Spirit Rover: Rear Wheel Trouble Continues

Dec 10, 2009
An artist's concept portrays a NASA Mars Exploration Rover on the surface of Mars. Image credit: NASA/JPL/Cornell University

(PhysOrg.com) -- Results of diagnostic tests on Spirit's right-rear wheel on Sol 2109 (Dec. 8, 2009) continue to indicate a troubled wheel, which may leave the rover with only four operable wheels.

The Sol 2109 plan included a check of the grind motor of Spirit's rock abrasion tool (RAT) because it shares the same motor controller as the right-rear wheel. It also included rotor resistance tests on the right-rear motor at three temperatures using opposite voltage polarity from earlier tests, backward and forward commanded motion of the right-rear wheel, and a check of rotor resistance on all other operating wheels. The RAT motor appears okay, although a more exhaustive test will be tried later.

The right-rear wheel rotor resistance tests continue to show very elevated resistance, although not as high as in previous tests, and exhibiting a curious voltage-dependent effect. No motion of the right-rear wheel occurred during the backward commanded motion. The forward motion was not executed since the initial backward motion did not occur. The rotor resistances on all the other operating wheels are nominal.

The plan ahead, still being developed, will likely include more resistance tests, an attempt to apply higher voltage to the right-rear wheel to see if any movement will occur, and a check of the right-front wheel to confirm its status and to see if it may offer insight into the right-rear wheel's condition. Further ahead, steering tests will be considered to explore an external jam as a possible explanation.

Concurrent with this, the project is exploring whether any meaningful rover motion would be possible with only four operable wheels. Spirit lost the use of its right front in 2006.

Because of the current rover tilt, the environmental conditions and accumulation on the , Spirit is at risk of inadequate power for surviving through the next southern Mars winter, which reaches solstice on May 13, 2009. Even if extrication is not possible, some limited rover motion may be able to improve rover tilt and increase the chance of winter survival.

Provided by JPL/NASA (news : web)

Explore further: SpaceX ship leaves ISS for Earth loaded with lab results

add to favorites email to friend print save as pdf

Related Stories

Further Tests Designed for Rover's Right-Rear Wheel

Dec 08, 2009

(PhysOrg.com) -- A series of diagnostic tests on Spirit's right-rear wheel on sols 2104 and 2105 (Dec. 3 and 4) investigated stalls that occurred on Sol 2099 (Nov. 28) and earlier. The rover team cannot draw ...

NASA Investigates Problems With Spirit

Oct 06, 2004

Engineers on NASA's Mars Exploration Rover team are investigating possible causes and remedies for a problem affecting the steering on Spirit. The relay for steering actuators on Spirit's right-front and lef ...

Spirit Completes Fourth Mile On Mars

Feb 14, 2006

Spirit is healthy and continues to make progress toward "Home Plate" after driving more than 150 meters (492 feet), taking images, making atmospheric observations, and analyzing geology.

Recommended for you

Hinode satellite captures X-ray footage of solar eclipse

Oct 24, 2014

The moon passed between the Earth and the sun on Thursday, Oct. 23. While avid stargazers in North America looked up to watch the spectacle, the best vantage point was several hundred miles above the North ...

User comments : 0