Orion Environmental Control and Life Support Systems Suit Loop and Pressure Control Analysis
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Under NASA’s Orion Multi-Purpose Crew Vehicle Environmental Control and Life Support System (ECLSS) Project at Johnson Space Center, the Crew and Thermal Systems Division has developed performance models of the air system using Thermal Desktop/FloCAD. The Thermal Desktop model includes an Air Revitalization System (ARS) Loop, a Suit Loop, a Cabin Loop, and Pressure Control System (PCS) for supplying make-up gas (nitrogen and oxygen (O2)) to the Cabin and Suit Loop. The ARS and PCS are designed to maintain air quality at acceptable O2, carbon dioxide (CO2) and humidity levels as well as internal pressures in the vehicle cabin and during suited operations. This effort required development of a suite of Thermal Desktop Orion ECLSS models to address the need for various simulation capabilities regarding ECLSS performance. An initial highly detailed model of the ARS Loop was developed to simulate rapid pressure transients (water hammer effects) within the ARS Loop caused by events such as cycling of the Pressurized Swing Adsorption (PSA) Beds and required high temporal resolution (small time steps) in the model during simulation. A second ECLSS model was developed to simulate events that occur over longer periods of time (more than 30 minutes) where O2, CO2, and humidity levels, as well as internal pressures, needed to be monitored in the cabin and for suited operations. Stand-alone models of the PCS and the Negative Pressure Relief Valve (NPRV) were developed to study thermal effects within the PCS during emergency scenarios (cabin leak) and cabin pressurization during vehicle reentry into Earth’s atmosphere. Results from the Orion ECLSS models were used during Orion Delta-PDR (July 2014) to address Key Design Requirements for Suit Loop operations for multiple mission scenarios.
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Imelda Stambaugh, NASA Johnson Space Center, USA
Bruce Conger, Jacobs, USA
Brad Eckhardt, UTC Aerospace Systems,USA
The 45th International Conference on Environmental Systems was held in Bellevue, Washington, USA on 12 July 2015 through 16 July 2015.