James Webb Space Telescope

NMDB is pleased to have played a role in helping the JWST pass its preliminary design review (PDR) and achieve confirmation. The JWST is a large, infrared-optimized space telescope designed to launch aboard an Ariane 5 launcher and to operate at the Sun-Earth/Moon L2 libration point. The flight dynamics team has played important roles in a variety of analyses. By combining automation techniques with advance targeting methods, our team was able to generate and analyze nearly 4000 JWST launch trajectories over the course of a few weeks, subsequently sifting through these to find the viable launch opportunities in 2013. We were instrumental in using Monte Carlo methods to analyze launch vehicle performance and dispersions that led to changes in the propellant allocation required to meet a launch window that reduced the risk of schedule slip.

In addition, we continued to champion 'flight dynamics as a subsystem' approach to our support to mission systems engineering. In the process we've provided valuable input to attitude control, sun-shield, propulsion, communications, command & data handling, and thermal subsystems. Working as an integral part of the Momentum Management Working Group (MMWG), our team developed a Kalman filter approach for orbit determination that accounts for the frequent stationkeeping and momentum unload maneuvers of the observatory and which models the 'sail-force' generated by solar radiation pressure on the sun-shield. These analyses have contributed to the design of the attitude control system and sun-shield and have figured into the propellant budget and thruster placement. By generating a project wide detailed reference trajectory that provides a high fidelity representation of the position and velocity of JWST from launch through 11 years of operations at L2, we've helped to eliminate disconnects in communications and commissioning requirements reducing risk and potentially reducing costs. In addition, our analysis of the powered flight trajectory and corresponding attitude is contributing to understanding the thermal loads during flight aboard the Ariane