This is my hardware - the SRB Thrust Vector Control (TVC) Subsystem. I was one of three Subsystem Managers on TVC. It's a hydrazine powered fuel system, which drives a hydraulic system to gimbal the Nozzle during flight. Remember the 'roll program' when the vehicle rolls onto its back just after launch?...that was the most visible indication that my hardware was working correctly. The SRBs provided 80% of thrust vector control during the first two minutes of ascent. The SSMEs provided the other 20%.