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An integration study was performed coupling an SP-100 reactor with either a Brayton or Stirling power conversion subsystem. A power level of 100 kWe was selected for the study. The power system was to be compatible with both the lunar and Mars surface environment and require no site preparation. In addition, the reactor was to have integral shielding and be completely self-contained, including its own auxiliary power for start-up. Initial reliability studies were performed to determine power conversion redundancy and engine module size. Previous studies were used to select the power conversion optimum operating conditions (ratio of hot-side temperature to cold-side temperature). Results of the study indicated that either the Brayton or Stirling power conversion subsystems could be integrated with the SP-100 reactor for either a lunar or Mars surface power application.

Governmental assurance documentation bibliography updated; new tabulation effective as of April 1, 1967. Latest revision indicated in all instances, but no attempt was made to list supplements or amendments. Department of Defense Index of Specifications and Standards (DODISS) published annually in three parts (alphabetic, numerical, and listing of Federal Supply Classification following unclassified documents.

In order to take full advantage of SiC, a high temperature package for power module using SiC devices was designed, developed, fabricated and tested. The details of the material selection and fabrication process are described. High temperature reliability test and power test shows that the package presented in this paper can perform well at the high junction temperature.

The objective of this project was to replace electromechanical power line contactors with a Static Transfer Switch (STS) to improve the transfer of electrical power between aircraft generators and decrease required maintenance. The switch requirements include high reliability, lightweight, and high speed (less than 15mS) power transfer. An STS can shorten the bus transfer time to less than the “ride-through” of aircraft electronic loads and therefore have the ability to control and transfer electrical power while maintaining critical mission requirements. The content of this paper and presentation will discuss the initial problem, the research and development approach, design, and initial testing of the STS.

Certain standard parts in the aerospace industry require qualification as a prerequisite to manufacturing, signifying that the manufacturer’s capacity to produce parts consistent with the performance specifications has been audited by a neutral third-party auditor, key customer, and/or group of customers. In at least some cases, a certifying authority provides manufacturers with certificates of qualification which they can then present to prospective customers, and/or lists qualified suppliers in a Qualified Parts List or Qualified Supplier List available from that qualification authority. If this list is in an infrequently updated and/or inconsistently styled format as might be found in a print or PDF document, potential customers wishing to integrate qualification information into their supplier tracking systems must use a potentially error-prone manual process that could lead to later reliance on out-of-date or even forged data.

This paper discusses various engine installations in Naval aircraft, looking especially at their costs of maintenance. Fuel systems, fuel control systems, and several engine accessories are discussed for present and future engines. It is concluded that simple, reliable equipment is necessary to keep aircraft in the air instead of in maintenance areas on the ground.

An electrical system composed of an integral main engine electrical starter/generator and a power management and distribution system for a high performance more electric airplane is presented. The paper emphasizes the fault tolerance and high reliability requirements and discusses the necessary architecture to satisfy them. A number of critical technical issues associated with the more electric airplane, such as severe EMI environment, regenerative power, and system integration and stability are discussed.

Several quite different waste-water processing subsystems have been tested for space mission applications. Mission choice, and choice of priority for further development, involves processor requirements for (electrical) power, launch and resupply weights, and space occupied, and developmental factors of reliability and reparability. For each subsystem one can identify theoretical power, etc., requirements, and current realistic requirements, and potential realistic subsystem requirements. Compared are reverse osmosis, vapor-compression-distillation, and TIMES processes, in terms of power, weight, and space requirements. Discussions of electrodialysis and CELSS are included as components of water treatment systems.

The paper defines a “best” estimate of system effectiveness or reliability as one that minimizes the potential loss due to either overestimating or underestimating such a system figure of merit. A loss function is expressed in terms of the decision maker's order of preference for the consequences of either overestimation (underkill) or underestimation (overkill). However, in order for an estimate to be optimal, sufficient information at the system level should be provided. This lack or abundance of information is reflected in the variability of the measurement of system effectiveness or reliability. The variability and central tendency of this measurement are obtained from the variability and central tendency of the component data. This is achieved through the combined use of effectiveness or reliability models, Monte Carlo simulation and/or probability moments, and Bayesian statistics.

This paper presents an approach to numerically simulate greenhouse windnoise. The term “greenhouse windnoise” here describes the sound transferred to the interior through the glass panels of a series vehicle. Different panels, e.g. the windshield or sideglass, are contributing to the overall noise level. Attached parts as mirrors or wipers are affecting the flow around the vehicle and thus the pressure fluctuations which are acting as loads onto the panels. Especially the wiper influence and the effect of different wiper positions onto the windshield contribution is examined and set in context with the overall noise levels and other contributors. In addition, the effect of different flow yaw angles on the windnoise level in general and the wiper contributions in particular are demonstrated. As computational aeroacoustics requires accurate, highly resolved simulation of transient and compressible flow, a Lattice-Boltzmann approach is used.

The Hubble Space Telescope (HST) was designed to be serviced from the shuttle by astronauts performing extravehicular activities (EVA). During the first HST Servicing Mission (STS-61) two types of power tools were flown, the Power Ratchet Tool (PRT) and the HST Power Tool. Each tool had both benefits and drawbacks. An objective for the second HST servicing mission was to combine the reliability, accuracy, and programmability of the PRT with the pistol grip ergonomics and compactness of the HST Power Tool into a new tool called the EVA Pistol Grip Tool (PGT). The PGT is a self-contained, microprocessor controlled, battery powered, 3/8-inch drive hand-held tool. The PGT may also be used as a non-powered ratchet wrench. Numerous torque, speed, and turn or angle limits can be programmed into the PGT for use during various servicing missions. Batteries Modules are replaceable during ground, Intravehicular Activities (IVA), and EVA operations.

Future vehicle power systems must achieve greater flexibility and reliability than those used in previous generations. New functions that enhance safety, such as arc detection and wiring integrity verification, are essential for new systems. Embedded autonomous control, and fault correction can be built into Fault Tolerant Processors that integrate into a vehicle Open System Architecture. This approach will provide status and fault detection information to maintenance interfaces and provide fault correction. Safety is enhanced by the prevention of dangerous restarts from crew and personnel. The embedded features allow for pre-flight mission configuration to setup systems before takeoff and on-board and off-board maintenance control. This enables operators to evaluate power system health and history to help reduce turn around time.

The Shuttle orbiter currently uses hydrazine-powered APU’s for powering its hydraulic system pumps. To enhance vehicle safety and reliability, NASA is pursuing an APU upgrade where the hydrazine-powered turbine is replaced by an electric motor pump and battery power supply. This EAPU (Electric APU) upgrade presents several thermal control challenges, most notably the new requirement for moderate temperature control of high-power electronics at 132 °F (55.6 °C). This paper describes how the existing Water Spray Boiler (WSB), which currently cools the hydraulic fluid and APU lubrication oil, is being modified to provide EAPU thermal management.

With the growing complexity and integration of systems as satellites, automobiles, aircrafts, turbines, power controls and traffic controls, as prescribed by SAE-ARP-4754A Standard, the time de-synchronization can cause serious or even catastrophic failures. Time synchronization is a very important aspect to achieve high performance, reliability and determinism in networked control systems. Such systems operate in a real time distributed environment which frequently requires a consistent time view among different devices, levels and granularities. So, to guarantee high performance, reliability and determinism it is required a performance evaluation of time synchronization of the overall system. This time synchronization performance evaluation can be done in different ways, as experiments and/or model and simulation.

Complex and/ or highly integrated systems such as satellites, airplanes, air traffic controllers, cars, etc., require Dependability (Reliability, Maintainability, Availability, Safety, Security, etc.) assessments throughout their life cycle, especially in their development, where the time and cost to make changes are smaller. Such systems must achieve high levels of Dependability through a variety of approaches and processes. Among these, the processes of analysis and decision making from the conception phase to the final phase of the detailed project stand out, because in these phases the most important decisions are taken. Thus, the purpose of this article is to present a discussion on detailing processes for improving the Dependability of aerospace and automotive systems.

Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems.

This paper presents a frequency domain multi-input/multi-output (MIMO) identification method. The accuracy, reliability and ability of handling repeated modes are verified by computer simulation and practical structures. The applications in an aircraft Ground Vibration Test (GVT) is given. The results have shown that compared with traditional multipoint sine excitation phase resonance method, operation is simplified, testing time is reduced reliability is improved and compared with time domain MIMO methods developed over the past several years, the order of the system (the number of modes) can be identified directly so that the calculating time is reduced and the user's judgement of distinguishing between structural modes and noise modes is avoided.

Environmental sustainability is morphing Automotive technical development strategies and driving the evolution of vehicles with a speed and a strength hardly foreseeable a decade ago. The entire vehicle architecture is impacted, and energy efficiency becomes one of the most important parameters to reach goals, which are now not only market demands, but also based on regulatory standards with penalty consequences. Therefore, rolling drag from all bearings in multiple rotating parts of the vehicle needs to be reduced; wheel bearings are among the biggest in size regardless of the powertrain architecture (ICE, Hybrid, BEV) and have a significant impact. The design of wheel bearings is a complex balance between features influencing durability, robustness, vehicle dynamics, and, of course, energy efficiency.