When Spirit and Opportunity descended to the Martian surface, seals from Eclipse Engineering were on board. One set of seals protects the asmith drive assembly from the very fine dust particulate found on the Martian surface. These seals allow the camera mast to rotate 360 degrees.

A second set of seals is located on the pivot point just below the camera to allow the camera to pivot up and down on the horizon. These seals also protect the drive mechanism from the Martian dust.

For more information on Spirit and Opportunity, please visit the following sites (links open new window):

NASA/JPL Mars Exploration Rover Mission
NASA/JPL Mars Exploration Rover Fact Sheet
Athena Mars Exploration Rovers