High-fidelity cryothermal test of a subscale large space telescope
High-fidelity cryothermal test of a subscale large space telescope
复制标题
亚尺度大型空间望远镜高保真低温热测试
DOI：
10.1117/12.734203
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发表时间：
2007
影响因子：
2
通讯作者：
A. Mastropietro
中科院分区：
文献类型：
--
作者：
M. Dipirro;J. Tuttle;S. Ollendorf;A. Mattern;D. Leisawitz;M. Jackson;J. Francis;T. Hait;P. Cleveland;D. Muheim;A. Mastropietro
为了利用太空的独特环境并优化对微弱光源的红外观测，太空望远镜必须冷却到低温。冷却大型太空望远镜的新范式是使用被动辐射冷却和机械低温冷却器的组合。被动系统必须保护望远镜免受太阳，地球和温暖的航天器部件的影响，同时为深空提供辐射冷却。这个屏蔽系统比望远镜本身还要大，必须衰减超过一百万的入射能量，以限制望远镜的热量输入。由于所需的热/真空室的大小以及屏蔽的室温和低温部分之间所需的热隔离程度，在地面上测试这种系统是一项艰巨的任务。解决这些问题的方法有两种：一种是设计一个缩小版的更大的遮阳板，另一种是小心地封闭辐射的潜通道。SPIRIT Origins Probe望远镜屏蔽的18%比例（最大直径屏蔽为1.5 m）版本在3.1 m直径x 4.6 m长的LN 2屏蔽真空室中的低成本氦气屏蔽中进行了测试。从三个屏蔽级连接到液氦冷却护罩的热带装有加热器和温度计，以模拟6 K，18-20 K和45-51 K的机械制冷机级。性能数据显示，在测试过程中，从防护罩的暖侧到冷侧泄漏的辐射热不到10微瓦。沿着与护罩施工技术的数据和热模型之间的良好协议进行了讨论。
To take advantage of the unique environment of space and optimize infrared observations for faint sources, space telescopes must be cooled to low temperatures. The new paradigm in cooling large space telescopes is to use a combination of passive radiative cooling and mechanical cryocoolers. The passive system must shield the telescope from the Sun, Earth, and the warm spacecraft components while providing radiative cooling to deep space. This shield system is larger than the telescope itself, and must attenuate the incoming energy by over one million to limit heat input to the telescope. Testing of such a system on the ground is a daunting task due to the size of the thermal/vacuum chamber required and the degree of thermal isolation necessary between the room temperature and cryogenic parts of the shield. These problems have been attacked in two ways: by designing a subscale version of a larger sunshield and by carefully closing out radiation sneak paths. The 18% scale (the largest diameter shield was 1.5 m) version of the SPIRIT Origins Probe telescope shield was tested in a low cost helium shroud within a 3.1 m diameter x 4.6 m long LN2 shrouded vacuum chamber. Thermal straps connected from three shield stages to the liquid helium cooled shroud were instrumented with heaters and thermometers to simulate mechanical cryocooler stages at 6 K, 18-20 K, and 45-51 K. Performance data showed that less than 10 microwatts of radiative heat leaked from the warm to cold sides of the shields during the test. The excellent agreement between the data and the thermal models is discussed along with shroud construction techniques.