NASA/GSFC 80 K Long-Life, Low Vibration Mechanical Cryocooler Performance Test Program Results

Abstract

To meet a variety of future cooling needs, Lockheed is developing a long-life, low vibration split-Stirling cycle mechanical cryocooler for the NASA Goddard Space Flight Center. Design requirements provide 0.8-W cooling at 80 K, while minimizing the specific power of the system and maintaining the exported vibration levels to less than 0.02 lb.

The cryocooler design is based on the flexure spring and gas gap seal design originally developed by Oxford University and enhanced by Lockheed and Lucas Aerospace from 1987 through 1993. The NASA 80-K baseline, however, incorporates additional design improvements that increase the cryocooler cooling capability and thus strengthens its performance efficiency above that of previous designs. These improvements are achieved through precise control of the compressor and the displacer moving masses by means of the Lockheed-developed digital error correction system (DECS), where vibration control is achieved through either position control (P-DECS), cancellation of residual acceleration (A-DECS), or cancellation of residual force (F-DECS). All these options have been built into the 80-K controller.