Space Shuttle Inspection and Repair Boom Sensor System for Return to Flight

摘要

As part of a comprehensive effort to safely return the Space Shuttle fleet to active flight duty following the Columbia accident, the National Aeronautics and Space Administration (NASA) has undertaken the development of a fixed boom sensor system to extend the reach of the Shuttle's robotic arm. This system, referred to as the Orbiter Boom Sensor System (OBSS), is required to perform on-orbit inspection of the Orbiter and provide a potential growth path for future stand-alone repair capability. This paper describes the challenges that were encountered in developing a system for performing on-orbit inspection and repair and how they have been or are being addressed in the design of the OBSS. A general discussion of both hardware and operational constraints that shaped the design of the OBSS is also detailed. It was determined that a 49 ft boom was sufficient to reach all surfaces of the orbiter within the operating range of the sensors. The large centre of mass offset from the tip of the Shuttle's robotic arm as well as the length of the boom posed arm control stability concerns that were determined to be acceptable through linear and non-linear control system analysis. To carry out Extra Vehicular Activity (EVA) Thermal Protection System repair work from the tip of the boom it was determined that additional worksite stabilization is required. As such, a near term International Space Station based repair strategy was developed while methods for repair stabilization are investigated. By exploiting existing resources and robotic operational capabilities, the OBSS forms an integral part of the Shuttle return to flight strategy.