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This paper summarizes the Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This paper covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies' to exchange messages and to perform audio tests of both inbound and outbound channels. This paper describes each test performed, defines the test, the data, and provides conclusions and recommendations.

As the US is getting ready for the Next Generation (NextGen) of Air Traffic System, there is a growing concern that the current techniques for verification and validation will not be adequate for the changes to come. The JPDO (in charge of implementing NextGen) has given NASA a mandate to address the problem and it resulted in the formulation of the V&V of Flight-Critical Systems effort. This research effort is divided into four themes: argument-based safety assurance, distributed systems, authority and autonomy, and, software intensive systems. This paper presents an overview of the technologies that will address the problem.

During the past two decades the occurrence of ice accretion within commercial high bypass aircraft turbine engines under certain operating conditions has been reported. Numerous engine anomalies have taken place at high altitudes that were attributed to ice crystal ingestion such as degraded engine performance, engine roll back, compressor surge and stall, and even flameout of the combustor. As ice crystals are ingested into the engine and low pressure compression system, the air temperature increases and a portion of the ice melts allowing the ice-water mixture to stick to the metal surfaces of the engine core. The focus of this paper is on estimating the effects of ice accretion on the low pressure compressor, and quantifying its effects on the engine system throughout a notional flight trajectory. In this paper it was necessary to initially assume a temperature range in which engine icing would occur.

Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice-crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations.

A new technique is proposed for computing particle concentrations and fluxes with Lagrangian trajectories. This method calculates particle concentrations based on the volume of a parcel element, or cloud, at the flux plane compared against the initial volume and is referred to as the Lagrangian Parcel Volume (LPV) method. This method combines the steady-state accuracy of area-based methods with the unsteady capabilities of bin-based methods. The LPV method results for one-dimensional (1D) unsteady flows and linear two-dimensional (2D) steady flows show that a quadrilateral element shape composed of a single parcel (with four edge particles) is capable of accurately predicting particle concentrations. However, nonlinear 2D flows can lead to concave or crossed quadrilaterals which produce significant numerical errors.

Particle trajectory and ice shape calculations were made for the Energy Efficient Engine (E₃) using the LEWICE3D Version 3 software. The particle trajectory and icing computations were performed using the new "block-to-block" collection efficiency method which has been incorporated into the LEWICE3D Version 3 software. The E₃ was developed by NASA and GE in the early 1980s as a technology demonstrator and is representative of a modern high bypass turbofan engine. The E₃ flow field was calculated using the NASA Glenn ADPAC turbomachinery flow solver. Computations were performed for the low pressure compressor of the E₃ for a Mach .8 cruise condition at 11,887 meters assuming a standard warm day for three drop sizes and two drop distributions typically used in aircraft design and certification. Particle trajectory computations were made for water drop sizes of 5, 20 and 100 microns.

The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations.

NASA is working to develop a new lunar lander to support lunar exploration. The development process that the Altair project is using for this vehicle is unlike most others. In “Lander Design Analysis Cycle 1” (LDAC-1), a single-string, minimum functionality design concept was developed, including life support systems for different vehicle configuration concepts. The first configuration included an ascent vehicle and a habitat with integral airlocks. The second concept analyzed was a combined ascent vehicle-habitat with a detachable airlock. In LDAC-2, the Altair team took the ascent vehicle-habitat with detachable airlock and analyzed the design for the components that were the largest contributors to the risk of loss of crew (LOC). For life support, the largest drivers were related to oxygen supply and carbon dioxide control. Integrated abort options were developed at the vehicle level.

Understanding the effects of dynamic thermal and vacuum regeneration on VOC desorption kinetics is needed for the development of regenerable trace contaminant control air revitalization systems. The effects of temperature and vacuum quality on the desorption kinetics of ethanol from Carbosieve SIII were examined using 1 hour regeneration cycles. The effect of vacuum quality on ethanol desorption was studied by exposing adsorption tubes loaded with ethanol to low pressures (1.0, 0.5, 0.3, and 0.12 atm) at various thermal regeneration temperatures (160, 100, 70, and 25 °C). At 1 atm of pressure, ethanol removal was found to increase from 2% at 25 °C, to 25% at 70 °C, to 55% at 100 °C, and to 77% at 160 °C. Decreasing the atmospheric pressure from 1 to 0.1 atm for 1 hr did not significantly enhance Carbosieve SIII regeneration at ambient temperatures (25 °C). However, heating the adsorbent at low pressures enhanced its regeneration.

Silver biocide offers a potential advantage over iodine, the current state-of-the-art in US spacecraft disinfection technology, in that silver can be safely consumed by the crew. As such, silver may reduce the overall complexity and mass of future spacecraft potable water systems, particularly those used to support long duration missions. A primary technology gap identified for the use of silver biocide is one of material compatibility. Wetted materials of construction are required to be selected such that silver ion concentrations can be maintained at biocidally effective levels.

Carbosieve SIII was used to filter dichloromethane (DCM) from a simulated spacecraft gas stream. This adsorbent was tested as a possible commercial-off-the-shelf (COTS) filtration solution to controlling spacecraft air quality. DCM is a halocarbon commonly used in manufacturing for cleaning and degreasing and is a typical component of equipment offgassing in spacecraft. The performance of the filter was measured in dry and humid atmospheres. A known concentration of DCM was passed through the adsorbent at a known flow rate. The adsorbent removed dichloromethane until it reached the breakthrough volume. Carbosieve SIII exposed to dry atmospheric conditions adsorbed more DCM than when exposed to humid air. Carbosieve SIII is a useful thermally regenerated adsorbent for filtering DCM from spacecraft cabin air. However, in humid environments the gas passes through the filter sooner due to co-adsorption of additional water vapor from the atmosphere.

This work describes the microbiological assessment and materials compatibility of a silver-based biocide as an alternative to iodine for the Crew Exploration Vehicle (CEV) and future spacecraft potable water systems. In addition to physical and operational anti-microbial counter-measures, the prevention of microbial growth, biofilm formation, and microbiologically induced corrosion in water distribution and storage systems requires maintenance of a biologically-effective, residual biocide concentration in solution and on the wetted surfaces of the system. Because of the potential for biocide depletion in water distribution systems and the development of acquired biocide resistance within microbial populations, even sterile water with residual biocide may, over time, support the growth and/or proliferation of bacteria that pose a risk to crew health and environmental systems.

A lab-scale testbed for screening and characterizing the chemical specificity of commercial “off-the-shelf” (COTS) polymer adsorbents was built and tested. COTS polymer adsorbents are suitable candidates for future trace contaminant (TC) control technologies. Regenerable adsorbents could reduce overall TC control system mass and volume by minimizing the amounts of consumables to be resupplied and stored. However, the chemical specificity of these COTS adsorbents for non-methane volatile organic compounds (NMVOCs) (e.g., methanol, ethanol, dichloromethane, acetone, etc) commonly found in spacecraft is unknown. Furthermore, the effect of humidity on their filtering capacity is not well characterized. The testbed, composed of a humidifier, an incubator, and a gas generator, delivers NMVOC gas streams to conditioned sorbent tubes.

Advanced water processors being developed for NASA's Exploration Initiative rely on phase change technologies and/or biological processes as the primary means of water reclamation. As a result of the phase change, volatile compounds will also be transported into the distillate product stream. The catalytic reactor assembly used in the International Space Station (ISS) water processor assembly, referred to as Volatile Removal Assembly (VRA), has demonstrated high efficiency oxidation of many of these volatile contaminants, such as low molecular weight alcohols and acetic acid, and is considered a viable post treatment system for all advanced water processors. To support this investigation, two ersatz solutions were defined to be used for further evaluation of the VRA. The first solution was developed as part of an internal research and development project at Hamilton Sundstrand (HS), and is based primarily on ISS experience related to the development of the VRA.

Selecting the appropriate atmosphere for a spacecraft and mission is a complicated problem. NASA has previously used atmospheres from Earth normal composition and pressure to pure oxygen at low pressures. Future exploration missions will likely strike a compromise somewhere between the two, trying to balance operation impacts on EVA, safety concerns for flammability and health risks, life science and physiology questions, and other issues. Life support systems and internal thermal control systems are areas that will have to respond to changes in the atmospheric composition and pressure away from the Earth-like conditions currently used on the International Space Station. This paper examines life support and internal thermal control technologies currently in use or in development to find what impacts in design, efficiency and performance, or feasibility might be expected.

NASA's plans to implement the Vision for Space Exploration include extensive human-robot cooperation across an enterprise spanning multiple missions, systems, and decades. To make this practical, strong enterprise-level interface standards (data, power, communication, interaction, autonomy, and physical) will be required early in the systems and technology development cycle. Such standards should affect both the engineer and operator roles that humans adopt in their interactions with robots. For the engineer role, standards will result in reduced development lead-times, lower cost, and greater efficiency in deploying such systems. For the operator role, standards will result in common autonomy and interaction modes that reduce operator training, minimize workload, and apply to many different robotic platforms. Reduced quantities of spare hardware could also be a benefit of standardization.

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.

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.

One of the most critical functions of ECLSS is to maintain the atmospheric oxygen concentration within habitable limits. On the ISS, this function is provided by the Major Constituent Analyzer (MCA). During ISS (International Space Station) crew increments 7 thru 9, the MCA was at risk of imminent failure as evident by sustained high ion-pump current levels. In the absence of continuous constituent measurement by the MCA, manual methods of estimating partial pressure of oxygen (ppO2) and concentration levels need to be developed and validated to: (1) ensure environmental control and life support, (2) prohibit ISS system and hardware damage, and (3) enable planned ISS activities that effect constituent balance.

Aviation Data Integration System (ADIS) project explores methods and techniques for integrating heterogeneous aviation data to support aviation problem-solving activity. Aviation problem-solving activities include: engineering troubleshooting, incident and accident investigation, routine flight operations monitoring, flight plan deviation monitoring, safety assessment, maintenance procedure debugging, and training assessment. To provide optimal quality of service, ADIS utilizes distributed intelligent agents including data collection agents, coordinator agents and mediator agents. This paper describes the proposed agent-based architecture of the Aviation Data Integration System (ADIS).