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The paper gives an update on an advanced development effort carried out under NASA Johnson Space Center (NASA/JSC) NAS 9-17775 by Ergenics Power Systems, Inc. (EPSI). The work was initiated in April 1987 to design and build a Fuel Cell Energy Storage System (FCESS) bench-test unit for the Space Station Freedom Extravehicular Mobility Unit (EMU). Fueled by oxygen and hydride stored hydrogen, the FCESS is being considered as an alternative to the EMU zinc-silver oxide battery. Superior cycle life and quick recharge are its main attributes. Design and performance of a non-venting 28V, 34 Ahr system with 7 amp rating are discussed. The FCESS is comprised of a 32-cell proton exchange membrane (PEM) stack, a metal hydride storage vessel and a control subsystem. The stack design incorporates passive product-water removal and thermal integration with the hydride vessel. The hydride vessel stores enough fuel for 5 hours.

The Major Constituent Analyzer (MCA) is a mass spectrometer-based atmospheric monitoring instrument in the Laboratory Module of the International Space Station (ISS). The MCA is used for continuous environmental monitoring of 6 major gas constituents in the ISS atmosphere as well as safety-critical monitoring for special Environmental Control and Life Support (ECLS) operations such as Pre-Breathe in the Airlock for Extra-Vehicular Activities (EVAs) and oxygen re-pressurizations. For the latter, it is desirable to make most efficient use of consumables by transferring the maximum amount from O2 re-supply tanks on board the shuttle or Progress. The upper safety limit for O2 transfer is constrained by the MCA measurement error bands. A study was undertaken to tighten these error bands and afford NASA-Mission Operations Directorate (MOD) more operational flexibility.

Extended manned missions to the lunar and martian surfaces pose new challenges for active thermal control systems (ATCS's). Moderate-temperature heat rejection becomes a problem during the lunar day, when the effective sink temperature exceeds that of the heat-rejection system. The martian atmosphere poses unique problems for rejecting moderate-temperature waste heat because of the presence of carbon dioxide and dust. During a recent study, several ATCS options including heat pumps, radiator shading devices, and single-phase flow loops were considered. The ATCS chosen for both lunar and martian habitats consists of a heat pump integral with a nontoxic fluid acquisition and transport loop, and vertically oriented modular reflux-boiler radiators. The heat pump operates only during the lunar day. The lunar and martian transfer vehicles have an internal single-phase water-acquisition loop and an external two-phase ammonia rejection system with rotating inflatable radiators.

Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites.

The Crew Exploration Vehicle (CEV), also known as Orion, will ferry a crew of up to six astronauts to the International Space Station (ISS), or a crew of up to four astronauts to the moon. The first launch of CEV is scheduled for approximately 2014. A stored water system on the CEV will supply the crew with potable water for various purposes: drinking and food rehydration, hygiene, medical needs, sublimation, and various contingency situations. The current baseline biocide for the stored water system is ionic silver, similar in composition to the biocide used to maintain quality of the water transferred from the Orbiter to the ISS and stored in Contingency Water Containers (CWCs). In the CEV water system, the ionic silver biocide is expected to be depleted from solution due to ionic silver plating onto the surfaces of the materials within the CEV water system, thus negating its effectiveness as a biocide.

Under a NASA sponsored technology development activity, Hamilton Sundstrand has designed, fabricated, tested and delivered a prototype solid amine-based carbon dioxide (CO2) and water (H2O) vapor removal system sized for Extravehicular Activity (EVA) operation. The prototype system employs two alternating and thermally-linked solid amine sorbent beds to continuously remove CO2 and H2O vapor from a closed environment. While one sorbent bed is exposed to the vent loop to remove CO2 and water vapor, the other bed is exposed to a regeneration circuit, defined as either vacuum or an inert sweep gas stream. A linear spool valve, coupled directly to the amine canister assembly, is utilized to simultaneously divert the vent loop flow and regeneration circuit flow between the two sorbent beds.

Under a cooperative agreement with NASA, Hamilton Sundstrand has successfully designed, fabricated, tested and delivered three, state-of-the-art, solid amine prototype systems capable of continuous CO2 and humidity removal from a closed, habitable atmosphere. Two prototype systems (CAMRAS #1 and #2) incorporated a linear spool valve design for process flow control through the sorbent beds, with the third system (CAMRAS #3) employing a rotary valve assembly that improves system fluid interfaces and regeneration capabilities. The operational performance of CAMRAS #1 and #2 has been validated in a relevant environment, through both simulated human metabolic loads in a closed chamber and through human subject testing in a closed environment.

The Urine Receptacle Assembly (URA) initially was developed for Apollo as a primary means of urine collection. The aluminum housing with stainless steel honeycomb insert provided all male crewmembers with a non-invasive means of micturating into a urine capturing device and then venting to space. The performance of the URA was a substantial improvement over previous devices but its performance was not well understood. The Crew Exploration Vehicle (CEV) program is exploring the URA as a contingency liquid waste management system for the vehicle. URA improvements are required to meet CEV requirements, including consumables minimization, flow performance, acceptable hygiene standards, crew comfort, and female crewmember capability. This paper presents the results of a historical review of URA performance during the Apollo program, recent URA performance tests on the reduced gravity aircraft under varying flow conditions, and a proposed development plan for the URA to meet CEV needs.

Fire detection, post fire atmospheric monitoring, fire extinguishing, and post fire atmospheric cleaning are vital components of a spacecraft fire response system, Preliminary efforts focused on the technology evaluation of fire detection, post fire atmospheric monitoring and post fire cleanup systems under realistic conditions are described in this paper. While the primary objective of testing is to determine the performance of a smoke mitigation filter, supplemental evaluations measuring the smoke-filled chamber handheld Commercial Off The Shelf (COTS) atmospheric monitoring devices (combustion product monitors) are conducted. The test chamber consists of a 1.4 cubic meter (50 cu. ft.) volume containing a smoke generator.

The NASA-developed space-suit configurations for Project Mercury and the Gemini Program originated from high-altitude-aircraft full-pressure-suit technology. These early suits lacked sophisticated mobility systems, since the suit served primarily as a backup system against the loss of cabin pressure and required limited pressurized intravehicular mobility functions for a return capability. Beginning with the Gemini Program, enhanced mobility systems were developed to enable crewmembers to perform useful tasks outside the spacecraft. The zero-prebreathe Hark III (ZPS Mk III) model of a higher operating pressure (57.2 kN/m2 (8.3 psi)) space-suit assembly represents a significant phase in the evolutionary development of a candidate operational space-suit system for the Space Station Program. The various design features and planned testing activities for the ZPS Mk III 57.2-kN/m2 (8.3 psi) space suit are described and identified.

A High Heat Flux Demonstration Program has been initiated to investigate and demonstrate the performance of a number of candidate cooling technologies to address the need of dissipating the large thermal loads and high heat fluxes associated with Directed Energy Weapons (DEW) systems. The technologies selected for these investigations utilize both single-phase and two-phase cooling concepts. The single-phase devices investigated are based upon the concept of jet impingement with and without extended surface areas. The two-phase devices investigated extend the jet impingement concepts into the liquid-vapor phase change regime, as well as a device based upon vapor injection spray cooling technology. In addition, all devices must demonstrate scalability. For each device a unit cooling cell has been defined and greater surface area capability is to be achieved with the addition of adjacent cells without significantly affecting the performance of neighboring cells.

This paper summarizes the first 5 plus years of on-orbit operation for the Major Constituent Analyzer (MCA). The MCA is an essential part of the International Space Station (ISS) Environmental Control and Life Support System (ECLSS). The MCA is a mass spectrometer instrument in the US Destiny Laboratory Module of the International Space Station. The MCA provides critical monitoring of six major atmospheric constituents (nitrogen (N2), oxygen (O2), hydrogen (H2), carbon dioxide (CO2), methane (CH4) and water vapor (H2O)) sampled continuously and automatically in all United States On-Orbit Segment (USOS) modules via the Sample Distribution System (SDS). Sample lines have been routed throughout the U.S. modules with valves to facilitate software-automated sequential sampling of the atmosphere in the various modules.

This paper summarizes the first seven plus years of on-orbit operation for the Major Constituent Analyzer (MCA). The MCA is an essential part of the International Space Station (ISS) Environmental Control and Life Support System (ECLSS). The MCA is a mass spectrometer instrument in the US Destiny Laboratory Module, which provides critical monitoring of six major atmospheric constituents (nitrogen (N2), oxygen (O2), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and water vapor (H2O)). These gases are sampled continuously and automatically in all United States On Orbit Segment (USOS) modules via the ISS Sample Delivery System (SDS). Continuous readout of the partial pressures of these gases is critical to verifying safe operation of the Atmosphere Re-vitalization (AR) system, Atmosphere Control System (ACS), and crew safety for Airlock Extravehicular Activity (EVA) preparation.

The International Space Station (ISS) United States Operational Segment (USOS) currently provides a Temporary Sleep Station (TeSS) as crew quarters for one crewmember in the Laboratory Module. The Russian Segment provides permanent crew quarters (Kayutas) for two crewmembers in the Service Module. The TeSS provides limited electrical, communication, and ventilation functionality. A new permanent rack sized USOS ISS Crew Quarters (CQ) is being developed. Up to four CQs can be installed into the Node 2 element to increase the ISS crewmember size to six. The new CQs will provide private crewmember space with enhanced acoustic noise mitigation, integrated radiation reduction material, controllable airflow, communication equipment, redundant electrical systems, and redundant caution and warning systems.

The International Space Station (ISS) Russian Segment currently provides potable water dispensing capability for crewmember food and beverage rehydration. All ISS crewmembers rehydrate Russian and U.S. style food packages from this location. A new United States On-orbit Segment (USOS) Potable Water Dispenser (PWD) is under development. This unit will provide additional potable water dispensing capability to support an on-orbit crew of six. The PWD is designed to provide incremental quantities of hot and ambient temperature potable water to U.S. style food packages. It will receive iodinated water from the Fuel Cell Water Bus in the U.S. Laboratory element. The unit will provide potable-quality water, including active removal of biocidal iodine prior to dispensing. A heater assembly contained within the unit will be able to supply up to 2.0 liters of hot water (65 to 93°C) every thirty minutes.

The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) was originally intended to be installed in ISS Node 3. The OGS rack delivery was accelerated, and it was launched to ISS in July of 2006 and installed in the US Laboratory Module. Various modification kits were installed to provide its interfaces, and the OGS was first activated in July of 2007 for 15 hours. In October of 2007 it was again activated for 76 hours with varied production rates and day/night cycling. Operational time in each instance was limited by the quantity of feedwater in a Payload Water Reservoir (PWR) bag. Feedwater will be provided by PWR bag until the USOS Water Recovery System (WRS) is delivered to ISS in fall of 2008. This paper will discuss operating experience and characteristics of the OGS, as well as operational issues and their resolution.

The International Space Station (ISS) is gaining many new capabilities in 2008. The delivery of the United States Operation Segment (USOS) Regenerative Environmental Control and Life Support (ECLS) Systems allow for the ISS crew expansion from 3 to 6 members. The ability to process recovered condensate and produce oxygen from water has been available on the Russian Segment (RS) since the astronauts and cosmonauts have been living on the ISS. The U.S. systems introduce the ability to process urine in addition to condensate greatly reducing the amount of water needed from the ground each year while also reducing the amount of time astronauts need to spend maintaining the systems. However, the interconnectedness of these systems may create operational difficulties and cause the loss of otherwise recoverable water. This paper outlines the current and future USOS and Russian system architectures, system interdependencies and the inter-segment relationships.

In this study, lightning effects on hydraulic transport elements in composite aircraft have been considered for the first time. Based on recent test results and analysis, several forms of possible structural damage and system component failures are presented. A unique approach in analysis has been taken to account that hydraulic transport elements, as a part of several aircraft systems, have a common interface with electrical wiring, and become complex electric networks. When an aircraft is exposed to a direct lightning strike, a metal skin on the wings and fuselage will conduct lightning currents in a way that only a small amount of induced electromagnetic energy will be present on hydraulic transport elements. So, in the past, hydraulic tubes, actuators, manifolds, and all other hydro-mechanical devices, as parts of various aircraft systems, have never been considered as lightning sensitive components.

The Major Constituent Analyzer (MCA) is a mass spectrometer system that measures the major constituents of the International Space Station (ISS) atmosphere. Experience has indicated that the operating life of the mass spectrometer is limited by the operating life of the ion pump, which maintains mass spectrometer vacuum. This paper summarizes the use of trend data from on orbit operations and ground testing to identify and understand the factors affecting ion pump life and to predict ion pump life on orbit. In addition, potential improvements currently under consideration to increase ion pump life, and therefore mass spectrometer life, are discussed.

The International Space Station Carbon Dioxide Removal Assembly (CDRA) uses regenerable adsorption technology to remove carbon dioxide (CO2) from cabin air. CO2 product water vapor measurements from a CDRA test bed unit at the NASA Marshall Space Flight Center were made using a tunable infrared diode laser differential absorption spectrometer (TILDAS) provided by NASA Glenn Research Center. The TILDAS instrument exceeded all the test specifications, including sensitivity, dynamic range, time response, and unattended operation. During the CO2 desorption phase, water vapor concentrations as low as 5 ppmv were observed near the peak of CO2 evolution, rising to levels of ∼40 ppmv at the end of a cycle. Periods of high water concentration (>100 ppmv) were detected and shown to be caused by an experimental artifact.