- About PSI
|Senior Research Scientist
Planetary Science Institute
I currently have three primary research interests: (1) rock and grain morphology and what they reveal about geologic processes; (2) photogeologic and spectroscopic mapping as a tool for revealing the underlying geologic processes and placing those processes into a global, contextual framework; and (3) spacecraft mission planning and operations. I am also active in education/public outreach (E/PO).
The Planetary Science Institute is my home institution. While I lived for several years in Tucson, my home office is in Brunswick, ME.
Me at Lambeau Field, 2009 (sorry, it was September, too warm to wear my Cheesehead). Go Pack!
Morphology and Texture of Rock Outcrops and Clasts
Rock and particle morphology (shape, texture, fabric and roundness) provide an important component to any study seeking to understand how transport and wear have altered the landscape, and the methods employed can be utilized on any terrestrial planet with a rock population. I approach the problem from two directions: (1) size, shape and textural assessment of cobble-sized clasts; and (2) characterization of individual grains in loose rocks and outcrop imaged at the handlens-scale. For the first case, we are imaging and analyzing morphologic characteristics (size, shape, roundness, texture) of surface particles on Earth to create a set of “standard” values to compare to values for clasts imaged on other planets (such as in Gusev Crater imaged along the path of the Spirit rover). At present, terrestrial standards tend to be heavily focused on fluvial or glacial transport processes, and while these may be important for Mars, processes such as ballistic impact and various volcanic eruptive types have clearly played a dominant role on both the Moon and Mars, as well as other rocky bodies. Providing standards of morphology and texture for the products of these processes will be crucial in determining the history of rock populations.
For the second case, we are currently photodocumenting, cataloging and analyzing thousands of terrestrial clast characteristics at the handlens scale. These are posted in database format on the PDS (http://pds-geosciences.wustl.edu/missions/labdata/marshandlens.htm) and used to identify and interpret microtextures as clues to martian clast formation, alteration, and transport. This work is also directly applicable to my research being conducted at the MER Spirit site and will support the Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI).
Skeiðarársandur, Iceland — a glacial outwash plain. The most recent deposition seen above is a high-volume flow deposited in 1996. Here, I'm taking notes on the morphologic characteristics of the surface cobbles.
Geologic Mapping as a Tool for Deciphering Geologic Processes
Creating a coherent, end-to-end understanding of a particular geologic process hinges upon the utilization and effective blending of a variety of methods of data collection and analysis. For example, the characteristics of a planet's volcanic deposits, as manifested on the surface, provide clues to its thermal evolution. Impact craters not only reveal much of the stratigraphy of surface units, they often serve as windows into the vertical structure and composition of a planet’s crust. In this context, my research focuses on the relationship of the morphology and composition of surface units on small, rocky bodies, to the processes that formed them. My approach combines photogeologic mapping techniques and multispectral data analysis to first characterize and map surface features, and then to compare the morphology of these features with analogous terrestrial examples to better understand geologic context, processes, and stratigraphy. Current mapping projects include a global geologic map of the asteroid Vesta (as part of the Dawn at Vesta mission) and geologic maps of lunar quadrangles 29 (PI) and 10 (Co-I).
Current Mission Activities
I am currently the deputy Principal Investigator on the Mars Hand Lens Imager (MAHLI) instrument on Mars Science Laboratory (MSL), as well as a Co-Investigator on of the combined Mastcam, MAHLI, and MARDI (Mars Descent Imager) science team. I also serve as a Participating Scientist on MER and on the Dawn at Vesta mission.
Much of my work effort for MSL is focused on contributing to the design of the instrument calibration plans and the MAHLI calibration target, and support of analog and operational field work activities. On MER, I continue to support operations through several roles, including Payload Uplink Lead for the Microscopic Imager and engineering cameras, Long-term Planning lead, and SOWG Chair and Documentarian.
Here I am with the Mastcam/MAHLI/MARDI team on a team field trip to Santa Clarita, CA.
Future Mission Support: Science Operations Strategies for Semi-Autonomous Rovers
What are the surface expressions of important planetary analog materials, and at what concentration can we detect them using semi-autonomous rover-inspired methodology (that is, how, when, in what order and in what priority, rover instruments are used to answer scientific questions)? We are exploring and evaluating strategies that may maximize scientific return from lunar semi-autonomous robotic surface activities, specifically through the refinement of exploration science methodology. To isolate methods of rover-driven field activities from variables introduced in utilizing rover-associated hardware and instruments, we conduct field work using commercial instruments that provide similar information as flight-ready instruments (e.g., off-the-shelf digital cameras and field spectrometers), and utilize humans for mobility. Our ultimate goal is to outline changes in field methods required to adapt Mars-based robotic survey methods to the unique goals, environment and architecture of lunar exploration.
From the first GHOST (GeoHeuristic Operational Strategies Test) rover operations experiment in the Santa Clara volcanic field, New Mexico. The analog studied is the diversity of volcanic, upper and potentially lower crustal (xenolithic) materials that might be sampled within the lunar South Pole-Aitken Basin. From right to left, Nathan Lutterman, me (in the stupid hat), Mariek Schmidt, Larry Crumpler and a few of our bovine field assistants. Not shown are Barbara Cohen (laughing at us) and Christian Schrader (taking the picture). The results from this field test are published at: http://marsjournal.org/contents/2011/0002/.
From left to right, Mariek Schmidt, Brian Hynek, Barbara Cohen, me (the PI) and “rover” Ross Nova, the field team for the second GHOST rover operations (not pictured: Christian Schrader, behind the camera). The analog studied is subsurface water ice underlying a diverse regolith sampled from a broad geographic region. This picture represents one of the only ones where the PI actually looks up and smiles.