Timken a supplier of highly engineered bearings and alloy steels has supplied super precision bearings that are currently being used on both of NASA's Mars Rovers, Spirit and Opportunity.
Starsys Research, one of the subcontractors that worked with NASA on the Rover project, fit the bearings onto each of the Rovers. In all, Starsys placed Timken(R) ball bearings on 13 different designs, including the deployment and operational gearboxes on wheel transmissions, solar array panel drives, rock abrasion tool drives, and all four actuators that deploy, rotate and maneuver the pan cameras, or camera mast.
Spirit landed on Mars January 4. Opportunity landed on the other side of the planet 21 days later, January 25. "The decision to use Timken bearings for the mechanized parts on the Rovers was based on the thin section series and the higher radial capability of the Timken bearings versus other manufacturers," said Jon Evans, director of engineering for Starsys. "The bearing envelopes fit our designs nicely for the high-speed bearings used in all the planet gears on every transmission on the Rover. Also, previous space success with the thin section bearings and the smaller high-speed bearings helped contribute to Starsys's decision to go with Timken as the preferred vendor." "Many of the ball bearings used are of the angular contact thin-section variety," Galehouse said. "These types of bearings offer a great amount of rigidity, which is important when positioning an instrument for an analysis or steadying a camera."
The Timken bearings provided a lower mass to help reduce weight; a decreased contact angle on some applications provided a higher radial capability which provides greater mobility; and a decreased radial play for improved radial run out at the rotating outputs to allow for accurate steering and pointing.
Timken also ran numerous tests to make sure the bearings would be able to operate in the harsh environment of space. Most of the testing was analytical in nature and involved looking at different load cases to make sure that the bearings are not over-stressed. Starsys also performed its own tests to be sure the bearings could operate under a certain torque level so the motors are not overworked.
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