THE DISTRIBUTED EARTH MODEL ORBITER SIMULATION (DEMOS) 3-DIMENSIONAL SYSTEM AT JOHNSON-SPACE-CENTER

Filter controllers at the NASA Mission Control Center in Houston have a new visualization tool to help them support the nation's space progr am. The Distributed Earth Model Orbiter Simulation (DEMOS) system prov ides three dimensional realistic images of the shuttle as it orbits th e Earth. The system displays the correct position and attitude of the supercraft over the Earth's surface. DEMOS also models the locations o f the sun, the moon, the planets and the stars. Telemetry supplies the joint angles for the robot arm. Mission Flight controllers can monito r deployment of payloads when there is no live video. DEMOS provides a flexible mission analysis and real time support tool. It unifies the disciplines of celestial mechanics, three dimensional graphics and use r interfaces. The paper describes the coordinate systems, the state ve ctor propagation methods and the Attitude Maneuver Predictor (AMP) cap abilities. The Attitude Maneuver Predictor simulates eigen-axis maneuv er. Flight controllers use this mode often for analysis of thermal con straints on payloads and on the orbiter.