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As the optical performance requirements of space telescopes get more stringent, the need to analyze all possible error sources early in the mission design becomes critical. One large telescope with tight performance requirements is the Large Ultraviolet / Optical / Infrared Surveyor (LUVOIR) concept. The LUVOIR concept includes a 15-meter-diameter segmented-aperture telescope with a suite of serviceable instruments operating over a range of wavelengths between 100nm to 2.5um. Using an isolation architecture that involves no mechanical contact between the telescope and the host spacecraft structure allows for tighter performance metrics than current space-based telescopes being flown. Because of this separation, the spacecraft disturbances can be greatly reduced and disturbances on the telescope payload contribute more to the optical performance error. A portion of the optical performance error comes from the disturbances generated from the motion of the Fast Steering Mirror (FSM) on the payload. Characterizing the effects of this disturbance gives insight into the specifications on the FSM needed to achieve the tight optical performance requirements of the overall system. Through analysis of the LUVOIR finite element model and linear optical model given a range of input disturbances at the FSM, the optical performance of the telescope and recommendations for FSM specifications can be determined. The LUVOIR observatory control strategy consists of a multi-loop control architecture including the spacecraft Attitude Control System (ACS), Vibration Isolation and Precision Pointing System (VIPPS), and FSM. This paper focuses on the control loop containing the FSM disturbances and their effects on the telescope optical performance.

CMM metrology provides simple, 3D surface data used for prescription retrieval, figure error, and alignment with high accuracy without null-correctors. Two freeform mirrors for a compact telescope were successfully characterized and aligned using the CMM.

We present a general optical design survey of two-mirror unobstructed plane-symmetric freeform (FF) telescopes to provide a standardized framework and reference for further developments in the field of FF optics. We find that there are fundamentally two main design forms: those that use a positive tilt of the secondary and those that employ a negative rotation to achieve the unobstructed condition. Utilizing this survey, results can be categorized into simple groups of two-mirror unobstructed FF telescopes, analogous to the distinction between a Gregorian-type telescope and Cassegrain-type telescope. Allowing FF surfaces in optical design can enable more compact telescopes while potentially improving the image quality and allowing wider fields of view (FOVs). We define a FF optic as a nonrotationally symmetric mirror or lens, typically with large departures from a best-fit spherical surface (many microns or even millimeters). New manufacturing and testing methods have enabled the production of these types of surfaces. The telescopes we present maintain a 4 ∶ 1 aspect ratio of the FOV and utilize X–Y polynomials for mirror surface description. We impose a plane symmetric constraint on the system and an accessible entrance pupil. We generate charts documenting the relationship between FOV and F / # for the presented optical design forms. We also compare our results to a baseline rotationally symmetric system. These results provide a general method of evaluating baseline designs for two-mirror unobstructed FF telescopes.

The large UV/optical/IR surveyor (LUVOIR) is a concept for a highly capable, multiwavelength space observatory with ambitious science goals. Finding and characterizing a wide range of exoplanets, including those that might be habitable, is a major goal of the study. The ambitious science goals drive the challenges of optical design. This paper will present how the optical design meets the unique challenges for coronagraphs on large telescopes to achieve high contrast for a wide wavelength range from 200 to 2000 nm. Some of these unique challenges include the position and size of occulter masks, deformable mirror placement and separation, tight tolerances on the optical system and each element, and finally, packaging all instruments in a limited space. Three types of modules are designed after the coronagraph to explore the exoplanets and analyze the spectrum of detected exoplanet signals: two imaging cameras, two integral field spectrographs, and one high-resolution spectrometer. All of them work together to provide information to meet scientific challenges in searching for habitable planets. The optical designs, unique challenges, and the solutions for all coronagraph and spectral modules are presented. Their specifications derived from science goals are also presented.

A suite of CODE V macros has been developed to assist the optical designer in visualizing and manipulating optical data. Limits within the CODE V macro language and graphics functions are surpassed by accessing a MATLAB subroutine. A number of extension macros are discussed and examples are shown.