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As humans move into outer space, need for air, clean water and food require that green plants be grown within all planetary colonies. The complexities of ecosystems require a sophisticated understanding of the interactions between the atmosphere, all nutrients, and life forms. While many experiments must be done to find the relationships between mass flows and chemical/energy transformations, it seems necessary to develop generalized models to understand the limitations of plant growth. Therefore, it is critical to have a robust modelling capability to provide insight into potential problems as well as to direct efficient experimentation. Last year we reported on a simple leaf model which focused upon the mass transfer of gases, radiation/heat balances, and the production of photosynthetically produced carbohydrate. That model indicated some of the plant processes which had to be understood in order to obtain parameters specific for each species.

Contamination control is a critical safety requirement imposed on experiments flying on board the Spacelab. The General Purpose Work Station, a Spacelab support facility used for life sciences space flight experiments, is designed to remove volatile compounds from its internal airpath and thereby minimize contamination of the Spacelab. This is accomplished through the use of a large, multi-stage filter known as the Trace Contaminant Control System. Many experiments planned for the Spacelab require the use of toxic, volatile fixatives in order to preserve specimens prior to post-flight analysis. The NASA-Ames Research Center SLS-2 payload, in particular, necessitated the use of several toxic, volatile compounds in order to accomplish the many inflight experiment objectives of this mission. A model was developed based on earlier theories and calculations which provides conservative predictions of the resultant concentrations of these compounds given various spill scenarios.

As mission length and the number and complexity of payload experiments increase, so does the probability of thermodegradation contingencies (e.g. fire, chemical release and/or smoke from overheated components or burning materials), which could affect mission success. When a thermodegradation event occurs on board a spacecraft, potentially hazardous levels of toxic gases could be released into the internal atmosphere. Experiences on board the Space Shuttle have clearly demonstrated the possibility of small thermodegradation events occurring during even relatively short missions. This paper will describe the Combustion Products Analyzer (CPA), which is being developed under the direction of the Toxicology Laboratory at Johnson Space Center to provide necessary data on air quality in the Shuttle following a thermodegradation incident.

A number of specimen life performance tests were conducted on three test lubricants selected to demonstrate their gross ranking capabilities. The results indicated that the test rigs should be used only for gross ranking. A large difference in magnitude of life values were obtained even though agreement in gross ranking was obtained by three out of the five participating laboratories. Further testing is recommended under preselected test conditions and lubricants.

Nickel-5 Aluminum (95 % Nickel-5 % Aluminum) is widely used in the aircraft engine industry. The excellent adhesive and cohesive strength of the coating, oxidation resistance and machinability make it an ideal material as both a bond coat for subsequent topcoats and as a build up material for dimensional restoration of worn or mismachined components. Plasma spraying has traditionally been the thermal spray process used to apply nickel aluminum, and the technical properties and performance characteristics are well documented. More recently, wire arc sprayed nickel aluminum is becoming widely used as an alternative to plasma spraying due to higher bond strengths, reproducibility, better machinability and more favorable economics. This paper presents the results of a testing program designed to compare the technical properties of arc sprayed versus plasma sprayed Nickel-5 Aluminum coatings.

A general computer program has been developed for analytic fatigue crack growth. It is designed so that the user does not need to have an extensive background in Fracture Mechanics Theory. This FORTRAN program can analyze the growth of most common types of cracks and accounts for the transition from part-thru to completely thru-the-thickness crack. The input loading may be a mission profile or arbitrary cyclic stresses with or without concentrated loads and may be repeated a number of times. There are built-in corrections for geometry, plastic-zone size, plane-stress vs. plane-strain and applicability of Linear-Elastic-Fracture-Mechanics, and there are options available for crack growth rate calculations, retardation models and plastic zone corrections.

Successful trace chemical contamination control is one of the components necessary for achieving good cabin atmospheric quality. While employing seemingly simple process technologies, sizing the active contamination control equipment must employ a reliable design basis for the trace chemical load in the cabin atmosphere. A simplified design basis that draws on experience gained from the International Space Station program is presented. The trace chemical contamination control design load refines generation source magnitudes and includes key chemical functional groups representing both engineering and toxicology challenges.

The fastener analysis for an airframe panels under random cyclic loading conditions were analyzed with various elaborate solutions. But here a simple technique is proposed to analyze the problem and prove the necessity for a design solution. It is shown that the misfit in the fastener system reduces the load capacity of the joint due to the lack of contact or reduced contact. This reduced contact also produces various stress concentration at the contact zones. In the cyclic loading environment this reduced load capacity and increased stress concentration produces elastic plastic deformation around the contact locations and at the same time a crack develops and propagates beyond the fastener system. This creates a load leak transparent to the fastener system. Thus the misfit fastener systems have a higher probability of aging than the fit fasteners. With the proof in hand various design patterns were proposed to improve the fatigue characters under varying types of loading conditions.

The BSTCA (Battery Section Thermal Control Assembly) is a module of the Columbus MTFF (Man Tended Free Flyer). Electrical power required during eclipse periods, is made available from six nickel hydrogen batteries. A sophisticated multi-radiator configuration, with a hybrid heat pipe network, has evolved. Autonomous control of the assembly heat rejection capability has been achieved by a integrated network of LTHP's (Liquid Trap Heat Pipes) and CCHP's (Constant Conductance Heat Pipes) under the control of a conventional HCU (Heater Control Unit). The process of design selection and verification is discussed, for the BSTCA, with a detailed LTHP component presentation.

As mankind explores the planets, human needs for air, clean water, and food suggest that plants be carried to and exist on his colonies. The complexities of even a simple ecosystem of humans and a single plant crop require a sophisticated understanding of the interactions between atmosphere, nutrients and lifeforms. While many experiments could be done to find the relationships between mass flows and chemical/energy transformations, it would be simpler to develop a generalized model of plant growth, to validate it, and to use it to test the variations possible within a closed environment. Such a model specifically designed for a closed space system should focus on gas mass transfers through the photosynthetic processes, leaf radiation/heat balances, and the production/distribution of carbohydrates.

One of the major problems faced in Extravehicular Activity (EVA) glove development has been the absence of concise and reliable methods to measure the effects of EVA gloves on human-hand capabilities. NASA has sponsored a program to develop a standardized set of tests designed to assess EVA-gloved hand capabilities in six performance domains: Range of Motion. Strength, Tactile Perception, Dexterity, Fatigue, and Comfort, Based upon an assessment of general human-hand functioning and EVA task requirements, several tests within each performance domain were developed to provide a comprehensive evaluation. All tests were designed to be conducted in a glove box with the bare hand, an EVA glove without pressure, an EVA glove at operation pressure. Thus, the differential effect on performance of the glove with and without pressure was tested. Bare hand performance was used to “calibrate” the effects. Ten subjects participated in the test setup as a repeated-measures experimental design.

The problems involved in resonance response of structual elements are examined in a somewhat different perspective. Important basic principles are briefly stated and supported with experimental data. Fundamental conditions delineated by a simple elastic system in one degree of freedom are found to be applicable with due modifications to an apparently nonlinear behavior. The use of a “Duffing’s curve” is established with adaptations to random responses.

Yardney Technical Products is developing a high energy density Li-ion cell tailored for NASA's Extravehicular Mobility Unit battery. The goal of the program is to develop a Li-ion technology which offers long storage and cycle life in a system which provides energy density and exercise performance comparable to the current 6.7kg Zn-AgO battery. The Zinc-Silver Oxide cells which are most commonly used in this application provide 400 Wh/l with a 32 cycle life at 26.6Ah and 1.55V with a rated wet life of 425 days. To improve the energy density of the Li-ion cells we have focused on improving the energy density of its components. In addition to using thin metal foil current collectors, the energy density of the cathode material was improved by utilizing a high capacity Co doped nickel oxide material. Further efforts have focused on developing a more energy dense carbonaceous anode material. The results of this effort are reviewed.

Specifications describing performance characteristics for lubricating oils are examined. The author describes the engine performance requirements, and physical and chemical tests required by the military and by the leading automobile manufacturers. Specifications for passenger car automatic transmission fluids are also examined, as are synthetic aircraft lubricants for commercial and military use.

Mathematical modeling of the Ni-H2 cell based on the fundamental electrochemical processes is necessary for accurately simulating the battery behavior on Space Station Freedom. Accurate predictions are incorporated as part of the development of the Space Station Electric Power System simulation. This simulation will be used to develop and test control algorithms which will maximize the available power in the most efficient way. This is a deviation from the approach used on smaller satellite power systems which are designed with substantial margin. Hence, the use of an empirical battery model is not feasible due to its low fidelity. This paper covers the electrochemical theory related to the Ni-H2 cells, and the analysis of experimental data used to develop relations between the cell state of charge and certain cell properties. Theoretical results are compared against well-documented experimental data.

Thermo-mechanical fatigue and natural aging due to environmental conditions are difficult to simulate in an actual test with the advanced fiber-reinforced composites, where their fatigue and aging behavior is little understood. Predictive modeling of these processes is challenging. Thermal cyclic tests take a prohibitively long time, although the strain rate effect can be scaled well for accelerating the mechanical stress cycles. Glass fabric composites have important applications in aircraft and spacecraft structures including microwave transparent structures, impact-resistant parts of wing, fuselage deck and many other load bearing structures. Often additional additively manufactured features and coating on glass fabric composites are employed for thermal and anti-corrosion insulations. In this paper we employ a thermo-mechanical fatigue model based accelerated fatigue test and life prediction under hot to cold cycles.

Aerospace structural components grapple with the pressing issue of high-cycle fatigue-induced micro-crack initiation, especially in high-performance alloys like Titanium and super alloys. These materials find critical use in aero-engine components, facing a challenging combination of thermo-mechanical loads and vibrations that lead to gradual dislocations and plastic strain accumulation around stress-concentrated areas. The consequential vibration or overload instances can trigger minor cracks from these plastic zones, often expanding unpredictably before detection during subsequent inspections, posing substantial risks. Effectively addressing this challenge demands the capability to anticipate the consequences of operational life and aging on these components. It necessitates assessing the likelihood of crack initiation due to observed in-flight vibration or overload events.

A patented, in-tank, four-in-one system pumps, filters, agitates, and carbon treats airline/aerospace metal finishing solutions while eliminating the possibility of dangerous and costly leaks and spills. Excellent field performance has been reported for electroless nickel, hard chromium, cadmium, sulfamate nickel, and many other solutions for plating and electroforming. The portable, lightweight, preassembled systems consume no floorspace, provide from 1 to 3,000 gallons of filtered solution per hour, and are often employed with a reusable filter media to reduce the costs associated with filter cartridge consumption and disposal.

Currently used instruments for the analysis of total inorganic carbon (TIC) and total organic carbon (TOC) in water and wastewater samples require the use of hazardous chemicals which is not acceptable in their application for long-term space missions. A new design concept of the “reagentless” carbon analyzer (RCA) for determination of both TIC and TOC for water quality monitoring in space is proposed and tested. The concept is based on generating all the chemicals needed for the TIC and TOC analysis within the instrument, and avoiding the need for storing a supply of chemicals. The chemicals are either generated or recirculated in the instrument, or an alternative approach for their use is developed, such as using photocatalytic oxidation instead of oxidizing chemicals for TOC analysis. The fully developed miniaturized instrument will incorporate microfluidic based design principles.

The Naval Research Laboratory (NRL) and Johnson Controls Inc. (JCI) have joined together in a cooperative research and development effort to “space qualify” the JCI Common Pressure Vessel (CPV) Nickel Hydrogen (NiH2) battery. JCI is providing two (2) NiH2 batteries to NRL. One is for qualification tests and the second is for the flight experiment. NRL is responsible for the design, test and integration of the battery with an existing spacecraft electrical power system, launch of the battery with the host spacecraft, and providing data from the flight experiment. Since the intent of the experiment is to “space qualify” the JCI NiH2 CPV design, the battery will be “on-line” and fully charged during the launch of the host spacecraft. This paper will describe the NRL-JCI Cooperative Research and Development Agreement, the NiH2 CPV battery experiment design, and the qualification test program.