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This paper describes an analytical model that may be used to determine the impact of maintainability (operational and resource requirements) on aircraft system design. The major advantage of analytical computer oriented models is the depth and detail of investigation that can be accomplished as a basis for design decisions. The model, designated SOURCE (Simulation of Utilization, Resources, Cost, and Efficiency), is designed to accept empirical data to determine realistically the interrelationships between maintainability and aircraft design characteristics.

This paper records the results of some fuel system testing being carried on in England in an effort to simulate the Concorde fuel system and to study the behavior of fuels. The accuracy of the ASTM-CRC Fuel Coker in specifying fuel quality is examined.

The Thor standard launch vehicle (SLV-2) was designed and first flown more than 10 years ago as a quick response IRBM with completely air transportable launch equipment. After deployment overseas in squadron strength, several years ago it was removed from the strategic weapon system inventory. However, the descendants of the vehicle are still in production as an operational space booster after undergoing continuous improvement through such methods as uprating the main engine and electronics, addition of solid propellant thrust augmentation motors, extension of the propellant tanks, and adding the ability to mate with various upper stage vehicles. Furthermore, the Thor IRBMs returned from overseas have been refurbished and used by the military. Of the two original launch sites, the R&D facilities at Cape Kennedy and some of the Weapon System Training sites at Vandenberg AFB have been converted to space launch duty, making maximum use of the original equipment.

Mars landing vehicle descent propulsion is discussed in the light of the constraints of the mission, the environment, and the interfacing functions. The presence of a largely undefined, tenuous atmosphere is shown to produce a great variability of initial and boundary conditions for the propulsion phase of descent. The mission provides numerous subtle constraints of formidable importance to the propulsion implementation. The current requirement for prelaunch, in-situ, thermal sterilization is paramount among these. A significant, and unresolved, mission-related problem is that of the interaction of landing propulsion on the native environment. For a mission which has as its primary objective the investigation of the Mars environment, landing site alteration is a significant concern. The principal intersystem constraint is that of the flight path guidance logic choice.

Deposits form in the “empty” wing tank environment as a result of a complex autoxidative degradation of the hydrocarbon fuel. For the past two years, Esso Research and Engineering Co. has been carrying out a fundamental study for the Air Force of the variables which control such deposit formation. Extensive studies have been carried out in a specially designed apparatus which simulates the kinetic environment found in a wing tank. Independent Advanced Aircraft Fuel System Simulator studies have shown that this apparatus is the only small test apparatus currently available which accurately rates the wing tank deposit formation tendency of jet fuels. Rigorous exclusion of oxygen has been demonstrated to eliminate deposit formation at temperatures up to 500 F. The rate of deposit formation from typical jet fuels exhibits a 10 kcal/mole apparent activation energy and a 0.2 order in oxygen partial pressure at moderate oxygen partial pressure levels.

In 9 years of operational experience on Air Force and NASA programs, the Agena has proved to be a reliable vehicle. This paper describes the improving methods of operation over the years. Among these are testing the complete flight vehicle system under the closest possible simulation of the flight environment, the use of telemetry in conjunction with automated data handling systems, use of computerized data handling, and delivery of mate-ready flight vehicles to the launch bases. Each is discussed in detail.

NASA's Saturn I/IB Launch Vehicle Program has been a remarkable success story in terms of flight accomplishments. Fourteen launch vehicles have flown without a single significant launch vehicle failure; that is, a failure that affected the mission objective. The present Saturn IB launch vehicle comprises an S-IB stage, an S-IVB stage, and an Instrument Unit stage. The S-IB stage and the S-IVB stage are propulsion or booster stages. The Instrument Unit houses the navigation, guidance, and control equipment. A variety of payloads has been flown on the launch vehicle and different types of payloads are planned for future flights; however, the primary payloads for which the launch vehicle was designed are the Command Service Module and the Lunar Module.

Titan III is the first space launching system development program directed from the start toward the objective of standardization; it is also the first such program to use the building block concept to achieve wide mission flexibility. The program objectives of the Titan III launching system are detailed, and its design philosophy explained. The development of the Titan III system is described, as is the test philosophy of the program. A chronological summary of flight test experience is included.

The reliability and maintainability problems confronting environmental control/life support systems for long duration space flight present the designer with one of the most challenging tasks in the wide array of still unproved approaches to the design of manned space systems. Examination of the realities of current equipment experience indicates that reliability and maintainability of most aerospace equipments are far from meeting requirements of long duration missions, and some concepts currently influencing designs are not applicable to the true characteristics of the manned spacecraft environment. Several examples are given of analytical processes and design techniques which show promise of making progress toward practical goals. Emphasis is placed on the requirement to see reliability and maintainability progress made as an integrated part of an orderly design maturation process.

A 60-day manned test of a closed-cycle life-support system was completed in a Space Cabin Simulator. Life-support equipment was installed within the chamber and was operated, maintained, and repaired by a 4-man crew. Major objectives of the test included demonstrations of the recovery of potable water from urine and humidity condensate, and the recovery of oxygen from carbon dioxide. Other life-support equipment included a thermal-control subsystem, a two-gas atmosphere control, a trace-contaminant removal subsystem, and a fecal-waste collector that featured vacuum dehydration.

Extensive maintainability (M) and reliability (R) studies of a number of manned spacecraft missions indicate that the Environmental Control/Life Support System (EC/LSS) generally requires more scheduled and unscheduled maintenance than any other subsystem. This paper summarizes the EC/LSS M and R analyses performed on some of these studies. The expected redundancy and spares required to achieve a desired reliability is discussed. The requirements for scheduled and unscheduled maintenance are evaluated in terms of expected spares usage, maintenance time, and potential problem areas.

In a study conducted to evaluate low-gravity capabilities of life support components and processes of the Langley Research Center Integrated Life Support System (ILSS), primary emphasis was placed on: 1. Identification and analysis of gravity sensitivities inherent in performance of ILSS components and processes. 2. Investigation of methods for experimentally evaluating critical items for which zero-gravity performance could not be determined by analytical techniques. 3. Formulation of generalized criteria for assessing gravity sensitivity of alternate or advanced life support processes as well as those originally incorporated in the ILSS. Of 92 ILSS processes identified, the majority were of such nature that their g sensitivities could be satisfactorily assessed by analyses, precluding the need for extensive testing. Experiments included gravity-sensitive aspects of liquid droplet release, heat exchanger passage plugging, and liquid film stability.

A new family of transmission line component assemblies for interconnection of electronic subsystems to transmit digital pulses is described. These assemblies consist of flat cable with closely controlled electrical characteristics terminated to printed circuit boards which either plug into standard card-edge connectors, or have standard connectors mounted on them. The construction of the flat cables and their electrical, mechanical, chemical, and thermal properties are described as are those of the printed circuit boards. The fabrication of the assemblies is outlined including cutting, stripping, soldering, and strain relief; and a time and cost study for a typical assembly is detailed.

This paper describes the use of the electron microprobe analyzer as an analytical tool for microelectronic devices. A comprehensive description of the construction and working of the electron microprobe analyzer is first presented. Included is a brief description of some of the basic physical laws regarding X-ray generation and analysis. Three major innovations which have made the probe the tool for microelectronic analysis are described in detail; these are: the electron beam scanning system, secondary electron display, and high resolution nondispersive energy analysis. Several examples are shown Of how these techniques may be applied to microelectronic analysis.

Begins with a review of semiconductor wire bonding techniques utilizing both thermocompression and ultrasonic methods. Next, disadvantages of using interconnect leadwires are covered. Finally, a description of leadless face bonding is included with emphasis on the important functions in state-of-the-art techniques as well as on simplicity, accuracy and repeatability.

The development of a laser welder to produce multiple welds/laser pulse for use in a flip-chip process is described. Using a glass laser with a blocking mask to split the laser beam into a multiplicity of spots, the simultaneous welding of all 14 interconnect points between an aluminum interconnect pattern on a glass substrate and an unplated Kovar lead frame is possible, weld shear strength of from 800 – 1200 grams in eight-spot samples was achieved in an experimental system.

Translation from a schematic to fabrication of a thick film hybrid microcircuit requires a knowledge of both circuit and process design. A lack of information in proper layout procedures often results in circuits which are unnecessarily difficult to fabricate. Design guidelines are given which aid in optimization of the circuit layout. Optimum geometries are discussed with particular emphasis on resistors. Examples of circuits are given from schematic to the finished product to illustrate the design layout procedure.

One of Honeywell Aerospace Division's major efforts to reduce design and production costs has been the application of standard Functional Electronic Blocks (FEB's) in systems design. The FEB's are thick-film, screen printed passive networks fired on ceramic substrates to which integrated circuits and miniature discrete components are attached. Each FEB provides a complete circuit function such as a servo amplifier, summing amplifier, or demodulation amplifier which can easily be incorporated into a system mechanization. This paper presents the results of a program to develop the interconnection techniques needed for attachment of components to the thick-film networks and describes some of the capabilities and advantages of these Functional Electronic Blocks.

This discussion describes the relationships of the amount of paste deposited on a ceramic substrate by screening, to certain aspects of the screening process - - such as the mesh size, paste rheology, line width, etc. It is not intended to be a vigorous mathematical or mechanical analysis of the process. The conclusions can be extrapolated not only to an understanding of a part of the mechanism of paste transfer, but to a prediction of screened thickness - - as well as to methods for increasing the uniformity and thickness of screened images. Emulsion screens with stainless steel mesh and etched metal masks are discussed.

Degradation of weld strength beyond that which is unacceptable in the end product can always be detected non-destructively. This detection is best made during the weld cycle by monitoring a combination of three parameters: voltage pulse, infrared radiation, and setdown. Other measurements evaluated but found impractical are: eddy current, joint resistance, and sonic/ultrasonic methods. Laboratory experiments show that weld criteria and instrumentation are easily developed.