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Mission Update by Steve Squyres

(View archived mission updates)

January 23, 2007

I haven't done one of these updates in ages, so here you go...

Spirit's about to start moving again. For the last little while we've been parked at the outcrop named Troll, working it over thoroughly with the IDD. The stuff here looks very much like what we found back at Graham Land: Lots of little round spherules in the rock, and lots of hematite.

Now it's time to move on. After a good deal of of thought, we've decided we need to take a closer look at Tyrone. If you recall, Tyrone was a morass of ferric sulfate salt that we nearly got stuck in right before we scooted off to Low Ridge for the winter. We were in such a hurry to get to our winter haven that we never really checked Tyrone out scientifically... so now it's time.

Don't worry... we're not going to drive all the way back to Tyrone and get stuck again! But there's a lot we can do with Pancam and Mini-TES from a safe standoff distance, so that's the plan. Then, once we've wrapped up our work at Tyrone, it'll be time to head back to Home Plate.

Over at Meridiani, Opportunity continues the spectactular trek around Victoria. A significant recent stop was at a rock we named Santa Catarina. This was one of a field of cobbles that we encountered between Bottomless Bay and the Bay of Toil. We hadn't seen a cobble field quite this dense before, so we stopped and worked it over carefully. We're still going through the data, but the most likely interpretation seems to be that Santa Catarina is a meteorite. If so, it's the fifth one we've found.

We're now working our way around the Bay of Toil to our next imaging spot at the tip of Cape Desire. Driving here has been difficult. Because we're near the rim of the crater we have to be very careful, so we make extensive use of something we call "Visual Odometery", or visodom. When using visodom, the rover takes images of the terrain as it drives, and uses the features in the images to figure out exactly how far and in what direction it has moved. Problem is, there are very few features in the terrain here... the soil is so bland that there's almost nothing for the visodom software to "lock on" to. This has created problems for us, and we've had a couple of busted drives as a result.

Our rover drivers, however, are nothing if not creative. If Mars doesn't give us features to look at, they figured, we'll make our own features. So recently, we've done a drive where the rover did a strange little dance as it moved along, scuffing the soil and weaving from side to side, making some of the strangest-looking rover tracks you've ever seen. (One of the maneuvers they came up with they called the "drunken sailor walk".) It looks weird, but it works. We did 40 visodom tests on that drive, and 39 of them worked. So next time you see some strange-looking wheel tracks, it's just the rover scuffing up the terrain so it can figure out where it is.

December 7, 2006

A very quick update: We just learned this morning that the Mars Odyssey spacecraft has gone into "safe mode". This is something that can happen when there's a glitch of some sort on board the spacecraft... it puts itself into a very safe state and waits for commands from Earth. Mars Odyssey appears to be in great shape and should be back in business in a few days. A likely cause of the event was a big blast of high-energy particles from the Sun that got to Mars right before it happened. So there doesn't appear to be anything to worry about, and both rovers came through the particle event unscathed. But because we relay most of our data through Mars Odyssey, we won't see very much data from the rovers until Odyssey is back online.

December 3, 2006

We're under way at Gusev. After a couple of weeks of checking out some of the craziest-looking rocks we've ever seen on that side of the planet, we're off to something new.

The rock we've been looking at for the past couple of weeks is one called King George Island, and it's got some of the best-rounded grains we've ever seen in a martian rock. It's tempting to get very excited about grains that are that big and that round, until you remember that we know that the martian wind can transport and round off even bigger grains. Those of you with good memories will recall that we saw some really well rounded coarse granules in wind ripples out on the Gusev plains early in the mission. (One of them was named Serpent; there were several others.) So while we're not ready to jump to any big conclusions, King George Island sure is a cool-looking rock.

Anyway, with that behind us, we're not headed for something new: Esperanza. This is a "vesicular" rock... a lava block that's full of bubbles, like a piece of Swiss cheese. We've been seeing these for quite awhile, and we've even taken quick looks at a couple of them. But we've never had the time to look one over carefully. So that's a shortcoming we intend to rectify.

Getting to Esperanza may be a bit of an adventure. With the right front wheel on Spirit no longer working, maneuvering the vehicle to get to within arm's reach of a carefully-chosen target isn't going to be easy. It's a skill I'm sure we'll develop with experience, and Esperanza is going to give us some of that experience. So off we go.

Over at Meridiani, we have arrived at Bottomless Bay. This happened a sol earlier than I expected it to. We did a drive on Sol 1016 to put us reasonably close to the rim, and then we were expecting to have to do another short "bump" on 1019 to put us where we could see the whole cliff on the far side of the alcove. Instead, the 1016 Navcams show the cliff in all its glory. It may not make sense to spend a whole sol trying to creep just a tiny bit closer, so right now I'm thinking we may just shoot it from where we are on 1019, and be on our way on 1020. We'll decide tomorrow morning.

And despite the fact that our meager early-spring power numbers still mostly keep us from doing nighttime communications passes with Mars Odyssey, we're slowly but surely clearing out the huge backlog of images stored in Opportunity's onboard memory. This is a tough situation for us, since what we're doing with Opportunity right now is all about driving and taking lots of Pancam images, both of which generate huge volumes of data.

Still, the images are worth it. The stuff at the base of Cape St. Mary that we shot from Cape Verde is probably the best so far, showing some spectacular "cross-bedding" in the layers that tells us that these rocks preserve the passage of ancient martian sand dunes. And the shot from Cape St. Mary back at Cape Verde is pretty cool too, showing some of the most striking jumbled impact ejecta we've ever seen. This jumble, of course, is why we haven't been using the arm instruments lately. All the surface rocks along this part of the crater rim are ejecta from who knows where inside the crater, meaning that any measurements we made here would be impossible to put into proper context. So for now we're going to focus on driving hard and fast around the crater, taking lots of pictures, and looking for good places where we'll be able to study bedrock in place.

November 27, 2006

Another quick one tonight...

Spirit's on the move. We've done a nice little rotation to the right, and now we've got a bunch of new stuff within reach of the arm. We'll do our business here, and then it's going to be time to do some real driving. Everybody is really itching to start covering some ground again.

And on the other side of the planet Opportunity is on the move too. The pictures of the eastern of Cape Verde were specacular, and finished up our business at Cape St. Mary. We just did a 43-meter drive to the northeast, and there'll be more driving in the coming week... though it may be slowed down a little by a checkout of more of our new software. Once that software check is out of the way, our next target will be the southwestern side of a really big alcove that we've named Bottomless Bay, or Bahia sin Fondo. It's going to be like this for awhile, driving from one lookout on the rim of Victoria to the next, taking spectacular Pancam images of cliff faces.

One more thing: Keep your eyes peeled for some new images of both rover landing sites from our friends on the MRO HiRISE team. That's one heck of a camera they've got, and we're expecting some pretty spectacular new images soon.

November 3, 2006

I don't have much time to write tonight, but I'll hit the highlights...

Both rovers have come through superior conjunction in excellent health. It was good to hear from them again!

We've had to start up a little bit slowly with Opportunity, because the rover's flash memory was very full post-conjunction... mostly with all the images we took during conjunction. It'll take a little while to clear those out. The good news is that the power situation is starting to get good enough again that we can occasionally wake up in the middle of the night to do a wee-hours-of-the-morning communications relay via Mars Odyssey. We haven't been able to do those in quite awhile. So those should help to increase the data return substantially.

Once we do start moving Opportunity again -- probably early next week -- our direction will be toward the east and north... clockwise around the crater. We haven't decided how far we'll go in that direction, but it seems clear that some of the most intriguing geology we can see from the rim is to be found that way. So that's where we're headed for now. The next big topographic feature in that direction is a tall promontory that's one of the highest spots on the rim. We've named it Cape St. Mary.

And speaking of increases in power, keep an eye on Spirit... we should be moving again soon. It won't be anything really dramatic at first, but the power has gotten high enough now that we're starting to feel confident about moving the rover safely. It'll be good to get the wheels turning again.

September 28, 2006

Wow.

The last couple of days have been among the most exciting of the entire mission. The only other events I can compare this to are the two landings and the arrival of Opportunity at Endurance crater. And in terms of sheer visual impact, this beats those.

Opportunity has arrived at Victoria Crater. As we expected, we came upon the view quite abruptly... it went from just the very tops of distant cliffs to a full-blown vista of the crater floor in just a handful of sols. And now we are perched just back from the lip of the crater at Duck Bay, with the whole thing laid out below us.

Our first order of business here, obviously, is going to be to take a very big Pancam panorama. We'll be starting on that very shortly, though of course it will take quite awhile to get it all back to Earth.

After that has been shot, we're heading for our next location... Cape Verde. We were considering both Cape Verde and Cabo Frio, and when we looked at all the factors together, Cape Verde won out. Wherever we stop next is where the rover will spend "superior conjunction" -- the upcoming period when Mars will be out of sight behind the sun, making communications impossible for a short while. Conjunction is coming soon, so we want to get to our conjunction spot quickly, and Cape Verde looked like an easier drive than Cabo Frio. Another factor is that we want to be parked on rock over conjunction, so that we can do some work on rock with the IDD. There seems to be good exposure of rock at Cape Verde, but little or none of it at Cabo Frio. So Cape Verde it is.

This doesn't mean that we're going to traverse clockwise around the crater... we won't make that decision for quite awhile yet. And it also doesn't mean we'll never go to Cabo Frio. And, to be honest, we can't even say for sure that we'll make it all the way to Cape Verde before conjunction... you have to be very careful when driving near cliffs this big! So we'll be driving slowly and cautiously. But Cape Verde is the next thing we're going to head off toward after we finish shooting the pan.

And how about that view?!? We're still feeling a little awestruck. The analytical part of my brain looks at that and is already doing science analysis and planning. The rest of me, though, just wants to sit back for a little while and take in the scenery.

September 20, 2006

We seem to have cleared an important hurdle. Sol 944, which was yesterday Earth time, was "Boot Day" for Opportunity... the day we rebooted the rover computer with brand new flight software. The rover woke up that afternoon with the new software running, and sent us data right on schedule. We're still going through the data, but so far everything looks good. We're also going through the same process for Spirit on more or less the same timescale.

This new software is going to be a pretty big deal for us. It includes lots of new capabilities... things that we've figured out over all these sols of flight operations that we've now, with this new software load, taught the vehicle to do. One capability is something we call "go and touch"... the ability to send the rover to a target and deploy the arm onto that target all in one sol. That's something we've never done on Mars before. Another is automated dust devil finding, which should be pretty cool if Spirit is still hanging in there once summer rolls around. And there are a bunch of other things too. The rovers are getting older, but they're suddenly a whole lot smarter.

All of this software has been thoroughly tested on Earth, of course, but today is the first time we've used it on Mars. It's good to see everything working the way it's supposed to so far.

It's going to take a little while to shake out all of the new software, and to convince ourselves that it's all functioning properly. There'll be two sols of checkout at least... one to upload a bunch of new software parameters and confirm they've gotten onboard safely, and another to make sure all the key driving commands work properly. That sol is going to be interesting... just a lot of little rover moves that don't really go anywhere, but that give us confidence that we're ready to start driving again.

And, of course it could take longer than that. You have to proceed carefully when you're dealing with new flight software.

You may be wondering why we chose now to do the boot with the new flight software. The reason is that in a few weeks we will go into what's called "superior conjunction", when Mars goes out of sight behind the sun. There will be a stretch of time when we can't send commands to the rovers at all, and during that time we want to have complete, unequivocal confidence in the software that's onboard. Getting the software onboard now will give us the time to gain that confidence.

Anyway, once we've got this initial few sols of software checkout behind us, we know where we're going! As of right now, we are just about 50 meters away from the rim of Victoria Crater. The latest images show the upper part of the far wall in some detail for the first time. The topography there is substantial, to say the least... the images show near-vertical cliffs that are roughly 15 meters high, and that's just the upper lip. There's a lot more crater below that that we can't see yet.

We are, frankly, feeling a little overwhelmed by what we see so far. It's very reminiscent of our first glimpse into Endurance Crater, more than two years ago. We figured out how to deal with that then, and in time we'll figure out how to deal with Victoria too. But for the moment we're feeling a bit awestruck.

And the best is yet to come. Once the software checkout has been completed, we're going to drive to the closest point on the rim. This is the alcove between Cape Verde and Cabo Frio, which we have named Duck Bay. We'll have to tiptoe up to Duck Bay pretty carefully; if those images of the far side are any indicator, it my drop off pretty steeply! We'll shoot some Navcam and a bit of Pancam from there, pick either Cape Verde or Cabo Frio for the big Pancam pan, and then start moving into position.

So the next few weeks are going to be interesting. It's tempting celebrate a little now, frankly... having come all this way, over so many months, and finally having our goal in sight. But I'm not really going to feel like we've "reached" Victora Crater until that first big Pancam picture of it is on the ground. Stay tuned.

September 14, 2006

It has been a terribly long time since I have done one of these updates. Far too long, and the only excuse I can offer is that we have simply been overwhelmed with operating the rovers and writing papers about what we've found. I'll try to do better in the future. But with Opportunity about to arrive at Victoria Crater, I really felt I had to do one.

Right now, Opportunity is parked next to a crater that we've named Emma Dean. The thing that makes Emma Dean intersting is that it punches down into the "annulus" of smooth material that surrounds Victoria. We're not entirely certain what this stuff is, but logically it should be largely material that was excavated from Victoria when Victoria formed. Problem is, like so much of the rest of Meridiani, the place is covered with sand and blueberries, so we can't get at the rock underneath. Emma Dean, though, excavates into the annulus, and so may expose some of the material that comprises it. In fact, it could even expose stuff that originally came from deep in Victoria. So we've stopped to give it a look.

Another reason we're interested in Emma Dean is that we recently dug a shallow trench with the wheels, and what we found in the trench was very weird. Unlike every other trench we've dug at Meridiani, this one had a lot of sulfates in the bottom. We're not certain what this means. It could be that there are sulfates in the soil here, which would be interesting and different. It's also possible, though, that the wheels simply dug through a few centimeters of sand and then ran into sulfate-rich bedrock underneath, scraping and churning it up. We expected the trench to be significantly deeper than it turned out to be, which may mean that we encountered hard, bedrock-like material close to the surface. At any rate, we've had a few mysteries to deal with here before we make the final move to the rim.

But now, the time for the final move to the rim is now almost upon us. As soon as we have finished at Emma Dean -- and I still can't say for sure when that will be -- we will do it. We're only 110 meters away, so it should only take a couple of sols. We're initially going to drive to the very closest point on the rim, along a large "alcove" in the crater wall. This alcove is bordered on both sides by sharp promontories that stick out into the crater. We've named the promontory to the north of the alcove Cape Verde, and the one to the south Cabo Frio. Both names are places that were visited by the ship Victoria on Magellan's circumnavigation of the globe. Our current plan is to take some Navcam images from the arrival point at the alcove, pick either Cape Verde or Cabo Frio, and then move out onto the chosen promontory and take what should be one heck of a spectacular Pancam panorama.

So stay tuned... things are going to be very interesting at Meridiani for a while.

Over at Gusev Crater, things have been a little more quiet. Spirit is parked safely on Low Ridge, tilted toward the sun and with enough power to survive the winter. We have just passed through the darkest and coldest part of winter, and the sun is starting to come back to us. We're not seeing a big increase in power yet, though, because at the same time the sun is getting higher, the atmosphere is getting a little dustier, blocking out some of that sunlight. We're hoping to move the rover in the not too distant future, rotating it to the right a little bit to get some new and very interesting-looking targets within reach of the arm. But with power still low, we're going to play it safe and stay put for at least a few more weeks.

What we're all really looking forward to, of course, is real springtime on Mars, with enough power for Spirit to start driving again. That's still at least a couple of months down the road. But when it does happen, we've got a lot to do. We haven't worked out the full plan of attack yet, but one thing high on the agenda is a return to Home Plate. That was one of the most interesting places we've ever been with either rover, and we feel like we have some unfinished business there. For now, though, patience is the name of the game.

January 29, 2006

Well, I've fallen way behind again, so I'll try to cram two weeks of action into one report.

At Meridiani, Opportunity is moving again. We've found a way to drive short distances with the IDD deployed, and we used it successfully to get to the lower part of Overgaard. The MI imaging there has gone beautifully, and we're about to make a move to the upper part of Overgaard, where the festoons are.

Once we've hit all the festoons on Upper Overgaard, then there are a couple of other nearby targets we've got our eyes on... one called Bellemont and another called Roosevelt. We'll go after one or both of those, and then it will be time to hit the road in a big way.

The drive south from here is going to be interesting. Victoria crater beckons, and we really want to lay down some serious mileage. At the same time, we have to keep the vehicle safe, and we have to make sure we don't blow by anything too interesting. A balance is necessary, but our hoped-for drive strategy is a pretty aggressive one. A lot of it, of course, will depend on whether or not Mars cooperates.

At Gusev, Arad turned out to be worth the stop. It's extraordinarily high in ferric sulfate salts, and it now holds the record for the saltiest place ever discovered on Mars. Interestingly, though, it doesn't seem to have the phosphates that Paso Robles did. We're still pondering on this one.

Since Arad, we've been pretty much sprinting for Home Plate. One thing that we've been noticing lately is that there seem to be a lot of very porous basalt blocks in this neighborhood. We've been resisting the temptation to stop at one, but we got lucky a couple of days ago and had one pop up just by chance in front of us. We whipped out the IDD and took what have to be some of the coolest MI images of the whole mission, on Sol 736. The name of this thing is GongGong, and it is what can happen when you have a very frothy, gas-rich lava that solidifies with lots of voids in it and then gets eroded by the wind for a very long time.

You may ask where a name like GongGong came from. We have several Chinese members of our team, and in honor of Chinese New Year, we have been assigning names from Chinese mythology and history to the rocks at Gusev. GongGong, I'm told, was the king of water from the north, who knocked down Mount BuZhou with his head. You can learn all kinds of things by doing a mission to Mars.

As I write this, Spirit is near the north end of Mitcheltree Ridge, the most significant topographic feature between us and Home Plate. Mitcheltree Ridge is named after the late Bob Mitcheltree, one of the real intellectual leaders of the Entry, Descent and Landing team that got our rovers safely down onto the surface of Mars. We should get our first close-up look at Home Plate soon, and we're all anxious to see what we'll see.

January 13, 2006

Good stuff is happening on both sides of the planet.

At Meridiani, the main source of excitement continues to be the festoons. The low-light imaging we've been doing is great for bringing this stuff out, and we've come to realize that it's present in a whole lot of the rocks around us.

The real news, though, is that it looks like we're finally about ready to move the rover again. I can't give you a definite date, but I'd say that sometime next week is very likely. Our first move, of course, is going to be to get into position to get some nice MI mosaics on the festoons. The rock we're going after first is one called Overgaard.

At Gusev, a funny thing happened on the way to Home Plate. We swore we were just going to sprint for Home Plate and not stop for anything unless something extraordinary popped up. Then something extraordinary popped up. On our most recent drive, we hit some pretty soft soil and churned it up a bit. And when looked at the disturbed soil, we realized it was bright... really, really bright. Somehow our churning dug up something very different from everything around it.

Something like this has happened to us once before, at a spot just below Larry's Lookout that we named Paso Robles. Paso Robles was one of the most extraordinary finds of Spirit's mission to date. It was very light-toned soil dug up from just beneath the surface, and when we measured its composition we found that it was more than fifty percent salts. Most of it was ferric sulfate salts, and there were also some phosphate salts as well.

So what is this new stuff (which we have named Arad)? The same kind of salt? Something different? Similar concentration or even saltier? It was too tempting a target to pass up, and we're going to spend the weekend doing IDD work on it before moving on.

And then we'll be off to Home Plate again... really!

January 3, 2006

The last week and a half has been remarkably productive, especially considering the fact that most of it was taken up by the holidays.

At Gusev, we have been to El Dorado, sampled the sands there thoroughly, and moved on. We got a spectacular Pancam panorama of the whole area that'll be ready to be released very soon. We also got some stunning MI images that show that the grains are very well rounded and remarkably "well sorted" -- i.e., all nearly the same size. And we got solid Mini-TES, APXS and Moessbauer data that tell us that the sands of El Dorado are composed of a very clean, olivine-rich basalt.

So now it's time for the sprint to Home Plate. Power is still reasonably good at Gusev, with about 500 watt-hours per sol, and we're going to drive hard and fast while the sun shines.

Over at Meridiani we're still at the Olympia outcrop, but we have come to realize that our extended stay here has yielded a very important find. We've spent a lot of time recently taking high-resolution Pancam images of the rocks around us at a range of lighting angles, to bring out fine details in the layering. And if you look at one of the Pancam images that came down on Sol 690, you'll see that we have now found the best example of small scale "festoon cross-bedding" that we've seen the whole mission.

When you're talking about layering in rock, "festoon" geometry means little nested concave-upward shapes. They look like little smiles a few centimeters across. This kind of layering is seen in sedimentary rocks on Earth, and when it's found at small scales like this it provides solid evidence for deposition in flowing liquid water. It was small-scale festoon cross bedding that led us to conclude that liquid water had been present not just below the surface at Meridiani, but occasionally at the surface as well. If you're interested in the gory scientific details, check out the paper by Grotzinger et al. that we recently published in Earth and Planetary Science Letters.

We've seen small-scale festoon cross-bedding before, of course, at Eagle Crater and again at Endurance Crater, but this is by far the best example that we've seen yet. Once we've got Opportunity moving again, our first task is going to be to drive over to this spot and take a big Microscopic Imager mosaic on it, to document the cross-bedding in detail.

The thing I find really striking here is that if it hadn't been for the busted wire in the motor on Opportunity's arm, we would have blown right by this without seeing it. Ironic.

Oh yes, and happy anniversary, or happy birthday, or whatever it is. Spirit landed two years ago tonight.