Concepts and Approaches for Mars Exploration 6058.pdf

ON THE GROUND: TRAINING FOR PLANETARY EXPLORATION. Patricia Wood Dickerson1 and William R. Muehlberger2, 1Lockheed Martin, NASA - Johnson Space Center, C 23, Houston, TX 77058, [email protected]..gov. 2Department of Geological Sciences, University of , Austin, TX 78712, wmuehl@ mail.utexas.edu.

Scientific questions about martian origins exploration, a field geophysical exercise was and evolution will be addressed and resources as- launched. Astronaut teams acquired roughly 16 sessed through both human and robotic explora- km of gravity data in the course of a planetary tion — essential and complementary strategies. exploration simulation conducted in northern New Satellite imaging, robotic reconnaissance, sample Mexico. The gravimetric survey was the first examination, and base-map construction will pre- cede the arrival of humans at any exploration site. Field exploration is learned in the field. Geological field surveys, petrological/ geochemical laboratory experience, polar geology and other polar field programs, oceanographic voyages, pa- leobiological field programs, scientific drilling projects, volcanological field work, and eventually, multiweek stays aboard the Space Station or at a lunar outpost could all provide needed experience. All would combine real scientific work for the crew with realistic support from an integrated ground team. Beginning with the Apollo program, as- tronaut training has included geological field in- struction in northern . Field observa- tions and discussions are reinforced by means of photographs taken by of Earth and the Moon, to provide an orbital perspective. Partici- pants are exposed to excellent examples of geo- logical features that illustrate not only terrestrial concepts and processes, but also analogous ones Figure 1. John Young, lunar field explorer (with on other planetary bodies. gravimeter), and James Reilly, geologist astronaut Mars analogues include ancient and mod- (right), assess the relevance of the simulation. Bill ern sand dune fields, river-cut canyons, ground- Muehlberger (center) instructs as Duane Ross, Leo water sapping features, and volcanoes of all sizes Eyharts, and Lee Archambault (left to right) ob- with lavas of various chemical compositions. Lu- serve. nar analogues include basaltic lava plains and a one-to-one scale model of Hadley Rille, the Apollo phase of a geophysical assessment of the ground- 15 landing site. In addition, the region furnishes water resources around Taos, an arid region of examples of active faults, glacially cut valleys, rapid population growth; it was executed to help marine fossils (now at elevations more than 8,000 delineate buried structures that influence ground- feet above sea level), a major rift valley and its water flow and accumulation in the valley. internal complications, and continental to marine The known geology and hydrology of the sedimentary sequences. site and the probable magnitude of the buried In 1999 NASA began field training in sur- faults suggested that gravity surveying, a tech- face science operations. To initiate instruction in nique attempted on the Moon, would provide geophysical methods appropriate for planetary Concepts and Approaches for Mars Exploration 6058.pdf

ASTRONAUT FIELD TRAINING: P. W. Dickerson and W. R. Muehlberger

needed data on the large buried structures. The The 31 participants learned a technique contrast in density between bedrock (Precambrian with direct relevance for lunar and planetary ex- metamorphic rock and massive Carboniferous ploration, from data acquisition through interpre- limestone) versus unconsolidated valley sediment tation and planning of further work. They also would permit definition of faults that juxtapose the took a substantive step toward revitalizing the ex- two. Gravity surveying is passive — that is, no ploration culture within and beyond NASA. energy must be put into the ground in order to ac- quire data, and the small portable instruments permitted walking traverses. Both are critical con- siderations in planetary field exploration. Each field crew was briefed on the geo- logic setting, on the scientific objectives, and on gravimetric surveying. Then, in the field, the sta- tions where gravity readings would be taken were located by means of laser rangefinder, newly flown aerial photographs, and detailed topographic maps. Field station locations and gravity-meter readings were radioed to "Mars base" and the data were processed in real time by geophysics gradu- ate students from New Mexico Institute of Tech- nology. The next morning, each crew viewed the profile that they had acquired, participated in its interpretation, saw the data entered on the Bureau map, and helped select the location for the next traverse.

Figure 2. Complete Bouguer gravity profile ac- quired during the field exercise. The inflection at station 5 coincides with a major buried range-front fault that was delineated in the course of the exer- cise. That at station -10 marks the probable west- ern edge of the fault block.