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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.

A pressure regulating valve is a type of flow control device that is a combination of a control orifice and a flow compensator. The compensator orifice modulates its opening to regulate the flow rate at a constant pressure drop across the control orifice. The objective of this paper is an experimental and numerical analysis of flow compensation forces on pressure regulating valve applied on aircraft engine and control systems in a Fuel Metering Unit (FMU). The CFD analysis was applied to analyze and evaluate the various flow rates and patterns and thus estimate the pressure regulating control valve flow compensation force and characteristic curve. The CFD model is used to validate the dynamic behavior of the pressure regulating valve to bypass the fuel flow from a high pressure gear pump and to compensate burn flow of the metering valve. The model can then be used to evaluate and improve the design and operation of the valve for specific operations.

This paper addresses the issues of data reduction, visualization, clustering and classification for fault diagnosis and prognosis of the Liquid Cooling System (LCS) in an aircraft. LCS is a cooling system that consists of a left and a right loop, where each loop is composed of a variety of components including a heat exchanger, source control units, a compressor, and a pump. The LCS data and the fault correlation analysis used in the paper are provided by Hamilton Sundstrand (HS) - A United Technologies Company (UTC). This data set includes a variety of sensor measurements for system parameters including temperatures and pressures of different components, along with liquid levels and valve positions of the pumps and controllers. A graphical user interface (GUI) is developed in Matlab that facilitates extensive plotting of the parameters versus each other, and/or time to observe the trends in the data.

Materials used for manned space flight are tightly controlled to ensure the safety of the crewmembers. Significant changes to the economic environment as well as impact from environmental restrictions have resulted in material obsolescence that requires recertification or revalidation, increasing cost and risk to the program. This paper will review the impact this issue has had on the Shuttle Extravehicular Mobility Unit (EMU) Space Suit Assembly (SSA) and will provide insight into challenges expected for the Constellation Space Suit System (CSSS) program. Factors that affect availability, the impacts of material obsolescence, identification processes and risk reduction and management are described.

The health of inflatable structures, including space suits and habitats, is dependent upon the integrity of the gas retention structural layer. Inflatable structures typically utilize a coated fabric gas retention layer, or bladder. Threats such as Micrometeoroid and Orbital Debris (MMOD) penetration and inadvertent impact with sharp objects can cause a breach of the gas retention layer. Leakage as a result of bladder breach will impact operations due to loss of consumables and time spent locating and repairing the defect. Crew safety can be at risk where high rate leakage could cause loss of mission or loss of life. ILC has recently researched self-healing technologies that prevent leakage by closing penetrations of the gas retention structure and that are viable and scalable for various future missions and applications ranging from the Constellation Space Suit System (CSSS) to deployable lunar habitats. Several candidates of passive self-healing systems were studied.

Future spacesuit systems for the exploration of Mars will need to be much lighter than current designs, while at the same time reducing the consumption of water for crew cooling. One of the technology paths NASA has identified to achieve these objectives is the replacement of current high pressure oxygen storage technology in extravehicular activity (EVA) systems with cryogenic technology that can simultaneously reduce the mass of tankage required for oxygen storage and enable the use of the stored oxygen as a means of cooling the EVA astronaut. During the past year NASA has funded production of a prototype system demonstrating this capability in a design that will allow the cryogenic oxygen to be used in any attitude and gravity environment. This paper describes the design and manufacture of the prototype system. The potential significance and application of the system is also discussed.

During STS-116 extravehicular activity (EVA), a crewmember received a cut in the Glove Thermal Micrometeoroid Garment (TMG) as a result of contact with an unknown, external sharp object that did not meet sharp edge requirements. Since that mission, several additional gloves have experienced similar damage. Although sharp edge requirements exist for equipment interfaces with the space suits, damage to equipment can produce sharp edge conditions. In addition, crewmembers may be required to handle equipment or items not intended for crew contact resulting in exposure. This hazardous condition will still be possible for Constellation missions and therefore will continue to be a concern for the Constellation Space Suits System (CSSS) program. An investigation has been conducted into the cut glove TMG including material property reviews, material cut resistance properties, Glove response to cuts and system impacts.

Effective thermal and micrometeoroid protection as afforded by the Thermal Micrometeoroid Garment (TMG) is critical in achieving safe and efficient missions. It is also critical that the TMG does not increase torque or decreased range of motion which can cause crewmember discomfort, fatigue, and reduced efficiency. For future exploration missions, removable and replaceable TMGs will allow the use of different pressure garment protective covers and TMG configurations for launch, re-entry, 0-G Extra Vehicular Activity (EVA), and lunar surface EVA. A study was conducted with the goal of developing high Technology Readiness Level (TRL), scalable, interface design concepts for TMG systems. The affects of TMG segmentation on mobility and donning were assessed. Closure mechanisms were investigated and tested to determine their operability after exposure to lunar dust. A TMG configuration with the optimum number of segments and location of interfaces was selected for the Mark III spacesuit.

A trade study was conducted with a goal to develop relatively high TRL design concepts for an Exploration Cooling Garment (ExCG) that can accommodate larger metabolic loads and maintain physiological limits of the crewmembers health and work efficiency during all phases of exploration missions without hindering mobility. Effective personal cooling through use of an ExCG is critical in achieving safe and efficient missions. Crew thermoregulation not only impacts comfort during suited operations but also directly affects human performance. Since the ExCG is intimately worn and interfaces with comfort items, it is also critical to overall crewmember physical comfort. Both thermal and physical comfort are essential for the long term, continuous wear expected of the ExCG.

As part of NASA's initiative to develop an advanced portable life support system (PLSS), a baseline schematic has been chosen that includes gaseous oxygen in a closed circuit ventilation configuration. Supply oxygen enters the suit at the back of the helmet, passes over the astronaut's body, and is extracted at the astronaut's wrists and ankles through the liquid cooling and ventilation garment (LCVG). The extracted gases are then treated using a rapid cycling amine (RCA) system for carbon dioxide and water removal and activated carbon for trace gas removal before being mixed with makeup oxygen and reintroduced into the helmet. Thermal control is provided by a suit water membrane evaporator (SWME). As an extension of the original schematic development, NASA evaluated several Helmet Exhalation Capture System (HECS) configurations as alternatives to the baseline.

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 development of the Advanced Life Support (ALS) Sizing Analysis Tool (ALSSAT) using Microsoft® Excel was initiated by the Crew and Thermal Systems Division of the NASA Johnson Space Center (JSC) in 1997 to support the ALS and Exploration Offices in Environmental Control and Life Support System (ECLSS) design and studies. It aids the user in performing detailed sizing of the ECLSS for different combinations of Exploration Life Support (ELS) regenerative system technologies. This analysis tool will assist the user in performing ECLSS preliminary design and trade studies as well as system optimization efficiently and economically.

This paper addresses the issue of fault diagnosis in the heat exchanger of an aircraft Air Conditioning System (ACS). The heat exchanger cools the air by transferring the heat to the ram-air. Due to a variety of biological, mechanical and chemical reasons, the heat exchanger may experience fouling conditions that reduces the efficiency and could considerably affect the functionality of the ACS. Since, the access to the heat exchanger is limited and time consuming, it is preferable to implement an early fault diagnosis technique that would facilitate Condition Based Maintenance (CBM). The main contribution of the paper is pre-flight fault assessment of the heat exchanger using a combined model-based and data-driven approach of fault diagnosis. A Simulink model of the ACS, that has been designed and validated by an industry partner, has been used for generation of sensor data for various fouling conditions.

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.

The Portable Life Support System (PLSS) emergency oxygen system is being reexamined for the next generation of suits. These suits will be used for transit to Low Earth Orbit, the Moon and to Mars as well as on the surface of the Moon and Mars. Currently, the plan is that there will be two different sets of suits, but there is a strong desire for commonality between them for construction purposes. The main purpose of this paper is to evaluate what the emergency PLSS requirements are and how they might best be implemented. Options under consideration are enlarging the tanks on the PLSS, finding an alternate method of storage/delivery, or providing additional O2 from an external source. The system that shows the most promise is the cryogenic oxygen system with a composite dewar which uses a buddy system to split the necessary oxygen between two astronauts.

NASA's Exploration Architecture announced in September 2005, calls for development and flight of a Crew Exploration Vehicle (CEV) no later than 2014 and return to the moon by 2020 with a goal to reach and explore Mars. Intra-Vehicular Activity (IVA) suit systems will need to comfortably protect the crew during launch entry and abort scenarios. Extra-Vehicular Activity (EVA) suit systems will need to provide the capability to perform contingency zero-gravity EVA from the CEV as well as surface EVA to explore the moon and Mars. Studies currently underway to begin definition of the IVA and EVA suits point to a two suit architecture, the first being a launch, re-entry, and contingency EVA system used from CEV, the second and later being a lunar surface mobility suit only. An important consideration, yet to be determined, is the level of commonality between the early CEV and late Lunar suits.

ILC Dover, LP designed and manufactured a rear entry upper torso prototype for the I-Suit advanced spacesuit. In September 2005 ILC Dover participated in the Desert Research and Technology Study (RATS) led by the Advanced Extravehicular Activity (EVA) team from National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC). Desert RATS is a two-week remote field test at Meteor Crater, Arizona. Team members are from NASA, several universities, and a number of industry partners. These groups come together to gain hands-on experience with advanced spacesuit systems and to develop realistic requirements for future Moon and Mars exploration. Desert RATS gave ILC Dover the opportunity to put the rear entry I-Suit through many rigorous tests. The lessons learned there will be valuable for determining basic requirements for future lunar and Mars missions. Desert RATS utilizes a ‘learn-by-doing’ approach for understanding what future requirements should be developed.

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.

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.