Real-time berthing simulator for space station and space shuttle

Abstract

A real-time pilot-in-the-loop berthing simulator is being developed at NASA/JSC (National Aeronauticsand Space Administration/Lyndon B. Johnson Space Center) to conduct a berthing study and to measure forces during contact conditions of the actual docking hardware mechanisms or ports for the Space Station Freedom (SSF) and the Space Shuttle (shuttle). In berthing, the docking ports of the SSF and the shuttle are brought together using the shuttle Remote Manipulator System (RMS) to control the relative motion of the vehicles. The berthing simulator consists ofa dynamic docking test system (DDTS), computer system, simulator software, and RMS workstation. During the real-time berthing simulation, the docking ports of the SSFand the shuttle, mounted on a six- degree-of-freedom (6 DOF) table of the DDTS and a fixed platform above the table, are brought together by a computer simulated 6 DOF shuttle RMS. Load cells are used on the fixed platform to measure forces during contact conditions of the docking ports. The point of resolution (POR) of the shuttle RMS is selected as the SSF docking port. The dynamic initialization, developed to synchronize the POR with the 6 DOF table, the data structure, and the real-time sequence of the berthing simulation are briefly described in this paper. The berthing test can be extended for any two orbiting vehicles, using a simulated RMS.