NGST Advanced Cryocooler Technology Development Program (ACTDP) Cooler System

Abstract

The NGST ACTDP cooler system features a three-stage integral pulse tube cooler coupled, as a precooler, to a 6 K Joule-Thomson (JT) cooler. The system is configured to provide remote cooling (12 m) at 18 and 6 K. The cooler is being developed under contract to the Jet Propulsion Laboratory with the objective of providing cooling for future NASA space observatory missions such as Terrestrial Planet Finder (TPF), Constellation X, and James Webb Space Telescope (JWST). The cooler development effort is to deliver an engineering model cooler with rack electronics that provide a flight-simulated interface.

This paper presents a cooler system overview and data collected during cooler development testing to date. Designed conservatively for a 10-year life, the hybrid cooler is required to provide 150 mW of cooling at 18 K together with 30 mW of cooling at 6 K while rejecting to 300 K and minimizing input power to the electronics. The total mass of the cooler and electronics system is less than 40 kg. The software driven control electronics provide the cooler control functions that are fully re-configurable and based on the NGST flight-qualified Advanced Cooler Electronics (ACE) with minor modification to measure and control temperatures in the 6 K range.