Habitable World Observatory Modeling -Optical and Metrology Models, and Performance Predictions

The Habitable Worlds Observatory (HWO) is a future NASA flagship mission which will use a segmented telescope and coronagraphic instruments to discover and characterize exoplanets, including exoEarths – Earth-like planets orbiting other stars. HWO will require extraordinary optical stability, with wavefront drift performance measured in the picometers. This paper explores how active control of the telescope optics, using metrology systems that include laser distance gauges, segment edge sensors, and picometer precision actuators, can provide the needed telescope stability. Together with wavefront sensing and deformable mirrors in the coronagraph, this approach can control the entire coronagraphic beam train, to stabilize the electric field in the coronagraph. The HWO Technology Assessment Group is developing three “Exploratory Analytic Cases,” which are conceptual designs for HWO that differ in some aspects, to provide a basis for detailed analysis. This paper addresses EAC1, a deployed-aperture concept that draws on JWST heritage. EAC1 uses 19 1.8-meter hexagonal segments to form its off-axis Primary Mirror (PM), as sketched in Figure 1. EAC2 will use fewer, larger “keystone” segments in a non-deployed off-axis PM configuration, and EAC3 will be a larger, on-axis deployed telescope using smaller keystone shaped segments.

可居住世界天文台（Habitable Worlds Observatory, HWO）是NASA未来旗舰级任务，将通过分段式望远镜与日冕仪设备，发现并表征系外行星，包括系外地球——即环绕其他恒星运行的类地行星。HWO需要极高的光学稳定性，其波前漂移性能需以皮米为单位进行量化。本文探讨了如何通过包含激光测距仪、分段边缘传感器以及皮米精度促动器的计量系统，对望远镜光学系统进行主动控制，以实现所需的望远镜稳定性。结合日冕仪中的波前传感与可变形反射镜技术，该方案可实现对日冕仪整条光束链路的控制，从而稳定日冕仪内的电场。HWO技术评估小组正在开发三个“探索性分析案例（Exploratory Analytic Cases）”，这些案例是在部分细节上存在差异的HWO概念设计方案，旨在为后续详细分析提供基础。本文聚焦EAC1：这是一种借鉴詹姆斯·韦布空间望远镜（James Webb Space Telescope, JWST）技术遗产的展开式孔径概念方案。EAC1采用19块直径1.8米的六边形分段镜组成其离轴主镜（Primary Mirror, PM），如图1所示。EAC2则采用数量更少、尺寸更大的梯形分段镜，采用非展开式离轴主镜配置；而EAC3则是一款尺寸更大的共轴展开式望远镜，采用更小的梯形分段镜。