The role of integrated modeling in the design and verification of the James Webb Space Telescope

Abstract

The James Web Space Telescope (JWST) is a large, infrared-optimized space telescope scheduled for launch in 2011. System-level verification of critical optical performance requirements will rely on integrated modeling to a considerable degree. In turn, requirements for accuracy of the models are significant. The size of the lightweight observatory structure, coupled with the need to test at cryogenic temperatures, effectively precludes validation of the models and verification of optical performance with a single test in 1-g. Rather, a complex series of steps are planned by which the components of the end-to-end models are validated at various levels of subassembly, and the ultimate verification of optical performance is by analysis using the assembled models. This paper describes the critical optical performance requirements driving the integrated modeling activity, shows how the error budget is used to allocate and track contributions to total performance, and presents examples of integrated modeling methods and results that support the preliminary observatory design. Finally, the concepts for model validation and the role of integrated modeling in the ultimate verification of observatory are described.

Data-driven Estimation, Tracking, and System Identification of Deterministic and Stochastic Optical Spot Dynamics

“…By propagating (11) one time step, and by substituting ( 5), (6), and (10) in the resulting equation, we obtain…”

“…Stabilization, disturbance rejection, and precise control of optical beams and optical spots are fundamental and ubiquitous problems that appear in a number of applications and optical systems. For example, these problems are crucial for the development of sensing and control systems for space and ground optical telescopes, [1][2][3][4][5][6][7][8][9][10][11][12] freespace optical communication terminals, 13,14 turbulence compensation systems, 13 precise laser beam steering and jitter compensation systems, 15,16,[16][17][18][19][20][21] and for other optical instruments and devices. [22][23][24][25][26][27] Optical spot and wave-front disturbances can originate from various sources and phenomena.…”

Simulating and Testing Microvibrations on an Optical Satellite Using Acceleration Sensor-Based Jitter Measurements

“…Pixel offset of the whole optical system can be calculated by integrating the displacement and angular displacement of each optical component with its optical amplification factor, computed by a linear optical model. The simulation scheme can not only predict the pixel offset of the whole camera, but also analyze the effect of perturbation influences on each optical component, which can provide guidance for later experiments [17]. The experiment scheme based on high-precision acceleration sensors can reflect the amplification of microvibrations along a loading path as well as measure pixel offset of the whole optical system by integrating an optical amplification factor.…”

Active vibration isolation using a six-axis orthogonal vibration isolation platform with piezoelectric actuators

“…The performance of these facilities will be significantly reduced because of the perturbation generated by rotating machineries and compliant mechanisms, such as control moment gyroscope, reaction flywheel and solar wing [5][6][7]. A common way to deal with this problem is adding vibration isolation system between the vibration source and the precision devices [8][9][10][11]. Vibration isolation platform is usually applied because of compact structure and good capability of multi-degree-of-freedom vibration isolation.…”