Multidisciplinary Senior Design Project

Flight Ready Heat Switch for Deep Cryogenic Use

Our customer: Dr. Zemcov is interested in launching spectrometers into space on sounding rockets. In order to get the best possible readings from these sensors they must be cooled to incredibly low temperatures to reduce noise and any internal heat emitted from the sensor. In order to keep these devices cool, an adiabatic demagnetization refrigerator (ADR) is used. Our team was tasked with building the heat switch component of the ADR. The ADR and heat switch must cool the detector and then mechanically disconnect before flight. A prototype was previously designed and nearly ready for testing but was not completed due to COVID-19 shutting down the cryogenics lab. The prototype designed by the previous P20129 team did not work at room temperature, but offered design changes from the first team (P19129) that would be carried over to this year's design. The prototype utilizes a rotary solenoid, a ratchet, and a peanut cam to open and close the arms which would clamp and unclamp to the sensory package. This year's design features a newly designed camshaft plate to reduce lateral movement of the ratchet mechanism, new springs, and bronze components instead of aluminum. Together these modifications have made the heat switch tremendously reliable at room temperature, in a vacuum, and up to 77K in the cryostat. The heat switch has also survived the required NASA vehicle level 2 vibrations as well as random vibration testing. Work continues on making this heat switch flight ready with manuals and "plug and play" electronics. Visitors can expect to learn more about cryogenics, flight ready systems, and about adiabatic demagnetization refrigerators.