Research Laboratory Space Vehicles Research Articles

Commanding and controlling satellite clusters

Many organizations, including the National Aeronautics and Space Administration (NASA) and the US Department of Defense, want to use constellations or fleets of autonomous spacecraft working together to accomplish complex mission objectives. At the Air Force Research Laboratory's Space Vehicles Directorate, we are developing architectures for commanding and controlling a cluster of cooperating satellites through autonomous software development for the TechSat 21 program. Large clusters of satellites flying in formation must have some level of onboard autonomy in order to: fly within specified tolerance levels; avoid collisions; address fault detection, isolation, and resolution (FDIR); share knowledge; and plan and schedule activities. Commanding and controlling a large cluster of satellites can be very burdensome for ground operators as well. The article describes efforts to address these issues through the technology development for TechSat 21.

Advanced smart structures flight experiments for precision spacecraft

This paper presents an overview as well as data from four smart structures flight experiments directed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate in Albuquerque, New Mexico. The Middeck Active Control Experiment $ ̄ Flight II (MACE II) is a space shuttle flight experiment designed to investigate modeling and control issues for achieving high precision pointing and vibration control of future spacecraft. The Advanced Controls Technology Experiment (ACTEX-I) is an experiment that has demonstrated active vibration suppression using smart composite structures with embedded piezoelectric sensors and actuators. The Satellite Ultraquiet Isolation Technology Experiment (SUITE) is an isolation platform that uses active piezoelectric actuators as well as damped mechanical flexures to achieve hybrid passive/active isolation. The Vibration Isolation, Suppression, and Steering Experiment (VISS) is another isolation platform that uses viscous dampers in conjunction with electromagnetic voice coil actuators to achieve isolation as well as a steering capability for an infra-red telescope.