Mars Science and Rover Operations

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Mars Science and Rover Operations
Michael H. Sims, Ph.D. Center for Mars
Exploration Computational Sciences Division NASA
Ames October 10, 2002
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Introduction

• Science objectives are coupled with physical and
  engineering constraints leading to planetary
  rover operations

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Topics of Discussion

• How missions occur
• 3 missions one past (Pathfinder), one present
  (MER) one possible future mission (Long Days
  Drive)
• Players and contraints on rover planetary surface
  operations

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1997 Mars Pathfinder Sojourner

• Imaging
• Other instruments
• Sol (24 1/2 hour day) schedule
• Unusual mission
• Science team
• Science operations

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MER 2003 Dual Rover Mission

• Imaging
• Other instruments
• Sol (24 1/2 hour day) schedule
• Science team
• Science operations

http//athena.cornell.edu/the_mission/index.html
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MER Rover
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MER Daily Ops Schedule
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How are missions chosen to go to Mars?

• Main Mars Exploration Program
• Mars Scout Missions
• Human Missions
• Players Congress/OMB, NASA HQ, science
  community, design teams, engineering development
  teams, operations teams outreach teams.

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Current US Mars Surface Exploration Plans

• Mars Science Exploration Program
• Main program(Orbiters, MER, Mars Smart Lander
  2009)
• Mars Scout Program (2007)
• Human Exploration of Mars
• ?

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A Long Days Drive on Mars

• Mars Scout Proposal
• Here used an example of the interplay between
  science, engineering and operations

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Long Days Drive Mars Scout Proposal
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Long Days Drive (LDD) Proposal to 2007 Mars
Scout Program

• LDD proposes to
• Explore the Northern Polar Region of Mars
• Explore during the Northern Summer (continuous
  sunlight)
• Explore the polar region with a robot
• Focus on the climate and geologic history in the
  polar layered deposits
• Although LDD would not carrying any specific life
  detection instruments, LDD will look for
  signatures of life in what is possibly the most
  promising surface region on Mars for the
  existence of life.

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Example of Polar Layered TerrainMOC image
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Close up of Example PLD
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Northern Polar PLD distribution and landing
ellipse sizes
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MEPAG - Official voice of the Mars science
community

• The LDD mission will further the following MEPAG
  goals
• I. Goal - Life Determine whether life ever arose
  on Mars.
• (Determine if life exists on Mars at present)
• (Determine if life existed on Mars in the past)
• Assess the possible presence of prebiotic
  organics
• II. Goal - Climate
• (Characterize Mars' present climate and climate
  processes)
• Characterize Mars' past climate and past climate
  processes
• III. Goal - Geology
• Determine the geological process(es) that
  resulted in the formation of the martian crust
  and surface
• IV. Goal - Prepare for human exploration
• Acquire appropriate martian environmental data
• Conduct in-situ engineering and science
  demonstrations

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MEPAG Goal 1 - LIFE

• Determine whether life ever arose on Mars.
• Determine if life exists on Mars at present
  (search for organics with elemental analysis for
  C/N and Raman spectroscopy look for evidence of
  temperature and pressures consistent with
  meltwater formation)
• Determine if life existed on Mars in the past
  (search for remnant organics preserved in the
  polar ice).
• Assess the possible presence of prebiotic
  organics (search for organics preserved in the
  polar ice).

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MEPAG Goal 2 - Climate

• Characterize Mars' present climate and climate
  processes (measure the surface texture of the
  polar layers and recent dust and ice
  accumulation)
• Characterize Mars' past climate and past climate
  processes (measure the layering of the PLD over
  10-100 M-yr of Martian climate history -- many
  obliquity cycles)

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MEPAG Goal 3 - Geology

• Determine the geological process(es) that
  resulted in the formation of the Martian crust
  and surface (measure elemental composition and
  trace volatiles in the dust/ice mixture in PLD
  showing variations that may relate to geological
  processes that influence the dust, such as
  volcanic ash, acid weather)

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MEPAG Goal 4 - Prepare for human exploration

• Acquire appropriate Martian environmental data
  (determine the ice content of PLD validating the
  Odyssey results and giving higher resolution
  local data)
• Conduct in-situ engineering and science
  demonstrations (demonstrate long distance solar
  rover functioning and polar operations)

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Specific MEPAG goals are directly relevant to the
LDD mission

• Map the 3-d distribution of ice in all its
  forms...temporal (seasonal) changes in
  near-surface water budgets (IA1)
• Conduct in-situ searches for subsurface water
  (IA2a)
• Map biogenic elements (C,H,N,O,P and S) (IA4a)
• Determine locations of sedimentary deposits
  formed by ancient and recent surface and
  subsurface hydrological process ... ground truth
  of mineralogy and geochemistry for remote sensing
  (IB1)
• Perform in situ measurements (laser Raman)(IB1c)
• Determine timing and duration of hydrologic
  activities (IB3)
• Characterize history of stratigraphic records of
  climate change at the polar layered deposits, the
  residual ice caps. (IIB2)

• Sense 100s of sites in the visible at 15 cm/pixel
  or better to characterize fine scale layers in
  the layered deposits (IIB2a)
• Perform in situ, local exploration of layered
  deposits (IIB2c)
• Perform in situ measurements, including traverses
  across sedimentary units of different ages, for
  several sites to determine physical properties of
  rocks and fines and their chemistry, mineralogy,
  lithology and petrology. (IIIA2c)
• measure engineering properties of the Martian
  surface (IVA6)
• Conduct in situ engineering science
  demonstrations (IVB)

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Science Questions

• A.What is the nature and record of the northern
  polar layered deposits?
• Determine structure of PLD. ice/ icedust
  mixtures
• Find well exposed layering
• Imaging of sedimentary mixing
• B.What is the nature and the distribution of
  ground ice in polar region?
• Seek and examine exposed snow, ice, crystals
• Determine surface structural properties by wheel
  digging
• Near surface hydrogen GPR search for ice
  associated with dielectic boundaries
• C. What is the nature of polar terrains?
• Image and spectra of wheel trench
• Survey depth of overlying slag
• Seek exposed outcrops
• Texture and compressibility of surface
• Evaluate large scale topological and geological
  formations possible dunes, sand sheets, mounds,
  ice penitents, eskers, etc.
• D. What is the mineralogy and geochemistry of the
  polar region?
• Large scale basalt andesite? Small scale
  variability? Northern erg of mafic material?
• E. Are organics present in the polar region?
• Organics would be preserved by ice and dust -
  allow inventory of impact delivered organics
• Possible past subsurface liquid water

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Proposed measurements across the PLD

• Ice to dust ratio in the PLD
• Layering in the PLD to 1 mm thickness
• Trace elemental composition of the dust particles
  in the PLD
• Organic content of the PLD at a sensitivity level
  of 1 ppm by mass.
• Content of ice in the upper 100 m of the PLD

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Science to instrument mapping

• Geomorphology and mineralogy
• Cameras, spectral instruments
• Water
• remote spectral instruments
• Simple, opportunistic instrumentation
• microphone

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Example of Pre-EDL Operations
Prepare for EDL
Turn on B-side CDH Switch to Semaphores Pressur
ize and Fill Prop System
Initiate Slew to Entry Attitude
Complete Slew to Entry Attitude
Final Star Camera Update
Jettison Cruise Stage
Entry (accel 0.03 g)
UHF TELECOM During EDL
g -14.3 deg
V
5 min
1 min
1 min
10 min
8 min
Nominal Duration
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Example of Terminal Descent Phases
Altitude above Surface
Velocity
Lower Lander
750 m
Inflate Airbags
Nominal VV 43 m/s /- 15 VH /- 20
m/s Design-to VV 50 m/s VH /- 25 m/s
Release Subsonic Chute
500 m
Perform Tip-up manuever on Throttled Thrusters
Initiate Deceleration Profile
375 m
Ignite Fixed thrusters
Constant Velocity
Nominal VV 1 m/s VH /- 0.5 m/s
5 m
UHF TELECOM During EDL
Nominal VV 1 m/s VH 0.5 m/s Design-to
VV 4 m/s VH 2 m/s
Land
0 m
Release Bridle at Touchdown Control Descent
Stage Fly-away via Tether Release Tether
Deflate airbags Self-right Stand-up Egress

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LDDs Operation Stages