Ever since it was announced that there may be evidence of liquid water on present-day Mars, NASA scientists have wondered how best to further investigate these long, seasonally changing dark streaks in the hope of finding evidence of life — past or present — on the Red Planet.
“It’s not as simple as driving a rover to a potential site and taking a scoop of soil,” said Jim Green, NASA’s director of planetary science. “Not only are these on steep slopes, we need to ensure that planetary protection concerns are met. In other words, how can we search for evidence of life without contaminating the sites with bugs from Earth?” (…)
The features of interest have been observed by NASA’s High-Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter (MRO). They appear as dark lines that appear to ebb and flow over time. Planetary scientists think these gullies or recurring slope lineae (RSLs) may appear seasonally as a form of briny water at or near the surface of the Red Planet under warmer conditions.
There are two RSL candidates that may be within Curiosity’s reach, on the side of the 3.1-mile-high (5-kilometer-high) Mount Sharp. The rover’s Remote Micro-Imager (part of ChemCam) would be the main instrument for imaging the possible sites. The goal would be to study the regions over time to see if there are any changes and to rule out other causes for the changes, such as dry avalanches. [More at link]