Opportunity Crawls Its Way Free Of Sand Dune
The Mars rover Opportunity has successfully escaped from a sand trap. JPL engineers cheered when images returned from Mars showed the rover's wheels were free. Engineers worked for nearly five weeks to carefully maneuver the rover out of the sand dune.
Steve Squyres in his online journal at Athena.Cornell reports as follows...
"Boy, this has been a good day.
We've had a feeling over the past several days that this was coming. On each of the last few drives, the rover slipped a little bit less than it had been for most of the extraction.
In addition, the right bogey (the part of the suspension that the right middle and right wheels are mounted on) recently started moving in a way that suggested that the wheels were finally coming over the crest of the dune.
And we knew from all our earth-based testing that when a stuck rover breaks free, it tends to do it very abruptly. So all the signs were suggesting that the big breakout was almost upon us. Still, it's hard to describe how good it felt to check out the downlink this morning and see all six wheels back on solid ground again.
You develop pretty strong feelings for these vehicles once you've spent enough time with them, and when one of them gets into trouble you really sweat it until the trouble is over.
So what comes next? The first thing we're going to do is simply take a very hard look at the stuff we were stuck in. Much of the worst terrain was under the belly of the rover through all of this, down where we couldn't see it.
From our new position, everything that was under us for all those weeks is now visible. So we're going to take a little while just to look at where we were. We may also turn to take a look at our tracks (or trenches, or whatever you want to call them) with some of the instruments on the arm. But we'll see about that one... we'll only do it if we're convinced it's safe.
After that -- and there is no timetable for any of this -- we will begin a cautious set of moves to get us on our way again. And just so there's no doubt about it, this little incident is not going to deter us from continuing our southward exploration.
South is where we think the best science is, and we're not going to turn tail and run because of one unfortunate episode. Now if we find after continued driving that the southward road is simply impossible, then it'll be time to start thinking about something else. But for now, south is where we plan to go.
And lest I forget our other baby in all the excitement... Spirit is doing very nicely. We were just about to hit the gas and head on out of here, but in the last couple of days something interesting and unexpected came up.
Mini-TES, our infrared spectrometer, is a very nice compositional survey instrument. In other words, it's a tool we can use quickly to look around and learn something about what rocks are made of.
We've been doing lots of Mini-TES observations on the rocks around Spirit for awhile now, it's gotten to the point that nearly every rock type is pretty familiar. But late last week, we came across a rock called Backstay that looks, to Mini-TES, a bit different from anything we've ever seen before.
It's a loose rock, not bedrock, so it may be a piece of impact ejecta from someplace far away. The Mini-TES spectrum is nothing wildly exotic... the thing certainly seems to be some kind of basalt. But if it's a flavor of basalt we haven't seen before, then it's definitely worth a quick look.
And luckily, a quick look is possible. Just about the time that we realized that Backstay was something interesting, our most recent drive had put us just four meters away from it. So the plan for the next few sols is to drive to Backstay and figure out what it is before moving on to anything new.
Time to go celebrate...
earlier related report
We're out! The Sol 484 downlink from Opportunity just hit the ground, and all six wheels are on top of soil. More later when I've got some details, but I wanted to get the news out now while it's hot. We've been confident all along that this would happen but still... what a relief!
June 2, 2005
Steady progress on both sides of the planet.
At Meridiani, we've picked up the tempo a little bit. On each of the last two sols we've commanded 20 meters worth of wheel turns, and on each we've seen about 12 cm worth of motion.
That's encouraging; it's a rate of progress at or above anything we've seen so far. Perhaps more significantly, we're starting to see some changes in the geometry of the rover's suspension that suggest that we're making real progress over the crest of the ripple, which we were straddling back when all this started.
The right rear wheel is starting to come up now with respect to other parts of the suspension, which means that the right middle wheel (which we can't see) has to be going down. And if the right middle wheel is going down, that probably means that it has crossed the crest of the ripple and is starting to go down the other side.
I'm still not ready to guess when we'll be on our way again, but it's really heartening to see the kinds of changes that we knew we'd need to see before we could get free.
Over at Gusev, we've finished up our work on Larry's Lookout. In fact, we've only got a few odds and ends to tie off now before we leave this region for good.
The most important of those will be to motor back toward Methuselah and get one more set of Pancam images there, aimed primarily at allowing us to make some fairly precise calculations of the orientation of the layering... what geologists call strike and dip.
Once that's done, we'll be ready to leave the whole Lookout/Jibsheet/Methuselah region behind, and strike out toward new territory.
Mars Rovers at JPL
Mars Rovers at Cornell
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Spirit, The Problem Child
Moffett Field CA (SPX) Jun 02, 2005
"Spirit is the problem child, so to speak. It took us a lot longer to reach our science objectives with Spirit, but it's really coming into its own right now.
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