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KENNEDY SPACE CENTER, FLA. - Workers in the Vertical Processing Facility maneuver the replacement Reaction Wheel Actuator for the Hubble Space Telescope into position on the Large Orbital Protective Enclosure (LOPE), which is contained in the Multi-Use Lightweight Equipment (MULE) for flight. Part of Hubble's Pointing Control System, the actuators receiving information from sensors and physically adjust Hubble's position and orientation so that Hubble can view the required celestial bodies. The reaction wheels work by rotating a large flywheel up to 3000 rpm or braking it to exchange momentum with the spacecraft which will make Hubble turn. The RWA is part of the payload on mission STS-109, the Hubble Servicing Mission, scheduled to launch Feb. 28, 2002