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Assessment of Lithium Hydroxide Conservation Via International Space Station Control of Orbiter Carbon Dioxide
ISSN: 0148-7191, e-ISSN: 2688-3627
Published July 15, 2002 by SAE International in United States
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In order to conserve mass and volume, it was proposed that the International Space Station (ISS) control the level of carbon dioxide (CO2) in the Space Shuttle Orbiter while the Orbiter is docked to the ISS. If successful, this would greatly reduce the number of lithium hydroxide (LiOH) canisters required for each ISS-related Orbiter mission.
Because of the impact on the Orbiter Environmental Control and Life Support Subsystem (ECLSS), as well as on the Orbiter flight manifest, a Space Shuttle Program (SSP) analysis was necessary.
STS-108 (ISS UF1) pre-flight analysis using the Personal Computer Thermal Analyzer Program (PCTAP) predicted that the ISS would be able to control the level of CO2 in the Orbiter (and throughout the stack) under nominal conditions with no supplemental LiOH required. This analysis assumed that the Carbon Dioxide Removal Assembly (CDRA) located in the U.S. Lab would be operating in its off-nominal “single bed” mode, and that the Vozdukh CO2 removal system located in the Service Module would be in its highest performance mode of operation.
Post-flight analysis was also conducted in order to fine-tune and expand the pre-flight analysis.
This paper will assess the assumptions and predictions of the PCTAP analysis, explain any discrepancies between the analysis and flight data, provide suggestions for improvement of the analysis, make predictions for future flights based on changes in Environmental Control and Life Support (ECLS) hardware performance or system configuration, and suggest performance improvements for future missions.
CitationDunaway, B., "Assessment of Lithium Hydroxide Conservation Via International Space Station Control of Orbiter Carbon Dioxide," SAE Technical Paper 2002-01-2271, 2002, https://doi.org/10.4271/2002-01-2271.
- Kanon, Eric C., Rockwell International, Personal Computer Thermal Analyzer Program, SSD96D0552, Revision B, October 1996.
- Martin Marietta Company, Thermal Radiation Analyzer System (TRASYS), MCR 73-105, Revision 5, June 1983.
- Martin Marietta Company, Systems Improved Numerical Differencing Analyzer (SINDA), MCR-90-512, Revision 4, March 1990.
- Dunaway, Brian R., Rockwell International, Employing TRASYS Database for PC Model, SE-TSAT-95-043, 2 June 1995.
- A fuller explanation of this database can be found in a paper by Dunaway, Brian R., Boeing, and Edeen, Marybeth, NASA JSC, Orbiter Capability for Providing Water to the International Space Station according to the Most Probable Flight Attitudes, presented at the International Conference on Environmental Systems, Toulouse, France, July 2000, 2000-01-2518.
- The test data was extracted from a paper by Knox, James C., NASA MSFC, International Space Station Carbon Dioxide Removal Assembly Testing, presented at the International Conference on Environmental Systems, Toulouse, France, July 2000, 2000-01-2345, Figures 7 through 10.
- The Vozdukh mode referred as “ideal” corresponds to “Mode 5” operation.
- Thacker, Karen, The Boeing Company, ECLSS/Active Thermal Control, Houston, STS-108 ECLSS/Payload Thermal Compatibility Verification Analysis, HSF&E01HB775, October 2001.
- Documented via electronic mail from Dunaway Brian to Metcalf Jordan, et al., “Best Guess CO2 Control Performance for STS-108 DTO,” 20 Nov 2001, 09:26:27.
- There is very poor “visibility” into the operation of the Vozdukh.
- It is understood that shortly after the mission the U.S. Lab CO2 sensor failed.
- However, during STS-110 (ISS 8A), the Vozdukh appeared to be operating in “Mode 5.”
- Dunaway, Brian R., Boeing, Study Regarding Crewmember Water Vapor Generation Rates, presented at the International Conference on Environmental Systems, Orlando, Florida, July 2001, 2001-01-2150.