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Mission Update by Steve Squyres

(Return to archived mission updates list)

September 2005
September 26, 2006

The decision's made... we're going to go west, counterclockwise around Erebus Crater.

September 23, 2006

It's been a good week at Meridiani. We've had several solid drives, and we're now effectively at the northern rim of Erebus Crater. We're currently parked on a large outcrop named South Shetland, and we're going to spend the weekend working it over with the instruments on the IDD.

After that comes the big decision... which way do we drive to attack Erebus?

The good outcrops at Erebus are on the southeastern rim (called the Vermillion Cliffs) and on the western rim (called the Mogollon Rim). The Vermillion Cliffs look easier to get to, but not as high. The Mogollon Rim exposes more rock, but looks harder to get to. There's a particularly tasty-looking promontory on the Mogollon Rim named Payson that's probably the biggest outcrop anywhere along the rim, but whether we can actually get to it or not is an open question

At the same time we're doing the IDD work on South Shetland, we're going to be taking a big Pancam panorama that hits most of Erebus at the highest resolution possible. And then, on Monday afternoon, we're going to sit down, look at the images carefully, and make a decision. We may go left, we may go right, or we may cut straight across the crater... stay tuned.

It has also been a good week at Gusev. We spent much of the past week on a big wind-blown drift that we called Cliffhanger, right at the top of Tennessee Valley. We scuffed it with the wheels and did a good set of IDD measurements both inside and outside the drift, just like we did long ago on a drift called Serpent, back down on the plains.

With Cliffhanger done, the remaining items in the summit campaign are to finish up the long-baseline stereo imaging of Tennessee Valley, and to do some IDD work on the rocks at the true summit. This weekend we're driving to the position for the next position for the Tennessee Valley stereo, and by early next week we should be ready to pick a target on the true summit and go after it.

And with that, we'll then face a decision at Gusev much like the one we now face at Meridiani: Which way do we go? We know we want to descend the south side of Husband Hill, and we know we eventually want to head toward Home Plate. But what route do we pick? The hill is very steep in places on this side, and the orbital images show a lot of tasty geology, some of it in pretty nasty-looking places. All in all, the next several weeks are going to present us with some of the most interesting route-finding decisions that we've faced in a long time, on both sides of the planet.

September 15, 2006

It's been quite awhile since I've done one of these updates, but I'm now back in Ithaca and spending all my time on flight operations again... which feels really good!

Things have been going splendidly at Gusev. Starting a couple of weeks ago, Spirit took two spectacular panoramas down the south side of Husband Hill. Those images gave us a stereo view that we'll be able to turn into a topographic map we'll use to plan our descent.

After that came investigation of a target called Irvine. This turned out to be a lot like what happened with the rock we called Backstay, back down on Cumberland Ridge. Sometime back, Mini-TES had spotted a rock we named Cherry Bomb, which had a spectrum that looked like a basalt that was different from any we'd ever seen before. We passed Cherry Bomb by, but since then we've been on the lookout for another piece of the same stuff. Irvine, we learned, has the same Mini-TES spectrum as Cherry Bomb, and this time we were in a good position to go after it with the IDD. So after the big stereo pans, we drove back to Irvine and looked at it with the instruments on the arm. And lo and behold -- just like what happened with Backstay -- Irvine seems really to be a different rock type from anything we've seen before. If this holds up, we're now up to eight or nine different rock types in the Columbia Hills.

With Irvine done, we have just a handful of remaining tasks to complete during our "summit campaign". One, which we'll be doing this weekend, is to use a rover wheel to "scuff" one of the fabulous wind-blown drifts near the summit, and to use the IDD to see what's inside it. After that, we're going to look closely at some outcrops near the true summit of the hill, and we're also going to take some pictures down the north and east sides of the hill, both of which we're unlikely ever to see again.

And with that, it'll be time to head south and downward toward new adventures.

Life has been a bit more frustrating lately over on the other side of the planet. On Sol 563, Opportunity experienced an unexpected "reset"... a spontaneous rebooting of the onboard computer. We don't know why it happened, and while it's not deeply worrisome, it is a puzzle that we've been trying to solve.

Unfortunately, recovering from something like a reset is a slow, lengthy process. You don't know what caused the problem, and the immediate concern is that whatever triggered it will do it again next time you try it. The thing you have to do is fire up each of the rover's capabilities one at a time, checking each one carefully and individually to see whether it would cause another reset or not. Standard spacecraft troubleshooting practice, but it takes time. So over a number of sols we put Opportunity through each of its paces, checking to see if we had another reset. The good news is that the whole rover now has a clean bill of health, as far as we can tell, because no new resets were triggered. The root cause of the reset remains a mystery, but I guess the occasional odd glitch is to be expected from a vehicle that's been on Mars for almost 600 sols.

So then what happens once Opportunity finally does get a clean bill of health? We lose another sol when rodents at one of the Deep Space Network tracking stations gnaw through some insulation and short out a cable. (I'm not making this up... the stations are out in the desert, and there are critters all over the place.) Easy problem to find and fix, but it happened at just the wrong time and cost us data, and one more sol. Another first for the Mars Exploration Rover Project.

Anyway, Opportunity is now healthy, happy, and solidly on the "Erebus Highway", and her job is to pick up the pace and get to Erebus Crater, pronto.