Adaptive Optics Prototype for a Meter-class Telescope used for Space Surveillance

TECHNOLOGY AREA(S): Space Platforms OBJECTIVE: Build and demonstrate an adaptive optics prototype which can be deployed at 1 m class telescopes for the Space Surveillance Network (SSN) to accomplish characterization of Low Earth Orbit (LEO) objects and area inspection around high value assets at Geosynchronous Earth Orbit (GEO). DESCRIPTION: The goal of this project is to design, build and test an adaptive optics (AO) system which can be deployed to 1 m class telescopes at an AFRL or at a Ground-based Electro-Optical Deep Space Surveillance (GEODSS) site. An affordable AO system would enhance the value of future meter-class telescopes developed for the Space Surveillance Network (SSN). The AO system shall be flexible enough to be integrated with telescopes ranging between 0.5 m - 1.5 m. The system field of view (FOV) should allow for imaging Low Earth Orbit (LEO) objects and spatially separating closely-spaced Geosynchronous Earth Orbit (GEO) objects. An effective AO system shall presumably include a tracker, a low-order mode corrector - steering mirror (SM), a high-order mode corrector - deformable mirror (DM) or micro-electro-mechanical system (MEMS), an established wavefront sensor, an auxiliary path to split the visible light to a second novel WFS, an imaging camera, reconstruction algorithm, software, and an interface mechanism that allows closed-loop communication between the corrector elements, the WFS, and the reconstruction algorithm. The AO system should be able to correct a range of seeing between 0.7 to 2 arcseconds at 500 nm. The servo loop shall be able to run at kilo-hertz speeds. For the imaging camera, the number of pixels selected and the pixel pitch shall be able to sample D/r0 = 20. The system shall record reconstructed wavefronts from the visible WFS, and I-band or J-band PSFs from the imaging camera. A mechanism is needed to either allow all the light to the baseline WFS or different percentages (25%, 50%, 75%, 100%) of light to the baseline WFS while sending the remaining light to the auxiliary WFS. The design, construction, and integration of the second WFS is independent of this SBIR. Successful bidders will to the greatest extent possible show: 1. Ability to design and build an AO system adhering as much as possible to the previous description and based as much as possible on COTS parts. Provide a conceptual optical design with FOV specifications. Include a conceptual electrical design. 2. Ability to design, code, and test a reconstruction algorithm that is linear, has a high dynamic range and allows user modification. 3. Ability to integrate rapidly with a telescope for on-sky testing (target < 4 weeks). The baseline is a 1 m telescope with f/100 and a connected coude room operated by AFRL at the Starfire Optical Range. 4. Ability to build a compact AO system which can be transported to potential GEODSS sites. 5. Ability to switch rapidly (minutes) between the base-line WFS and the auxiliary novel WFS without effecting alignment. 6. Ability to deliver specifications and performance metrics for the scoring, WFS, and imaging cameras. 7. Ability to accurately predict and model telescope hardware and AO system performance as well as photometric and radiometric performance for objects of mv = 7 - 14 magnitude. Derive a metric for observing closely-spaced objects. 8. Show understanding of the cost of, hardware, people-hours required to assemble and interface the AO system, and software development. 9. Ability to provide follow-on use of the AO system and the software by the Air Force under a cooperative agreement to be arranged in the future. PHASE I: Carry out simulations to test the performance of the AO system in conjunction with the listed metrics. Design an AO system that can be integrated with a 1 m class telescope using metrics given above, especially being able to correct seeing between 0.7 - 2 arcseconds at 500 nm, operate at kilo-hertz speeds, and sample D/r0 = 20. The system should be built for a coude room but be compact enough to be transportable. Provide a cost-estimate for the hardware, software, and people-hours required to design, build, and integrate the system. PHASE II: Work in consultation with the government to build and install the AO system on a 1 m telescope. Carry out on-sky observation with the AO testbed using different magnitude (mv = 7 - 14) sources as well as different separations (3 lambda/D - 4 lambda/D). From the observations record reconstructed wavefronts from the WFS and corrected PSFs from the imaging camera. Provide a report on system performance based on metrics and goals outlined in the description. PHASE III: Integrate and demonstrate one or more AO systems. Work with the government to operate the prototype to conduct an SSA mission. Analyze the performance of the AO system using the metrics in the description. Prepare a final report on the AO prototype. REFERENCES: 1. J. W. Hardy. Adaptive Optics for Astronomical Telescopes. Oxford University Press, July 1998.2. Fugate et. al. Experimental Demonstration of Real Time Atmospheric Compensation with Adaptive Optics Employing Laser Guide Stars. BAAS, Vol. 23, p. 88, March 1991.3. O. Guyon. Limits of Adaptive Optics for High-Contrast Imaging. ApJ, 629:592 614, August 2005. KEYWORDS: Adaptive Optics, AO, Wavefront Sensors, WFS, Shack Hartmann Wavefront Sensor, SHWFS, Ground-based Electro-optical Deep Space Surveillance, GEODSS, Space Surveillance Network, SSN, Space Situational Awareness, SSA