John Marshall
John Marshall

Senior Research Scientist

Disciplines: Planetary Geology

Degree/Major: Ph.D., Geomorphology, 1979, University College London, UK

jmarshall@seti.org
Biography

Planetary geologist John Marshall specializes in the study of particulate matter –dust and sand-size materials that comprise nebulae clouds, volcanic eruptions, dust storms, sand dunes, beach and river sediments, and the regoliths of the terrestrial planets, rocky moons, and asteroids. These particles are being studied from three perspectives: (1) their electrostatic behavior – how they form aggregates in dust clouds and nebulae; (2) how they are transported by wind, water, and in the pyroclastic flows that surge down the sides of volcanoes, and (3) their microscopic properties – how their size, shape, and surface texture provide clues about processes which have shaped them, such as wind, water, and chemical action.

To study particle transport, John operated the Mars Wind Tunnel and the Venus Wind Tunnel at NASA Ames, and developed the Ames Venus Simulator. Currently he is part of a consortium of investigators developing a new wind tunnel to simulate aeolian action on Titan. To study the electrostatics of particles, John has flown his experiments on the KC 135 (zero-gravity) aircraft, and twice on Space Shuttle Columbia, as well as diving into dust devils in the Mojave Desert and conducting a number of laboratory simulations of Mars. Currently he is developing a Lunar Laboratory for NASA Ames and has successfully duplicated electrostatic levitation of dust as seen on the Moon.

Heavily involved in the flight world, he has developed instruments for three Mars missions, for Space Shuttle, and Space Station, as well as a coffee-can size X-ray analyzer for use on the Moon or Mars. At the moment, John’s fingers are crossed for a safe landing of the Phoenix mission to Mars. John is a co-investigator, and will be interpreting the first ever microscopic images of Martian soil to be transmitted back in the Spring of 2008.

Publications

Carol R. Stoker, Nathalie Cabrol, John Marshall, Marsokhod Rover Team, Marsokhod Rover Team, Jeffrey E. Moersch, Ted Roush, 2001. The 1999 Marsokhod Rover Mission Simulation at Silver Lake California: Mission Overview, Data Sets, and Summary of Results Journal of Geophysical Research106, 7639-7664.

John Marshall, 1998. Towards a theory for planetary aeolian transport Geophysical Research Letters

John Marshall, J Borucki, Clayton Bratton, 1998. Aeolian sand transport in the planetary context: Respective roles of aerodynamic and bed-dilatancy thresholds LPSCXXIX, 1131.

L.N. Koppel, John Marshall, 1998. A miniature metal -- ceramic X-ray source for spacecraft instrumentationReview of Scientific Instruments69, 1-5.

John Marshall, 1997. Unique Aeolian Transport Mechanisms on Mars: Respective roles of percussive and repercussive grain populations in the sediment load GSA, A-214

John Marshall, Friedemann Freund, 1996. Aggregation in particulate clouds in astrophysical and planetary settings: Preliminary results from USML-2 LPSXXVII, 811.

John Marshall, Friedemann Freund, Todd B. Sauke, 1996. Microgravity studies of agglomeration in particulate clouds: Implications for volcanic and impact events Geophysical Research Letters

John Marshall, J Borucki, C. Sagan, 1996. Behavior of windblown sand on Mars: Results from single-particle experiments LPSCXXVII, 813.

John Marshall, 1994. Particle Dispersion Experiment (PDE): Preliminary results from the USML-1 gloveboxNASA Conference Proceedings 327211, 717-732.

Glenn Carle, Daniel Kojiro, John Marshall, Todd B. Sauke, Jose Valentin, 1994. Advanced Instrumentation for Exobiology SPIE Proceedings Series2267,

Rocco Mancinelli, Melissa R. White, John Marshall, 1992. Analyses of exobiological and potential resource materials in the Martian soil Advances in Space Science Research12, 111-116.

John Marshall, Ronald Greeley, 1992. An Experimental Study of Aeolian Structures on Venus Journal of Geophysical Research97, 1007-1016.

Verne Oberbeck, John Marshall, 1992. Impacts, Flood Basalts, and Continental Breakup Lunar and Planetary ScienceXXIII, 1013-1014.

Rocco Mancinelli, John Marshall, Melisa R. White, 1992. Anylyses of Exobiological and Potential Resource Materials in the Martian Soil Advances in Space Research12, (4)111-(4)116.

Verne Oberbeck, Hans Aggarwall, John Marshall, 1992. Impacts, Tillites, and the Breakup of GondwanalandJournal of Geology

John Marshall, Guy Fogleman, Ronald Greeley, Raymond Hixon, David W. Tucker, 1991. Adhesion and Abrasion of Surface Materials in the Venusian Aeolian Environment Journal of Geophysical Research96, 1931-1947.

Verne Oberbeck, John Marshall, Thomas Shen, 1991. Prebiotic Chemistry in Clouds Journal of Molecular Evolution32, 296-303.

Judith Huntington, John Marshall, Deborah Schwartz, 1990. Exobiological Implications of Dust Aggregation in Planetary Atmospheres: An Experiment for the Gas-Grain Simulation Facility Fourth Symposium on Chemical Evolution and the Oribook, 26.

John Marshall, Guy Fogleman, Ronald Greeley, 1989. Cold Welding of Aeolian Materials in the Venusian Environment: Experimental and Theoretical Considerations Lunar and Planetary Science

Deborah Schwartz, Rocco Mancinelli, John Marshall, 1989. Crystal Properties as Bio-markers: A Potential MRSR Experiment Origins of Life19, 501-502.

Deborah Schwartz, John Marshall, 1989. Crystal Properties as Bio-markers: A Potential MRSR ExperimentOrigins of Life19, 501-502.

John Marshall, Ronald Greeley, James B. Pollack, David W. Tucker, 0000. Accretionary Layers on Venusian Surface Rocks Produced by Aeolian Impact LPSCXIX, 726-727.