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Mars Exploration

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Mars Basics. Most Earth-like planet (climate, geology) ... Mars may have similar conditions ... Discovered Mariner Valley, Tharsis volcanoes ... – PowerPoint PPT presentation

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Title: Mars Exploration


1
Mars Exploration
  • Trey Smith
  • November 9, 1999

2
Overview
  • Mars Background
  • Exploration Missions
  • Focus on rovers
  • CMU space activities
  • Blue-sky plans for Mars

65 minutes, about 8 slides each
3
Mars Basics
  • Most Earth-like planet (climate, geology)
  • 6 millibar pressure of mostly CO2 at sea level
  • Day length 24 h 37 m
  • Inclination similar to Earths (Earth-like
    seasons)
  • Orbit period 1 year 10 months

4
Geological Map
5
Mars Geology
  • Northern hemisphere
  • Mostly plains young, low altitude features
  • Some are clearly volcanic, others attributed to
    sedimentation and action of sub-surface ice
  • High points are volcanic plateaus of Tharsis
    (4000 km wide, 10 km high) and Elysium (2000 km
    wide, 5 km high)

6
Mars Geology
  • Southern hemisphere
  • Highlands similar to those on the moon, but
    craters are more eroded, and there are channels
    evidence of running water.
  • Just south of the equator, the Valles Marineris
    (400 km long, up to 600 km wide and 7 km deep)
    dwarfs the Grand Canyon
  • Impact basins Argyre (1800 km) and Hellas (900
    km)
  • Poleward of 30 degrees south, heavier erosion
    seems to indicate large quantities of ice

7
Mars Geology
  • Chaos terrain
  • Jumble of broken blocks
  • Leads into large dry valleys, interpreted as
    floodplains
  • Linear features at ends lake shorelines?
  • Lack mature drainage system features
  • Floodplains were target of Viking 1 and
    Pathfinder
  • Groundwater under extreme artesian pressure?
  • Broken dams on large lakes?
  • Other areas have small, more mature drainage
    basins
  • Morphology of impact craters suggests ice
    everywhere at depths of a few hundred meters,
    closer to surface at poles

8
Climate History
  • Erosion completely wiped out small craters and
    degraded others process stopped about 3.5 Gyr
    ago
  • Liquid water requires high temperatures. CO2
    insufficient. CH4? NH3?
  • Original water inventory estimated at 0.5 km over
    entire surface
  • Isotopic studies suggest that up to 99 of
    Martian nitrogen, substantial CO2 and H2O went
    through nonthermal escape
  • Some features younger than 3.5 Gyr (Elysium
    basin) have been attributed to shoreline wave
    action from a Northern ocean, but MGS found no
    such evidence
  • In a few recent periods of high obliquity,
    conditions may have been warmer and wetter

9
Evidence for Life
  • Requirements for Earth life water, certain
    organics, and an energy source
  • Likely environments
  • Groundwater energy source geothermal
  • Ancient surface water
  • Earth extremophile experts find bacteria
    everywhere they look on bare rocks in
    Antarctica, in Yellowstone hot springs, hundreds
    of meters down oil wells.
  • Earth life evolved less than 2 Gyrs into its 4.6
    Gyr history, almost as soon as conditions made it
    possible
  • Minority opinion says that Earth life first
    evolved deep underground using geothermal energy.
    Mars may have similar conditions
  • Panspermia theory life evolved once and spread
    through meteorite exchange.
  • Mars cooled sooner, could have had life first

10
ALH 48001 (August 1996)
  • Classified as a SNC meteorite based on isotopic
    ratio of trapped gases
  • Three lines of evidence suggest life
  • PAHs
  • Biominerals
  • Shapes like nanobacteria
  • Findings widely criticized
  • Formation temperatures too high
  • No known nanobacteria on Earth
  • PAHs apparently resulted from post-impact
    contamination
  • Nonetheless, gave NASA its current Mars mandate

11
Mars Missions
  • Pre-Viking space-race days
  • Viking and biology studies
  • Eighties doldrums
  • Current Mars mania

12
Pre-Viking Missions
  • Mariner 4 (July 1965)
  • Five Soviet fly-by attempts failed, 1960-62
  • Sister ship Mariner 3 failed on launch
  • 22 pictures, 1 of the Martian surface
  • Mariners 6 7 (July, August 1969)
  • 400 pictures of southern hemisphere and equator
  • Studies of polar caps, moons, climate
  • Mariner 9 (May 1971)
  • First US spacecraft to orbit another planet
  • Discovered Mariner Valley, Tharsis volcanoes
  • Mapped 100 of the surface and took high-res
    pictures of Marss moons

13
Pre-Viking Missions
  • Mars 2 3 (May 1971)
  • Two orbiter/lander pairs
  • Mars 3 First successful soft landing, but failed
    20 seconds later
  • Both orbiters continued returning surface and
    atmosphere images into 1972
  • Mars 4, 5, 6, 7 (July, August 1973)
  • 4 5 were orbiters, 6 7 were landers
  • Orbiters scout landing sites in advance
  • Only Mars 5 meets mission objectives

14
Viking 1 2 (1975)
  • Two orbiter/lander pairs
  • Viking 1 First US landing on Mars (July 20,
    1976)
  • First took orbital images at 150-300 m resolution
    to select a landing site
  • When the pictures came back, the ground crew
    thought the sky color was wrong and recalibrated.

15
Viking Biology Experiments
  • Pyrolitic Release (PR)
  • Incubate soil in CO2/CO mixture tagged with C-14,
    pyrolize at 650 C collect and combust any
    organic compounds and search for tagged CO2/CO
  • Labeled Release (LR)
  • Incubate soil with C-14 tagged nutrient soup,
    look for evolved gases
  • Gas exchange (GEX)
  • Measures production and uptake of CO2, N2, CH4,
    H2, and O2 using gas chromatograph

16
Viking Biology
  • Gilbert Levin, one of the investigators for the
    LR experiment, still believes life was found by
    Viking

17
After Viking
  • Phobos 1 2 (July 1988)
  • Largely European instruments
  • US contributed DSN tracking
  • Carried surface hoppers for Phobos
  • Phobos 1 lost in transit, Phobos 2 lost just
    before Phobos rendezvous
  • Mars Observer (September 1992)
  • High-budget orbiter
  • Lost contact just before orbit insertion
  • Gamma ray spectrometer and other instruments
    flew/will fly on later missions
  • Mars 96 (November 1996)
  • European and US support
  • Orbiter, 2 landers, 2 penetrators
  • Crashed on Earth days after launch

18
Better, Faster, Cheaper
  • After Mars Observer, NASA space science effort is
    demoralized.
  • Two new (on-going) series of missions are
    initiated
  • New Millenium missions are test-beds for advanced
    technology
  • Discovery missions have more conservative science
    objectives, this time with a cost cap
  • ALH 48001 gives NASA a new mandate for Mars.
    Missions are now planned at every launch window
    until 2005

19
Modern Mars Missions
  • Mars Pathfinder
  • Mars Global Surveyor (November 1996)
  • Orbiter now returning highest resolution surface
    images to date (3 meters)
  • Also carries thermal emission spectrometer
  • Due to failed solar panel actuator aerobraking
    took a year longer than expected. Primary
    mapping didnt begin until March 1999
  • Nozomi (July 1998)
  • First Japanese interplanetary probe
  • Orbiter to study atmosphere, plasma, dust,
    possible magnetic field
  • Due to trajectory errors at Earth fly-by, Nozomi
    wont reach Mars until late 2003

20
Modern Mars Missions
  • Mars Surveyor 98
  • Mars Climate Orbiter (Jan 1999)
  • Intended to study Martian atmosphere
  • Carried DS2 microprobes
  • Impacted Mars due to software error in insertion
    burn September 23
  • Mars Polar Lander (January 1999)
  • Surface imager, robot arm, thermal and evolved
    gas analyzer
  • Landing site is at the retreating edge of the ice
    cap
  • Will land December 3

21
Reaching the Moon Lunokhod
  • Lunokhods 1 2 (November 1970, January 1973)
    were the first planetary rovers
  • Teleoperated with echo time around 5 seconds
  • Weighed in at 840 kg
  • Operated for 10 km (5 months) and 37 km (4
    months)
  • Engineering accomplishments
  • Teleoperated control at lunar distances
  • Toilet-bowl thermal strategy
  • Drilling from a moving platform
  • Solved antenna pointing issue (?)

22
Reaching the Moon Apollo
  • The Lunar Rover was first used on Apollo 15 (July
    1971)
  • It weighed 462 lbs. empty
  • Loaded, it could move 10-12 kph for about 50 km
    before exhausting its batteries
  • Engineering accomplishments
  • Wheels and suspension successfully adapted to
    regolith each wheel driven independently
  • Guidance used an internal gyro and odometry to
    estimate relative positions, good to about 100
    meters

23
To Mars Pathfinder
  • Launched Dec 1996, landed July 4, 1997. Operated
    for
  • Engineering challenges
  • 40 minute echo time, once-a-day operations
  • Extremely limited power
  • Rocky terrain
  • Cold conditions
  • Mobility sensors
  • Stereo cameras dense stereo
  • Laser light striper

24
To Mars Pathfinder
  • Information integration on the ground
  • Registration of 3D meshes to form global terrain
    map
  • Virtual Dashboard allowed operators to
    visualize command results
  • Operated through command sequence from ground,
    but could adjust for obstacles
  • Not only successful, but also extremely popular
  • Mars 2001
  • Orbiter carries GRS for elemental composition
  • Lander will demonstrate ISRU propellant
    production with view to human missions
  • Sojourner duplicate Marie Curie

25
Mars Autonomy Athena
  • 2003 and 2005 missions will form the two legs of
    a sample return (land in the same place)
  • FIDO (Rocky 8) rover
  • Sojourner-style steering and suspension
  • 1 meter scale
  • Stereo pairs pointing in all directions
  • Can elevate a mast to get longer view
  • Goal 100 meter traverse in one day of operations
  • Cant reliably see the intervening terrain
    demands autonomy

26
Mars Autonomy at CMU
  • Three year NASA program started last fall
  • Studying software needed for 100 m scale traverse
    with a FIDO-like rover
  • Two-prong approach
  • Local obstacle avoidance reactive controller to
    dodge rocks
  • Global path planning slower planning of optimal
    path to goal using current information

27
Mars Autonomy at CMU
  • First reduce stereo data to grid of goodness and
    certainty
  • Local obstacle avoidance
  • For each steering arc, integrate goodness and
    certainty of cells along the arc to get a score
  • Global path planning
  • Uses D (dynamic A) algorithm
  • Scores a steering arc based on the path cost from
    the end of an arc to the goal
  • Optimistically assumes uncertain areas are
    traversable
  • Both modules vote/veto to determine executed
    command

28
Space Initiative at CMU RI
  • Icebreaker Discovery proposal to be submitted in
    March (for launch 2003)
  • Lunar Prospector has detected hydrogen
    concentrations at the lunar poles
  • The best explanation is ice in permanently
    shadowed regions like craters
  • Icebreaker would travel in and out of permadark,
    verifying the presence of ice and assaying
    quantity, distribution

29
Space Initiative at CMU RI
  • Sky Worker
  • Nine month NASA grant from space solar power
    program (demonstration in April 2000)
  • Implementing a scaled-down prototype assembly,
    inspection and maintenance robot
  • The prototype has 3 arms, walks hand over hand

30
Space Initiative at CMU RI
  • Robotic Antarctic Meteorite Search
  • 3 year NASA program, ends spring 2000
  • Attempts to autonomously find the next ALH 48001.
    Final field test in December
  • Visually identifies rocks and classifies them as
    meteor/non-meteor with a magnetometer
  • Demonstrates teleoperation, endurance, autonomy
    capabilities needed for Icebreaker
  • Uses local obstacle avoidance module similar to
    that of Mars Autonomy

31
CMU Astrophysics Projects
  • Sloan Digital Sky Survey study
  • Looking for patterns in huge deep-sky image
    databases
  • Viper Telescope
  • Assembled in August in Antarctica
  • 2 meter IR telescope resolves 0.1 arc-second
    features in cosmic background
  • Also measures velocities of nearby galaxies
    relative to background, providing independent
    measure of H0

32
Blue-Sky Plans for Mars
  • NASA has no long-term plan for human exploration.
  • From the HEDS web site Currently, NASA's efforts
    in human space flight are focused on the Space
    Shuttle and International Space Station Programs.
    Both of these programs are important to the
    development of a capability for human exploration
    beyond low-Earth orbit.

33
1997 Reference Mission
  • NASA bowed to pressure from engineers both within
    and outside its ranks to create a mission design
    which cut costs and extended mission times using
    ISRU
  • Based largely on Robert Zubrins Mars Direct
  • 4 launch mission
  • Unfueled Mars Ascent Vehicle
  • Earth Return Vehicle
  • Nuclear reactor powered propellant plant
  • Two years later, with all the pre-launched
    components verified, astronauts take a fast (6
    month) transfer orbit to Mars

34
1997 Reference Mission
  • Propellant plant uses water and Mars atmosphere
    2H20 CO2 - CH4 O2
  • Obstacles to development
  • No full-scale CH4/O2 thrusters
  • A new HLLV is needed to launch each component
  • Long-term effects of reduced gravity, radiation
    still not well understood (though probably not as
    dangerous as NASA would have us think)
  • Overall, this is a very big mission and not on
    NASAs political agenda right now

35
Cheap Launches
  • The raw energy costs of launch from a planetary
    surface (Earth included) are on the order of per pound
  • Heres why it currently costs so much more
  • Rocket equation you need to carry your launch
    vehicle and fuel, which wastes energy
  • With expendables or high-maintenance reusable
    hardware, the bulk of the cost is in the launch
    vehicle assembly and maintenance
  • Since each vehicle has never flown before, the
    risks are higher, leading to high insurance costs

36
Mars Beanstalk
  • How do you get around all of these problems?
  • Dont launch the launcher
  • On the moon you can use a mass driver
  • On Mars, you use a beanstalk
  • Part is above the geosynchronous orbit level,
    balances the part below. Zero energy cost to
    stay in orbit
  • Now launch is just riding an elevator
  • An Earth beanstalk would require exotic materials
    like buckytubes to handle the enormous tension
  • Lower Mars gravity allows current construction
    technology to suffice.
  • In the future, Mars may be a supply station for
    asteroid colonies

37
Terraforming
  • Making other planets more Earth-like
  • Mars is probably the best candidate
  • Bring cometary water (greenhouse gas)
  • Darken the surface with engineered lichens
  • First habitable areas are deep in impact basins
  • Engineered plants can survive unprotected well
    before humans
  • Mars land area approximately equal to Earths
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