1. Since the institution of its space sensor test facilities in the 1950's, AEDC has continued to examine the gaps in test capabilities and respond by performing upgrades whenever possible. This has resulted in the present state of the 7V and 10V Chambers as described previously, as well as other AEDC space sensor chambers. In the 1980s the emphasis was on FPA testing, but the methodology was established to extend this to sensor systems. Analysis of developmental systems (particularly the SSTS and BSTS programs) indicated the need to test articles with very large-aperture (between 1 and 3 m) optics and off-axis rejection down to within 0.4 deg of the optical axis. This led to the conceptual design of a large space facility called the Space Systems Test and Evaluation Facility (SSTEF). There was advocacy from Space Command to construct this very challenging facility in the 1990s, but due to the difficulty of building (and launching) large-aperture sensor systems, there was a shift back to smaller aperture opticaldesignsand thefacilitywasnotbuilt.
2. It would be desirable to be able to present scenes to the SUT at two different segments of its FOV simultaneously. One concept that could accomplish this uses the COS and brings a second projection at an alternate angle using the SFLC and a turning mirror. Configurations that use optical elements to produce the fusion of scenes for multiple FOV segments are also being considered.
3. OARfacilities should be capable of measuring performance of SUTs to nominally 10-9/sr (same units as bidirectional reflectance distribution function, or BRDF) with a measurement dynamic range of 14 orders of magnitude. This demands high-level collimated source irradiance (with known polarization characteristics) and extremely low levels of stray radiation. The angular range needed is from 0.1 to 45 deg as measured from the edge of the sensor FOV. Broadband spectral output and a uniform intensity profile are desired, although lasers have been used to furnish the necessary power levels. The performance of the OAR measurement system relies heavily on the proper placement of field stops, radiation traps, and shields.10A roll-positioning capability is also needed to investigate asymmetry in the baffle, or sunshade used on the sensor. An OAR test was conducted in the Mark I Chamber for the SIRE sensor in the early 1980s11(seeFig.16). InitialplanningforamajorSpaceSystemsTestand Evaluation Facility development to accommodate large-aperture sensor and OAR testing was performed in the later partofthatdecade,butthisprojectwasneverbroughttofruition.