Orbiter Boom Sensor System and Shuttle Return to Flight: Operations Analyses

Abstract

The Orbiter Boom Sensor System (OBSS) consists of an Inspection Boom Assembly (IBA) with two grapple fixtures for Shuttle Remote Manipulator System (SRMS) and Space Station Remote Manipulator System (SSRMS) grappling, and two sensors (LCS and LDRI) at the boom tip. With the SSRMS or SRMS, the OBSS will be used to survey the Shuttle Thermal Protection System (TPS) and provide a platform for TPS repair if necessary. As the prime contractor for the IBA development, MDA has performed analyses and dynamics simulations to ensure the stability of the SRMS and the OBSS during both SRMS maneuvering and EVA repair operations. Motion of the boom tip was analyzed using a flexible boom model in order to verify sensor performance during survey maneuvers. Loads in the SRMS were also evaluated for both OBSS maneuvers with sensors only and with EVA crew to ensure arm loads remained within safe limits. The motion and loads analysis results were used in part by NASA to help design a 3-DOF platform on air bearings to estimate the loads that an EVA astronaut working off the IBA can apply during typical TPS repair and inspection activities. Simulations were also performed using the Contact Dynamics Toolkit developed by MDA to determine the conditions for successful berthing of the IBA to the Shuttle cargo bay. The results supported the development of an IBA berthing procedure. This paper gives an overview of the analyses performed by MDA, summarizes the findings, and discusses the importance of the issues that were analyzed.