9. Trafficability
2005: IVA-6
2010: 4
Priority: Low
Investigation: Assess landing
site-related hazards, including those related both to safe landing and safe
operations within the possible area to be accessed by possible elements of a
human mission.
Artist's rendering of
a rover encountering rocks while traversing the Martian surface. Image
credit: NASA/JPL-Caltech
Trafficability refers to the ability of a
vehicle to traverse any given terrain. At a landing site especially, it is
important to make sure that there are no big rocks or other potential hazards
that would adversely affect operations. Landing sites are selected based on
finding an acceptable balance between terrain hazards and scientific interest,
since sometimes the most potentially interesting sites are also the most
dangerous. Hazards are categorized into two groups: those related to landing
safely, and those related to movements along the Martian surface.
This image shows the
large rut created by the Opportunity rover as it extracted itself from the
section of Meridiani dubbed "Purgatory Dune." Image credit:
NASA/JPL-Caltech/Cornell (Jim Bell)
The main factors relevant to landing
safety are: size and concentration of surface rocks, terrain slopes, and
concentration of dust. When traversing a surface, rock fields, terrain slopes,
and soft soil (see above picture) are hazards to be considered. Measurements
from previous rover expeditions as well as orbital imaging can help reduce risks
involved by allowing scientists to identify obstacles, dust, and soft material
in potential landing areas. This knowledge would enable effective and efficient
expedition planning.
Click on the expanding links below to see the 2005 and 2010
versions of the investigation.
2005 Version of Investigation (old version)
2010 Version of Investigation (current version)
Many investigations have led to better understandings of
trafficability on the Martian surface. The movements of the Mars Exploration
Rovers (MER) Spirit and Opportunity in particular have contributed greatly to
the field of terramechanics – rover wheel torques, ruts, and trenches have been
analyzed to determine internal friction angles and provide rolling statistics.
HiRISE, TES, and THEMIS data are also used to map surfaces and determine
properties and potential hazards that the rovers may encounter.
Currently, there is a lot of research going on in the field of
terramechanics (study of interaction of wheels with various surfaces), mostly
focused on discrete element modeling and dynamic modeling packages. These
programs use known information about the properties of soil to create realistic
terrains to simulate rover drive paths as accurately as possible. The results
of this new research would allow scientists and engineers to identify risky
areas along a rover’s driving route and alter its path to avoid slipping or
sinking into the ground.
Although the operation of the MER rovers has significantly
improved the general understanding of the issues related to trafficability on
the martian surface, an assessement would need to be made on a site-by-site
basis given the range of mobile elements associated with a human mission.
The following list of references includes sources that touch on
all the above topics.
- Arvidson, R. E., R. C. Anderson, P. Bartlett, J. F. Bell, D. Blaney, P. R.
Christensen, P. Chu, L. Crumpler, K. Davis, B. L. Ehlmann, R. Fergason, M. P.
Golombek, S. Gorevan, J. A. Grant, R. Greeley, E. A. Guinness, A. F.C.
Haldemann, K. Herkenhoff, J. Johnson, G. Landis, R. Li, R. Lindemann, H.
McSween, D. W. Ming, T. Myrick, L. Richter, F. P. Seelos, S. W. Squyres, R. J.
Sullivan, A. Wang, and J. Wilson (2004). “Localization and Physical Properties
Experiments Conducted by Opportunity at Meridiani Planum.”Science, v.
305, p. 821-824.
- Arvidson, R. E., R. C. Anderson, P. Bartlett, J. F. Bell, P. R. Christensen,
P. Chu, K. Davis, B. L. Ehlmann, M. P. Golombek, S. Gorevan, E. A. Guinness, A.
F. C. Haldemann, K. Herkenhoff, J. Johnson, G. Landis, R. Li, R. Lindemann, H.
McSween, D. W. Ming, T. Myrick, L. Richter, F. P. Seelos, S. W. Squyres, R. J.
Sullivan, A. Wang, and J. Wilson (2004). “Localization and Physical Properties
Experiments Conducted by Spirit at Gusev Crater.”Science, v. 305, p. 821-824.
- Arvidson, et al. (2008). “Spirit Mars Rover Mission to the Columbia Hills,
Gusev Crater: Mission overview and selected results from the Cumberland Ridge
Home Plate.” Journal of Geophysical Research, v. 113, E12S33, doi:
10.1029/2008JE003183.
- Arvidson, et al. (2010). “Spirit Mars Rover Mission: Overview and Selected
Results from the Northern Home Plate Winter Haven to the Side of Scamander
Crater.” Journal of Geophysical Research—Planets, 2010JE003625, submitted.
- Bibring, Jean-Pierre and the OMEGA Team (2006). “Aqueous Mars History
derived from OMEGA/Mars Express mineralogical results.” European Planetary
Science Congress 2006.
- Bibring, J.-P., R. E. Arvidson, A. Gendrin, B. Gondet, Y. Langevin, S. Le
Mouelic, N. Mangold, R. V. Morris, J. F. Mustard, F. Poulet, C. Quantin, and C.
Sotin (2007). “Coupled Ferric Oxides and Sulfates on the Martian Surface.”
Science, v. 317, p. 1206-1210.
- Hopkins, et al. (2008) “Discrete element modeling of a rover wheel in
granular material under the influence of Earth, Mars, and Lunar gravity.”
Proceedings of the ASCE Earth and Space Conference.
- Kirk, R. L., E. Howington-Kraus, M. R. Rosiek, J. A. Anderson, B. A.
Archinal, K. J. Becker, D. A. Cook, D. M. Galuszka, P. E. Geissler, T. M. Hare,
I. M. Holmberg, L. P. Keszthelyi, B. L. Redding, W. A. Delamere, D. Gallagher,
J. D. Chapel, E. M. Eliason, R. King, and A. S. McEwan (2008). “Ultrahigh
resolution topographic mapping of Mars with MRO HiRISE stereo images:
Meter-scale slopes of candidate Phoenix landing sites.” Journal of Geophysical
Research, v. 113, E00A24, doi: 10.1029/2007JE003000.
- Moore, H.J., D. B. Bickler, J. A. Crisp, H. J. Eisen, J. A. Gensler, A. F.
C. Haldemann, J. R. Matijevic, L.K. Reid, and F. Pavlics (1999). “Soil-like
Deposits observed by Sojourner, the Pathfinder Rover.” Journal of Geophysical
Research, v. 104, p. 8729-8746.
- Scharringhausen, et al. (2009). “A Wheel-Soil Interaction Model for
Planetary Applications.” 11th European Regional Conference of the International
Society for Terrain-Vehicle Systems.
- Richter, L. et al. (2006). “A Predictive Wheel-Soil Interaction Model for
Planetary Rovers Validated in Testbeds and Against MER Mars Rover Performance
Data.” 10th European Conference of the International Society for Terrain-Vehicle
Systems.
- Schmidt, M. E., W. H. Farrand, J. R. Johnson, C. Schröder, J. A. Hurowitz,
T. J. McCoy, S. W. Ruff, R. E. Arvidson, D. J. Des Matais, K. W. Lewis, D. W.
Ming, S. W. Squyres, and P. A. de Souza (2009). “Spectral, mineralogical, and
geochemical variations across Home Plate, Gusev Crater, Mars indicate high and
low temperature alteration.” Earth and Planetary Science Letters, v. 281, p.
258-266.
- Squyres, S. W., et al. (2004) “The Spirit Rover’s Athena Science
Investigation at Gusev Crater, Mars.” Science, v. 305, p. 794 – 799.
- Squyres, S. W., et al. (2004). “The Opportunity Rover’s Athena Science
Investigation at Meridiani Planum, Mars.”Science, v. 306, p. 1698 – 1703.
- Squyres, S. W., et al (2004). “Exploration of Victoria Crater by the Mars
Rover Opportunity.” Science, v. 324, p. 1058-1061.
- Sullivan, R., R. Anderson, J. Biesiadecki, T. Bond, and H. Stewart (2010).
“Cohesions, friction angles, and other physical properties of martian regolith
from MER wheel trenches and wheel scuffs.” Journal of Geophysical
Research--Planets, 2010JE003625, submitted.
- Yingst, R. A., L. Crumpler, W. H. Farrand, R. Li, N. A. Cabrol, and L. D.
Neakrase (2008). “Morphology and texture of particles along the Spirit rover
traverse from sol 450 to sol 745.” Journal of Geophysical Research, vol. 113,
E12S41, doi: 10.1029/2008JE003179.