FOSSIL：热-机械架构

中文摘要 AI 辅助

FOSSIL（用于宇宙微波背景谱畸变探索的傅里叶变换光谱仪）是一项拟议的欧空局M8级任务，旨在以比COBE/FIRAS遗产测量高三个数量级的灵敏度测量宇宙微波背景（CMB）的谱畸变。实现这一灵敏度需要极具挑战性的低温架构：科学仪器必须维持在尽可能低的温度（4.5 K），而探测器焦平面组件需在50 mK下运行。本文介绍了FOSSIL载荷和仪器的热架构，从293 K的航天器服务舱到亚开尔文探测器级。热设计借鉴了普朗克（Planck）和ARIEL任务的经验，依赖于分级被动冷却链，包括多层绝热毯、三个V形槽辐射器（分别工作在约130 K、90 K和50 K）以及由欧空局提供的4 K低温制冷机链供冷的25 K主动冷却屏蔽。亚开尔文温度通过为NewAthena/X-IFU开发的多级绝热退磁制冷机（ADR）系统实现，该系统在1.8 K和350 mK下提供连续冷却，并在50 mK下以80%的工作循环运行。焦平面组件（FPA）容纳四个50 mK下的动能电感探测器（KID）阵列，通过碳纤维增强聚合物（CFRP）六脚架结构从4.5 K平台热隔离，并具有分级热截获。我们给出了所有级的稳态热预算，表明在每个温度水平都有充裕的余量，并讨论了黑体内部参考（BBIR）的关键热设计驱动因素。

英文摘要

FOSSIL (FTS fOr CMB Spectral diStortIon expLoration) is a proposed ESA M8 mission tailored to measure the spectral distortions of the Cosmic Microwave Background (CMB) with a sensitivity three orders of magnitude beyond the COBE/FIRAS legacy measurement. Achieving this sensitivity demands an extraordinarily challenging cryogenic architecture: the scientific instrument must be maintained at the lowest achievable temperature (4.5 K), while the detector focal plane assembly operates at 50 mK. This paper presents the thermal architecture of the FOSSIL payload and instrument, from the spacecraft service module at 293 K down to the sub-kelvin detector stage. The thermal design draws on heritage from the Planck and ARIEL missions and relies on a staged passive cooling chain comprising a multi-layer insulation blanket, three V-groove radiators (operating at approximately 130 K, 90 K, and 50 K), and a 25 K actively cooled shield fed by an ESA-provided 4 K cryocooler chain. Sub-kelvin temperatures are achieved via a multi-stage adiabatic demagnetisation refrigerator (ADR) system developed for NewAthena/X-IFU, providing continuous cooling at 1.8 K and 350 mK, and 50 mK with an 80% duty cycle. The Focal Plane Assembly (FPA), which houses four Kinetic Inductance Detector (KID) arrays at 50 mK, is thermally isolated from the 4.5~K bench via a carbon-fibre reinforced polymer (CFRP) hexapod structure with staged heat interception. We present the steady-state thermal budget across all stages, demonstrating comfortable margins at every temperature level, and discuss key thermal design drivers on the Blackbody Internal Reference (BBIR).

发表机构

• Université Paris Saclay, CNRS, Institut d’Astrophysique Spatiale（巴黎萨克雷大学）
• Université Grenoble Alpes, CNRS, CEA, IRIG, DSBT（格勒诺布尔阿尔卑斯大学）
• UCL（伦敦大学学院）

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