Curiosity drills its 49th hole on Mars, in a rock crowded with what may be crystal shapes

NASA's Curiosity rover has drilled the 49th sample hole of its mission on Mars, its science team reported in two blog posts dated November 9. The target, a block of rock informally named Nazca, was picked because its surface is crowded with disc- and needle-shaped forms that the team is trying to explain. A Mastcam image of the finished hole was taken on the mission's sol 5050, which NASA dates to October 20, 2026, in UTC.

The posts, written by team members, cover sols 5050 to 5062, with planning days dated October 23 and October 30. When the first was written, the results of the CheMin mineral analysis of the drilled powder were still on their way to Earth, and neither post reports them.

Why this rock

Curiosity came back to the area after its previous drilling, at a site called Basque Lakes, and stopped a few meters from a block named Chiu Chiu that showed the same texture but was not a good drilling candidate, Lucy Lim, a planetary scientist at NASA's Goddard Space Flight Center, wrote in an October 28 post. Close-up images of the block beyond it showed it was “jam-packed” with the lumps, and the team gave the go-ahead to drill there.

One major hypothesis, Lim wrote, is that the shapes first formed as minerals crystallized, and their fairly large size may say something about the temperature at the time and about which salts and fluids were around. She added a caution: the minerals in the rock now may not be the original ones, because a crystal can later be replaced by a different mineral that keeps its outline, a form geologists call a pseudomorph.

Before drilling, the rover had to pass a stability check, with all its wheels on solid ground, and a preload test, in which the drill bit presses on the rock to check how it and the arm respond, Susanne Schwenzer, a professor of planetary mineralogy at The Open University in the UK, wrote in one of the November 9 posts. The team also studied the spot with the APXS, MAHLI and ChemCam instruments, then delivered powder to the CheMin instrument and aimed ChemCam's laser at the drill tailings and down the wall of the hole.

A power budget for an older rover

Drilling and the analyses that follow use a lot of power. In the second November 9 post, Remington Free, an operations systems engineer at NASA's Jet Propulsion Laboratory, wrote that the team planned three quieter sols, 5060 to 5062, to recharge before finishing the campaign. Still to come were a further delivery to the SAM instrument, for a different kind of analysis, and a cleanup that shakes leftover powder out of the drill.

On sol 5061 the team also tried something new: running a CheMin data transfer during a communications pass with an orbiter. Free wrote that the rover's power output is slowly falling as it ages, so pairing activities that are safe to run together lets it spend less time awake. The test appeared to go well, he wrote, but the engineers had yet to analyze the results.

Where Curiosity is now

Curiosity landed in Gale crater in 2012 and has since been climbing the slope of Mount Sharp. The mission set out to learn whether Mars ever had conditions suited to microbes, and NASA says the rover found chemical and mineral evidence of past habitable environments early on. Its drill collects powdered rock for the instruments inside the rover.

The Basque Lakes hole lies in an area the team calls the Cache Creek quad, after a geologically varied region of British Columbia, team member Lucy Thompson of the University of New Brunswick wrote in early October. She also pointed to the power limits of drilling with what she called an aging rover. Free ended his post by promising more on how the rest of the Nazca campaign went, and NASA collects the team's posts on its Curiosity mission updates page.