Shuttle Stability and Control during the Orbiter Repair Maneuver

The Orbiter Repair Maneuver (ORM) is a challenging on-orbit operation designed to use the Shuttle robotic arm to rotate and present the underside of the Space Shuttle to the Space Station, hence allowing access and repair to Shuttle thermal protection system damage. The operation calls for the Shuttle and Space Station to be mated via (and only) the Shuttle arm, introducing extremely low frequency structural dynamics and hence proposes a significant control/structure dynamic interaction problem. This paper provides an overview of the Shuttle on-orbit control system design for ORM. Given the low frequency dynamics, saturation limits of the arm robotic joints, and close proximity of the two space vehicles, the Orbiter Repair Maneuver represents one of the most challenging on-orbit operations for Shuttle control design to date.