Assembly and servicing of a large telescope at the International Space Station

This paper explores the major issues, concerns, limiting conditions and requirements that must be satisfied if a large (10´s of meters diameter) infrared telescope astronomy mission is to be successfully assembled and boosted to its operational orbit around the Sun-Earth Lagrange 2 (L2) point. Techniques for returning the satellite to the International Space Station (ISS) for servicing are also presented. The trade-off between astronaut alone, robot alone and an astronaut supervised robot assembly is discussed. The conclusion is that the ISS robots would do the actual assembly work with the supervision of an astronaut during critical phases of the assembly. The robot would use a preprogrammed sequence that had been thoroughly checked out in a neutral buoyancy water tank on the ground. The astronauts would closely monitor the assembly from inside the ISS, as it progressed. They would be aided in this with television systems and independent collision avoidance software that would stop the robot´s motion before a collision could occur. The primary benefit of using astronauts in this way is that they can respond to and correct any unanticipated actions.