Mars rover Curiosity runs a rare chemical test for life-related material.

Curiosity used a solvent called TMAH to treat a powdered rock sample from the Nevado Sajama site to search for carbon-based molecules; two of three phases of the redesigned three-stage experiment have been run and scientists say results will take months to interpret.

After Mars emerged from solar conjunction, scientists planned a rare experiment for the Curiosity rover. The test uses a solvent called tetramethylammonium hydroxide (TMAH) in methanol mixed with powdered rock to make certain carbon-based molecules easier to detect. Curiosity gathered the sample near a hole drilled in November at a site dubbed Nevado Sajama, where fine-grained sedimentary rock and clay minerals suggest past water activity. The mission team rehearsed the sample transfer and began the experiment on Feb. 2, and two of the three stages of a redesigned, three-stage process have already run. Key details: - The solvent TMAH is mixed with powdered rock to free certain organic molecules for Curiosity’s onboard lab. - Curiosity carried just two small containers of TMAH during the mission and one had been used earlier; overall solvent supplies for wet chemistry are limited. - The Nevado Sajama site lies in a boxwork region with clay minerals and fine-grained sedimentary rock, which scientists view as favorable for preserving organics. - After an initial TMAH test in 2020, the experiment was redesigned into a three-stage method to better match laboratory procedures on Earth; the 2020 interpretation took about seven months and revealed more kinds of organic molecules than simple heating had. - Two of the three phases of the latest experiment have been completed, and the team says interpreting the analyses will take several months. Summary: The test gives scientists a different chemical approach to search for carbon-based molecules that could shed light on past habitability in Gale Crater. Results are pending and the team expects to take a few months to interpret the complex data.