Science Summary:

Science discussion on sol 12 dealt heavily with following the evidence of water in the ancient and recent past at the landing site. The crossbedding seen in Kaibab suggested either a fluvial or aeolian origin. Analysis of science data has conclusively proven that this crossbedding is fluvial rather than aeolian in origin. Image data shows large clastic grains embedded within the layers in Kaibab, clasts that are too large for aeolian transport. So we now have a key observation allowing us to conclude we are dealing with an aqueous rather than aeolian paleoenvironment, possibly a distal alluvial fan. The team feels that we have characterized the three layers of the Kaibab formation rather well with Pancam, IPS, and MiniTES of all three layers and in-situ analysis of the lowest layer on sol 12. Work is continuing on the creation of a stratigraphic column.

The Soil STG presented a theory regarding recent signs of water near the landing site. The STG presented a tentative hypothesis about the Bonneville area, which is a low-lying, bright, smooth area approximately 20m from Kaibab. Based on morphology and brightness seen in the original Pancam panorama, the STG suggests that during the waning stages of recent water flow through the valley, Bonneville becomes a small isolated pond holding the last of the water until it evaporates away. The area may hold evidence of biologic activity. Even if flow in the valleys is due to brief flash floods (an idea suggested because of the channel deposits and alluvium seem indicative of bedloads common in flash floods), the remnant standing water need be present for only a few hours for microbial photosynthetic activity to begin.

The Mineralogy STG continues to see kaolinite features in IPS spectra. The 10 spot IPS vertical scan of Coles Point near Kaibab on sol 11 showed kaolinite in the lowest layer with arkose-like rock with quartz, feldspar, and clay also present. The three IPS spectra targeted on the three stratigraphic layers on sol 11 showed a similar kaolinite feature. Currently, the Geology and Mineralogy STGs are hypothesizing that these kaolinite signatures are a result of in-situ weathering of K feldspar in the arkosic sandstone of the Kaibab stratigraphy.

MI data from three soil locations indicate a heterogeneity in the soils. Near Kaibab, the MI image acquired on sol 11 shows better sorting and a lack of aggradation seen in other soils. In addition, there appears to be two types of grains; one of these types appears aeolian in nature because the frosted grains are smooth, rounded, and small. The Soil STG hypothesizes that the soil near Kaibab is primarily material weathered off Kaibab, while the soils sampled earlier in the mission toward the center of the channel represent alluvium. The unique soil particle aggregates seen in the landing site soil but not in soil near Kaibab may be due to the presence of water in the lower channel area.

The rover has acquired enough spectral data to begin supplying ground truth to link orbital spectral observations with rover ground observations. Analysis of MiniTES data indicates two rock types are present in the landing area: Woodstock/Plainfield, and sandstone in the Kaibab formation. Orbital data shows the basalt flow corresponds to the MiniTES analysis of Woodstock and Plainfield, and valley floor corresponds to MiniTES sandstone

Tactical Operations Summary:

The sol 12 planning process lacked some DTE data acquired on sol 11 due to high winds at the DSN. The downlinked hazcams indicated, however, that the approach on sol 11 placed the rover adjacent to Kaibab, and was clear to use the IDD and in-situ instruments on sol 12 for a spectroscopy sol. The rover and instruments remain healthy.

The major challenge in planning the sol 12 in-situ observations was finding a location on the Kaibab outcrop to place the MI, APXS, and MB instruments due to the complex geology and topology of the outcrop. The consensus opinion was that another approach sol was not needed because there appeared to be suitable locations for in-situ measurements to test the fluvial hypothesis for Kaibab. Also, there is a strong need to finish the Kaibab observations and drive to another location to meet mission success. The planned observations included:

• The atmospheric science group requested five sequences to investigate atmospheric dust and water vapor content: 1) A total of six MiniTES observations were acquired consisting of measurements at 30, 15, and 5 deg elevations and a NE and again with a NW azimuth. 2) A sequence of 12 Navcam images will be used to generate a cloud movie. 3) Repeat IPS measurements at two elevations to gather information on atmospheric dust and water vapor content was acquired to replace the sequence deleted from Sol 11. 4) A sky zenith scan was executed. 5) A color Pancam wedge of the calibration target to look for dust accumulation was acquired.
• Remote sensing observations included several IPS measurements targeted on the top of the Kaibab outcrop and a Pancam image pointed toward Bonneville for possible rover localization and planning if Bonneville is selected as the next feature to approach.
• DD deployment of the MI, APXS, and MB on Kaibab. Arm workspace constraints forced us to place the APXS and MB on a different target on Kaibab than the MI. However, the two positions were within a foot of one another, and the area of Kaibab, which was observed was thought to be fairly homogeneous. This arm deployment failed when the CMI contact sensor was triggered. Engineering analysis indicates that the front hazcam range maps are not as accurate as expected, and future arm deployments must be more conservative to account for this. Engineering says we will need at least two more sols to attempt a second IDD placement on Kaibab.

Strategic Summary

Currently we are deciding between continuing an investigation of the ancient aqueous environment of the site vs. recent aqueous activity. Since the sol 12 spectroscopy on Kaibab would provide in-situ data on the lowest stratigraphic layer of Kaibab, there is interest in investigating the upper and intermediate stratigraphic sequence by visiting fallen blocks from those layers. These observations would perhaps not be in-situ but at least close enough for good quality remote sensing (IPS, MiniTES). This suggests a traverse to Stony Point (about 30m away) or Towas (about 90m away) where we believe blocks from the upper layers have fallen to the surface.

Or we could investigate the more recent aqueous activity by visiting Bonneville, which is about 23m away. This traverse is in the direction on Stony Point and would allow remote sensing observations of that area at closer range. However, if Bonneville does not contain evidence of recent fluvial activity, the sense is we should head toward Towas.

The plan is to create two traverses for sol 13: one to Bonneville and one to Towas. A Pancam mosaic of Bonneville on the sol 12 UHF at closer range than we currently have will be used to assess if Bonneville is still likely to contain evidence of recent fluvial activity. Based on this, the IST will decide which traverse to make while they are in the IST meeting.

Additionally, there is strong interest from orbital data to conduct a long 200m traverse to the south to an area that orbital remote sensing data suggests has two lithologies.

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