It’s hard to believe that Curiosity, the successor to the incredibly successful Spirit and Opportunity Mars Exploration Rovers, has been on the martian surface for a total of 2 years now. Not only did it prove many of the complicated engineering processes behind getting such a large craft onto Mars’ surface it’s also greatly improved our understanding of our celestial neighbour. Like its predecessors Curiosity has already outlived its original mission parameters, although not by the same margin, and barring any catastrophic failures it’s highly likely that it will continue to be productive long into the future. However it did recently come dangerously close to falling victim to one of Mars’ most insidious features: the sand traps.
Curiosity’s current mission is to get to Mount Sharp, a 5KM tall peak which NASA scientists hope will have varying layers of rock they’ll be able to study as they climb up it. This would give a better insight into the evolution of Mars’ environment over the years, showing us how it transitioned from a once wet planet into the barren desert that it is today. However between Curiosity and the base of Mount Sharp there’s a trench of wavy sand that’s been dubbed the “Hidden Valley” and up until recently NASA scientists were just going to drive across it. However upon attempting to do this Curiosity has found that the sand is far more slippery than it first anticipated and thus it has been turned back whilst NASA figures out what approach they’ll take.
This is a very similar situation to the one that was eventually the downfall of Spirit. A lot of the surface of Mars looks visually similar however often the makeup of the underlying surface varies drastically. In both Curiosity’s and Spirit’s cases the soil lacked cohesion making it extremely difficult for the rovers to get traction. For Spirit this meant that it was no longer able to get its solar panels into the required angle for the martian winter, meaning it couldn’t generate enough electricity to keep its circuits functioning. If the same fate had befallen Curiosity however it wouldn’t matter as much (well apart from the obvious) as it’s internal power supply doesn’t rely on solar energy.
In terms of the mission profile it’s likely that this will probably just be a delay more than anything else as whilst there aren’t many ways out of the valley that Curiosity is currently in there are other potential paths it can take to get to Mount Sharp. In actual fact the delay might not be all bad news for Curiosity either as the return journey from the slippery slopes of Hidden Valley actually revealed a potential rock for further investigation, dubbed the Bonanza King. We’ll have to wait and see if anything interesting can be derived from that, however.
I guess things like this just go to show that no matter how well you prepare, nor how good the equipment is that you bring with you, it’s still entirely possible for old problems to come back and bite you. Thankfully this time around we were prepared for such things and we haven’t ended up with another stationary science platform. Hopefully this won’t delay Curiosity’s mission for too long as it’s proven to be incredibly valuable thus far and the Mount Sharp mission could really give us clarity over how Mars became the desolate place that it is today.
Title of the post had me freaked out there. I was expecting to see it half buried in the sand (via what camera, I don’t know). Do they know whether the dust on Mars has the same jagged properties that Lunar dust has? And did they every figure out a satisfactory way to deal with that stuff?
Apologies! I had the same minor freak out when I read the various articles around the Internet and didn’t think my title through enough before posting.
From what I’ve read about Mars’ soil vs Lunar regolith they do vary in terms of composition mainly due to the way that the majority of the surface was formed. The Moon’s regolith was generated by asteroid impacts whilst Mars’ was mostly generated back when its surface was still covered by liquid water. Thus I don’t believe that Mars has the same jagged regolith that the Moon does but they do have the same lack of cohesion that causes issues with the rovers.
Looking over the design specifications for the wheels of the MER rovers and Curiosity it seems that the drive systems are very similar, with the latter having much larger wheels which would provide much better traction (although that’s somewhat offset by Curiosity’s increased heft). Curiosity does have a different pattern on its wheels that’s supposed to improve traction (and also writes Morse code for JPL wherever it goes) but apart from that we’re still falling prey to the same issues.
A good excuse to send some humans over there, I’d say 🙂