Mars Rover by dffhrtcv3

VIEWS: 5 PAGES: 32

									            Mars Rover
         Acknowledgements:
              NASA website:-
http://mars.jpl.nasa.gov/mer/
                                                    Objectives
   Overall Mars science strategy to "Follow the Water."
    Understanding the history of water on Mars is important
    to meeting the four science goals of NASA's long-term
    Mars Exploration Program:
       Determine whether Life ever arose on Mars
       Characterize the Climate of Mars
       Characterize the Geology of Mars

       Prepare for Human Exploration



                                                                     shuvra das,
                                                      University of Detroit Mercy
                                              Objectives
    Because scientists cannot go to Mars themselves at this
    point in time, they will have to rely on robot geologists--
    the rovers--to look for signs of past water activity on
    Mars for them.


   To do their job, the rovers will carry a number of science
    instruments that will analyze rocks and soils on the
    Martian surface and perform other important tasks and
    studies.


                                                                 shuvra das,
                                                  University of Detroit Mercy
  Mars-Earth Comparison
                     Mars                        Earth
Distance from sun    142 million miles           93 million miles
Avg orbiting speed   14.5 miles per sec.         18.5 miles per sec.
Diameter             4200 miles                  7926 miles
Tilt of axis         25 degrees                  23.5 degrees
Length of year       687 earth days              365.25 days
Length of day        24 hrs 37 minutes           23 hrs 56 minutes
Gravity              0.375 times that of earth   2.66 times that of mars
Atmosphere           Mostly CO2, some water      N2, O2, Argon, etc.
                     vapor
# of moons           2                           1
Avg. temp.           -81 degrees F               57 degrees F




                                                                      shuvra das,
                                                       University of Detroit Mercy
               shuvra das,
University of Detroit Mercy
Mars Rover: A Mechatronic
System
   These will act as robot geologists on Mars
    Surface
   Robot Parts are similar to a living creature
       Body, Senses, Arm
       Brains
       Nerves
       Health

                                                      shuvra das,
                                       University of Detroit Mercy
The Body
 Strong outer layer that protects the
  computer, electronics and battery
 Responsible for protection and
  temperature
control



                                                   shuvra das,
                                    University of Detroit Mercy
The Body
   The warm electronics         The gold-painted,
    box is closed on the          insulated walls of the
    top.                          rover body controls
   The Rover Equipment           temp. (Mars night
    Deck makes the rover          temp can be -140 F)
    like a convertible car,
    allowing a place for
    the rover mast and
    cameras
                                                             shuvra das,
                                              University of Detroit Mercy
The Neck and Head
                 Called PanCam Mast
                  Assembly
                 Stands 1.4 m above base
                  of wheel
                 Human Geologists
                  perspective
                 Periscope for inside-body
                  equp. (Mini-TES)
                 Better point of view for
                  Pancams and Navcams

                                              shuvra das,
                               University of Detroit Mercy
The Neck and Head
                 A motor turns this 360
                  deg. In horizontal plane
                 A motor points camera 90
                  above and 90 below
                  horizon
                 A motor enables Mini-
                  TES to point 30 above
                  and 50 below horizon
                 During cruise Pancam
                  assembly lays horizontal
                  on equipment deck

                                              shuvra das,
                               University of Detroit Mercy
The rover's "eyes" and other
"senses"
                  Each rover has nine
                   "eyes."
                  Six engineering cameras
                   aid in rover navigation
                  three cameras perform
                   science investigations.
                  4 HAZCAMS
                  2 NAVCAMS
                  2 PANCAMS
                  1 Miro-Imager

                                              shuvra das,
                               University of Detroit Mercy
Brains
   Computer inside the        Special memory to
    Rover Electronics           tolerate extreme
    module (REM)                radiation in space
   Onboard memory of          Safeguard against
    128MB DRAM                  power-off cycles
   3MB of EEPROM
   Roughly equivalent to
    a high end laptop

                                                          shuvra das,
                                           University of Detroit Mercy
Nerves
   The rover carries an Inertial Measurement Unit
    (IMU)
   This provides 3-axis information on its position
   The rover makes precise vertical, horizontal,
    and side-to-side (yaw) movements.
   This device is used in rover navigation to
    support safe traverses and to estimate the
    degree of tilt the rover is experiencing on the
    surface of Mars.

                                                          shuvra das,
                                           University of Detroit Mercy
The rover´s "arm"
   Holds and maneuvers
    instruments
   Has flexibility through
    shoulder, elbow and wrist
    joints
   4 tools
    The Microscopic Imager
    The Mössbauer Spectrometer
    The Alpha Particle X-Ray
      Spectrometer
    The Rock Abrasion Tool
      (RAT)

                                                shuvra das,
                                 University of Detroit Mercy
The rover´s "arm"
   Forearm holds a small
    brush that the adrasion
    tool can spin against for
    cleaning
   30% of the mass comes
    from tools
   To make the titanium arm
    as lightweight as possible
    holes are drilled in places
    to minimize weight

                                                 shuvra das,
                                  University of Detroit Mercy
Protecting the arm
   Upon completion of task the arm stows itself underneath
    the "front porch" of rover body
   The elbow hooks back onto a pin, and the turret has a T-
    bar that slides back into a slotted ramp
   It can withstand shocks of 6 G´s while roving along the
    rocky terrain
   During launch and landing, the arm is restrained by a
    retractable pin restraint, and can withstand even higher
    loads of 42 G´s.


                                                               shuvra das,
                                                University of Detroit Mercy
The rover´s wheels "legs"
   The Mars Exploration Rover has six wheels,
    each with its own individual motor.
   The two front and two rear wheels also have
    individual steering motors (1 each). This
    steering capability allows the vehicle to turn in
    place, a full 360 degrees. The 4-wheel steering
    also allows the rover to swerve and curve,
    making arching turns.

                                                           shuvra das,
                                            University of Detroit Mercy
The rover´s wheels "legs"
   suspension system is a "rocker-bogie"
   "bogie" comes from old railroad systems. is a
    train undercarriage with six wheels that can
    swivel to curve along a track.
   "rocker" comes from the design of the
    differential, which keeps the rover body
    balanced, enabling it to "rock" up or down
    depending on the various positions of the
    multiple wheels.

                                                         shuvra das,
                                          University of Detroit Mercy
The rover´s wheels "legs"
   When one side of the rover goes up, the differential or
    rocker in the rover makes the other side go down to
    even out the weight load on the six wheels.
 The rover is designed to withstand a tilt of 45 degrees in
    any direction without overturning. However, the rover is
    programmed through its "fault protection limits" in its
    hazard avoidance software to avoid exceeding tilts of 30
    degrees during its traverses.



                                                                shuvra das,
                                                 University of Detroit Mercy
Wheels




                        shuvra das,
         University of Detroit Mercy
Rover Speed
   The rover has a top speed on flat hard ground of 5
    centimeters (2 inches) per second.
   To ensure a safe drive, the rover is equipped with
    hazard avoidance software that causes the rover to stop
    and reassess its location every few seconds. So, over
    time, the vehicle achieves an average speed of 1
    centimeter per second.
   The rover is programmed to drive for roughly 10
    seconds, then stop to observe and understand the
    terrain it has driven into for 20 seconds, before moving
    safely onward for another 10 seconds.
                                                               shuvra das,
                                                University of Detroit Mercy
The Rover´s Energy
   The main source of power for each rover comes from a
    multi-panel solar array.
   When fully illuminated, the rover solar arrays generate
    about 140 watts of power for up to four hours per sol (a
    Martian day).
   The rover needs about 100 watts (equivalent to a
    standard light bulb in a home) to drive.
   Includes two rechargeable batteries that provide energy
    for the rover when the sun is not shining, especially at
    night.

                                                                shuvra das,
                                                 University of Detroit Mercy
The Rover´s Energy
   Over time, the batteries will degrade.
   By the end of the 90-sol mission, the capability of the
    solar arrays to generate power will reduce to about 50
    watts due to anticipated dust coverage on the solar
    arrays
   Mars will drift farther from the sun as it continues on its
    yearly elliptical orbit, and because of the distance, the
    sun will not shine as brightly onto the solar arrays.
   Additionally, Mars is tilted on its axis just like Earth is,
    giving Mars seasonal changes. Later in the mission, the
    seasonal changes at the landing site and the lower
    position of the Sun in the sky at noon than in the
    beginning of the mission will mean less energy on the shuvra das,
    solar panels.                                      University of Detroit Mercy
Temperature controls
   night temperatures on Mars can drop to -96º C (-140º F)
   Temp variation during day could be 113C(235F)
   "vital organs" needs to be between -40º C to +40º C
   Several methods are used to control heat loss from rover
     • Preventing heat escape through gold paint
     • Preventing heat escape through insulation called “aerogel"
     • Keeping the rover warm through heaters
     • Making sure the rover is not too hot or cold through thermostats
        and heat switches
•   Making sure the rover doesn't get too hot through the heat rejection
    system

                                                                         shuvra das,
                                                          University of Detroit Mercy
Temperature controls
   The gold paint of rover minimizes radiation loss (like a
    thermos)
   A special layer of light-weight insulation called “solid-
    silica-aerogel” is used to block off heat loss.
   The rover will be heated by heat from electronics,
    radioisotope heater units and electricity from battery
    (~1W from each)
   Thermostats used to turn-off and-on heaters to control
    temp


                                                                  shuvra das,
                                                   University of Detroit Mercy
The Rover’s Antenna (voice and
ears)
   The rover has both a low-gain and high-gain antenna.
    They are located on the equipment deck (its "back").

   The low-gain antenna is "omni-directional." The antenna
    transmits radio waves at a low rate to the Deep Space
    Network (DSN) antennas on Earth. The high-gain
    antenna can send a "beam" of information in a specific
    direction and it is steerable.
   They can also communicate with other spacecraft
    orbiting Mars, utilizing the 2001 Mars Odyssey and Mars
    Global Surveyor
                                                               shuvra das,
                                                University of Detroit Mercy
               shuvra das,
University of Detroit Mercy
Test Tracks: A Race against Time

   An obstacle course dubbed the "rock gauntlet"
    challenged test wheels to scale everything from small
    rocks to concrete blocks.
   Engineers also conducted airbag interaction tests in
    which they drove the wheels into the deflated airbags
    again and again until they had enough information to
    proceed with wheel design changes.
   The mobility team and the assembly test and launch
    operations team gathered to conduct ramp tests with the
    flight rovers to make sure the rover brains were
    communicating effectively with its legs and wheels.

                                                              shuvra das,
                                               University of Detroit Mercy
Airbags




                         shuvra das,
          University of Detroit Mercy
Machinists




                            shuvra das,
             University of Detroit Mercy
First Steps
   The rover lands on Mars in January, 2004.
    Once the lander petals open and the rover "wakes up," it may
    take up to five days for it to drive off the lander.
   After every command given to the rover, engineers will wait to
    make sure everything is working properly before they
    proceed.
   Due to the delay in sending and receiving signals from Earth
    to Mars and back, it takes 20 minutes to see the difference
    When it is confirmed that all systems are working, they will
    tackle the decision of which direction to go. Rocks or deflated
    airbags will determine the route to leave the lander.
   GOAL: Not to break speed records. But to do important and
    interesting science
                                                                    shuvra das,
                                                     University of Detroit Mercy
What’s been happening?
   http://marsrovers.jpl.nasa.gov/spotlight/




                                                      shuvra das,
                                       University of Detroit Mercy

								
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