MER press briefing, January 28, 2004

by National Aeronautics and Space Administration

January 28, 2004

Natalie: Opportunity completed first part of standup. Spirit continues to improve.

Rick Welch: Really another great day for Opportunity at Meridiani. We did complete the first two parts of our four part standup. Graphic? Images we acquired during standup process, starts with wheels stowed, now released, lower now on deck. Last little raise up and set down to ensure rocker bogie mobility system latched. Very successful day getting standup done. We did other good things. Mini-TES actuator test good. Tomorrow for sol 5 complete standup activities including retracting lift and deploying rear wheels. Also do some prep for egress. Front direction pretty clear. We see a lot of airbag out the rear so we really want to drive off the front. Right now the lander tilted up at the front about 4 or 5° what we want to do is lower that front edge down about 5 degrees. Tomorrow afternoon we'll be dragging in the rear airbags to get them really bunched up and then we'll push down with that back petal about 40° further to push the lander up. Depending on how well that goes will determine how quickly we egress. Right now we're sort of planning for an egress on sol 9. That would be Sunday night. Ready for rest of standup.

Matt Golombek: 3 year effort to select sites. Most important aspect is a safe site. We had extensive evaluation using data gathered from MGS and Odyssey. Sites selected were best imaged and best studied sites in Mars history. We evaluated all data that existed to come up with predictions that the site would be safe for the lander and scientifically interesting. We used images down to 3 meters/pixel, thermal emission for albedo. Looked at topography and relief\ . Looked at radar to determine roughness of and competent soil was. Predictions: 1. safe for landing. 2. safe and trafficable for rover. 3. very few rocks. 4. look completely unlike any other place on Mars. All these predictions seem to have been the case. We expected a dark surface with little dust, basaltic sand like surface with a discontinuous outcroppings. Meridiani Planum also turned out to be the smoothest flattest surface we've ever seen on Mars. Since landing all our predictions matched. A "ground truth". Image tour of landing sites. Hubble view shows bright and dark regions. Four previous landing sites were in bright red areas dusty. This site is in a dark gray black region dust free. Next image postcard from Opportunity, dark, outcrops. Next shows topography outside the crater rim is flat. Spirit site at Gusev is brighter as you can see, more rocks, reasonably flat. Next shows gradient as we go to brighter and brighter locations. Pathfinder, rockier, brighter, dustier. Higher albedo. Next is gradient at Viking too. Brighter still. 20% rocks. Viking on even dustier and brighter. Final visual shows significant dunes. All of the predictions we expected for Opportunity site have come to pass. Bodes well for our ability to use remote sensing for picking sites. Final panorama of Opportunity site. See in the distance outside the rim how smooth and flat it is. In accord with our predictions. See pebbly surface with small outcroppings of white material. Seeing rim dive down and background picks up some of the flat terrain outside of the rim. Horizon is as flat as any place we've seen.

Jim Bell: Morning, afternoon :) Update on Pancam today and also mention that mini-TESS passed healthcheck. Science team happy about that. Pancam investigation going well. Completed acquiring mission success panorama with thumbnails. 75% down on the ground. We've had opportunity to insert some little sequences when we had a few extra minutes between engineering activities. Exciting for science team. Nice bonus. For Opportunity, we've acquired 514 full-frame Pancam images for about 240 Megabits. On Spirit 2239 Pancam images or 1.3 Gigabits of data. This image is the first part of the Pancam mission success panorama, full resolution, in color. Stitched together one part near outcrop. Covers about 130° so it's less than 20% of full panorama. Color is dark and reddish consistent with coarse basaltic particles Matt mentioned. No direct compositional info yet though. Background is the brighter and still reddish rocks. Color of those rocks is consistent with the color of the bright dust we see in the bright places that Matt talked about. Near the end of the pan here, see this beautiful outcrop showing layering and other stratigraphy. About 8 meters away and really tiny, only about 10 cm tall, somewhat of an illusion. Next is a zoom up on part of that panorama. Very high-res view of one part of that outcrop. Taken with blue filter, highest possible spatial resolution. Low compression at only 2:1. Challenge to creep up on full resolution because we're being careful around the flash situation and. Some of the detail is pretty phenomenal. Start to see small grains, pebbles, cobbles you can't see in lower res Pancam or Navcam images. Some of the layers seem to be composed of these grains and pebbles. There are many hypotheses as geologists almost ranging from volcanic lava flows, ash falls, sedimentary deposits from wind, from water. We don't have direct info on composition yet but these images help us decide where to go with the rover. For scale, little rock in very middle of scene just past outcrop. It's about 10 meters away and about one inch in size. Next visual is a color part of panorama. Circular smooth spot is a class of features resulting from airbags. Nice example in next visual. Zoom of two high-res Pancam images. Marks show the radial spokes in the circle. Right image about 3 meters or so away. These patterns come from (show slide of airbag inflated test at NASA last year). Each airbag is a big balloon with a circular center area and radial straps, support spokes. Seeing in Mars picture where it rolled across the ground. Perhaps EDL team putting together animation. We can see it traces out a figure-8 pattern in crater. Central circle in airbag print about the size of a basketball. Cool to think about but physical properties folks on science team having a blast with these. We're leaving an indent and it's acting like a fine grained material but material not sticking to airbags like at Spirit site. Physical properties are telling us about the grain size, electrostatic or other physical properties. Spectacular images and great debating. We're still mindful of Spirit out there and many of us on the team want to get back into that investigation and start solving some of that puzzle at Gusev.

Jennifer Trosper: Yes, we are very anxious to get Spirit back to science mission. Last week very little control. Over weekend, partial control. Now working to get complete control. Still not quite there. Yesterday determined it was safe to use HGA and today while we're communicating with Spirit over LGA, we're actually moving the HGA to calibration position and then to stow position. If that goes well, in a few hours we'll do an HGA communication session and be back on the communication plan that will allow us to transmit 11,000 bits per second instead of the between 40 and 120 bits per second so you can imagine the additional debug data we'll get. Other plans we have for today, I mentioned yesterday we are attempting to get a trace from flight software of the problem to see if our hypothesis was correct, to compare to the testbed and if so then begin to delete some of the files from flash files system. Had some difficulty getting script to run on the vehicle. Method is kind of a backdoor into flight software fairly surgical technique. If not able to complete surgical technique, we have larger hammers we can use to solve this problem. Plan is to maintain flash data, probably not corrupted. If we can't do that then we can delete the data in the flash memory. Talked to science team and almost all of it is replaceable. APSX and Mossbauer is replaceable. Moving forward. Getting on HGA. Attempt surgical technique for one more day. Hopefully be back doing science early next week.

Q. Status of that heater? Could it shorten surface life.

Rick: Issue maintains. Heater that stays on over night. Additional info from last night's data which corroborates that it is actually the mini-TES shoulder heater that we thought previously. Longterm issues, we're still working on that. Near term, not impacting us at all.

Q. Specific areas in outcrop that are best target? Selected area to recommend targeting?

Jim: we don't know how trafficable yet. Haven't done the driving detail approach. May be areas we can't access. May be easier or harder areas. We've seen the whole outcrop at modest res. Only seen one small piece in highest res. We have more data onboard that hasn't trickled down to earth yet.... (lost connection here, sorry)

Steve: ....those are the two hypothesis I've heard.

Jim: That coves the major ones. It takes high resolution to see that structure and detail. One sacrifice you make in heavy compression is that small scale features can be washed out. Being able to have the chance between standup activities to take these high res images is a real bonus.

Q. Acquired at Spirit site some high res images of crater off in the distance. May actually be exposed bedrock there as well?

Jim: this is subject of some debate. Unlike at Opportunity we had not had the opportunity to take low compression data. Most of the high-res was off on the distant hills and down at magic carpet and by our feet. The crater is going to be a near term target once we get back On he road. What we have is mission success panorama. We tried to take a long panorama across that crater but ran out of time and then the problems. Finishing that is a high priority.

Q. In terms of the dust, warned that 90 day life because dust clogging solar cells. What are you looking at for planned longevity.

Matt: Really question for engineers. The dust in atmosphere, tau 0.7-0.8 at both landing sites which is fair bit dustier than any time in Pathfinder mission and so far initial suggestions from solar panels is that dust is accumulating on solar panels at the same rate as Pathfinder. Longevity? Over to Rick.

Rick: Too early to tell. Solar input a little less than what we had expected because of the tau but we still have plenty of energy and watch it. 90 days is realistic. Matt: optimists think twice that. (question "any pessimists?") Not among the scientists (laughter).

Q. Now that you've seen high-res views of pebbly surface, what does that suggest about the kinds of measures on soil before you get to outcropping? Maybe measures of the soil and of the area where the airbags hit?

Matt: preliminary discussion with science team this morning. Agreement we're in unique spot and we need to characterize these soils the best we can. Chem measurements, mini-TES, hazard cam and Pancam images. Strong desire to trench to try to gain the mechanical properties of that material it's all sitting there for us. Also tantalizing clues in remote sensing data. So far data, DIMES, shows these craters have dark floors consistent with basaltic granule covered surface. I predict when we get out it will be generally brighter surface, either redder or a modeling of that white outcrop that will come up in various places, overall brighter and different from where we are so more important that we characterize this wonderful spot.

Jim: the act of getting ready to drive, checking out the rover, will also serve double-duty for science experiments, wheel motions, test motions from engineers. Just driving will accomplish two things. Almost anywhere we go we'll run into airbag bounce marks. Secondly we'll be creating wheel tracks. That gives us two data types. Rich data set for physical properties.

Q. Some confusion during landing about how long it was bouncing. Now that you've see bounce marks what do you think?

Jim: haven't seen EDL reconstruction.

Rick: they're reviewing data and coming up with an animation and we're all waiting for it.

Q. Layer of dust, why is it not dusty?

Matt: swept clean at surface by winds. Dust beneath these small pebbles. Characteristic of desert where you have high winds and you'll leave the pebbles and cobbles, too big to be moved, but dust can be swept up. Soil processes that will keep the pebbles and cobbles up at the surface. Places in Mojave where there's a meter or more of airborne dust where there are cobbles of this size that are kept up on the surface, elevated up by processes like freeze thaw, and dust infiltration below it so this layer stays up at the surface.

Jim: and there must be some processes in the bowl of this crater that assist in that because we're in the darkest spot around and out of the crater it's brighter.

Q. What you're doing data handling with Opportunity now that you know about Spirit problem. Also, division of labor>.

Jennifer: We have a process in place we've been using and tomorrow Opportunity will be deleting the cruise phase products we believe are the source of the number of files problem we have on Spirit. We're also setting the limits to be lower. Keep in mind that we've tested in the testbed filling up this flash completely and we have software that throws out based on priority and we've done tests like that so there's something about the situation we're in that we don't completely understand because we've filled up our file system and not hat this problem. Because we don't understand it completely, we're working to limit the number of files onboard. Team makeup a lot of shuffling in the last week. We have one team that's split in half for each of the vehicles. Opportunity landing and impact to egress it takes more than half of our one team because of complicated activities to land and get rolled off the lander. In the case of the Spirit problem, we have people in reserve that have been brought onboard to, strategic people familiar with process and flight software, working on Spirit. Anomaly team is probably 15-20 people. Last night we added another 10 people to move toward getting to our nominal time line and over the next few nights we will go toward our full overnight time line of staffing with science and engineering teams in prep for getting Spirit back on its feet for the science mission.

Q. Are you really seeing pebbly layer in the outcropping and also could you talk about that picture where you can actually see out through, will TES be able to do work out that region?

Matt: smaller than pebbles, gravel. Geologists have these specific categories. Indication in high res is that they're embedded in that material, not just sitting on top, on vertical faces poking out. When you look out to lowest part of rim where the easiest drive out, there is a reddish layer in foreground and behind that a darker layer. There's debate whether topography or just a different color. My eye sees topography. Certainly want to hit that with Mini-TES.

Jim: biggest area of debate about pebbly layer in outcrop is whether it's a continuous layer or a unique aspect of one rock, holding out judgement on distinct discreet layer.

Q. Gravels, pebbles and cobbles, are you seeing different colors.

Matt: certainly a dark small dark particle resolved in high res. For the first time an indication of different hued particles. No color yet but it looks like different color small particles among the dominant dark gray. Ideas are that they are particles weathered out of the brighter outcrop. Also possible carried in from impact or other processes. Way too early.

Jim: High quality images take longer to get off the vehicle and engineering takes priority. We're not complaining but it's gonna take a little while to leak off that high-res data.

Matt: we're horribly impatient scientists :D We want off now! (laughter).

Q. Magic carpet different from retraction of airbags at this site?

Jim: We've been discussing it today. Larry Sodablom (sp?) and others looking at this closely. Some indication soils are acting quite different. There was some apparent cohesion at Spirit, some different physical property. At Opportunity it was more like you ran a rake through it, very fine grained and not as cohesive. Some differences and we need some really good compositional information. We got data at Spirit site lot of sulphur and chlorine. Less cemented at Opportunity and one prediction is less salts.

Matt: don't see duracrust at Opportunity.

Q. Mapping out mission course from inside the crater? Do a second evaluation once you're out?

Matt: landing in a crater is a blessing. If we'd been on the plane, we'd have a devil of a time located. We are in a crater with a 20 meter diameter and there are only so many of those in the landing area so narrows it down. Using photogeologists mapping terrain around us using particularly DIMES images and using the inertial space from navigation in the spacecraft and so far we have relative agreement between those two but we're not there yet. We only have one DTE solution and a single odyssey coherent pass solution which gave us a navigation location. We need a second one of both of those to confirm. In addition there's the spectacular effort of taking the stereo images from camera and flattening it out and making a topo map which allows you to more easily compare it to the images. Like with Spirit, we'd like to know exactly where are located before we start traversing so we can pick the best location to go to. Debate if that 150 meter crater to the northeast is the best way to go because it might just be more of what we have in our current crater. So, you could go to the south what's in images we don't yet have (from MGS) there looks to be mottled terrain that has bright material coming up frequently. Driving to the south might be down the stratigraphic column which might be tremendously interesting. You can tell my bias (south).

Jim: Ray Arvidson and others have said how lucky we are to be where we are so we have to, it would be irresponsible not to study this location. We have to exploration here. Second thing is that this big panorama only covers a 20 meter diameter circle. When you look at Spirit's panorama, it covers several, 2, 3, 500 meters of stereo coverage. We have to get a bigger panorama when we get out. We'll want to obtain the kind of panorama we got at Spirit. Find where we are and determine traverse directions.

Natalie: Friday at 9am next briefing.