. 24/7 Space News .
Spirit Team Facing Critical Decision As Martian Winter Approaches

Spirit has slipped in difficult terrain as the right front wheel has churned up the Martian soil. Image credit: NASA/JPL-Caltech.
  • Desktop available 1024 x 768
  • by Phil Berardelli
    SpaceDaily US Editor
    Washington DC (SPX) Apr 05, 2006
    Mars rover mission controllers announced Tuesday what had been suspecting for several days: Spirit has permanently lost its right-front wheel. The disclosure came exactly two years and three months after the rover landed in a formation called Gusev Crater, near the Martian equator - long after its planned 90-day mission had expired.

    Because of the mechanical failure, controllers at NASA's Jet Propulsion Laboratory said they are having a difficult time getting the rover to move toward a north-facing slope to survive the cold and dark Martian winter, which is still more than a month away.

    Spirit must position its solar panels northward in winter to collect enough solar energy to operate while the Sun lays low along the red planet's horizon.

    "Essentially, it's a race against time," controllers said in a statement. Even though the period of minimum sunshine in the Martian winter is more than 100 days away, Spirit already receives only enough power to drive for about an hour a Martian day, or sol, on flat ground.

    "The climate is changing rapidly, and we have to put our primary emphasis on keeping the rover safe," said Steve Squyres, the principal investigator for both rovers. "Assuring survival has to take priority over science until we've got the vehicle on safer ground."

    The problem is the route Spirit must take to reach that safer ground seems more and more difficult, because of the softness of the soil. That dragging front wheel has made progress painfully slow, and could paralyze the rover, perhaps permanently.

    So the team has devised what might turn out to be a last-ditch strategy: They have reversed Spirit's course, driving it back downhill for a while before moving laterally to a different slope that should be easier to climb and will provide the maximum available sunlight for the rover's solar panels.

    So far, the results are mixed. Spirit drove about 10 meters (33 feet) in one day after the wheel stopped working, but then lost traction on following days because of wheel slippage in the loose soil. A further problem has been caused by the rover's suspension system, which keeps all six wheels in contact with the ground.

    "Engineers designed the rovers so well that Spirit's weight remains evenly distributed on all six wheels," said Al Herrera, a computer sequencing specialist for Columbus Technologies and Services Inc. who oversees uplink commands to the rover. "That keeps the rovers balanced so they don't tip or roll backward."

    It also prevents relief against the dragging right-front wheel disrupting Spirit's progress, however, because it continues to maintain equal weight on it.

    Spirit's wheel difficulty emerged March 13, on sol 779, when the motor suddenly began drawing more electrical current than normal, then stopped drawing current altogether while the rover was turning to adjust the orientation of its communications antenna.

    Engineers determined that the fault occurred in a drive actuator, one of 10 motors that operate the six wheels. Following tests in the duplicate rover facility at JPL, engineers determined the motor could no longer be used.

    Spirit's problem is long overdue. The rover and its twin, Opportunity, have lasted more than two years, or nearly nine times longer than their mission design. Spirit's wheel motors have rotated more than 13 million times.

    Still, controllers are trying to maintain their optimism. "It is too early to tell how serious this is," said John Callas, the rover's project manager. "The nature of the terrain is a dominant factor."

    Related Links
    Mars at JPL
    MERs at Cornell



    Memory Foam Mattress Review
    Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
    XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


    Spirit Team Gives Up On Front Wheel
    Pasadena CA (SPX) Apr 2, 2006
    NASA mission controllers have determined that Spirit's right-front wheel is permanently faulty, so they have decided to stop trying to use the wheel's drive motor - and from now on the rover will run on five wheels instead of six.







  • Former Astronaut Details Mars Trip Hazards
  • Software Pioneer Signs To Become Fifth Space Tourist
  • Top Microsoft Programmer Signs Up For Space Mission
  • NASA Announces New Communications Policy Of Openness

  • Spirit Team Facing Critical Decision As Martian Winter Approaches
  • MRO Begins Adjusting Orbit And Collecting Data
  • Spirit Team Gives Up On Front Wheel
  • NASA Selects Teachers To Aid In Mars Phoenix Mission

  • Ariane 5 Receives New Upper Stage
  • Sea Launch Set For April Mission From Pacific Floating Pad
  • Next Ariane 5 Launch Taking Shape
  • ATK Rocket Motors Power Successful Launch of Pegasus XL

  • Envisat Makes Direct Measurements Of Ocean Surface Velocities
  • NASA Scientist Claims Warmer Ocean Waters Reducing Ice Worldwide
  • Space Tool Aids Fight For Clean Drinking Water
  • FluWrap: Deadly Strain Divides

  • New Horizons Payload Gets High Marks on Early Tests
  • "Zero G and I Feel Fine"
  • To Pluto And Beyond
  • New Horizons Update: 'Boulder' and 'Baltimore'

  • Hubble Spies Nearby Dust Clouds In Milky Way
  • Visible Universe Trapped In A Dark Matter Web
  • Jodrell Bank Astronomers Spy Giant Alcohol Cloud
  • Is Europa A Bottle Blonde In Disguise

  • SMART-1 Tracks Crater Lichtenberg And Young Lunar Basalts
  • Quantum Technique Can Foil Hackers
  • Noah's Ark On The Moon
  • X PRIZE Foundation And The $2M Lunar Lander Challenge

  • GLONASS To Be Made Available For Civilian Use In 2006
  • New York School Districts Install GPS Tracking Systems in Buses
  • Glonass System To Open For Russian Consumers In 2007
  • TomTom Unveils a Range of New and Updated Content And Services

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement