I. Report on research
For calendar year 2012, my focus was on the Mars Science Laboratory (MSL) mission, leading up to the successful landing on August 5, 2012 and operations that followed. My involvement with MSL is in roles with two instruments, as deputy-PI of the CheMin X-ray diffraction (XRD) and X-ray florescence (XRF) instrument and as a co-investigator on the ChemCam laser-induced breakdown spectroscopy (LIBS) and remote micro-imager (RMI) instrument. In addition to MSL operations and science, there were collaborations with David Bish and students at Indiana University on a Mars Fundamental Research (MFR) project involving field sampling at analog sites and laboratory experiments on mineral transformations relevant to brine-phyllosilicate reactions on Mars. There were also collaborations with Anna Szynkiewicz at University of Texas, El Paso on research into the formation of Mg- and Ca-sulfate salt efflorescence in Jurassic and Cretaceous outcrops along the Rio Grande rift, and collaboration in a new MFR project of Anna’s examining primary, secondary, and climate-related sulfur isotope cycling in rocks and waters of the Valles Caldera in New Mexico. An additional collaboration with Suzanne Schwenzer of the Open University, Milton Keynes, UK has focused on Mars hydrology relevant to the MSL landing site at Gale Crater.
(1) Research at the MSL Gale Crater Field Site on Mars
(1a) CheMin Instrument on MSL.
I’m the Deputy PI of the CheMin instrument on Mars Science Laboratory (MSL); the PI is David Blake of NASA Ames. During 2012 the PSI representation on the CheMin instrument increased with the addition of Steve Chipera as a Senior Research Associate, operating with and reporting to me. Steve Chipera is a Co-I on the CheMin instrument but was unable to participate in mission operations until funded through NASA Ames with a contract to PSI. Chipera had been a part of the original team that developed the CheMin instrument concept and hardware and is an expert in X-ray diffraction. His support through PSI is a tremendous benefit to the MSL mission.
Both Chipera and I have tactical roles during the mission; in addition, I fill strategic operations and planning roles as needed. On August 5, 2012, I began a period of co-location at Jet Propulsion Laboratory for the first 90 days of the landed mission. Chipera was onsite at JPL in October. After this period both of us returned to our home facilities to perform required MSL mission functions remotely, although I am based near JPL and return to work onsite periodically.
As a member of the CheMin Science Team, I participated in or led pre-landing activities and testing for mission operations. This included participation in MSL-led test and training exercises, particularly MSL “flight school” attendance, walkthrough/rehearsals, and Operational Readiness Tests (ORTs). I also helped to prepare CheMin training materials as part of MSL-organized flight schools and for Science Theme Groups to use in operations on Mars. I co-chaired the group tasked with challenging the Qualification Model Dirty Testing (QMDT) system to determine whether environmentally sensitive samples might plug or otherwise compromise the MSL sample collection (drill, scoop) and processing (sieve and delivery) system. Research into challenging drill samples involved compilation of literature data and my published and unpublished data on properties of salt hydrates and clay minerals. These data were used to design tests at JPL that evaluated the properties of Ca, Mg, and Fe salt hydrates, clay minerals, mixtures of these phases, magnetic minerals, and minerals prone to development of electrostatic charge. Results of this study showed that rotary, percussion, and combined rotary/percussion drilling in rocks with such minerals is generally more successful at Mars conditions than in the more humid environment of Earth.
Operation of the CheMin instrument on Mars required about 60 sols of preliminary rover checkout before the first sample could be ingested for analysis. Data from the first sample collected, the Rocknest eolian soil, identify a basaltic mineral suite, predominantly plagioclase (~An50), forsteritic olivine (~Fo58), augite and pigeonite, consistent with expectation that detrital grains on Mars would reflect widespread basaltic sources. Minor phases (each <2 wt% of the crystalline component) include sanidine, magnetite, quartz, anhydrite, hematite and ilmenite. Significantly, about a third of the sample is amorphous or poorly ordered in XRD. This amorphous component is attested to by a broad rise in background centered at ~27° 2θ (Co Kα) and may include volcanic glass, impact glass, and poorly crystalline phases including iron oxyhydroxides; a rise at lower 2θ may indicate allophane or hisingerite. Constraints from phase chemistry of the crystalline components, compared with a Rocknest bulk composition from the APXS instrument on Curiosity, indicate that in sum the amorphous or poorly crystalline components are relatively Si, Al, Mg-poor and enriched in Ti, Cr, Fe, K, P, S, and Cl. All of the identified crystalline phases are volatile-free; H2O, SO2 and CO2 programmed-heating volatile releases from a split of this sample analyzed by the SAM mass spectrometer on Curiosity are associated with the amorphous or poorly ordered materials. The Rocknest eolian soil may be a mixture of local detritus, mostly crystalline, with a regional or global set of dominantly amorphous or poorly ordered components.
At the time of writing this report the Curiosity rover is poised to collect the first drill sample from sediment. The site for this sample is a fine-grained deposit with concretions, Ca-sulfate phases, associated chloride, and evidence of extensive veining and enterolithic growth of sulfate salts. The CheMin results are likely to have a significant impact on our understanding of sedimentation on Mars. For the 2013 LPSC meeting, the CheMin team has prepared 6 abstracts summarizing results from the first X-ray diffraction analyses on another body beyond Earth.
(1b) ChemCam instrument on MSL
As with CheMin, much of the research on ChemCam this year was focused on instrument characterization and calibration prior to landing. However, after MSL landed the ChemCam instrument did not need to wait on commissioning of the sample collection system to obtain data. Results from the ChemCam laser ablation breakdown spectroscopy (LIBS) and remote microimager (RMI) began to come in within days of landing. At the time of this report several thousand plasma spectra have been obtained from hundreds of ~0.5 mm analysis spots on rocks and soils at the MSL field area.
I’m a Co-investigator on the ChemCam instrument on Mars Science Laboratory (MSL); the PI is Roger Wiens of Los Alamos National Laboratory. Before landing the team prepared a paper on “The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests” that was published in Space Science Reviews during the report period (see Wiens et al. in peer-reviewed publications). In this same volume, we participated in preparation of the mission overview paper “Mars Science Laboratory Mission and Science Investigation” by John Grotzinger and co-authors. In addition, I was lead author of a paper describing preparation and characterization of the sulfur-bearing ceramic calibration standards that are carried on Curiosity (“Ceramic ChemCam Calibration Targets on Mars Science Laboratory”). Calibration efforts were intensive before landing and continue, as new data are obtained on Mars. The LIBS method is a new technology and we are constantly learning as data from targets around the rover, and from the calibration targets carried on the rover, stream in.
ChemCam has proved its importance to the MSL mission by providing geochemical context at ranges out to 7 m each time the rover stops. The small ~0.5 mm laser ablation spot size and accurate laser pointing permit targeting of small features that cannot be interrogated for chemical composition by any other instrument on the rover. Results to date include identification of Ca-sulfate as a vein-filling and enterolithic phase within the first sedimentary section that the rover accessed; we are currently located within that sedimentary section and analyzing it in detail. The science return from this location is growing daily and will greatly impact our concepts of sedimentation and aqueous processes on Mars.
Presentations for ChemCam during this year included contribution to two posters at the 2012 Lunar and Planetary Science Conference in Houston. One poster presented results of pre-landing calibration of the laser-induced breakdown spectroscopy (LIBS) instrument on Curiosity, including analysis of the sulfur-bearing ceramic standards that I synthesized at LANL and are carried in a mount on the rear deck of Curiosity. The other presentation described plans for LIBS operation during the mission, including strategies for raster and grid analysis of layered sediments and the integration of LIBS spot analysis with context imaging by the ChemCam Remote Micro-Imager (RMI). It is worth noting that for the 2013 LPSC meeting, the ChemCam team has prepared 16 abstracts summarizing results from the first 90 sols of the mission.
(2) Research Collaborations on Mars Fundamental Research Projects
The joint Mars Fundamental Research Project with David Bish at IU has yielded results that quantify the extent of cation exchange between Mg-sulfate brines and several representative smectites. Salts produced by cation exchange include gypsum as well as a magnesium sulfate (when precipitated at 2 to 50 °C the magnesium sulfate is epsomite, but direct precipitation of hexahydrite or kieserite occurs at higher temperatures). Experiments are being conducted at ~75 °C to determine whether smectites will convert to mixed-layer clay minerals or chlorite at temperatures associated with ~5 km of burial under sediment fill at Gale Crater. To date no such transformations have been induced.
In association with the Mg-sulfate brine study we have been working in the field along the Rio Grande rift, examining formation of Mg- and Ca-sulfate salt efflorescence in outcrops of the Dakota sandstone but not in closely associated Mancos shale, where only Ca-sulfate efflorescence is observed. Anna Szynkiewicz at UTEP has been leading the efflorescence study; I support her S-isotope analyses with field work and X-ray diffraction analyses of the salt efflorescences. A paper in preparation suggests that cycles of salt dissolution and reprecipitation appear to be a major process that migrates sulfate efflorescence to sites of surface deposition and ultimately increases the aqueous sulfate flux along drainages (average 41,273 metric tons/year in the Rio Grande). The paper further suggests that a similar process may explain occurrence of hydrated sulfates on the scarps and valley floors of Valles Marineris. Estimates of salt mass and distribution are in accord with other studies suggesting a rather short-lived process of sulfate formation (~100 to 1,000 years) and restriction by prevailing arid conditions on Mars.
A new collaboaration with Anna Szynkiewicz of UTEP and with Fraser Goff of LANL, beginning this year, is an MFR study of the primary, secondary, and climate-related sulfur isotope cycling in rocks and waters of the Valles Caldera in New Mexico. This study includes the history of hydrothermal and lacustrine systems of the caldera and the major caldera drainage via the Jemez River into the Rio Grande. Anna is the PI of this study, which has ties to the origin and fate of sulfate salts on Mars. Preliminary data were presented at the fall AGU meeting in San Francisco.
Collaboration with Susanne Schwenzer of the Open University, Milton Keynes, UK resulted in a publication on the hydrogeologic environment of Gale Crater that has implications for the MSL mission. The formation of large (>100 km diameter) impact craters in Mars’ water-rich crust, such as Gale Crater, must have produced extensive, long-lived hydrothermal circulation systems beneath and around the craters. These hydrothermal systems, and associated lakes and springs, could have provided suitable conditions for habitability by creating sites where pre-biotic chemistry could progress and mature and elements necessary to support life were available, and by providing hydraulic connectivity into the deep subsurface, where this chemistry (and possibly life) may be preserved. Evidence of this hydrothermal and aqueous activity can be detected as alteration minerals in the rocks of an impact crater, bearing witness to local thermochemical conditions, dissolution and transport of material, and transformation of the original materials to alteration minerals such as clays, chlorite, serpentine, and zeolites.
Collaboration with Susanne Schwenzer also produced a second publication, of the more widespread hydrogeological effects of smaller impacts than the one that produced Gale Crater. Where a cryosphere is present, medium-sized (few 10s of km diameter) impact craters can physically and/or thermally penetrate into the cryosphere, creating liquid water through the melting of subsurface ice in an otherwise dry and frozen environment. Interaction of liquid water with the target rock produces alteration phases that thermochemical modeling predicts will include hydrous silicates (e.g., nontronite, chlorite, serpentine). Thus, even small impact craters are environments that combine liquid water and the presence of alteration minerals that make them potential sites for life to proliferate. Expanding on the well-known effects of large impact craters on target sites, we concluded that craters as small as ~5-20 km (depending on latitude) may excavate large volumes of material from the subsurface while delivering sufficient heat to create liquid water (through the melting of ground ice) and drive hydrothermal activity. This connection between the surface and subsurface made by the formation of these small, and thus more frequent, impact craters may also represent favorable sites to test the hypothesis of microbial life on Mars.
Blake D., Vaniman D., Achilles C., Anderson R., Bish D., Bristow T., Chen C., Chipera S., Crisp J., Des Marais D., Downs R.T., Farmer J., Feldman S., Fonda M., Gailhanou M., Ma H, Ming D.W., Morris R.V., Sarrazin P., Stolper E., Treiman A., and Yen A. (2012) Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory. Space Sci. Rev., 170, p. 341-399, doi: 10.1007/s11214-012-9905-1.
Grotzinger J.P., Crisp J., Vasavada A.R., Anderson R.C. Baker C.J., Barry R., Blake D.F., Conrad P., Edgett K.S., Ferdowski B., Gellert R., Gilbert J.B., Golombek M., Gómez-Elvira J., Hassler D.M., Jandura L., Litvak M., Mahaffy P., Maki J., Meyer M., Malin M.C., Mitrofanov I., Simmonds J.J., Vaniman D., Welch R.V., and Wiens R.C. (2012) Mars Science Laboratory Mission and Science Investigation. Space Sci. Rev., 170, p. 5-56, doi: 10.1007/s11214-012-9892-2.
Schwenzer S.P., Abramov O., Allen C.C., Clifford S.M., Cockell C.S., Filiberto J., Kring D.A., Lasue J., McGovern P.J., Newsom H.E., Treiman A.H., Vaniman D.T., and Wiens R.C. (2012) Puncturing Mars: How impact craters interact with the Martian cryosphere. Earth Planet. Sci. Lett., 335–336, p. 9–17, doi:10.1016/j.epsl.2012.04.031.
Schwenzer S.P., Abramov O., Allen C.C., Bridges J.C., Clifford S.M., Filiberto J., Kring D.A., Lasue J., McGovern P.J., Newsom H.E., Treiman A.H., Vaniman D.T., Wiens R.C., and Wittmann A. (2012) Gale Crater: Formation and post-impact hydrous environments. Planet. Space Sci., 70 p, 84–95, doi.org/10.1016/j.pss.2012.05.014.
Vaniman D., Dyar M.D., Wiens R., Ollila A., Lanza N., ·Lasue J., Rhodes M., Clegg S., and Newsom H. (2012) Ceramic ChemCam Calibration Targets on Mars Science Laboratory. Space Sci. Rev., 170, p. 229-255, doi: 10.1007/s11214-012-9886-0.
Wiens R.C., Maurice S., Barraclough B., Saccoccio M., Barkley W.C., Bell, J.F. III, Bender S., Bernardin J., Blaney D., Blank J., Bouyé M., Bridges N., Bultman N., Caïs P., Clanton R.C., Clark B., Clegg S., Cousin A., Cremers D., Cros A., DeFlores L., Delapp D., Dingler R., D’Uston C., Dyar M.D., Elliott T., Enemark D., Fabre C., Flores M., Forni O., Gasnault O., Hale T., Hays C., Herkenhoff K., Kan E., Kirkland L., Kouach D., Landis D., Langevin Y., Lanza N., LaRocca F., Lasue J., Latino J., Limonadi D., Lindensmith C., Little C., Mangold N., Manhes G., Mauchien P., McKay C., Miller E., Mooney J., Morris R.V., Morrison L., Nelson Y., Newsom H., Ollila A., Ott M., Pares L., Perez R., Poitrasson F., Provost C., Reiter J.W., Roberts T., Romero F., Sautter V., Salazar S., Simmonds J.J., Stiglich R., Storms S., Striebig N., Thocaven J.-J., Trujillo T., Ulibarri M., Vaniman D., Warner N., Waterbury R., Whitaker R., Witt J., and Wong-Swanson B. (2012) The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests. Space Sci. Rev., 170, p. 167-227, doi: 10.1007/s11214-012-9902-4.
Clegg S., Lasue J., Forni O., Bender S., Wiens R.C., Maurice S., Barraclough B., Blaney D., Cousin A., DeFlores L., Delapp D., Dyar M.D., Fabre C., Gasnault O., Lanza N., Morris R.V., Nelson T, Newsom H., Ollila A., Perez R., Sautter V., and Vaniman D.T. (2012) ChemCam Flight Model Calibration. 43rd Lunar and Planetary Science Conference, March 19–23, 2012, The Woodlands, Texas. Abstract #2076.
Newsom H.E., Blaney D., Wiens R.C., Clegg S., Lanza N., Vaniman D., Maurice S., Gasnault O., King P., Bridges N., Dyar M.D., Melikechi N., Blank J.G., Cousin A., Ollila A., Baxter A., Vasavada A., Mangold N., Le Mouelic S., and the ChemCam Team (2012) Operational Strategies for the ChemCam LIBS Experiment on MSL. 43rd Lunar and Planetary Science Conference, March 19–23, 2012, The Woodlands, Texas. Abstract #2477.
Szynkiewicz A., Borrok D.M., Vaniman D.T., and Goff F. (2012) Hydrological sulfur cycling in the volcanic complex of Valles Caldera – geochemical and astrobiological implications for Mars. Am. Geophys. Union Fall Mtg., San Frrancisco, California. Abstract P11B-1815.
Yen A.S., Bish D.L., Blake D.F., Vaniman D.T., Treiman A.H., Ming D.W., Morris R.V., Farmer J.D., Downs R.T., Chipera S.J., Des Marais D.J. and Chen C.W. (2012) Definitive Mineralogy from the Mars Science Laboratory CheMin Instrument. 43rd Lunar and Planetary Science Conference, March 19–23, 2012, The Woodlands, Texas. Abstract #2741.
IV. Service to the Science Community (e.g., advisory panels, society offices)
a) Peer review of five papers (for Icarus, EPSL, Space Science Reviews, and Astrobiology)
b) Completed 18 proposal reviews for Cosmochemistry, PGG, MFRP and MDAP .
c) Participated in the Mars Data Analysis review panel, January 9-13, in Baltimore, MD.
V. Teaching Activities/Public Lectures
a) Presentation on Mars at Madera Elementary School in Simi Valley, CA.
b) Presented results of the first X-ray diffraction analysis on another planet in a Mars Science Laboratory press conference, October 30, 2012.
c) Phone interview with Yan Jiang of Xinmin Evening Newspaper, Shanghai, on Mars Science Laboratory and the Curiosity rover.
d) Phone interview with Ruvini Samarasinha of University of Arizona on working at PSI.
e) Video interview with Kevin Roark of Los Alamos National Laboratory on the CheMin XRD/XRF