Snap Shot -Joint Effort

Joint Effort


	Product Development Effort: The successful acceptance of the ADR cryogenic device for spacecraft nose cone instrument temperature control. The Adiabatic Demagnetization Refrigerator (ADR) was developed in conjunction with University of Wisconsin Space Science and Engineering Center (SSEC) under a joint project with NASA's Goddard Space Center and the Japanese space science agency ISAS. The main purpose of the ADR is to maintain critical instrumentation, such as an x-ray spectrometer detector, at a constant cold temperature of 0.65 degrees Kelvin (just above absolute zero).

	The key features of the design include an eutectic salt energy exchange system, extensive use of highly conductive gold, and proprietary metallurgical techniques to join materials that will experience vast temperature swings.

	The ADR functions by utilizing a strong magnetic field to align the individual magnetic poles within the salt pill. The salt pill is connected to a liquid helium bath through a mechanical heat switch to reduce the magnetic field to a very low level, but not zero. This allows the spins of the salt molecules to begin moving randomly due to increased entropy. Because it requires energy to move the spins, energy is absorbed by the salt, cooling it even further. Eventually the molecular spins become completely random and the cooling stops. Then the magnetic field is increased, which in turn warms up the salt and the process starts over.