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This paper presents an overview of the Computer Aided Systems Engineering and Analysis (CASE/A)-ECLSS series which is designed as a generalised ECLSS design and analysis package. This system was developed under NASA MSEC contract NAS8-36407 to meet the Systems Analysis requirements of the Space Station ECLSS. The Space Station represents an order of magnitude increase in complexity over current Spacecraft technologies and will seriously tax current analysis techniques. This program is capable of simulating atmospheric revitalization systems, water recovery and management systems, and single phase active thermal control systems. The program evolved from both the G189A and the SINDA programs and shares the G189A architectural concepts. The designer/ analysis interface is graphics based and allows the designer to build a model by constructing a schematic of the system under consideration.

Recent development of the solid amine/water desorbed (SAWD) CO2 control system technology has resulted in two preprototype systems. The SAWD I system was developed under NASA Contract NAS9-13624 and is currently under test in the NASA Johnson Space Center, Crew Systems Division Advanced Environmental Control Systems (ECS) Laboratory. The SAWD II system is being developed at Hamilton Standard Division of United Technologies (HSD) under NASA Contract NAS9-16978. This paper reviews the development history of solid amine CO2 control systems and describes the SAWD I and SAWD II systems. In the development of the SAWD II system, special attention was given to reducing its power requirements and to designing the system to be compatible with zero-gravity operation. Energy saving features are discussed, and the zero-gravity solid amine canister test program and selected design are described.

This paper examines the ability of the space station intermodule ventilation system to maintain centralized control of CO2 removal and O2 supply. The resulting concentration gradients that will arise are calculated by assuming steady state, ideal gas, isothermal conditions, and perfect mixing of air within and between the pressurized elements. In order to estimate the degree of mixing actually obtained for a given ventilation scheme, a program has been developed under ECLSS Integration Analysis Contract NAS8-36407 for Marshall Space Flight Center based on a potential flow solution technique. Preliminary results from this study indicate that substantial short circuiting and recirculation air flow patterns could arise if a simple duct and diffuser air exchange method at the docking port interface were employed.

The Carbon Dioxide Removal Assembly (CDRA) is a part of the International Space Station (ISS) Environmental Control and Life Support (ECLS) system. The CDRA provides carbon dioxide (CO2) removal from the ISS on-orbit modules. Currently, the CDRA is the secondary removal system on the ISS, with the primary system being the Russian Vozdukh. Within the CDRA are two Desiccant/Adsorbent Beds (DAB), which perform the carbon dioxide removal function. The DAB adsorbent containment approach required improvements with respect to adsorbent containment. These improvements were implemented through a redesign program and have been implemented on units on the ground and returning from orbit. This paper presents a DAB design modification implementation description, a hardware performance comparison between the unmodified and modified DAB configurations, and a description of the modified DAB hardware implementation into the on-orbit CDRA.

The International Space Station (ISS) underwent a dramatic buildup in life support equipment since the delivery and activation of the U.S. Laboratory module in February 2001, followed by the Joint Airlock in July 2001. Since Laboratory activation, several Environmental Control and Life Support (ECLS) equipment failures have occurred. This paper addresses these failures, occurring through February 2002, and, where known, the root causes, with particular emphasis on probable micro-gravity causes are highlighted. Impact to overall ISS operations and proposed or accomplished fixes also are discussed.

The International Space Station continues to build up its life support equipment capability. Several ECLS equipment failures have occurred since Lab activation in February 2001. Major problems occurring between February 2001 and February 2002 were discussed in reference 1. Major problems occurring between February 2002 and February 2003 are discussed in this paper, as are updates from previously ongoing unresolved problems. This paper addresses failures, and root cause, with particular emphasis on likely micro-gravity causes. Impact to overall station operations and proposed and accomplished fixes will also be discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2006 and February 2007 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2007 and February 2008 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station continues to build up and operate its life support equipment. Major events occurring between February 2004 and February 2005 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major events of the last year of ISS operation. Impact to overall station operations is discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2005 and February 2006 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station (ISS) United States Laboratory module has been under test for approximately two years in the Space Station Processing Facility (SSPF) at NASA Kennedy Space Center (KSC) preparing for launch. Preparation activities for closing out the Environmental Control and Life Support (ECLS) system have included Closed Hatch testing to verify the capability of the life support equipment to support the crew, final manufacturing steps, and the close-out process itself. These activities were accomplished by an integrated Boeing and NASA team, located at the Johnson Space Center (Houston, Texas), Marshall Space Flight Center (Huntsville, Alabama) and Kennedy Space Center, Florida. On December 13, the Laboratory module hatches were sealed prior to loading into the Shuttle Orbiter payload bay for launch on February 7, 2001.

The International Space Station (ISS) program consists of three distinct phases. Phase 1 consists of the joint Shuttle-Mir missions. Phase 2 establishes the ISS initial research capability with a three person crew permanent presence. Phase 3 completes the assembly, establishing six person crew permanent presence with multiple International Partner (IP) research facilities. Phase 1 is nearing completion, while Phase 2 is in the subsystem delivery and element integration stage. This paper provides a status of the U.S. Environmental Control and Life Support (ECLS) system for Phases 2 and 3 of the ISS program, focusing on updates and changes in the past year.

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies which provide the basic life support functions to support the crew, while maintaining a safe and habitable shirt-sleeve environment. Significant progress has been made over the past year in preparing for the initial assembly phase of the ISS program, now scheduled to begin construction in November 1998. Almost all ECLS hardware supporting the Phase 2 ISS assembly period has been delivered, with significant element integration testing completed for the early elements. Additionally, design activities have begun on the U.S. Phase 3 regenerative ECLS hardware. This paper provides a summary of the U.S. Environmental Control and Life Support (ECLS) system activities over the past year.

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies which provide the basic life support functions to support the crew, while maintaining a safe and habitable shirt-sleeve environment. Significant progress has been made over the past year including initial assembly flights of the Functional Cargo Block (FGB) and Node 1 modules. The remaining Phase 2 elements have completed significant element integration testing with ECLS hardware deliveries complete, while the Phase 3 elements and regenerative ECLS design activities have continued. This paper provides a summary of the U.S. Environmental Control and Life Support (ECLS) system activities over the past year.

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies which provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S ECLS system activities over the past year, covering the period of time between May 1999 and April 2000. Assembly of the ISS has been delayed due to changes in element processing schedules. The 2A.1 logistics flight to ISS occurred in May 1999. The remaining Phase 2 elements have completed most of the element level testing and integration and are approaching final reviews for acceptance for flight. The Phase 3 regenerative ECLS designs have reached the Critical Design Review phase, while several of the Phase 3 elements have held Preliminary or Critical Design Reviews.

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between May 2000 and April 2001. Significant progress was made on assembly of the ISS, with permanent crew occupation established in November 2000. The Phase 2 portion of the assembly has just one additional flight scheduled prior to completion, with Flight 7A scheduled to bring the Airlock in June 2001. ISS budget limitations, which are still not completely resolved, have led to a reassessment of the late Phase 3 elements schedule and eventual growth to a seven person crew. The Node 3 regenerative ECLS design activities have continued with flight component manufacturing initiated.

With the advent of the Space Station Program, regenerative Environmental Control and Life Support Systems (ECLSS) are being considered to minimize logistics requirements. In addition to the potential to improve system performance and reduce life-cycle costs, rationale for adopting regenerative techniques . is based on sixteen years of National Aeronautics and Space Administration (NASA) sponsored regenerative ECLSS hardware development. This technological progress has been obtained through the Space Station Preprototype (SSP) and the Regenerative Life Support Evaluation (RLSE) programs, and ongoing Advanced Preprototype subsystem development and testing. The SSP program focused on regenerative life support techniques to satisfy projected goals of long-duration earth orbital missions.

A microgravity whole body shower (WBS) and a waste water recovery system (WWRS) were used in a closed loop test at the Johnson Space Center. The WWRS process involved chemical pretreatment, phase change distillation and post-treatment. A preprototype Thermoelectric Integrated Hollow Fiber Membrane Evaporation Subsystem (TIMES) was used for distillation after pretreatment and the post-treatment was accomplished with activated carbon, mixed ion exchange resin beds and microbial check valve (MCV) iodine bactericide dispensing units. The purposes of this test were to evaluate a NASA approved Shuttle soap for whole body showering comfort; evaluate the effects of the shower water on the WBS and the TIMES; and evaluate purification qualities of the recovered water in a closed loop operation.

The space station environmental control and life support system (ECLSS) is divided into seven functional groups: temperature and humidity control (THC), atmosphere control and supply (ACS), atmosphere revitalization (AR), fire detection and suppression (FDS), water recovery and management (WRM), waste management (WM), and EVA support (ES). This paper addresses the distribution among the modules of the ECLSS subsystems within each of these groups, both in terms of physical and functional distribution. The module resource requirements and safety implications, particularly with regard to safe haven operations are discussed. The implications of subsystem sizing are also addressed. The major recommendation is to physically distribute, but functionally centralize the air revitalization and potable water reclamation systems, while sizing each of these subsystems to support a six person crew under emergency conditions.

Future human space exploration missions present significant challenges for life support system (LSS) development. These life support systems will require incorporation of regenerative technologies to reduce or eliminate expendables and be low risk, demonstrating high reliability and long-term performance capability. A regenerative LSS for Space Station is a key step toward meeting these future space exploration requirements. In the development of the Space Station regenerative LSS, the challenges have been both technical and budgetary. Currently, the International Space Station Alpha (ISSA) program will consist of three Phases. Phase I will be MIR/Shuttle Orbiter flights with United States (US) crews attending to the various US flight experiments on-board the MIR. Phase II will consist mostly of Russian launched modules and the United States (US) Laboratory module. Phase III will launch the US Habitat module to implement US regenerative LSS.