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In order to estimate the exposure to a crew in space, there are three essential steps to be performed: first, the ambient radiation environment at the vehicle must be characterized; second, the mass distribution properties of the vehicle, including the crewmembers themselves must be developed, and third a model of the interactions of space radiations with matter must be employed in order to characterize the radiation field at the dose point of interest. The Space Radiation Analysis Group (SRAG) at the NASA, Johnson Space Center carries the primary responsibility for the operational radiation protection support function associated with manned space flight. In order to provide support during the various planning, execution, and analysis/recording phase activities associated with a given mission, tools have been developed to allow rapid, repeatable calculations of exposure on orbit.

A thermal analysis of the compressible carbon dioxide (CO2) flow for the Portable Fire Extinguisher (PFE) system has been performed. A SINDA/FLUINT model has been developed for this analysis. The model includes the PFE tank and the Temporary Sleep Station (TeSS) nozzle, and both have an initial temperature of 72 °F. In order to investigate the thermal effect on the nozzle due to discharging CO2, the PFE TeSS nozzle pipe has been divided into three segments. This model also includes heat transfer predictions for PFE tank inner and outer wall surfaces. The simulation results show that the CO2 discharge rates and component wall temperatures fall within the requirements for the PFE system. The simulation results also indicate that after 50 seconds, the remaining CO2 in the tank may be near the triple point (gas, liquid and solid) state and, therefore, restricts the flow.

This paper provides an overview of the IMMWPS Integrated Ground Test Program, completed at the NASA Johnson Space Center (JSC) during October and November 2001. The JSC Crew and Thermal Systems Division (CTSD) has developed the IMMWPS orbital flight experiment to test the feasibility of a microbe-based water purifier for use in zero-gravity conditions. The IMMWPS design utilizes a Microbial Processor Assembly (MPA) inoculated with facultative anaerobes to convert organic contaminants in wastewater to carbon dioxide and biomass. The primary purpose of the ground test program was to verify functional operations and procedures. A secondary objective was to provide initial ground data for later comparison to on-orbit performance. This paper provides a description of the overall test program, including the test article hardware and the test sequence performed to simulate the anticipated space flight test program. In addition, a summary of significant results from the testing is provided.

A closed-loop air revitalization system requires continuous removal of CO2 from the breathing air and an oxygen recovery system to recover oxygen from the waste CO2. Production of oxygen from CO2 is typically achieved by reacting CO2 with hydrogen in a reduction unit such as a Sabatier reactor. The air revitalization system of International Space Station (ISS) currently operates on an open loop mode where CO2 is being vented into the space vacuum due to lack of a Sabatier Reactor. A compressor and a storage device are required to interface the Carbon Dioxide Removal Assembly (CDRA) and the Sabatier reactor. This compressor must acquire the low-pressure CO2 from CDRA and provide it at a high enough pressure to the Sabatier reactor. The compressor should ensure independent operations of CDRA and Sabatier reactor at all times, even when their operating schedules are not synchronized.

In July 2001, during Space Shuttle Flight 7A, the Joint Airlock was added to the International Space Station (ISS) and utilized in performing the first extravehicular activity (EVA) from the ISS. Unlike previous airlock designs built by the United States or Russia, the Joint Airlock provides the ISS with the unique capability for performing EVAs utilizing either U.S. or Russian spacesuits. This EVA capability is made possible by the use of U.S.- and Russian- manufactured hardware items referred to as Servicing and Performance Checkout Equipment (SPCE) located in both the Joint Airlock's Equipment and Crew Locks. This paper provides a description for each SPCE item along with a summary of the requirements and capabilities provided in support of EVA events from the ISS Joint Airlock.

An analysis model has been developed for analyzing/optimizing the integration of a carbon dioxide removal assembly (CDRA), CO2 compressor, accumulator, and Sabatier CO2 reduction assembly. The integrated model can be used in optimizing compressor sizes, compressor operation logic, water generation from Sabatier, utilization of CO2 from crew metabolic output, and utilization of H2 from oxygen generation assembly. Tests to validate CO2 desorption, recovery, and compression had been conducted in 2002-2003 using CDRA/Simulation compressor set-up at NASA Marshall Space Flight Center (MSFC). An analysis of test data has validated CO2 desorption rate profile, CO2 compressor performance, CO2 recovery and CO2 vacuum vent in the CDRA model. Analysis / optimization of the compressor size and the compressor operation logic for an integrated closed air revitalization system is currently being conducted