Evaluation of the carbon dioxide removal assembly requirements for the Space Station Freedom in the Manned Tended Capability through Permanently Manned Capability configurations

Analyses have been conducted to assess the capability of the Atmosphere Revitalization Subsystem to control ambient CO2 levels of the Space Station Freedom (SSF). The adequacy of the Carbon Dioxide Removal Assembly (CDRA) performance to meet design requirements has been evaluated. Analyses considered transient effects of crew location and metabolic loading on SSF Restructure configurations. The analyses consisted of computer simulations of on-orbit conditions using both supplier-provided and adjusted CO2 removal performance approximations along with derived crew metabolic activities and locations. Results show that while the current performance of the CDRA will maintain CO2 levels within specifications for Man-Tended Operations, it cannot maintain the SSF atmosphere below specifications during Permanently Manned Operations. Potential design options are discussed and other relevant analyses are summarized.