Geo016 - Exploration of Mars

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Geo016 / Exploration of Mars / (M) 3:00-5:20 / Lincoln Field 105 / Prof. James Head

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[04.09] Opportunity begins traverse, encounters sinuous trough

On sol 69 Opportunity finished its examination of the rock "Bounce" by driving over it in an attempt to test how hard the rock is.  Rear haz-cam images that should reveal how well the rock held together have not been made available by JPL.

The rover then traversed the obstacle-free terrain of Meridiani in the direction of Endurance Crater for a distance of 100 meters on sol 70.  The rover then encountered a sinous trough in the soil dubbed "Anatolia," which is a series of connected pits that expose underlying rock at some locations.  These troughs have been observed in MOC imagery of the landing site and are common in the terrain surrounding Endurance Crater. 

After driving alongside the trough for ~50 m, the rover dug a trench in the soil to compare the near subsurface of the surrounding terrain to the previously studied soil of Eagle Crater.  In coming sols, Opportunity will be examining the exposed rock within Anatolia before it continues its drive to the rim of Endurance Crater.

 

[04.09] Spirit enters extended mission, images rim of Gusev Crater

Spirt has fullfilled all necessary criteria for mission success on Mars and has entered its extended mission.  The two primary objectives that must be met are duration of time on the surface (at least 90 sols) and the cumulative length of rover traverses (at least 600 meters).  The rover met both of these within the last week and NASA has granted funding for five more months of operation.  Other necessary objectives, like implementation of all of the scientific instruments, were met soon after landing in Gusev Crater.

Spirit spent this week traversing the ejecta blanket of Bonneville and is currently stationed in front of "Route 66," another light-toned rock that is scalloped and fractured, like the previous target, "Mazatzal."  The rocks that are scattered across the Gusev planes show a range in albedo but the science team has decided to focus on the light-toned rocks that are in the rover's path to the Columbia Hills.  Science operations have been suspended for ~4 days as updated flight software is sent to the rover.  The new software will help the rover conserve power as it receives less and less sunlight and it will boost the Autonomous Navigation System, as the rover's primary goal for the rest of its mission is traversing the planes of Gusev in the direction of the Columbia Hills.

On Sol 91, before Spirit arrived at Route 66, the atmosphere at Gusev cleared up to the degree that pan-cam images revealed the south-eastern rim of Gusev Crater, about 80 km away.  The rim tapers further to the south where it meets the mouth of Ma'adim Vallis. 


Spirit (Gusev Crater)

Opportunity (Meridiani Planum)


[04.02] Spirit finishes work at Mazatzal

After completing its analysis of the scalloped rock Mazatzal, Spirit has begun what is anticipated to be a 60-90 sol drive to the Columbia Hills .  Investigation of the ejecta on the rim of Bonneville Crater showed no evidence that the impact that formed Bonneville penetrated through the surface layer of volcanic material and excavated any sedimentary deposits that might be in the subsurface.

The rover's stint at Mazatzal included a brushing/grinding of the target " New York ," which was the deepest ratting (~8 mm) of any rock so far, and a series of brushings at " Missouri ."  After completing the IDD examinations of these targets, the rover retreated 0.9 m to acquire Mini-TES data from the exposed surfaces.  Microscopic Imager imagery of New York  has been released by JPL, and compositional data obtained by the APXS instrument show that the rock is another basalt, like Adirondack and Humphrey.  This data led to the decision to abandon Bonneville and begin the drive to the eastern hills.

Monday will be sol 90 on Mars for Spirit, which means that the rover is entering its extended mission phase.  Considering that the rover's primary objective for the remainder of its mission is to drive to the Columbia Hills, the operation team for the rover will switch to working on Earth time for the first time since landing in early January.


[04.02] Opportunity investigates "Bounce"

Opportunity began the week by acquiring a high-resolution pan-cam mosaic from its location outside of Eagle Crater, which has been processed and released .  This operation required all of the rover's flash memory, which prevented it temporarily from acquiring any data from " Bounce ," the rock currently in front of the rover.  The rock, according to Mini-TES data, is rich in hematite and is one of the few rocks observed on the Meridiani planes.  The rock sits within an airbag imprint, meaning that Opportunity encountered it before, as it was bouncing to its landing location within the crater.

Once the pan-cam data were downlinked from the rover, the IDD began its investigation of Bounce.  Initial MI frames were acquired to help choose a RAT target, and a Mossbauer integration was performed on the undisturbed surface.  Once these data were processed, a target named " Case " was ratted and analyzed by both the Mossbauer and APXS instruments. 

After completing its work at Bounce in the next few sols, Opportunity will begin its ~700m traverse to the rim of Endurance Crater.  Like the team that operates Spirit, the Opportunity team will be switching to Earth hours as the rover covers the relatively obstacle-free terrain of Meridiani.

 

 


[03.26] Spirit brushes Mazatzal, preps for ratting

Spirit spent the week approaching and then examining "Mazatzal," a 2-meter wide rock that sits just outside the southern rim of Bonneville.  The RAT was used to brush the scalloped surface of the rock in two locations ("New York" and "Illinois") in preparation for grinding, which should occur on sol 81 (Friday, March 26).  After brushing, the IDD was used to take microscopic images of the brushed face, and Mossbauer and APXS spectra were obtained.  The first attempt to open the door of the APXS instrument failed, but a command sent for the rover to repeat the APXS integration was successful.  Mission engineers are unclear about what caused the door not to fully open, but the instrument appears to be fully functional once again.

In coming sols, Spirit will complete its analysis of Mazatzal by grinding the surface, followed by a complete IDD analysis of the interior of the rock.  The rover will then be commanded to continue it's advance along the southern rim of Bonneville, obtaining Pan-Cam/Mini-TES data and examining soil samples along the way.


[03.26] Opportunity exits crater

Opportunity's second attempt to exit Eagle Crater was successful on sol 57, which ended last Monday night.  The rover approached the rim at a less-direct angle than its first attempt, which avoided the slippage problem encountered one sol before.  Once it reached the Meridiani plains, the pan-cam and nav-cam were used to image the rock-free, hematite-rich surface that is dominated by eolian ripples. 

After the rover advanced 9 meters, it turned around and went back to a patch of bright material on the outside of the crater rim, first spotted in images acquired by the rover's rear haz-cam.  The IDD has spent the last 3 sols stationed at this location, where it has been taking MI images and performing Mossbauer/APXS integrations of specific targets.  After analysis at this site is complete, the rover will begin its advance to Endurance Crater, 700 m away.

 

 


[03.22] Spirit scuffs "Serpent"

Spirit divided its week between examining a prominent drift on the rim of Bonneville crater dubbed " Serpent ," and traversing the southern rim of the crater, using both direct commands to advance and its Autonomous Navigation System.  The rover used its left front-wheel to scuff the surface of Serpent and then retreated and deployed its IDD to investigate the structure and composition of the exposed location, named "Bear Paw."  Four specific targets within Bear Paw were selected for imaging and spectral analysis, all with bear-related nomenclature: Polar, Kodiak, Spectacled and Panda.  Seven MI images were taken of each target, including false-color pictures of Spectacled and Kodiak.  Mossbauer and APXS spectra were obtained of Panda and downlinked, but no compositional data have been released.

Microscopic Imager frames show that the drift is covered by a layer of spherical grains (~1-2 mm in diameter) that have a higher albedo than the material within the drift.  The interior is comprised of dark and surprisingly fine-grained material that would be unlikely to form collect as a drift on Earth.

After finishing at Bear Paw, Spirit followed the drift along the southern rim of Bonneville, scuffing the drift at five different locations along the way.  As the rover advanced, it turned its mast 180 degrees so that the Mini-TES could analyze the disturbed portions of the drift.  Mini-TES data have also yet to be released.


[03.22] Hematite found in spherules

Opportunity has completed its examination of the outcrop but has failed to exit the small crater in which it landed.

Before attempting to traverse the crater rim, the science team wanted to examine five soil targets that had been chosen from pan-cam and Mini-TES maps of the crater floor. Each site received complete IDD analysis, but the fourth target was chosen as a trenching site, which was completed on sol 54 (Saturday). Microscopic Imager frames from each location are available through JPL, but Mossbauer/APXS data are still being downlinked and analyzed by the science team.

After completing analysis of the fifth soil target (“Brian's Choice”), Opportunity attempted to exit the crater for the first time, but encountered greater slippage than expected and was unable to complete the traverse. The rover is fully functional and has not encountered any mechanical problems as a result of the failed exit, and mission engineers have taken Opportunity to another location within the crater where it will make its second attempt on sol 57.

And the hematite has finally been found.  Mossbauer spectra acquired from "Berry Bowl" show a strong hematite signature that is absent in spectra acquired from the underlying rock.

 


[03.12] Spirit looks inside Bonneville Crater

Spirit completed its advance to the rim of Bonneville Crater and has begun to compile a pan-cam/mini-TES mosaic of the 200m wide depression.  Initial nav-cam imagery reveals mostly disaggregated boulders but a few areas of possibly coherent material along the crater wall, though nav-cam resolution is too low to be able to decipher conclusively.  The engineering team is currently assessing the risk of entering the crater and the feasibility of the rover being able to exit the crater safely, and the science team is waiting for pan-cam/mini-TES data to determine whether entering the crater would provide data worthy entering the crater.  

The rover has also been using its pan-cam to perform atmospheric analysis by imaging known constellations and determining what effect the Martian atmosphere has on a star's magnitude.  The first target chosen was Orion, which was found and images have been released here .  Betelgeuse (Orion's right shoulder) is the brightest star in the frame, and the three stars that comprise the belt are at the very bottom of the image.  Through the course of this investigation, Spirit took a picture of the Earth, and also unexpectedly found a distinct streak in the sky .  This is either the chance observation of a meteor entering the Martian atmosphere, or one of the ten satellites currently in orbit around Mars.  Of the ten, three are still in communication with Earth, and none of those were in that location when Spirit took the picture.  And of the remaining 7, 6 are still tracked and none of those were in that location at that time.  That leaves Viking Orbiter 2 as the only man-made candidate, or this was simply debris falling through the Martian atmosphere.


[03.12] Opportunity advances to Berry Bowl

Opportunity has advanced to a location dubbed "Berry Bowl," which is a low in the outcrop that has a large concentration of spherules.  This will be the site where the science team hopes to answer the largest unanswered question with regard to the outcrop: what is the composition of the spherules?  The rover is now situated in a position where it will perform a complete IDD analysis of the spherules. 

This follows the ratting and IDD analysis of "Flat Rock," where the rover encountered some difficulty applying the RAT to the surface of the rock.  Before each ratting, the IDD must perform a "seek and scan" operation to determine the precise location for the grinding.  The RAT stalled too early when analyzing its target, due to lower-than-expected temperatures at the site.  A command was sent to increase the voltage to the RAT, which was was successful.  Once grinding commenced, the RAT proceded to get stuck on a spherule.  Previous implimentations of the RAT suggested that the spherules are soft and show little resistance to grinding.  This suggests that the RAT getting stuck on a spherule is more a function of low-voltage to the RAT. 

Opportunity's pan-cam also caught three solar eclipses in the last week: one by Deimos and then two by Phobos.  Deimos eclipsed the sun on sol 39, then Phobos (the larger of the two satellites) tangentially eclipsed the sun on sol 42 and then, most impressively, cut right through the sun on sol 45.

 


[03.05] Spirit struggles with RAT

Spirit spent this week stationed at "Humphrey," a rock that sits in the small depression called "Middle Ground."  After brushing three distinct targets on the face of the rock, the RAT encountered its first obstacle, when a 4-hour ratting session on Humphrey was abruptly terminated 20 minutes into the operation.  Sensors on the device detected a loss of contact with the face of the rock, which automatically comanded the IDD to pull away from Humphrey.  This was due to the surface slope of the rock, which was more irregular than estimated from nav-cam/pan-cam imagery.  The following sol (sol 59 - Wednesday), Spirit successfully ratted a target slightly to the left of the previous grinding, and completed Mossbauer/MI/APXS analysis of the depression.  Mossbauer/APXS data have yet to be released.

While sitting in Middle Ground, the rover obtained full Pan-cam and Mini-TES panoramas of the surrounding terrain.  This should be completed today, at which point the rover will drive approximately 25 meters in the direction of Bonneville Crater. 


[03.05] Opportunity leaves El Capitan

Opportunity began the week by backing away from El Capitan, the site of the IDD measurements that provided the strongest evidence for water having flowed through the outcrop.  The rover's immediate task was to take images of two more targets within the outcrop: "Last Chance" and "Big Bend."  Moderate slipping along the slope of the outcrop (at some points up to 22 degrees) left the rover ~0.5 m short of Last Chance, but the rover was able to complete the drive and deploy its IDD. 

Opportunity took over 128 Microscopic Imager frames of this portion of the outrcop in an attempt to compile the first stereo panorama of a section of the outcrop.  At each station within Last Chance, the MI has to take images at five different depths (for fucusing) and at different angles (in order to compile the mosaic).  This makes the mosaic time-consuming to create, but once completed it will provide the most detailed topography of the outcrop to date.

Meanwhile, the rover's pan-cam attempted to view Diemos as it eclipsed the sun, which occurs twice per Martian year.  This operation took place on sol 39 (yesterday), but pan-cam images have not been released to the public yet. 

 

 

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