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Spacecraft cold-plate designs are small, relatively complex, and expensive. A large-size, low-cost approach is required for the new generation of space power modules and platforms. This paper describes part of an on-going investigation of the feasibility of using large aluminum extrusions attached side-by-side to form a large, two-sided cold plate with integral coolant passages. The objective was to establish and verify a cold-plate-to-equipment interface design that would meet thermal performance requirements and allow easy replacement by extravehicular activity (EVA) component changeout. Approximately twelve filler materials and six interface designs were studied, and these were selected: three filler approaches, an existing adjustable interface pressure design, and a conventional design with no filler and no adjustment. Thermal conductance tests performed on simulated implementations of these approaches measured the contact conductances of each.

The United States Navy F/A-18 aircraft uses two 30/40 KVA generating systems to provide precise 400 Hz power to their respective isolated busses. Each generating system is composed of a six phase generator running at a speed proportional to engine rpm, feeding an SCR-based, naturally commutated cycloconverter. This was the first integral package with shared cooling oil, production, 400 Hz VSCF system. Over 2,000 units have been produced to date. Due to the radical shift from historical, mechanically supplied constant speed technology, the F/A-18 VSCF design initially raised numerous reliability questions. This paper serves to address those concerns and provide development questions with historical field performance/analyses in response. Reliability predictions using MIL-HDBK-217 procedures are compared to Navy 3-M field performance data over the last eight year production period.

Several aspects of V/STOLs for short-haul transportation are considered: production time needed to produce a craft with suitable operational characteristics, profitable operation, noise, safety and reliability, air traffic system control, landing facilities, passenger comfort, marketability, size. The author urges that a joint effort by military and civilian departments of the government and industry be undertaken to develop a V/STOL transport system. Factors to be considered are discussed.

Many engineering systems operating in a cold environment are challenged by ice accretion, which unfavorably affects their aerodynamics and degrades both their performance and safety. Precise characterization of ice adhesion is crucial for an effective design of ice protection system. In this paper, a fracture mechanics-based approach incorporating single cantilever beam test is used to characterize the near mode-I interfacial adhesion of a typical ice/aluminum interface with different surface roughness. In this asymmetric beam test, a thin layer of ice is formed between a fixed and elastically deformable beam subjected to the applied loading. The measurements showed a range of the interfacial adhesion energy (GIC) between 0.11 and 1.34 J/m 2, depending on the substrate surface roughness. The detailed inspection of the interfacial ice fracture surface, using fracture surface replication technique, revealed a fracture mode transition with the measured macroscopic fracture toughness.

AVSCOM has been collecting maintenance data via TAERS/TAMMS since 1964 and the files containing this data encompass millions of records. RAMMIT (Reliability and Maintainability Management Improvement Techniques) is a system designed to process maintenance data and other data relevant to the operations and support of Army aircraft. RAMMIT has been in development for approximately one year and management type information is being made available on a scheduled and as requested basis. Omissions and errors in reported data have been studied extensively and the determination made that if the data are properly processed, useful and reliable information can be provided. This report describes some of the methods used to identify and quantify these discrepancies so that valid values could be presented for each item's characteristics. The large volume of data input and the numerous types of data elements being reported has necessitated the development of a well organized series of reports.

Noise environmental control is an important design consideration for Space Station Freedom (SSF), both for crew safety and productivity. Acoustic noise requirements are established to eliminate fatigue and potential hearing loss by crew members from long term exposure and to facilitate speech communication. VAPEPS (VibroAcoustic Payload Environment Prediction System) is currently being applied to SSF for prediction of the on-orbit noise and vibration environments induced in the 50 to 10,000 Hz frequency range. Various sources such as fans, pumps, centrifuges, exercise equipment, and other mechanical devices are used in the analysis. The predictions will be used in design tradeoff studies and to provide confidence that requirements will be met. Preliminary predictions show that the required levels will be exceeded unless substantial noise control measures are incorporated in the SSF design.

The transition from the current Shuttle Space Transportation System (STS) payload delivery capability to an advanced launch system has been the topic of several studies and proposals. The need for an early, reliable, low cost heavy lift vehicle has been identified and supported by NASA as a response to that need. This paper will provide a brief background and description of the Shuttle-C, and will primarily focus on cargo bay sizing and manifesting for one of the three identified design reference missions: Space Station Freedom assembly.

A new systematic approach to ensure a holistic integration of renewable energies in local energy supply based on the QFD (Quality function deployment) method has been developed. With this methodology it is possible to include the different aspects and needs of all parties who are involved in energy planing at a very early stage. This helps to ensure successful installations. Also a time dynamic tracking of the changes in technical, economical and social conditions is possible this allows predictions - based on experience- of the acceptance of RE systems. In order to verify the method, data is collected by analysing a number of RE implementation projects in different European countries from the last 10 years. Data from ongoing studies is examined and included in the studies to ensure time tracking. Bottlenecks and problems which are identified by this method are compared to those identified by the field survey.

Commercial tools for measurement and analysis of noise and vibration signals have traditionally been very expensive. In the last decade, however, multi-channel measurement systems have become relatively inexpensive. The analysis functionality in most inexpensive instruments is limited. Therefore, many companies are using alternatives for post processing of measurement results. Matlab is a platform that is popular for this purpose and which offers many advantages over dedicated, menu driven systems. The open functions in Matlab assure flexibility and the possibility to modify functions for specific needs. In addition, a command based programming environment provides for traceability and quality assurance, including qualification of used algorithms, important aspects particularly in the aerospace industry. In the past, basic functions for signal analysis and vibration analysis have had to be developed before taking full advantage of the Matlab platform.

Aerospace engineers continually strive to identify materials which provide processing flexibility, reduce manufacturing costs, and prove durable in harsh environments. PEEK™ polymer, successfully displaces metals, traditional composites, and other plastics in a growing number of aerospace applications due to its exceptional properties and ability to be easily fabricated into high tolerance parts through multiple manufacturing techniques.

Although a mechanical shock test machine is usually used to determine whether equipment is rugged enough for service in the field, the numerous uncertainties involved in the choice of a test level result in unsatisfactory test criteria. Therefore, engineering judgment plays a major part in reachinga practical solution. Unfortunately “judgment” is subject to challenge in such areas as design and factors of safety. This paper suggests that this approach should be replaced with statistical decision theory and shows how the newer and more rational method can be applied to selection of test levels.

Last year we presented a short paper regarding using Statistical Process Control (SPC) on CE Rivets. This year we would like to update you on the status of this project. In addition, we would like to introduce you to another application of this process. The application is regarding the window frames installed on the 737 airplane. In this paper, we will deal with the interaction of the operators and the SPC focal, the short term results and the long term effects. In the new example of window frame, we will deal with the Statistical Quality Control (SQC) software developed by Boeing for ourselves and our vendors. We will touch on our changing relationship with our vendors and the cost justification to improve our product.

This SAE EDGE™ Research Report builds a comprehensive picture of the current state-of-the-art of human-robot applications, identifying key issues to unlock the technology’s potential. It brings together views of recognized thought leaders to understand and deconstruct the myths and realities of human- robot collaboration, and how it could eventually have the impact envisaged by many. Current thinking suggests that the emerging technology of human-robot collaboration provides an ideal solution, combining the flexibility and skill of human operators with the precision, repeatability, and reliability of robots. Yet, the topic tends to generate intense reactions ranging from a “brave new future” for aircraft manufacturing and assembly, to workers living in fear of a robot invasion and lost jobs. It is widely acknowledged that the application of robotics and automation in aerospace manufacturing is significantly lower than might be expected.

High energy density regenerative fuel cell systems that are used for energy storage require novel approaches to integrating components in order to preserve mass and volume. A lightweight Unitized Regenerative Fuel Cell (URFC) Energy Storage System concept is being developed at the NASA Glenn Research Center (GRC). This Unitized Regenerative Fuel Cell System (URFCS) minimizes mass by using the surface area of the hydrogen and oxygen storage tanks as radiating heat surfaces for overall thermal control of the system. The waste heat generated by the URFC stack during charging and discharging is transferred from the cell stack to the surface of each tank by loop heat pipes, which are coiled around each tank and covered with a thin layer of thermally conductive carbon composite. The thin layer of carbon composite acts as a fin structure that spreads the heat away from the heat pipe and across the entire tank surface.

The C-5A airplane is a very large airplane designed to transport extremely large quantities of cargo. The design requirements include the structural capability to sustain abnormally high lateral gust loads, of recovering from an upset at limit speed even though the horizontal stabilizer is trimmed full airplane nose down, and to provide a high degree of reliability. This paper presents some of the unique design considerations made during the engineering phase of the C-5A project to optimize reliability and safety and to minimize the structural weight of the airplane.

Current state-of-the-art space radiators are too heavy (5-7 kg/m2) and voluminous to be feasible for some future space missions. Accordingly, there is a need for a revolutionary advanced space radiator system. This paper describes an effort to satisfy that need through the development of an unfurlable heat pipe radiating system. The innovative portion of the unfurlable radiator is the pressure envelope: it is a thin, flexible, heat sealable polymer/metal laminate that is vacuum tight. The laminate allows the radiator to be compactly rolled or folded, easily stowed for transit to space and then unfurled to present a large radiating surface. Condensate return to the evaporator is achieved by a combination of capillary pumping via a flexible porous cable wick and the advanced capillary pumped loop methods of entrainment. The mass density of the radiator is 1.76 kg/m2, representing a reduction in mass of at least a factor of 3 over current radiator technology.

A proof-of-concept (POC) lightweight lunar radiator was fabricated and tested. The POC radiator has a specific weight of 5 kg/kW one quarter the specific weight of current space radiators. The significant weight reduction was due to the radiator's unique design. It is a multicellular heat pipe radiator utilizing the lunar gravity for condensate return. The innovation of this radiator is the laminated film material used as the heat pipe envelope. By utilizing a flexible, durable, leak tight laminate structure instead of the typical ridged heat pipe envelope, significant weight reductions were achieved. In addition, the resulting radiator is extremely flexible, allowing it to be rolled or folded and compactly stored during transit to the lunar surface. Testing demonstrated that a laminated film heat pipe radiator offers improved performance and significant mass savings over conventional space radiators.

One of the chief difficulties in producing close tolerance holes in aircraft aluminum alloys is the problem of exit burrs. This synopsis provides an explanation of the reasons for this phenomenon, as it is observed. This writing is not the result of an empirical study. Instead, it is based upon close observation and experience. Additionally, there is no attempt to explain the complexities of metallurgy and its effects on the drilling process. The assumption is that aircraft aluminum has a malleable quality that is necessary in terms of its function. However, this same property leads to challenges under certain circumstances during drilling.

Development of components to optimize on-line, gravity-independent measurement of Total Organic Carbon (TOC) in water to low ppb levels are being investigated for incorporation into water quality monitor hardware. A simple, flow- through device termed a reagentless separator has been designed for zero gravity operation that removes inorganic carbon from solution without using corrosive liquid acids. Flow-through, solid-phase TOC and Total Inorganic Carbon (TIC) functional check modules are being developed for replacement of liquid reagent calibration standards. Standard modules that impart 10 mg/1 TOC to product water have been demonstrated. Preliminary results indicate that expendable liquid reagents can be eliminated from the Process Water Quality Monitor (PCWQM) resulting in enhanced simplicity, safety, reliability, and significantly reduced hardware volume. Components and system operating parameters are described.

Spacecraft thermal control systems are essential to provide the necessary thermal environment for the crew and to ensure that the equipment functions adequately on space missions. The Ultralight Fabric Reflux Tube (UFRT) was developed by the Pacific Northwest National Laboratory as a lightweight radiator concept to be used on planetary surface-type missions (e.g., Moon, Mars). The UFRT consists of a thin-walled tube (acting as the fluid boundary), overwrapped with a low-mass ceramic fabric (acting as the primary pressure boundary). The tubes are placed in an array in the vertical position with the evaporators at the lower end. Heat is added to the evaporators, which vaporizes the working fluid. The vapor travels to the condenser end section and condenses on the inner wall of the thin-walled tube. The resulting latent heat is radiated to the environment. The fluid condensed on the tube wall is then returned to the evaporator by gravity.