Helium Loop Heat Pipe for Large Area Cryocooling

Next generation Far Infrared (FIR) Space Telescopes such as NASA?s SAFIR, SPIRIT, and SPECS require the entire mirrors, which can be as large as 10 meters in diameter, to be cooled to the temperature range of 4-40K. To meet the challenging cooling requirements of the missions mentioned above, TTH Research proposed the development of an advanced capillary pumped cryocooling transport system capable of providing temperature control for a large area in the 4-40K temperature range. Two-phase capillary pumped heat transport technology including Capillary Pumped Loops (CPLs) and Loop Heat Pipes (LHPs) offers many operational advantages over mechanically pumped counterparts. CPLs and LHPs contain no moving part to wear out or to introduce unwanted vibrations to the optical components. The transport lines can be made flexible (i) to accommodate the deployable mirror concepts and/or (ii) to isolate shocks/vibrations induced by mechanical cryocoolers from the telescope optics. For Phase II, an demonstration test unit shall be designed, built, and tested to show that cryocooling over a large area of the telescope mirror at 2.5K-4K can be achieved with the proposed concept of He-LHP.