Structural synthesis 1959-1969 - A decade of progress
Structural synthesis and analysis concepts, discussing design philosophy, failure modes, load conditions, algorithms and computer aided design
Schmit, L. A., Jr.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Inlets, exits, and cooling problems. 1 - Inlets
As design flight speeds are pushed progressively higher, the supersonic inlet becomes an increasingly important component of air-breathing propulsion systems. Currently, the turbojet engine is being considered for application at Mach numbers up to approximately 4 and the ramjet engine for application in the hypersonic region, or Mach numbers of 5 and above. Herein the inlet situation is surveyed and the merits of the various inlet-design philosophies are assessed on the basis of recent experimental data obtained at Mach numbers up to 5.
James F. Connors↗
A lightweight bimetallic actuator for spacecraft thermal control
The design, development, and construction of two types of active thermal-control systems are described. These designs are based on the controlled angular deflections of spiral-wound bimetallic actuators. The use of these actuators and lightweight louvers results in a frictionless system that is low in weight yet simple in design and low in cost. Both designs exhibit high reliability, good performance repeatability, and do not require power from the spacecraft. Design philosophy and implementation, design tradeoffs, and materials selection are reviewed. The test program is described, and results are presented.
Schilling, K. L.↗
Flammability control in the oxygen environment of the Apollo guidance and navigation equipment
The Apollo guidance and navigation (G&N) equipment test program, the redesign philosophy, and the actual equipment modifications that were used to limit burn rates in an environment of 100 percent oxygen at pressures of 6.2 and 16 psia are described. The major approach was a serious basic review of the real function of the nonmetallic materials of concern. The result of this review was that the materials could be replaced, eliminated, or covered by nonflammable metallic materials. Although several low-flammability nonmetallic materials were investigated, the direct approach of cover, eliminate, or replace generally proved to be quicker and more effective.
Holley, M. D.↗
Satellite broadcasting system study
The study to develop a system model and computer program representative of broadcasting satellite systems employing community-type receiving terminals is reported. The program provides a user-oriented tool for evaluating performance/cost tradeoffs, synthesizing minimum cost systems for a given set of system requirements, and performing sensitivity analyses to identify critical parameters and technology. The performance/ costing philosophy and what is meant by a minimum cost system is shown graphically. Topics discussed include: main line control program, ground segment model, space segment model, cost models and launch vehicle selection. Several examples of minimum cost systems resulting from the computer program are presented. A listing of the computer program is also included.
Source record↗
Teleoperators for remote operations in space
The primary objective of the remote nuclear teleoperator study program was to define in detail a program plan which would provide a qualified operational space teleoperator system by about 1980. The concept and philosophy presented provides a product considered to be an advanced teleoperator when compared to today's state-of-the-art. The teleoperator concept is formulated to meet NERVA requirements.
Little, L. E.↗
Apollo telescope mount thermal systems unit thermal vacuum test
The Apollo Telescope Mount's thermal systems unit was utilized to conduct a full-scale thermal vacuum test to verify the thermal design and the analytical techniques used to develop the thermal mathematical models. Thermal vacuum test philosophy, test objectives configuration, test monitoring, environment simulation, vehicle test performance, and data correlation are discussed. Emphasis is placed on planning and execution of the thermal vacuum test with particular attention on problems encountered in conducting a test of this maguitude.
Trucks, H. F.↗
Apollo experience report: Command and service module environmental control system
A comprehensive review is presented of the design philosophy of the Apollo environmental control system together with the development history of the total system and of selected components within the system. In particular, discussions are presented relative to the development history and to the problems associated with the equipment cooling coldplates, the evaporator and its electronic control system, and the space radiator system used for rejection of the spacecraft thermal loads. Apollo flight experience and operational difficulties associated with the spacecraft water system and the waste management system are discussed in detail to provide definition of the problem and the corrective action taken when applicable.
Samonski, F. H., Jr.↗
Spacecraft thermal vacuum testing
An approach for developing a general thermal vacuum test program philosophy is discussed. Guidelines are established that will assist the project engineer in relating the risk associated with flying any spacecraft to its test program. Computerized techniques can be used to help ascertain these guidelines, which relate the risk to the level of test (component, subsystem, etc), as well as to the type of test (development, qualification, etc). The interrelationship between the test program and the analytical effort is also discussed. The Skylab Apollo telescope mount general thermal vacuum test program, including test schedules, instrumentation, and test results is also discussed.
Elam, B. F.↗
Monopropellant hydrazine resistojet preliminary design task
The design effort for the electrothermal hydrazine thruster (ETH) is summarized. The EHT decomposes hydrazine thermally and expands the decomposition products through a nozzle to provide the impulse necessary to fulfill spacecraft propulsive requirements. The thruster is capable of operation at pulse widths from 0.050 second to steady state and delivers specific impulse values from 175 to greater than 225 seconds, depending upon the duty cycle. The design of the EHT is the result of an analytical effort combined with a series of design verification tests. The design requirements, design philosophy and detailed design methods are outlined. A discussion of the rationale behind the selection of materials for the EHT is included. The results of the design verification tests are also presented.
Murch, C. K.↗
Apollo 14 flight support and system performance
The Apollo 13 incident and subsequent oxygen tank redesign for Apollo 14 placed unique requirements on the flight support activity. A major part of this activity was the integration of the various analytical efforts into a single team function. Additionally, the first flight of the redesigned system without an orbital test required an extensive analytical base. The support team philosophy, objectives, and organization are presented. Various analytical tools that were used during the flight are discussed. Investigations made during the postflight period are considered and their impact upon subsequent flights shown.
Rice, R. R.↗
Space shuttle environmental control/life support systems
This study analyzes and defines a baseline Environmental Control/Life Support System (EC/LSS) for a four-man, seven-day orbital shuttle. In addition, the impact of various mission parameters, crew size, mission length, etc. are examined for their influence on the selected system. Pacing technology items are identified to serve as a guide for application of effort to enhance the total system optimization. A fail safe-fail operation philosophy was utilized in designing the system. This has resulted in a system that requires only one daily routine operation. All other critical item malfunctions are automatically resolved by switching to redundant modes of operation. As a result of this study, it is evident that a practical, flexible, simple and long life, EC/LSS can be designed and manufactured for the shuttle orbiter within the time phase required.
Source record↗
Apollo experience report: Lunar module instrumentation subsystem
The design concepts and philosophies of the lunar module instrumentation subsystem are discussed along with manufacturing and systems integration. The experience gained from the program is discussed, and recommendations are made for making the subsystem more compatible and flexible in system usage. Characteristics of lunar module caution and warning circuits are presented.
Obrien, D. E., III↗
Apollo PLSS: Environmental control of the smallest manned space vehicle
The production of a portable life support system (PLSS) and associated backup equipment for supporting an astronaut working outside of the lunar module (LM) either in space or on the lunar surface is reported. Described are the system, the philosophy behind its design, basic requirements imposed on the system, and some of the evolutionary processes that led to the present configuration.
Beggs, J. C.↗
A fast acting electrical servo for the actuation of full span, Fowler-type wing flaps in DLC applications: A detail design study
The philosophy and detail design of an electro-mechanical actuator for Fowler-type wing flaps which have a response time constant of 0.025 seconds are described. A conventional electrical servomotor with a power rating twice the maximum power delivered to the load is employed along with adaptive, gain-scheduled feedback and various logic circuits, including one to remove electrical excitation from the motor during extended periods when no motion of the flap is desired.
Smetana, F. O.↗
Study of aircraft electrical power systems
The formulation of a philosophy for devising a reliable, efficient, lightweight, and cost effective electrical power system for advanced, large transport aircraft in the 1980 to 1985 time period is discussed. The determination and recommendation for improvements in subsystems and components are also considered. All aspects of the aircraft electrical power system including generation, conversion, distribution, and utilization equipment were considered. Significant research and technology problem areas associated with the development of future power systems are identified. The design categories involved are: (1) safety-reliability, (2) power type, voltage, frequency, quality, and efficiency, (3) power control, and (4) selection of utilization equipment.
Source record↗
Investigation of safe-life fail-safe criteria for the space shuttle
An investigation was made to determine the effects of a safe-life design approach and a fail-safe design approach on the space shuttle booster vehicle structure, and to recommend any changes to the structural design criteria. Two configurations of the booster vehicle were considered, one incorporating a delta wing (B-9U configuration) and the other a swept wing (B-16B configuration). Several major structural components of the booster were studied to determine the fatigue life, safe-life, and fail-safe capabilities of the baseline design. Each component was investigated to determine the practicability of applying a safe-life or fail-safe design philosophy, the changes such design approaches might require, and the impact of these changes on weight, cost, development plans, and performance.
Source record↗
Fatigue and fail-safe design features of the DC-10 airplane
The philosophy and methods used in the design of the DC-10 aircraft to assure structural reliability against cracks under repeated service loads are described in detail. The approach consists of three complementary parts: (1) the structure is designed to be fatigue resistant for a crack-free life of 60,000 flight hours; (2) inasmuch as small undetected cracks could develop from other sources, such as material flaws and manufacturing preloads, the structure also is designed to arrest and control cracks within a reasonable service-inspection interval; and (3) a meaningful service-inspection program has been defined on the basis of analysis and test experience from the design development program. This service-inspection program closes the loop to assure the structural integrity of the DC-10 airframe. Selected materials, fasteners, and structural arrangements are used to achieve these design features with minimum structural weight and with economy in manufacturing and maintenance. Extensive analyses and testing were performed to develop and verify the design. The basic design considerations for fatigue-resistant structure are illustrated in terms of material selection, design loads spectra, methods for accurate stress and fatigue damage analysis, and proven concepts for efficient detail design.
Stone, M. E.↗