Large scale refrigeration plant for ground testing the James Webb Telescope at NASA Johnson Space Center

Abstract

The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox will provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle - Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project. © 2010 American Institute of Physics.