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Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control
Technical Paper
2008-01-2170
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Spacecraft that must operate in cold environments at reduced heat load are at risk of radiator freezing. For a vehicle that lands at the Lunar South Pole, the design thermal environment is 215 K, but the radiator working fluid must also be kept from freezing during the 0 K sink of transit. A radiator bypass flow setpoint control design such as those used on the Space Shuttle Orbiter and ISS would require more than 30% of the design heat load to avoid radiator freezing during transit - even with a very low freezing point working fluid. By changing the traditional active thermal control system (ATCS) architecture to include a regenerating heat exchanger inboard of the radiator and using a regenerator bypass flow control valve to maintain system setpoint, the required minimum system heat load can be reduced by more than half. This gives the spacecraft much more flexibility in design and operation.
The present work describes the regenerator bypass ATCS setpoint control methodology. It includes analytical results comparing the performance of this system to the traditional radiator bypass system. Finally, a summary of the advantages of the regenerator bypass system are presented.
Authors
Citation
Ungar, E., "Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control," SAE Technical Paper 2008-01-2170, 2008, https://doi.org/10.4271/2008-01-2170.Also In
References
- Constellation Program Natural Environments Definition for Design (NEDD) 2008
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- Anderson, B. J. Natural Orbital Environment Guidelines for Use in Aerospace Vehicle Development 1994
- Morris, D. W. “Thermal Design and Performance of the Apollo Block II Environmental Control System,” Doc. No. CSD-A-1215 Crew Systems Division, NASA-Manned Spacecraft Center Houston, TX 1974