The Goddard mechanical cooler development program has concentrated on the development of highly reliable coolers for space applications. These coolers have reliable lifetimes of 10 years or more. The goal has been to have the lifetime limited only by the electronics that operate the cooler. We believe that we have now reached that goal. In addition, Goddard is supporting the development of low cost coolers with long life and high reliability that can be used both in space and for commercial applications on the ground.
Are you planning to use a mechanical cryocooler on your next flight project? The choice of which cooler requires some thought. These cooler user questions will help you sort out the issues.
Types of Coolers: a discussion of large, miniature, and vibration free coolers.
Photos of available cryocoolers.
Goddard has been involved in the development of mechanical coolers for over 20 years. A cooler with magnetic bearings was developed by Phillips Laboratory (North American Phillips) and completed a five year life test in 1990. However, the magnetic bearings resulted in a relatively large, complex and expensive cooler. Therefore Goddard began the development of coolers with flexure bearings (at Hughes, Lockheed, Ball, TRW and Stirling Technology, Inc.); with gas bearings (at Creare); and with diaphragms (at Creare).
Goddard presently has several on-going contracts for the development of long lifetime coolers. Multi-stage linear Stirling cycle coolers are being developed by Ball Aerospace in Boulder, CO.; a low cost miniature pulse tube cooler is being developed by Lockheed in Palo Alto, CA.; and several reverse Brayton cycle coolers are being developed by Creare, Inc. in Hanover, NH. The Goddard cooler program is effectively a joint program with Phillips Laboratories in Albuquerque, NM. Philips has provided funding to Goddard to support the development of coolers at Creare and to produce a three-stage Stirling cycle cooler at Ball. In addition, Goddard has provided funding to Phillips to support a Philips contract for the development of a miniature pulse tube cooler by TRW in Redondo Beach, CA.
Goddard is also pursuing the development of inexpensive coolers. Relatively inexpensive coolers, called "tactical coolers" are produced on quantity for the military. However, these coolers presently have mean lifetimes on less than 1 year. Vendors are now attempting to produce inexpensive coolers that are also reliable and have long life. Goddard is presently contracting, either directly or through other government agencies, with a number of these vendors.
Goddard also has an in-house cooler program. This program has developed analytical tools that have been provided to manufacturers under contract to Goddard andothergovernment agencies. In addition Goddard has developed a vibration control system that is now widely used by American cooler venders. Finally, Goddard has developed a sophisticated cooler test facility. This facility allows comprehensive testing of space flight coolers under simulated on orbit conditions. Simultaneously, the residual vibration from the cooler is recorded with a 6-axis force dynamometer and accelerometers. The force data is so sensitive that it can be used as a diagnostic tool to, for example, determine if significant rubbing is occurring within the cooler.
Mechanical Cooler References , with some absracts.