Research Summaries

Back Key Technologies for Large Segmented Mirror Space Telescopes

Fiscal Year 2011
Division Graduate School of Engineering & Applied Science
Department Mechanical & Aerospace Engineering
Investigator(s) Agrawal, Jr., Brij N.
Sponsor National Reconnaissance Office (DoD)
Summary For an imaging spacecraft to provide truly persistent surveillance capability, the satellite should be in a higher orbit, requiring large aperture lightweight deployable mirrors, in the range of 10-20 meters in diameter. Achieving high surface accuracy for these mirrors is very challenging and adaptive optics techniques are under development to meet this challenge. The objective of this research program is to develop key technologies for large segmented mirror space telescope. Spacecraft Design Center (SRDC) at NPS has been very active for the last several years in developing these technologies. SRDC has participated in the development of Segmented Mirror Demonstrator (SMD), Segmented Mirror Testbed (SMT), and Advanced Mirror Development (AMD). This participation has helped SRDC to identify the critical technologies to be developed in this area and has developed new surface control techniques and wavefront sensors. Several testbeds have been also developed to validate these techniques. In Fall 2009, NRO/ITT is transferring SMT to SRDC. This is a unique testbed to develop these technologies. In the first year, the emphasis will be in the four areas. First area will be system identification of SM mirror and increase of damping for critical modes using tuned mass dampers or alternative techniques. SMD finite element model will also be evaluated. Second area will be developing new control techniques for SMD surface control using SMD analytical model. Third area will be developing new wavefront techniques to increase dynamic range. Fourth area will be to make SMT operational for segment surface and alignment research. Since SRDC will not receive 3 m collimator mirror, it will not be operational for this research. Two alternate techniques are currently considered, null corrector and double pass. In the second year, the techniques developed in the first year will be implemented on SMT and their performances will be evaluated. These techniques will be robust control techniques for surface control, wavefront sensing techniques for segment alignment, and active and passive damping techniques. This project will also collaborate with AMD program. In addition to these primary areas, improved control techniques will be developed for jitter control and spacecraft slew maneuvers for flexible space mirrors.
Keywords
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal