Which Mars rover detected organic molecules in Martian rock?

Curiosity was the Mars rover that detected organic molecules in Martian rock. Its Sample Analysis at Mars, or SAM, laboratory found carbon-containing compounds in powdered samples drilled from rocks in Gale Crater.

In 2015, Curiosity drilled into the Cumberland rock at a location called Yellowknife Bay. Analysis later revealed chlorobenzene and other organic compounds in the ancient mudstone. Scientists also reported organic molecules in additional Gale Crater samples, including benzene and propane discovered in material roughly three billion years old.

Organic molecules are not proof that life existed on Mars. They can be produced by biological processes, but they can also form through non-biological chemistry or arrive on Mars in meteorites and dust. Curiosity’s findings therefore show that important carbon-based chemistry is preserved in Martian rocks, not that the rover found fossils or living organisms.

Perseverance also studies organic chemistry, but its central mission is to collect and cache rock and soil samples for possible return to Earth. Curiosity made the landmark in-place detections associated with this question.