JWST mirror and actuator performance at cryo-vacuum
JWST mirror and actuator performance at cryo-vacuum
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JWST 反射镜和致动器在低温真空下的性能
DOI：
10.1117/12.2312872
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
C. Davis
中科院分区：
文献类型：
--
作者：
Erin M. Wolf;B. Gallagher;J. S. Knight;T. Chonis;J. Sullivan;Koby Z. Smith;A. Rudeen;Kevin Babcock;B. Hardy;A. Barto;Eric Coppock;C. Davis
詹姆斯·韦伯太空望远镜（JWST）的次镜组件（SMA）和18个主镜片段组件（PMSAs）各自通过6个六足致动器对刚体位置进行主动控制。每个PMSA还额外有一个曲率半径致动器。镜子在发射环境中收起于镜子支撑结构内，然后在波前传感与控制（WFSC）对准和定相过程开始之前，必须展开12.5毫米以达到正常展开位置。JWST在发射前需要在低温真空（CV）环境中对整个光学系统进行测试。低温真空测试活动在得克萨斯州休斯敦的约翰逊航天中心（JSC）的A舱中进行。该测试活动包括一次常温真空测试、一次冷却测试、一次在65开尔文的低温稳定测试、一次升温测试，以及最后一次常温真空测试。该测试活动的一部分是对飞行镜上的六足致动器进行功能和性能测试。本文将描述对所有132个六足致动器和曲率半径致动器所进行的测试。测试活动首先对致动器逐个进行测试，然后测试致动器在六足系统中的性能。来自致动器上的飞行传感器的遥测数据以及来自干涉仪、摄影测量系统和图像分析等外部计量设备的测量结果被用于证明JWST致动器的性能。在JSC的低温真空测试期间，镜子移动指令过程被大量演练，并且出现了许多准确指令移动的实例。PMSA和SMA致动器在JSC低温真空测试期间表现极其出色，并且我们已经证明这些致动器在常温及低温下都能完全正常工作，而且镜子将以望远镜定相和对准所需的精度到达其指令位置。
The James Webb Space Telescope (JWST) telescope’s Secondary Mirror Assembly (SMA) and eighteen Primary Mirror Segment Assemblies (PMSAs) are each actively controlled in rigid body position via six hexapod actuators. Each of the PMSAs additionally has a radius of curvature actuator. The mirrors are stowed to the mirror support structure to survive the launch environment and then must be deployed 12.5 mm to reach the nominally deployed position before the Wavefront Sensing & Control (WFSC) alignment and phasing process begins. JWST requires testing of the full optical system in a Cryogenic Vacuum (CV) environment before launch. The cryo vacuum test campaign was executed in Chamber A at the Johnson Space Center (JSC) in Houston Texas. The test campaign consisted of an ambient vacuum test, a cooldown test, a cryo stable test at 65 Kelvin, a warmup test, and finally a second ambient vacuum test. Part of that test campaign was the functional and performance testing of the hexapod actuators on the flight mirrors. This paper will describe the testing that was performed on all 132 hexapod and radius of curvature actuators. The test campaign first tests actuators individually then tested how the actuators perform in the hexapod system. Telemetry from flight sensors on the actuators and measurements from external metrology devices such as interferometers, photogrammetry systems and image analysis was used to demonstrate the performance of the JWST actuators. The mirror move commanding process was exercised extensively during the JSC CV test and many examples of accurately commanded moves occurred. The PMSA and SMA actuators performed extremely well during the JSC CV test, and we have demonstrated that the actuators are fully functional both at ambient and cryo temperatures and that the mirrors will go to their commanded positions with the accuracy needed to phase and align the telescope.
影响因子：
1.3
作者：
Lightsey, Paul A.;Atkinson, Charles;Feinberg, Lee D.
通讯作者：
Feinberg, Lee D.