Characterization of the martian surface deposits by the Mars Pathfinder rover, Sojourner

Science

Volumn 278, Issue 5344, 1997, Pages 1765-1768

  Matijevic, J R ^a   Crisp, J ^a   Bickler, D B ^a   Banes, R S ^a   Cooper, B K ^a   Eisen, H J ^a   Gensler, J ^a   Haldemann, A ^a   Hartman, F ^a   Jewett, K A ^a   Matthies, L H ^a   Laubach, S L ^a   Mishkin, A H ^a   Morrison, J C ^a   Nguyen, T T ^a   Sirota, A R ^a   Stone, H W ^a   Stride, S ^a   Sword, L F ^a   Tarsala, J A ^a   Thompson, A D ^a   Wallace, M T ^a   Welch, R ^a   Wellman, E ^a   Wilcox, B H ^a   Ferguson, D ^b   Jenkins, P ^b   Kolecki, J ^b   Landis, G A ^b   Wilt, D ^b   Moore, H J ^c   Pavlics, F ^d   more..

^a CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

^b NASA GLENN RESEARCH CENTER   (United States)

^c U S GEOLOGICAL SURVEY   (United States)

^d NONE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

FERRIC OXIDE; FERROUS ION;

MARS; MARTIAN ROCK; PATHFINDER MISSION; PLANETARY SURFACE;

ASTRONOMY; CAMERA; CLAY; DUST; GEOLOGY; IMAGE ANALYSIS; MATERIAL STATE; PRIORITY JOURNAL; REVIEW; ROCK; SEDIMENT; SPACE FLIGHT;

FLIGHT EXPERIMENT; LONG DURATION; MARS PATHFINDER PROJECT; UNMANNED;

EXTRATERRESTRIAL ENVIRONMENT; MARS; MINERALS; WATER;

MARS;

EMMELICHTHYS STRUHSAKERI;

EID: 1842378043     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.278.5344.1765     Document Type: Review

References (17)

1. The Rover Team, J. Geophys. Res. 102, 3989 (1997). This reference includes the rover characteristics.
2. M. P. Golombek et al., ibid., p. 3967.
3. M. P. Golombek et al., Science 278, 1743 (1997).
4. P. H. Smith et al., ibid., p. 1758.
5. T. A. Mutch et al., J. Geophys. Res. 82, 4452 (1977); A. B. Binder et al., ibid., p. 4439.
6. T. A. Mutch et al., J. Geophys. Res. 82, 4452 (1977); A. B. Binder et al., ibid., p. 4439.
7. 2 + 0.2922T + 6.2084). No-load currents vary for each wheel. We solved for the friction angle and cohesion in several ways. In an initial analysis, rough graphical estimates of tan (α) for the sol 3 left front and sol 4 right rear wheel data were made, and the two equations were solved to yield φ near 38.4° and c near 0.28 kPa. In subsequent analyses, ratios of concurrent shear stresses and normal stresses were obtained (Fig. 1l) and averaged to yield a value of tan (α); each ratio was used concurrently with the shear stresses and normal stresses to solve for c with the assumption that φ equals the Θ value estimated from the images; the average of these c values is taken as one estimate of c. Linear least squares fits to the concurrent shear and normal stresses provide another estimate of the friction angle and cohesion (Fig. 1l). Cohesions are negative for 5 of 16 least squares fits to concurrent pairs of shear and normal stresses, but it should also be realized that the cohesions are small and difficult to estimate. The use of the rover wheel as a shear test device was validated in laboratory tests with various soil-like materials.
8. K. Terzaghi, Theoretical Soil Mechanics (Wiley, New York, 1948).
9. R. Rieder et al., Science 278, 1771 (1997).
10. Diameters of particles (in millimeters) are as follows: cobbles 256 to 64; pebbles, 64 to 4; granules, 4 to 2; sand, 2 to 0.062; silt, 0.062 to 0.005; and clay, 0.005 and less. Dust is composed of clay-and siltsized particles.
11. J. K. Mitchell et al., Geochim. Cosmochim. Acta 3, 3235 (1972).
12. H. J. Moore and B. M. Jakosky, Icarus 81, 164 (1989); R. E. Arvidson et al., Rev. Geophys. 27, 39 (1989); H. J. Moore et al., J. Geophys. Res. 87, 10043 (1982).
13. H. J. Moore and B. M. Jakosky, Icarus 81, 164 (1989); R. E. Arvidson et al., Rev. Geophys. 27, 39 (1989); H. J. Moore et al., J. Geophys. Res. 87, 10043 (1982).
14. H. J. Moore and B. M. Jakosky, Icarus 81, 164 (1989); R. E. Arvidson et al., Rev. Geophys. 27, 39 (1989); H. J. Moore et al., J. Geophys. Res. 87, 10043 (1982).
15. G. R. Olhoeft, in Sand and Dust on Mars, R. Greeley and R. M. Haberle, Ed. (NASA Conference Paper CP-10074, NASA, Greenbelt, MD, 1991), pp. 44-46.
16. J. B. Pollack et al., J. Geophys. Res. 84, 2929 (1979).
17. We thank M. Hirschbein, D. Lavery, A. Runkle, D. Alexander, and S. Arriola. Most of the work was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.