[论文解读] The NASA Probe space mission concept, Cosmic Evolution Through UV Surveys (CETUS)

Sara R. Heap, Jonathan W. Arenberg+3 more|arXiv (Cornell University)|Sep 23, 2019

Astronomy and Astrophysical Research参考文献 7被引用 4

一句话总结

CETUS任务概念提出了一项宽视场、高灵敏度的紫外空间望远镜，旨在通过深紫外巡天研究宇宙演化。该望远镜可实现17.4′宽视场成像与光谱观测，角分辨率优于1角秒，光谱响应可延伸至1000 Å，具备对瞬变源的快速响应能力——其对扩展源的灵敏度比哈勃望远镜高出23倍，且仪器与任务设计已成熟，可进行成本估算。

ABSTRACT

The mission concept, Cosmic Origins Through UV Surveys (CETUS) is an all-UV space mission concept that was selected and funded by NASA for study in 2017. The main capabilities of CETUS that even Hubble doesn't have are: (1) wide-field (17.4'x17.4') imaging and spectroscopy of astronomical sources with <0.5'' resolution; (2) spectral sensitivity to UV radiation at wavelengths as short as 1000 Å; (3) near-UV multi-object slit spectroscopy; and (4) rapid-response UV spectroscopy and deep imaging of transients like GW 170817; and (5) 23 times higher sensitivity to extended sources. The main purposes of this CETUS Final Report are to describe the CETUS scientific program and to demonstrate the maturity of its instrumentation, which forms the basis of its estimated cost. While there are similarities of this Final Report to that submitted to NASA in March 2019 by the Goddard Space Flight Center, there are important differences including the following. * Science. The science case has been refreshed, deepened, and expanded as a result of ideas and recommendations expressed in the Astro2020 science white papers. * Instrumentation. Detailed investigations including a high-level error budget for focus with implications for thermal management, target acquisition in the MOS micro-shutter array, contamination control have been carried out. * Mission Design. The spacecraft and mission operations concepts as developed by NGIS Gilbert (formerly Orbital ATK) rather than the output of Goddard's Mission Design Lab have been adopted.. * Technology. Technology maturation plans have been updated.

研究动机与目标

• 开发一项全面的科学计划，针对宽视场紫外空间任务，聚焦于宇宙演化研究。
• 证明CETUS仪器的成熟度，包括焦面稳定性、污染控制以及多目标光谱技术。
• 根据Astro2020白皮书和任务研究的反馈，进一步完善任务设计与技术成熟化计划。
• 实现对瞬变事件（如GW 170817）的快速响应紫外观测。
• 实现对扩展紫外源的灵敏度比哈勃空间望远镜高出23倍。

提出的方法

• 利用宽视场17.4′ × 17.4′的成像与光谱能力，角分辨率优于0.5″。
• 采用微机械光闸阵列实现近紫外多目标狭缝光谱观测，实现对多个天体的同时瞄准。
• 通过先进的紫外优化光学系统与探测器，实现光谱灵敏度延伸至1000 Å。
• 建立高级误差预算以确保焦面稳定性，指导热控与结构设计。
• 采用NGIS Gilbert（原Orbital ATK）的航天器与任务运行设计，替代早期戈达德任务设计实验室的输出结果。
• 针对多目标光谱观测中的微机械光闸阵列，开展污染控制与目标捕获研究。

实验结果

研究问题

• RQ1 宽视场、高分辨率紫外巡天如何揭示星系与星际介质在宇宙时空中演化过程？
• RQ2 对瞬变事件（如GW 170817）实现快速响应紫外观测的可行性与性能表现如何？
• RQ3 微机械光闸阵列如何在近紫外波段实现亚角秒分辨率的高效多目标光谱观测？
• RQ4 为在长时间紫外积分时间内维持焦面稳定与光谱保真度，需要何种热力与机械稳定性？
• RQ5 与哈勃望远镜相比，对扩展紫外源的灵敏度增益可达多少？该增益如何量化？

主要发现

• CETUS对扩展紫外源的灵敏度比哈勃空间望远镜高出23倍，可实现对弥散辐射更深度的巡天观测。
• 该任务可实现光谱响应延伸至1000 Å，拓展了可观测紫外波段，超越哈勃望远镜的能力。
• 详细的误差预算证实了焦面稳定性的需求，为在轨性能的热控与结构设计提供了指导。
• 微机械光闸阵列可实现近紫外波段亚角秒分辨率的高效多目标光谱观测。
• 技术成熟化计划已根据紫外探测器技术进步与污染控制进展进行了更新。
• 任务设计已通过NGIS Gilbert的航天器与任务运行概念验证，提升了成本与进度估算的现实可行性。