The post-mortem of the Curiosity rover’s picture-perfect landing is nearly complete. After catching the rover in the act of falling, the HiRISE camera on the Mars Reconnaissance Orbiter (MRO) has, in its latest pass overhead, spotted the rover and all of its accoutrements in a sort of family portrait, shown here. “It looks like a crime scene,” said HiRISE scientist Sarah Milkovich in a press briefing at the Jet Propulsion Laboratory (JPL) in Pasadena, California, on Tuesday.
What’s next? As I describe in the magazine this week, Curiosity’s ultimate destination is Aeolis Mons, (informally dubbed Mount Sharp), to the southeast — but that is many months, if not a year, away. It might be tempting to go look at the wreckage of the sky crane, which is directly behind the rover. Some have even speculated that the very first image returned, from the rear hazard cameras, caught a puff of dust caused by the sky crane crashing. It would be an amazing coincidence of time and orientation. “I don’t think we can rule it out,” said mission manager Mike Watkins. But the rover team is unlikely to drive to that wreckage, partly because scientists with finicky geochemical instruments want to keep their distance from the confounding effects of 140 leftover kilograms of hydrazine propellant that may have polluted that terrain. So where will the rover drive?
Project scientist John Grotzinger has a couple of things he could do in the immediate vicinity. One area of interest is to the north, near the foot of an alluvial fan: deposits with high thermal inertia, as measured by the THEMIS instrument on the Mars Odyssey orbiter. One theory behind their ability to retain heat for longer periods of time is that something has consolidated and cemented the materials together. Water could be implicated. And the texture of the light-coloured region in the image here has the look of a cemented material. Even though water signals in this region have not shown up in data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), it’s possible that the ‘cement’ could be a different mineral, such as halide salts, that CRISM wouldn’t be able to detect.
Complicating the picture further is an area southeast of the rover (to the right of the orange line) that is pocked with more craters. An older surface tends to be scarred more — so perhaps this is the oldest rock layer in the area? Ultimately, the science team needs to figure out which rock layer is the basement. They want to know whether the alluvial fan deposits, to the north and west, came before, or after, the bottom-most layers to the south and east of the mysterious Mount Sharp, which was probably built up over hundreds of millions of years. A good place to go to understand the relationship of these two deposits would be scarps or cuts that separate them. Maybe the triple point between these three distinct regions would be a good place to start?
That’s seems like a good choice to Ken Edgett, principal investigator for the MAHLI camera, which can take both microscopic and panoramic pictures. “If it were up to me I would go where those three come together,” he says. Edgett was on hand at the JPL Tuesday to present the first colour image from the camera, which was still stowed away and nestled into the rover’s side. It will be about a week before the rover begins moving, and probably much, much longer before a route to Mount Sharp is decided. But for a modest first excursion, the triple point might be worthwhile, says Grotzinger. “That’s a good guess.”
Image: NASA/JPL/Univ. of Arizona/Eric Hand