A self-portrait of the Curiosity rover on Mars. This picture was assembled from a series of images taken by the MAHLI camera, mounted on the end of Curiosity’s robotic arm. Credit: NASA / JPL / MSSS / Ed Truthan
A few days ago, the science team of the Mars Science Laboratory (MSL), also known as the Curiosity rover, described by some as a laser-armed nuclear robo-tank, announced their latest findings. In summary: The rover’s current location, a site named John Klein, has large amounts of clay minerals which formed in water with moderate or neutral pH. To a geologist, this means that the area is an ancient lake bed. The rock also contains elements in both their oxidized and reduced forms, which mission scientists say means that there are chemical gradients that Earth-like life could potentially exploit as an energy source. In other words, we can now say for sure that “Yes, Mars is in fact a place where life could potentially once have existed”. As I always understood it, answering that question was Curiosity’s primary mission.
But my understanding was a simplified one. The actual scientific goal of the mission is, and I quote, “to explore and quantitatively assess a local region on Mars‘ surface as a potential habitat for life, past or present”. So it’s not to show whether Mars can (or could have) support life, but to fully understand just what that particular region of Mars is capable of, in terms of supporting life. It sounds like we’re nitpicking the difference, but in fact it makes the entire mission very open-ended. Curiosity is free to continue searching for data, while the scientists back home continue to analyse and draw conclusions, learning more and more about the red planet for as long as the machinery lasts. And that was a very clever move on the part of the mission planners!