(U) The goals for this subthrust are: 1) improve pointing accuracy of precision space sensors by three orders of magnitude through the application of advanced, integrated active and passive structural controls; 2) decrease On-Orbit Disturbances by 90%; 3) decrease Pyrotechnic shock by 99%; 4) reduce the vibro-acoustic loads experienced by satellites during launch by one order of magnitude; 5) extend cryocooler lifetimes to five years; 6) reduce cryocooler power consumption by 20%; and 7) reduce cryocooler system mass by 40%.
(U) Controls: The Controls area implements system-level structural control to dramatically reduce satellite disturbances on precision sensors and optimize target resolution. Precision pointing is of utmost importance for satellite communications lasers and other directed communications media. Vibration suppression technologies decrease component settling times to shorten the time an imaging or communications system is out of operation due to station keeping maneuvers or other large satellite disturbances. Also falling in this area are vibration isolation systems, which prevent vibration transmission to critical components from the satellite bus. The precision optical platform isolates sensors from satellite disturbances to enable dramatically improved resolution without costly upgrades to satellite subsystems.
(U) Lightweight Flexible Solar Array: A previous program identified spacecraft com-ponents that have potential for reducing cost, weight, power, etc., or for improving performance and reliability. As the size of satellites decreases, the contribution of the power subsystem to the overall satellite weight increases significantly. This program will address mod-ifica-tions to the solar array that will significantly reduce weight, develop low-shock release and deployment systems, and increase packaging efficiency. Specifically, the program will: (1) explore the use of flexible thin-film photovoltaics such as Copper Indium diSelenide (CIS) and Amorphous Silicon (A-Si); (2) replace pyrotechnic releases and motor-driven deployment mechanisms with low-shock, lightweight Shape Memory Alloy (SMA)-powered deployment and tracking sys-tems designed for low stowage volume and self-compensation for thermal expansion of the array; (3) use concurrent battery development programs and integrate the batteries with the flexible array stowage tube; (4) use non-dissipative power source controller, possibly using concurrent embedded multi-chip module concepts; and (5) eliminate charge controller box and use command and data handling software as the battery charge controller. Bus component technologies such as this have strong dual use applications with dramatic payoff for DoD and commercial satellites.
(U) ACTEX Flight Support: This program provides data reduction and anal-ysis for the Advanced Controls Experiment (ACTEX)-I and -II flight experiments to demonstrate active vibration suppression using piezoceramic control elements embedded in advanced composite struts.
(U) Flywheels for Energy/Momentum Storage: The Energy/Momentum Storage program explores the possibility of integrating power and attitude control subsystems. Lightweight com-posite flywheels suspended on magnetic bearings will be arranged in a geometrical configuration that will allow bias momentum attitude control while simultaneously storing energy in the spinning wheels. By eliminating the need for electrochemical energy storage (batteries), significant weight savings should be realized.
(U) Deployable Precision Structures for Imaging Systems: The size of current space-based imaging systems employing monolithic reflectors is limited by the diameter of current launch vehicle payload shrouds. On-orbit deployment of reflectors would enable this limitation to be circumvented. This program investigates recent advances in lightweight optics and structures, metrology, precision hinges and latches, deployment schemes, and shape control to develop and build a complete deployable/restow-able system for ground demonstration. Initial target is infrared capability with the ultimate goal of near optical.
|Space Vehicles Technology||Space Vehicles Technology|
|TECHNOLOGY- RDT&E||SPACE TECHNOLOGY|
(U) National Security Space Road Map Team, NSSA, Open Phone: (703) 808-6040, DSN 898-6040.
(U) 15 July 1997
(U) Road Map Production Date: 23 June 2001