&lt;title&gt;Effects of aberrations (low order and quilting) on the performance of the all-composite design for the Herschel Space Observatory&lt;/title&gt;

Thomas, J. Alan; Backovsky, Stan; Barber, Daniel D.; Small, Donald W.; Johnston, Roger A.; Cohen, E. J.

doi:10.1117/12.447306

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…Cryogenic mirrors have been demonstrated to change figure as they are cooled. [14,15,16,17] This has often been attributed to material non-uniformity and in some cases adhesives (epoxy/CFRP or frit/glass); specifically thermal expansion properties. This type of aberration can lead to erroneous wavefront measurement in under sampled optical measurements.…”

Section: Potential Impact Of Cryo-quiltingmentioning

confidence: 99%

Herschel Space Telescope: Optical test and model correlation

Doyle

2009

2009 IEEE Aerospace Conference

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Subsequent to the cyrogenic optical testing of the 3.5 m silicon carbide ESA Herschel Space Telescope, a discrepancy between the prediction and measurement of the telescope back focal length was identified. Efforts to resolve this discrepancy involved both improvements to modeling and more thorough examination of the optical test techniques. The most significant input to modeling was the use of extremely precise cryogenic strain measurements. The optical test methods were extensively analyzed for accuracy, sensitivity, and systematic errors. Model results, error budgets, test results, and conclusions will be presented and discussed. 1, 2

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Section: Potential Impact Of Cryo-quiltingmentioning

confidence: 99%

Herschel Space Telescope: Optical test and model correlation

Doyle

2009

2009 IEEE Aerospace Conference

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“…Although the majority of the stray light specification was not related to interferometric surface error measurement, one specific portion of the specification was related to mid-spatial frequency errors. [3] Work testing CFRP mirrors [4,5,6] indicated that an infrared interferometer was a useful tool for measurement. However, due to the temperatures involved (i.e.…”

Section: Figure 1: Herschel Space Observatorymentioning

confidence: 99%

<title>Optical metrology for testing an all-composite 2-m-diameter mirror</title>

et al. 2001

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The Herschel Space Observatory (formerly known as FIRST) consists of a 3.5 m space telescope designed for use in the long IR and sub-millimeter wavebands. To demonstrate the viability of a carbon fiber composite telescope for this application, Composite Optics Incorporated (COI) manufactured a fast (F/1), large (2 m), lightweight (10.1 kg/m 2 ) demonstration mirror.A key challenge in demonstrating the performance of this novel mirror was to characterize the surface accuracy at cryogenic (70 K) temperatures. A wide variety of optical metrology techniques were investigated and a brief survey of empirical test results and limitations of the various techniques will be presented in this paper. Two complementary infrared (IR) techniques operating at a wavelength of 10.6 microns were chosen for further development: (1) IR Twyman-Green Phase Shifting Interferometry (IR PSI) and (2) IR Shack-Hartmann (IR SH) Wavefront Sensing. Innovative design modifications made to an existing IR PSI to achieve high-resolution, scannable, infrared measurements of the composite mirror are described. The modified interferometer was capable of measuring surface gradients larger than 350 microradians. The design and results of measurements made with a custom-built IR SH Wavefront Sensor operating at 10.6 microns are also presented. A compact experimental setup permitting simultaneous operation of both the IR PSI and IR SH tools is shown. The advantages and the limitations of the two key IR metrology tools are discussed.

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“…The purpose of the mirror demonstrator was to create an active deformable mirror to be used in a large ground-based telescope. The Planck telescope, launched alongside the Herschel Space Observatory, used a CFRP sandwich structure to observe 0.3-10mm range at 40K [2]. Due to the wavelength observed, the surface figure and form accuracy are factors less than required for the far infrared.…”

Section: Introductionmentioning

confidence: 99%

Design, simulation and manufacturing a CFRP prototype mirror for active/adaptive optics

2019

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In this work, we are aiming to reduce the mass of large precision mirrors for space missions by using space approved composite materials. We report the development of an active/adaptive optics prototype of carbon fiber reinforced polymer mirrors using a pre-impregnated (pre-preg) composite MTM44-1/IMS65. The carbon fiber mirror has 16 layers of carbon fiber and one layer of polishable resin which compensate the well-known problem of ''fiber print through''. The development of a fabrication method, suited for creating a CFRP mirror is outlined. As all materials will change properties to some degree, during cool down to cryogenic temperatures, FEA model is employed to investigate the change on overall form and figure of the mirror. Characterizing this dimensional change is critical in insuring that any mirror material can be used in this environment and, if required, corrected either by utilizing a deformable mirror control systems or by correction in the optical system. Two different piezoelectric actuators are modelled and used to create an active composite reflector. Push actuators and micro fiber composite (MFC) actuators are simulated and the performance of them are compared by surface deformation and dynamic response.

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<title>Effects of aberrations (low order and quilting) on the performance of the all-composite design for the Herschel Space Observatory</title>

Cited by 5 publications

References 2 publications

Herschel Space Telescope: Optical test and model correlation

Herschel Space Telescope: Optical test and model correlation

<title>Optical metrology for testing an all-composite 2-m-diameter mirror</title>

Design, simulation and manufacturing a CFRP prototype mirror for active/adaptive optics

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