NASA's Curiosity Rover has spent the better part of a year scooting from a low lying area called Yellowknife Bay to the base of Mount Sharp. As a recent chemical analysis performed by the robotic explorer shows, this region is distinctly different from that found within Gale Crater — which is exactly what NASA scientists were hoping for.
Above: The first holes drilled by NASA's Mars rover Curiosity at Mount Sharp. The loose material near the drill holes is drill tailings and an accumulation of dust that slid down the rock during drilling.
One of the reasons that Gale Crater was selected was on account of mineral identifications from orbit. In addition to looking for signs of habitability within the crater, NASA scientists were hopting to find elements at the base of the crater that could provide the necessary ingredients for life. Encouragingly, they may have found a potential microbial energy source in the new samples.
Curiosity is currently making an ascent towards the base. When it arrived at a place designated "Confidence Hills" within the "Pahrump Hills" outcrop, it stopped to sample some reddish rock powder — and it's pretty much what the scientists were expecting. It's the mission's first confirmation of a mineral mapped from orbit.
"We're now on a path where the orbital data can help us predict what minerals we'll find and make good choices about where to drill," noted team member Ralph Milliken in a NASA statement. "Analyses like these will help us place rover-scale observations into the broader geologic history of Gale that we see from orbital data."
The sample was extracted by the rover's robotic arm, and it was sampled by the Chemistry and Mineralogy (CheMin) instrument inside the rover.
A side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from rocks on Mars by NASA's Curiosity rover.
The sample contained much more hematite than any rock or soil sample previously analyzed by CheMin during the two-year mission. Hematite is an iron-oxide mineral that offers clues about ancient conditions from when it formed.
NASA explains more:
The latest sample has about eight percent hematite and four percent magnetite. The drilled rocks at Yellowknife Bay and on the way to Mount Sharp contain at most about one percent hematite and much higher amounts of magnetite.
"There's more oxidation involved in the new sample," said CheMin Deputy Principal Investigator David Vaniman of the Planetary Science Institute in Tucson, Arizona.
The sample is only partially oxidized, and preservation of magnetite and olivine indicates a gradient of oxidation levels. That gradient could have provided a chemical energy source for microbes.
The Pahrump HIlls outcrop includes multiple layers uphill from its lowest layer, where the Confidence Hills sample was drilled. The layers vary in texture and may also vary in concentrations of hematite and other minerals. The rover team is now using Curiosity to survey the outcrop and assess possible targets for close inspection and drilling. [emphasis added]
Mission planners say they might have Curiosity hang tight at this site for a few weeks or months before proceeding any further up the stack of geological layers forming Mount Sharp.
[NASA | Images: NASA/JPL-Caltech/MSSS]