James Webb Space Telescope Optical Simulation Testbed I: Overview and First Results

TL;DR

The paper introduces the JWST Optical Simulation Testbed (JOST), a tabletop setup that mimics JWST's wavefront sensing and control, enabling testing, training, and development for the space telescope's mission.

Contribution

It presents a compact, flexible optical testbed that simulates JWST's physics and control systems, supporting commissioning, algorithm evaluation, and staff training.

Findings

Achieved 80% Strehl ratio at HeNe wavelength

Successfully modeled segmented mirror control in piston, tip, and tilt

Demonstrated potential for commissioning activities and algorithm testing

Abstract

The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a tabletop workbench to study aspects of wavefront sensing and control for a segmented space telescope, including both commissioning and maintenance activities. JOST is complementary to existing optomechanical testbeds for JWST (e.g. the Ball Aerospace Testbed Telescope, TBT) given its compact scale and flexibility, ease of use, and colocation at the JWST Science & Operations Center. We have developed an optical design that reproduces the physics of JWST's three-mirror anastigmat using three aspheric lenses; it provides similar image quality as JWST (80% Strehl ratio) over a field equivalent to a NIRCam module, but at HeNe wavelength. A segmented deformable mirror stands in for the segmented primary mirror and allows control of the 18 segments in piston, tip, and tilt, while the secondary can be controlled in tip, tilt and x, y, z position. This will be sufficient to model many commissioning activities, to investigate field dependence and multiple field point sensing & control, to evaluate alternate sensing algorithms, and develop contingency plans. Testbed data will also be usable for cross-checking of the WFS&C Software Subsystem, and for staff training and development during JWST's five- to ten-year mission.