This paper describes the design, development, testing and performance at Ball Aerospace of long life, 4-10 K temperature space cryocoolers. For temperatures down to 10 K, Ball has developed long life Stirling cycle cryocoolers. For temperatures to 4 K and below, Ball has developed a hybrid Stirling/J-T (Joule-Thomson) cooler. The hybrid cooler has been verified in test to 3.5 K on a Ball program and a 6 K Development Model is in development on the NASA/JPL ACTDP (Advanced Cryocooler Technology Development Program). The Ball ACTDP cooler Development Model will be tested in 2005. The ACTDP cooler provides simultaneous cooling at 6 K (typically, for either doped Si detectors or as a sub-Kelvin precooler) and 18 K (typically, for optics or shielding) with cooling stages also available at 40 and 180 K (typically, for thermal shields or other components). The ACTDP cooler is under development for the NASA JWST (James Webb Space Telescope), TPF (Terrestrial Planet Finder), and Con-X (Constellation X-Ray) missions. The 4-10 K Coolers are highly leveraged off previous Ball space coolers including multiple life test and flight units.
We have proposed to develop a prototype 0.5-meter far-infrared telescope and heterodyne receiver/spectrometer system for fully-automated remote operation at the summit of Dome A, the highest point on the Antarctic plateau. The unparalleled stability, exceptional dryness, low wind and extreme cold make Dome A a ground-based site without equal for astronomy at infrared and submillimeter wavelengths. HEAT, the High Elevation Antarctic Terahertz Telescope, will operate in the atmospheric windows between 150 and 400 microns, in which the most crucial astrophysical spectral diagnostics of the formation of galaxies, stars, planets, and life are found. At these wavelengths, HEAT will have high aperture efficiency and excellent atmospheric transmission most of the year. The proposed superheterodyne receiver system will be comprised of 0.8, 1.4 and 1.9 THz channels which will observe the pivotal J=7-6 line of CO, the J=2-1 line of atomic carbon, and the far-infrared fine structure lines of N+ and C+, the brightest emission lines in the entire Milky Way Galaxy. When combined with the HEAT telescope, the receiver system represents a uniquely powerful instrument for reconstructing the history of star formation in our Galaxy, with application to the distant Universe. The receiver system itself serves as a valuable testbed for heterodyne Terahertz components, using leading-edge mixer, local oscillator, low-noise amplifier, cryogenic, and digital signal processing technologies that will play essential roles in future Terahertz observatories. The proposed study will pave the way for future astronomical investigations from Dome A.