Optical design and analysis of the James Webb Space Telescope: optical telescope element

Contreras, James; Lightsey, Paul A.

doi:10.1117/12.559871

Cited by 16 publications

(9 citation statements)

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“…the Euclid mission 14 and the James Webb Space Telescope (JWST). 15,16 The GAME 17,18 and AGP 19,20 concepts (submitted respectively to the M3 and M4 ESA Calls) also rely on a TMA derived telescope, enforcing the concepts of differential measurement of fields close to the Sun, affected by fairly large light deflection, with a dedicated design deployed around a coronagraphic subsystem. TMAs may achieve extremely good performance, but they also feature comparably high sensitivity to misalignment, 21 as understandable from their large étendue (product of aperture area and field angular coverage).…”

Section: Concept Development and Optical Designmentioning

confidence: 99%

RAFTER: Ring Astrometric Field Telescope for Exo-planets and Relativity

Riva

Gai

Vecchiato

et al. 2020

Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave

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High precision astrometry aims at source position determination to a very small fraction of the diffraction image size, in high SNR regime. One of the key limitations to such goal is the optical response variation of the telescope over a sizeable FOV, required to ensure bright reference objects to any selected target. The issue translates into severe calibration constraints, and/or the need for complex telescope and focal plane metrology. We propose an innovative system approach derived from the established TMA telescope concept, extended to achieve high filling factor of an annular field of view around the optical axis of the telescope. The proposed design is a very compact, 1 m class telescope compatible with modern CCD and CMOS detectors (EFL = 15 m). We describe the concept implementation guidelines and the optical performance of the current optical design. The diffraction limited FOV exceeds 1.25 square degrees, and the detector occupies the best 0.25 square degree with 66 devices.

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Section: Concept Development and Optical Designmentioning

confidence: 99%

RAFTER: Ring Astrometric Field Telescope for Exo-planets and Relativity

Riva

Gai

Vecchiato

et al. 2020

Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave

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show abstract

“…Eqs. (12)- (16) show that the wave-front aberration of SFL is zero only when the five kinds of alignment errors are all zero, so the wave-front aberrations caused by the five kinds of alignment errors are linearly independent. So, the total wave-front aberration W 1 (x, y ) of SFL1 can be expressed as:…”

Section: The Alignment Error Modelsmentioning

confidence: 99%

“…Even though, the phase recovery technology still needs special devices. The NIRCam camera used by JWST includes Diffraction Hardman Sensor (DHS), Phase Difference Lens and other diagnostic elements to provide necessary information for the accurate phase determination of the telescope mirror [15], [16]. Besides, a good point target is the necessary prerequisite for JWST to measure and correct the alignment errors.…”

Section: Introductionmentioning

confidence: 99%

An Image-based alignment errors correction method for segmented Fresnel primary mirror

et al. 2020

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The alignment errors correction of segmented Fresnel primary mirror in multiple imaging scenes is simulated. Based on the linear relationship between five kinds of alignment errors and modulation transfer function metric or image frequency domain metric, an iterative correction method is introduced to compensate the alignment errors of segmented Fresnel lens at five degrees of freedom. The correction capability under point target imaging and the effect of alignment error correction under extended target imaging are studied. The simulation results show that the proposed correction scheme can effectively correct the alignment error when the rms value of segmented Fresnel primary mirror is less than 0.7λ. This method does not need to add any additional devices to the telescope, but optimizes directly based on the images, and is independent of the spatial structure of the imaging target. It may be suitable for fine phasing correction of segmented membrane diffractive optical telescope in orbit.

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“…[1][2][3] From IR to UV wavelengths, these telescopes require exceptionally accurate and stable reflecting surfaces. The aperture requirements and secondary mirror separation for many proposed systems exceed the volume limitations of available launch systems, and require on-orbit deployment of the telescope components.…”

Section: Introductionmentioning

confidence: 99%

Submicron friction mechanics at ambient and cryogenic temperatures

Hinkle

Peterson

Klein

et al. 2005

UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II

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Mechanism interface mechanics play an important role in the static and dynamic dimensional stability of deployable optical instruments. Friction mechanics in deployment mechanisms has been found to be a source of kinematic indeterminacy allowing elastic energy to be stored throughout the structure. At submicron scales, microslip mechanics allow this behavior to persist well below the classical Coulomb friction limit. This paper presents the design of a cryogenic tribometer for measuring this behavior in candidate mechanism interfaces in both room temperature and cryogenic environments. Room temperature results are presented and compared to a proposed generalized microslip model form. This model form is intended to allow the parametric characterization of microslip behavior caused by smooth nonconforming contact as well as roughness-induced microslip. Spherical ball-on-flat interface geometries were used with two unlubricated material combinations: 440C stainless steel ball on a 440C stainless steel flat and a silicon nitride ball on a 440C stainless steel flat. Consistent parameters were identified for the generalized microslip model from steady cyclic shear responses for both of these interface cases. While these parameters exhibited a measurable sensitivity to normal preload levels, the model form appears to provide the necessary level of robustness. Non-ideal transient shear phenomena including rate dependence were also observed but should play only a secondary role in future modeling efforts.

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Optical design and analysis of the James Webb Space Telescope: optical telescope element

Cited by 16 publications

References 0 publications

RAFTER: Ring Astrometric Field Telescope for Exo-planets and Relativity

RAFTER: Ring Astrometric Field Telescope for Exo-planets and Relativity

An Image-based alignment errors correction method for segmented Fresnel primary mirror

Submicron friction mechanics at ambient and cryogenic temperatures

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