At the heart of Peacekeeper’s guidance and navigation system is the Advanced Inertial Reference Sphere (AIRS) with its highly advanced Inertial Measurement Unit (IMU). A “beryllium ball” weighing 450 pounds, the AIRS assemblage was designed for exquisite accuracy and, in keeping with that, great resistance to stress and temperature changes.
Unlike Minuteman III’s gimbal-mounted, metal-touching-metal gyroscopes and accelerometers, those of Peacekeeper’s AIRS are snugly suspended in a highly viscous fluorocarbon liquid, which gives them free play but shields them against environmental fluctuations and keeps them from being bumped around. AIRS’s beryllium housing is also virtually impervious to the drastic changes of temperature that a ballistic missile undergoes in flight.I wonder what kind of fluorocarbon was used? (are they viscous?)