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Gullies on Mars. Mars is the fourth planet from the Sun


Gullies on Mars. Mars is the fourth planet from the Sun, referred as the red planet ... Mars rovers have excavated on the surface and collected samples to study ... – PowerPoint PPT presentation

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Title: Gullies on Mars. Mars is the fourth planet from the Sun

Designing Optical Probe for Regolith Analysis
  • Presented by
  • Obadiah Kegege
  • Advisor Dr. Larry Roe, PE
  • Arkansas Center for Space
  • and Planetary Science
  • University of Arkansas
  • July 2007

  • Introduction
  • Approach
  • Experimental Equipment
  • Preliminary Results
  • Summary and Conclusion

  • Mars is the fourth planet from the Sun, referred
    as the red planet
  • Martian atmosphere is composed primarily of
    carbon dioxide with small amounts of other gases
  • The surface temperatures range from -140
    C (-220 F) to 20 C (68 F)
  • Evidence of features resembling gullies,
    riverbeds, and erosions suggest that water or
    some fluid existed on the surface
  • Mars rovers have excavated on the surface and
    collected samples to study regolith - disturbs
    the sedimentary layering which hinders
    exploration and full information extraction
  • This work focuses on designing an optimum system
    for sampling Martian regolith - explore Mars
    without disturbing sedimentary layering.

Channel/riverbed on Mars
Gullies on Mars
  • First, we experimentally investigate the force
    required to insert different dimensions of
    sampling spikes into regolith
  • Next, use the optimum dimensions and design the
    shaft/penetrator with linear array of near-IR
    illuminators within a spectral range of 0.5 to 5
  • Real-time mineralogical and chemical profiling as
    a function of depth for undisturbed sediments.
  • This proposed system shall be applicable to any
    surface that has regolith or icy properties
    including Moon and asteroids.

Mars rover (Figure obtained from 1 )
Probe to be pushed below the surface by rovers
with minimum force
Overview of simple probe
  • The regolith resistance to probe
    penetration can be expressed as
  • where

Total force acting on the probe (tip sleeve)
Probe surface area (tip sleeve )
Experimental Equipment
  • We have two measurement setups
  • constant velocity system
  • constant force system

Regolith Two different types of regolith have
been used in these experiments JSC Mars-1
feldspar, Ti-magnetite, with minor olivine,
pyroxene and glass JSC Mars-2 45 clay, 45
basalt, 10 iron oxide
Constant velocity penetration test
Constant force penetration test
Experimental Equipment
  • To create relationship between regolith strength
    and depth
  • (1) Velocity Mode
  • Electric actuator pushes the probe down at
    certain speed to a designated depth and stops
  • At each depth level, the load cell will read the
    regolith strength (penetration force)
  • (2) Constant Force Mode
  • Pneumatic actuator pushes the probe down at
    certain constant force until balanced by the
    resistance strength from the regolith.
  • The LVDT will measure the penetrating depth
  • Computer program will measure the time between
    depth intervals

Preliminary Results Constant Velocity
  • It takes 210 N to insert a 19.05 mm cylindrical
    spike to 152 mm into JSC Mars-1
  • 79 N to insert a 12.70 mm cylindrical spike into
    JSC Mars-1
  • 6 N removing 19.05 mm spike
  • 3 N removing 12.70 mm spike
  • It takes about 1/10 of the force applied in JSC
    Mars-1 to insert the same spikes into JSC Mars-2.

Preliminary Results Constant Velocity
  • 19.05 mm diameter spike
  • 19 degrees tip angle 313N
  • 12 degrees tip angle 130N
  • 12.70 mm diameter spike
  • 19 degrees tip angle 145N
  • 12 degrees tip angle 123N
  • Reducing the spike tip angle reduces the
    penetration force for both 19.05 mm and 12.70 mm

Preliminary Results - Constant Force
JSC Mars-1 Data
Spirit/Opportunity rover on NASA's Mars mission
weigh 1800 N (397 lb)
JSC Mars-2 Data
Summary and Conclusion
  • Preliminary penetration force experiments show
    that regolith resistance is dependent on regolith
  • Possible to characterize the layering of
    undisturbed regolith by measured strength at
    different depths
  • The mechanical penetration of the probe will
    characterize regolith strength versus depth, and
    the near IR illuminators (under design by R.
    Pilgrim) would obtain mineralogical composition
    at each depth.
  • The ultimate goal is to design and build a
    simple, low cost, light weight, low power
    regolith sampling probe

Future Work
  • Collaboration and experiments using the simulated
    Martian environmental chamber to facilitate the
    development of a real-time autonomous regolith
    sampling sensor system.
  • Acknowledgements
  • I would like to acknowledge support from Space
    Center grant and faculties in the Arkansas Center
    for Space and Planetary Sciences

  • Rick Ulrich, Derek Sears, Matt Leftwich, Larry
    Roe, Vincent Chevrier, Walter Graupner, Fiber
    Optic Spectral Array on a Regolith Probe for
    Surface and Sub-Surface Mineralogical Profiling
    Optical Probe for Regolith Analysis, Arkansas
    Center for Space Planetary Sciences, University
    of Arkansas, June 2006
  • Peter M. Cao, Ernest L. Hall, Soil sampling
    sensor system on a mobile robot, Proceedings of
    SPIE, Intelligent Robots and Computer Vision XXI
    Algorithms, Techniques, and Active Vision, pp.
    304-310, October 2003
  • Jeffrey E. Herrick, Tim L. Jones, "A dynamic
    cone penetrometer for measuring soil penetration
    resistance", Soil Science Society of America
    Journal 661320-1324 , 2002
  • Bradley D.A, Seward D.W., Developing real-time
    autonomous excavation-the LUCIE story,
    Proceedings of the 34th IEEE Conference on
    Decision and Control, 1995
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