TABLE OF CONTENTS The fundamental issue of successfully using cryocoolers in a long-life space application is meeting the integration constraints of both the cryogenic application and the cryocooler itself and its drive electronics. Chapter 11 on cryocooler performance characterization covered what coolers do and how to measure their performance; in contrast, this chapter covers how one deals with the cooler attributes in a real flight application.
[*]Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California.
Fundamentally, a cryocooler is a thermal device designed to pump heat from one location to another. Thus, load estimation and cryocooler sizing are generally the first requirements to be addressed in the cryocooler integration process. Key estimation and sizing issues include
accurate estimation of the cryogenic load for a complex assembly where parasitic loads often represent 80% of the total load
scoping the cooling load variation over the mission's operational and thermal environmental range
estimation of cooling load growth at mission EOL (end-of-life) resulting from degradation of heat-rejection systems, increase in radiation shield temperatures, or other causes
estimation of cooling load growth in orbit resulting from contamination of low-emissivity cryogenic thermal control surfaces
acquisition of cryocooler performance data for the full range of projected cooling powers, cold-tip temperatures, and heat-rejection temperatures
estimation of cryocooler loss of capacity at EOL resulting from possible degradation
combining the cryogenic load projections with the cooler performance projections to achieve a successful cooling...
