NASA’s Curiosity Mars rover has started a road trip that will continue through the summer across 1.6 kilometres (roughly 1 mile) of terrain. By trip’s end, the rover will be able to ascend to the next section of the 5-kilometre-tall (3-mile-high) martian mountain it’s been exploring since 2014, searching for conditions that may have supported ancient microbial life.
Located on the floor of Gale Crater, Mount Sharp is composed of sedimentary layers that built up over time. Each layer helps tell the story about how Mars changed from being more Earth-like – with lakes, streams and a thicker atmosphere – to the nearly-airless, freezing desert it is today.
The rover’s next stop is a part of the mountain called the “sulfate-bearing unit.” Sulfates, like gypsum and Epsom salts, usually form around water as it evaporates, and they are yet another clue to how the climate and prospects for life changed nearly 3 billion years ago.
But between the rover and those sulfates lies a vast patch of sand that Curiosity must drive around to avoid getting stuck. Hence the mile-long road trip. Rover planners, who are commanding Curiosity from home rather than their offices at NASA’s Jet Propulsion Laboratory in Southern California, expect to reach the area in early fall, although the science team could decide to stop along the way to drill a sample or study any surprises they come across.
Depending on the landscape, Curiosity’s top speeds range between 25 and 100 metres (82 and 328 feet) per hour. Some of this summer road trip will be completed using the rover’s automated driving abilities, which enable Curiosity to find the safest paths forward on its own. Rover planners allow for this when they lack terrain imagery.
“Curiosity can’t drive entirely without humans in the loop,” said Matt Gildner, lead rover driver at JPL. “But it does have the ability to make simple decisions along the way to avoid large rocks or risky terrain. It stops if it doesn’t have enough information to complete a drive on its own.”
In journeying to the “sulfate-bearing unit,” Curiosity leaves behind Mount Sharp’s “clay-bearing unit,” which the robotic scientist had been investigating on the lower side of the mountain since early 2019. Scientists are interested in the watery environment that formed this clay and whether it could have supported ancient microbes.