spacetoday.net: NASA finds problems with shuttle rudder gears

Posted: Tue, Mar 23, 2004, 10:45 AM ET (1545 GMT)
STS-112 landing (NASA/KSC)

NASA engineers have discovered that gears within actuators that control the rudder speed brakes on space shuttle Discovery suffered a number of problems, including one gear that had been originally installed backwards, a potentially disastrous problem that was never previously noticed in the more than 20 years since the orbiter was built. The parts, used in the four hydraulic actuators that open and close the speed brake, were inspected after corrosion was found in one actuator in Discovery last year. In one case a gear was installed backwards. While the actuators never experienced problems during Discovery's 29 flights, shuttle managers said Monday that if exposed to unusual stresses, such as during an emergency landing, the brake could jam open or closed, a situation that officials said would have closed "loss of the vehicle, loss of the crew". Engineers are now inspecting the speed brakes in Atlantis and Endeavour, and NASA has ordered new sets of actuators from the manufacturer, Hamilton Sundstrand. Officials said they are also looking into why the problem was not caught earlier. Managers said they don't believe this problem should delay the planned March 2005 return to flight, but earlier officials had cautioned that this problem could push back the next shuttle launch until late 2005.