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Metabolic heat regenerated temperature swing adsorption (MTSA) technology is being developed for removal and rejection of carbon dioxide (CO2) and heat from a portable life support system (PLSS) to the Martian environment. Previously, hardware was built and tested to demonstrate using heat from simulated, dry ventilation loop gas to affect the temperature swing required to regenerate an adsorbent used for CO2 removal. New testing has been performed using a moist, simulated ventilation loop gas to demonstrate the effects of water condensing and freezing in the heat exchanger during adsorbent regeneration. Also, the impact of MTSA on PLSS design was evaluated by performing thermal balances assuming a specific PLSS architecture. Results using NASA's Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT), a PLSS system evaluation tool, are presented.

The Sensory Prognostics and Management Systems (SPMS) program sponsored by the Federal Aviation Administration and Boeing developed and evaluated designs to integrate advanced diagnostic and prognostic (i.e., Integrated Vehicle Health Management (IVHM) or Health Management (HM)) capabilities onto commercial airplanes. The objective of the program was to propose an advanced HM system appropriate for legacy and new aircraft and examine the technical requirements and their ramifications on the current infrastructure and regulatory guidance. The program approach was to determine the attractive and feasible HM applications, the technologies that are required to cost effectively implement these applications, the technical and certification challenges, and the system level and business consequences of such a system.

A number of amine-based carbon dioxide (CO2) removal systems have been developed for atmosphere revitalization in closed loop life support systems. Most recently, Hamilton Sundstrand has developed an amine-based sorbent, designated SA9T, possessing approximately 2-fold greater capacity compared to previous formulations. This new formulation has demonstrated applicability for controlling CO2 levels within vehicles and habitats as well as during extravehicular activity (EVA). Our current data demonstrates an amine-based system volume which is competitive with existing technologies which use metal oxides (Metox) and lithium hydroxide sorbents. Further enhancements in system performance can be realized by incorporating humidity and trace contaminant control functions within an amine-based atmosphere revitalization system. A 3-year effort to develop prototype hardware capable of removing CO2, H2O, and trace contaminants from a cabin atmosphere has been initiated.

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.

Carrier Injection Sensorless (CIS) rotor position estimation for electric machines depends on the rotor saliency “seen” from the stator terminals. Compared to permanent magnet and induction machines, wound field synchronous machine rotor saliency characteristics are more complex. At typical carrier frequencies subtransient characteristics dominate. Injecting positively rotating carrier voltages at the stator terminals of a machine having rotor saliency produces both positively and negatively rotating carrier currents. The impedances relating currents to injected carrier voltages are derived from the dq reference frame synchronous machine model. Analytical results are compared to simulation and limited test results for an aircraft starter/generator.

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.

Metabolically produced carbon dioxide (CO2) removal in spacesuit applications has traditionally been accomplished utilizing non-regenerative Lithium Hydroxide (LiOH) canisters. In recent years, regenerative Metal Oxide (MetOx) has been developed to replace the Extravehicular Mobility Unity (EMU) LiOH canister for extravehicular activity (EVA) missions in micro-gravity, however, MetOx may carry a significant weight burden for potential use in future Lunar or planetary EVA exploration missions. Additionally, both of these methods of CO2 removal have a finite capacity sized for the particular mission profile. Metabolically produced water vapor removal in spacesuits has historically been accomplished by a condensing heat exchanger within the ventilation process loop of the suit life support system.

Under a NASA-sponsored technology development project, a multi-disciplinary team consisting of industry, academia, and government organizations lead by Hamilton Sundstrand is developing an amine-based humidity and CO2 removal process and prototype equipment for Vision for Space Exploration (VSE) applications. Originally this project sought to research enhanced amine formulations and incorporate a trace contaminant control capability into the sorbent. In October 2005, NASA re-directed the project team to accelerate the delivery of hardware by approximately one year and emphasize deployment on board the Crew Exploration Vehicle (CEV) as the near-term developmental goal. Preliminary performance requirements were defined based on nominal and off-nominal conditions and the design effort was initiated using the baseline amine sorbent, SA9T.

This paper presents and discusses the results of an integrated 4-Bed Molecular Sieve (4BMS), mechanical compressor, and Sabatier Engineering Development Unit (EDU) test. Testing was required to evaluate the integrated performance of these components of a closed loop atmosphere revitalization system together with a proposed compressor control algorithm. A theoretical model and numerical simulation had been used to develop the control algorithm; however, testing was necessary to verify the simulation results and further refine the model. Hardware testing of a fully integrated system also provided a better understanding of the practical inefficiencies and control issues, which are unavailable from a theoretical model.

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.

Atmospheric monitoring is one of the most important elements in life support aboard U.S. Navy nuclear submarines. The Central Atmosphere Monitoring Systems have reliably served the U.S. Navy by accurately monitoring life gases and contaminants for nearly 30 years. However, as new knowledge of chemical effects on human health increases, the demand for monitoring additional compounds in these closed environments is also increasing. As a result, expanded capability for detecting trace compounds becomes more important and a next-generation monitoring system is warranted. In addition to improved analytical performance, the trend for submarine operation is to increase the degree of distribution and automation to minimize the resources needed for operation and maintenance. It is therefore desirable to incorporate the monitoring instrumentation into the atmosphere control system to provide real-time feedback and automated control.

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.

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006. Tests were run at a variety of cabin temperatures and with a range of operating conditions varying cycle time, vacuum pressure, air flow rate, and crew activity levels.

Under a NASA-sponsored technology development project, a multi-disciplinary team consisting of industry, academia, and government organizations led by Hamilton Sundstrand is developing an amine based humidity and carbon dioxide (CO2) removal process and prototype equipment for Vision for Space Exploration (VSE) applications. This system employs thermally linked amine sorbent beds operating as a pressure swing adsorption system, using the vacuum of space for regeneration. The prototype hardware was designed based on a two fault tolerant requirement, resulting in a single system that could handle the metabolic water and carbon dioxide load for a crew size of six. Two, full scale prototype hardware sets, consisting of a linear spool valve, actuator and amine sorbent canister, have been manufactured, tested, and subsequently delivered to NASA JSC. This paper presents the design configuration and the pre-delivery performance test results for the CAMRAS hardware.

A Distributed Engine Control Working Group (DECWG) consisting of the Department of Defense (DoD), the National Aeronautics and Space Administration (NASA)- Glenn Research Center (GRC) and industry has been formed to examine the current and future requirements of propulsion engine systems. The scope of this study will include an assessment of the paradigm shift from centralized engine control architecture to an architecture based on distributed control utilizing open system standards. Included will be a description of the work begun in the 1990's, which continues today, followed by the identification of the remaining technical challenges which present barriers to on-engine distributed control.

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.