Structural-thermal-optical performance (STOP) sensitivity analysis for the James Webb Space Telescope

Blaurock, Carl; McGinnis, Mark A.; Kim, Kevin; Mosier, Gary E.

doi:10.1117/12.618697

Cited by 18 publications

(9 citation statements)

References 1 publication

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“…However, this assumption is necessary in order to keep the derivations as simple as possible. As our experiments show, the developed algorithm works very well despite the fact that in experiments there might be some deviations from the condition (23). Even without this assumption, it is possible to derive the control algorithm, however, the mathematical apparatus will become more complex and it will involve expectation operators.…”

Section: B Control Algorithm Developmentmentioning

confidence: 91%

Dual-Update Data-Driven Control of Deformable Mirrors Using Walsh Basis Functions

Haber,

Bifano

2021

Preprint

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In this paper, we develop a novel data-driven method for Deformable Mirror (DM) control. The developed method updates both the DM model and DM control actions that produce desired mirror surface shapes. The novel method explicitly takes into account actuator constraints and couples a feedback control algorithm with an algorithm for recursive estimation of DM influence function models.In addition to this, we explore the possibility of using Walsh basis functions for DM control. By expressing the desired and observed mirror surface shapes as sums of Walsh pattern matrices, we formulate the control problem in the 2D Walsh basis domain. We thoroughly experimentally verify the developed approach on a 140-actuator MEMS DM, developed by Boston Micromachines. Our resultsshow that the novel method produces the root-mean-square surface error in the 14 − 40 nanometer range. These results can additionally be improved by tuning the control and estimation parameters. The developed approach is also applicable to other DM types, such as for example, segmented DMs. I. INTRODUCTION Deformable Mirrors (DMs) are one of the main components of Adaptive Optics (AO) systems [1], [2]. A typical DM consist of a reflective optical surface that is deformed by a set of actuators. By precisely shaping the surface of a DM, we can compensate for wave-front aberrations in AO systems [3]-[16].In this paper, we consider the problem of developing control algorithms for DMs. There are a large number of approaches for DM control. A complete survey of all the methods goes well beyond the length limits of this manuscript. Consequently, we briefly mention only the most

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Section: B Control Algorithm Developmentmentioning

confidence: 91%

Dual-Update Data-Driven Control of Deformable Mirrors Using Walsh Basis Functions

Haber,

Bifano

2021

Preprint

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“…Analysis of the changes in the front dome, in terms of physical geometry and refraction, demonstrated that influences on the direction of the emergent ray were mainly of four types, as shown in Figure 3: (a) the thermally induced surface slope changed the direction of normal lines and thus affected the emergent angle; (b) changing the emergent angle of the first surface affected the incident angle of the second surface; (c) changing the refractive index at the incident and emergent points of two surfaces affected the deflection angle; and (d) the radial gradient of the refractive index caused the propagation path to bend. According to the optical sensitivity method [6], the total change of ray propagation direction was equal to the sum of the four changes above. The deduction of the total angle change of emergent ray

Δ α

is described in Appendix B.…”

Section: Methodsmentioning

confidence: 99%

“…Few thermal analyses have been conducted on airborne rear optical lenses with external load changes. Based on the thermal sensitivity method, Blaurock et al investigated optical sensitivity to temperature using finite element analysis (FEA) [6]. Applewhite et al studied the effects of thermal gradients on the Mars Observer Camera primary mirror [4].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Effects of Thermal Environment on Optical Systems for Navigation Guidance and Control in Supersonic Aircraft Based on Empirical Equations

Cheng

Yang

Hao

2016

Sensors

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The thermal environment is an important factor in the design of optical systems. This study investigated the thermal analysis technology of optical systems for navigation guidance and control in supersonic aircraft by developing empirical equations for the front temperature gradient and rear thermal diffusion distance, and for basic factors such as flying parameters and the structure of the optical system. Finite element analysis (FEA) was used to study the relationship between flying and front dome parameters and the system temperature field. Systematic deduction was then conducted based on the effects of the temperature field on the physical geometry and ray tracing performance of the front dome and rear optical lenses, by deriving the relational expressions between the system temperature field and the spot size and positioning precision of the rear optical lens. The optical systems used for navigation guidance and control in supersonic aircraft when the flight speed is in the range of 1–5 Ma were analysed using the derived equations. Using this new method it was possible to control the precision within 10% when considering the light spot received by the four-quadrant detector, and computation time was reduced compared with the traditional method of separately analysing the temperature field of the front dome and rear optical lens using FEA. Thus, the method can effectively increase the efficiency of parameter analysis and computation in an airborne optical system, facilitating the systematic, effective and integrated thermal analysis of airborne optical systems for navigation guidance and control.

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“…This includes field-dependent aberrations and optical component misalignments which are a lingering threat on-orbit due to constantly changing thermal gradients which slowly warp and deform the spacecraft via thermal expansion and contraction. 20 In addition, geometric raytracing is useful for modeling active optics which rely on the bulk motion of optical elements to correct low-order wavefront errors (WFE) caused by optical misalignments. This becomes a powerful tool for correcting errors such as defocus and coma which are typically some of the largest in terms of peak-to-valley (PV) WFE.…”

Section: Introductionmentioning

confidence: 99%

Integrated modeling of wavefront sensing and control for space telescopes utilizing active and adaptive optics

Derby,

Milani,

Blomquist

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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Extreme wavefront correction is required for coronagraphs on future space telescopes to reach 10 -8 or better starlight suppression for the direct imaging and characterization of exoplanets in reflected light. Thus, a suite of wavefront sensors working in tandem with active and adaptive optics are used to achieve stable, nanometerlevel wavefront control over long observations. In order to verify wavefront control systems, comprehensive and accurate integrated models are needed. These should account for any sources of on-orbit error that may degrade performance past the limit imposed by photon noise.An integrated model of wavefront sensing and control for a space-based coronagraph was created using geometrical raytracing and physical optics propagation methods. Our model concept consists of an active telescope front end in addition to a charge-6 vector vortex coronagraph instrument. The telescope uses phase retrieval to guide primary mirror bending modes and secondary mirror position to control the wavefront error within tens of nanometers. The telescope model is dependent on raytracing to simulate these active optics corrections for compensating the wavefront errors caused by misalignments and thermal gradients in optical components. Entering the coronagraph, a self-coherent camera is used for focal plane wavefront sensing and digging the dark hole. We utilize physical optics propagation to model the coronagraphy's sensitivity to mid and high-order wavefront errors caused by optical surface errors and pointing jitter. We use our integrated models to quantify expected starlight suppression versus wavefront sensor signal-to-noise ratio.

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Structural-thermal-optical performance (STOP) sensitivity analysis for the James Webb Space Telescope

Cited by 18 publications

References 1 publication

Dual-Update Data-Driven Control of Deformable Mirrors Using Walsh Basis Functions

Dual-Update Data-Driven Control of Deformable Mirrors Using Walsh Basis Functions

Analysis of the Effects of Thermal Environment on Optical Systems for Navigation Guidance and Control in Supersonic Aircraft Based on Empirical Equations

Integrated modeling of wavefront sensing and control for space telescopes utilizing active and adaptive optics

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