AFRL COMPLETES 10-YEAR DEPLOYABLE OPTICAL TELESCOPE PROGRAM

  • Published
  • By Plans and Programs Directorate
  • AFRL/XP
AFRL scientists completed their final task of phasing multiple large mirror segments for the laboratory's Deployable Optical Telescope (DOT) system. The DOT ground demonstration enables space-based imaging apertures larger than launch vehicle fairing sizes through multiple-segment telescope phasing.
The AFRL Ultralightweight Imaging Technologies Experiment (UltraLITE) program, initiated in 1995, focused on the development of technologies vital to the success of future Department of Defense requirements for large space-based optical systems, such as the Space-Based Laser system. Current launch vehicle shroud and weight constraints limit the size of primary mirrors for such systems to less than 5 m, restricting systems to low earth orbits and, in turn, necessitating large, expensive satellite constellations to ensure global coverage. The UltraLITE and DOT programs provided an integrated ground demonstration of technologies that will allow future optical systems to be stowed for launch and deployed on orbit to their operational configuration.
AFRL scientists' final task, the last laboratory-funded activity under the DOT program, completes the Technology Readiness Level 5 milestone. The brassboard consists of three deployable 60 cm primary mirror segments and a deployable 3 m secondary mirror tower structure. The advanced control system automatically phases the mirrors from an initial deployment error exceeding 1/4 in. to a margin within 8 nm (1/5000 the width of a human hair). The control system also eliminated simulated satellite vibrations in the test. Previous program successes involved phasing smaller, 20 cm mirrors using simpler control systems that did not include rejection of simulated satellite vibrations. This program resulted in these specific technology developments: lightweight mirror structures, stiffness-critical precision composite structures, advanced control system architectures for autonomous phasing and maintenance, advanced structural dynamic system identification methods, and precision mechanisms for deployable space optics applications.