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An expert system based Environmental Control and Life Support System (ECLSS) trade study tool is under development which calculates resource requirements and penalties for given system configurations and mission definition parameters. The user friendly, graphical software application allows important ECLSS resources such as power, mass, volume, resupply mass (consumable and expendable), heat rejection and ultimately cost to be analyzed in an efficient hierarchical manner. Hardware resources are calculated using scaling algorithms specific to each technology, based on existing hardware where possible. Fluid mass balances are tracked and summarized as fluids input into the system and waste output leaving the system. This tool will aid in technology selection and optimization of transportation vehicle or surface habitat designs.

As manned spacecraft have evolved into larger and more complex configurations, the mandate for preventing, detecting, and extinguishing on-board fires has grown proportionately to ensure the success of progressively ambitious missions. The closed environment and high value of manned spacecraft offer the Fire Detection and Suppression (FDS) systems designer significant challenges. With the presence of Oxygen (O2), flammable materials, and ignition sources, it is impossible to completely remove the likelihood of a spacecraft fire. Manned spacecraft contain these three ingredients for fire; therefore, it becomes profitable to review past designs of FDS systems and ground testing to determine system performance and lessons learned in the past for present and future applications.

Long duration microgravity missions will require management of both free and dissolved gases in the numerous liquid fluid systems flown on spacecrafts. The multitude of possible problem areas associated with gas accumulation are presented along with the expected sources of the gas itself. A technology program has been initiated to address these concerns for future exploration missions. Research, analyses, and hardware prototyping are being employed to fully understand the problems and help implement design solutions. Our first hardware prototype utilizes semi-permeable hydrophobic membranes for gas removal that effectively eliminate free gas buildup in fluid systems by maintaining dissolved gas levels below the saturation point. The small, lightweight unit is currently undergoing development testing with promising results as discussed in the paper.

The Space Station Freedom Program (SSFP) has undergone major design changes within the last year due to reduced budget appropriations imposed by Congress. This paper outlines the impacts of the design changes on the Environmental Control and Life Support System (ECLSS), with emphasis on the system aspects of the ECLSS. Brief descriptions of design impacts to all six ECLSS subsystems are provided in addition to interactions with other distributed systems such as Data Management, Electrical Power, and Man Systems. The assembly sequence for SSF is addressed with emphasis on key flights with respect to the ECLSS.

This paper presents an updated overview of the Computer Aided System Engineering and Analysis (CASE/A)-ECLSS series modeling package. CASE/A is an Environmental Control and Life Support System (ECLSS) and Active Thermal Control System (ATCS) analysis and trade study tool developed primarily for VAX mainframe usage. The program was developed under NASA MSFC contract NAS8-36407 and is currently being used by MSFC and selected support contractors to support their Space Station Freedom WP-01 ECLSS preliminary design modeling activities. Many new additions and enhancements to the program have been incorporated since the first paper was presented on the topic three years ago. An extensive components verification program was completed to assure component modeling validity based on actual test data from the Phase II comparative test program recently completed at MSFC.