writing in the Curiosity Blog "Cashing in at Cache Creek," Earth planning date Sept. 25, 2026, published Oct. 4, 2026 on NASA Science. The quotation is word-for-word from the retrieved blog text.

The gold language is not decoration. The rover has just entered a new map quad of Gale crater named Cache Creek, after a region of British Columbia, Canada, that sits at the southern end of the 1860s Gold Rush Trail. The naming choice carries a scientific wager: whether the minerals in this Martian rock echo the unusual lake chemistry of the Canadian namesake.

The quad system and what it means

Before landing in 2012, NASA divided the planned exploration area of Gale crater into rectangular parcels called quadrangles, or quads, each named after a small town associated with significant geological features, with targets inside each quad given unofficial names on that quad's theme. Thompson explains that Curiosity has long since climbed beyond the quads selected before landing, and the team has entered the new Cache Creek quad.

Per the blog, the Canadian region includes exposures of oceanic crust, marine sediments, volcanic rocks and glacial deposits, and is home to lakes with unusual chemistry that, in the team's view, may be analogous to lakes that once existed on Mars. That last clause is an interpretation by the mission team, not a measurement; the comparison is a hypothesis that the new sample can begin to test.

The practical meaning of a quad change is modest: a new batch of place names on a map, including the drill target Basque Lakes. The scientific meaning is larger: the rover is now sampling bedrock from a stretch of Mount Sharp it has never examined before, and the first drill there is the team's opening assay.

A 14-year-old robot still doing lab work

The number 48 is the headline figure, but the context is the more striking one. Curiosity landed in Gale crater in August 2012 on a mission designed to last about two years. As of the week of this plan, the rover had operated for 14 years and traveled 38 kilometers (24.6 miles), including more than 1 kilometer (0.6 miles) of elevation gain up the slopes of Mount Sharp, per the blog post.

Drilling is among the most demanding things the rover does. It requires a functioning percussion drill, stable rock, careful sequencing, and, as Thompson notes, significant power; the rover is nuclear-powered but aging, and power constraints shaped what else the team could schedule this week. That a 14-year-old robot can still acquire a pristine interior sample of Martian bedrock and run it through onboard laboratory instruments is the quiet achievement underneath the news. A laboratory on wheels, launched in 2011, is performing X-ray diffraction mineralogy on another planet this week, on a rock nobody on Earth has touched.

How the team decided to drill here

Drilling is only the middle of the process. Before the team committed the drill, Curiosity characterized the target. According to the blog, Thompson helped plan the triage contact science: the APXS instrument was placed in contact with the rock to measure its chemistry, and the MAHLI camera was brought to within 1 centimeter (about 0.4 inches) to examine textures in detail. ChemCam fired its laser at the target to further characterize composition from a distance.

Engineers also checked the stability of the rock with a pre-load test, and MAHLI imaged the target afterward, the step that produced the close-up image of the Basque Lakes drill site acquired on Sept. 23, 2026 (Sol 5023) at 03:56:10 UTC. The results from all these activities helped determine whether to proceed with drilling. In short: chemistry, texture, laser spectroscopy and a mechanical stability check, all before committing the drill.

APXS measures the abundance of chemical elements in rocks and soils and sits on the turret at the end of the robotic arm, according to NASA's Curiosity science instruments page. MAHLI provides close-up views of minerals, textures and structures at scales smaller than the diameter of a human hair. ChemCam vaporizes rock surfaces with a laser and reads the resulting plasma's light to identify elemental composition. These are the surveying tools; the drill is how you get beneath the weathered surface.

What CheMin does, in plain language

CheMin, the Chemistry and Mineralogy instrument, is an X-ray diffraction and fluorescence instrument about the size of a laptop computer inside a carrying case, located inside the rover's body, per the NASA instruments page. Its main job is to identify and measure the abundances of minerals on Mars. It can take up to 10 hours of analysis time spread over two or more Martian nights, which is why the team expected the result in the weekend plan rather than immediately.

X-ray diffraction, in plain terms: X-rays are shone through the powdered sample, and the atoms in each mineral crystal scatter the beam in a pattern specific to that mineral's atomic structure. Read the pattern, and you can name the minerals and estimate how much of each is present. Chemistry alone, which APXS and ChemCam provide, tells you which elements are present; diffraction tells you which minerals those elements are locked into, and minerals record how the rock formed and how water altered it afterward.

That distinction matters for the Cache Creek question. If the drilled powder contains minerals such as certain sulfates, carbonates or other evaporite-related phases, that would be consistent with briny or chemically unusual lake waters. Which minerals, in which amounts, is exactly what the CheMin result will determine.

The British Columbia analogy, and what it can and cannot show

The mission team's stated rationale for the Cache Creek naming, per the blog, is that the British Columbia region is home to lakes with unusual chemistry that may be analogous to lakes that once existed on Mars. This is the interpretive layer of the story, and it should be held as a hypothesis, not a finding.

What would count as evidence? If CheMin identifies a mineral suite associated with highly concentrated or chemically distinctive waters, similar in character to the mineralogy tied to some lakes in the Cache Creek area of British Columbia, then the team's analogy gains support for this particular rock exposure. If the minerals instead point to ordinary dilute lake conditions or to later groundwater alteration, the analogy weakens for this site, though it may fit elsewhere on Mount Sharp.

Nothing in the retrieved material yet supports any claim about life, habitability or even about the sample's specific minerals. Thompson's own questions in the blog post are framed as open: what can the minerals tell us about the depositional and alteration history of this rock exposure, and might there be similar minerals present as those associated with some of the British Columbia lakes? Until CheMin reports, the honest answer is that nobody knows.

SAM comes next week

The second lab instrument is next in line. Per the blog, analysis of the Basque Lakes drill sample should continue next week with delivery of material to SAM, the Sample Analysis at Mars suite, which Thompson says will reveal more nuggets of information regarding the history of this particular rock sample. NASA describes SAM as a suite of instruments, about the size of a microwave oven and roughly 40 kilograms, that identifies a wide range of organic, carbon-containing compounds, with a gas chromatograph, a mass spectrometer, a tunable laser spectrometer, and ovens that heat rock samples to about 1,000 degrees Celsius (about 1,800 degrees Fahrenheit) to extract gases.

CheMin and SAM answer different questions. CheMin identifies crystal structures and mineral abundances; SAM heats and sniffs the sample, looking for gases and organic molecules. The team also expects the rover to stay at this location for about another week, per the blog, before dumping the sample and driving away to continue exploring Mount Sharp and Gale crater. Even the sample's disposal is scheduled science; the dumped tailings will be imaged before the wheels roll on.

Everything else the rover did this week

The blog notes that despite significant power constraints associated with drilling and the accompanying analyses, and the aging rover, the team planned additional activities. Mastcam imaged the surrounding terrain to give the new drill sample geological context. ChemCam analyzed the chemistry of a nearby bedrock target named "Peace River" and used its imaging and passive spectroscopic capabilities to examine the new drill hole and the tailings around it. ChemCam remote imaging was also pointed at an interesting-looking deposit of jumbled blocks at the base of a nearby butte named "Cordillera." Navcam and Mastcam imaging continued the routine monitoring of environmental and atmospheric conditions in Gale crater.

Each drill campaign doubles as a survey of the neighborhood, and the Cordillera block deposit in particular may feed future target selection. A single week of operations on an aging spacecraft still bundles drilling, three kinds of chemical analysis, close-up and remote imaging, atmospheric monitoring and route planning, all paid for out of the rover's remaining power and mechanical life.

What is known, pending and speculative

Separating the layers of this story keeps it honest. Observed, per the retrieved primary sources: Curiosity completed its 48th drill in Gale crater on the target Basque Lakes within the newly entered Cache Creek quad; pre-drill APXS, MAHLI and ChemCam characterization and a pre-load stability test preceded drilling; the drill site was imaged on Sept. 23, 2026 (Sol 5023); CheMin X-ray diffraction analysis was planned for the weekend plan; SAM delivery was expected the following week; the rover was expected to remain about another week before dumping the sample and driving on. Also observed: the rover's 14-year tenure, 38-kilometer traverse and more than 1 kilometer of elevation gain, and the power constraints on this week's plan.

Pending: the CheMin mineralogy result itself and the SAM chemistry result. As of this writing, no specific minerals from the Basque Lakes powder have been reported in the retrieved sources.

Interpretation: the mission team's framing that the British Columbia Cache Creek region's unusually chemistry-rich lakes may be analogous to lakes that once existed on Mars, and the gold-prospecting framing of the blog post. These are expectations and rhetorical framing, not results. Any statement that this rock proves anything about Martian habitability would outrun the evidence; what is legitimately on the table this week is a mineral list, and what that list, once published, will let scientists say about the water that shaped this rock.

Sources, image rights and disclosure

About the image: the credited lead image could not be loaded for publication during independent review, so the raw-image copy of the MAHLI Basque Lakes close-up is not used here. The image accompanying this article is instead a NASA photograph hosted on Wikimedia Commons showing reddish rock powder from an earlier Curiosity drill campaign, the first hole drilled into a Martian mountain at the Confidence Hills target within the Pahrump Hills outcrop, whose sample was delivered to CheMin. The file page on Wikimedia Commons documents the source as NASA, dated Nov. 4, 2014, and licenses it as public domain in the United States as a work of the U.S. federal government, noting that NASA material is not protected by copyright unless noted. It is a drill-campaign illustration from an earlier, clearly identified part of the mission, not a picture of the Basque Lakes drill site; the MAHLI close-up of the actual Basque Lakes target, Sol 5023, Sept. 23, 2026, remains verifiable on the NASA raw-image page listed in sources, with credit NASA/JPL-Caltech/MSSS.

This article is based on the NASA Curiosity mission blog post of Oct. 4, 2026, retrieved and verified by the author, and on NASA's Curiosity science instruments reference page. The author is a machine-assisted writer for this publication; the piece was written under the publication's editorial standards and goes to independent editorial review before any publication decision.