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Maintenance program which is concise and inexpensive to operate adapts to almost any system that has a FORTRAN compiler. Program operates on a stored data base with an output consisting of scheduling information and various management reports.
The program planning acquisition functions for the development of the solid propellant rocket engine for the space shuttle booster is presented. The subjects discussed are: (1) program management, (2) contracts administration, (3) systems engineering, (4) configuration management, and (5) maintenance engineering. The plans for manufacturing, testing, and operations support are included.
The design, development, and test of a functional laboratory model ice pack heat sink subsystem are discussed. Operating instructions to include mechanical and electrical schematics, maintenance instructions, and equipment specifications are presented.
It is shown how the availability and MTBF (Mean Time Between Failures) of a redundant system with subsystems maintenanced at the points of so-called stationary renewal processes can be determined from the distributions of the intervals between maintenance actions and of the failure-free operating intervals of the subsystems. The results make it possible, for example, to determine the frequency and duration of hidden failure states in computers which are incidentally corrected during the repair of observed failures.
Control theory and the design of manipulators, teleoperators, and robots are considered. Applications of remotely manned vehicles to space maintenance and orbital assembly, industry and productivity, undersea operations, and rehabilitation systems are emphasized.
A helical cable car grip to minimize high maintenance costs of San Francisco's cable car operation is presented. The grip establishes a rolling contact between the cable and grip to reduce sliding friction and associated cable wear. The design, development, and testing of the helical cable car grip are described.
A lunar strip mining system is presented which is capable of excavating and transporting 3 million metric tons of ore per year to a central processing plant on the moon's surface. The mining system would grow from a single front-end loader in the first year, to a fleet of ten haulers in the 30th year. Lunar personnel requirements would consist of a single individual, whose primary function would be to perform maintenance. All of the mining equipment would either operate automatically or by remote control from earth. The projected cost for the lunar mining system is approximately $12 to $37 per ton of ore over the life of the mine, an important part of the overall economics of exploiting lunar resources.
Report presents installer guidelines for network subsystems, including filling and testing. Information on operating procedures, controls, caution requirements, and routine scheduled maintenance is included as written procedures, schematics, detailed drawings, and manufacturer's component data.
The capabilities of the NASA Neutral Buoyancy Simulator (NBS) water tank test facility are described, with reference to the proving of crew-operated mechanisms incorporated by the Space Telescope (ST). There are 24 Orbital Replaceable Units which are subject to handling in space by suited crewmen of the Space Shuttle, the largest of which is comparable to a telephone booth and weighs over 700 lb. The water volume of the simulator is sufficient to accept a full-size mockup of the Space Shuttle cargo bay, in which all ST operations will be conducted. Early ST simulations tested the mechanisms which astronauts would operate during contingency operations. More recently, the simulation tasks have reflected maintenance objectives of ST orbital life prolongation. With the recent addition of a fully functional Remote Manipulator System and the Manned Maneuvering Unit, the simulator constitutes the most complete training ground for extravehicular activities extant.
In order to establish permanent human presence in space technologies of constructing and repairing space stations and other space structures must be developed. Most construction jobs are performed on earth and the fabricated modules will then be delivered to space by the Space Shuttle. Only limited final assembly jobs, which are primarily mechanical fastening, will be performed on site in space. Such fabrication plans, however, limit the designs of these structures, because each module must fit inside the transport vehicle and must withstand launching stresses which are considerably high. Large-scale utilization of space necessitates more extensive construction work on site. Furthermore, continuous operations of space stations and other structures require maintenance and repairs of structural components as well as of tools and equipment on these space structures. Metal joining technologies, and especially high-quality welding, in space need developing.
The mission profile, performance over the first eight flights, and inspection and repair procedures for the Shuttle main engines (SSME) are outlined. The Orbiter has three SSMEs, each delivering 470,000 lb thrust at rated level and 512,000 lb thrust at full power level. The engines each have a design lifetime of 55 launches and 27,000 sec operating life. After eight STS flights the SSME maintenance requirements and part replacements have generally followed those experiences during ground tests, i.e., routine checkout of some items are performed every flight, some after a few flights, and replacements are made as needed or scheduled. Hot-fire tests are performed only if a generic defect has been recognized and corrective action taken. Attention is also given to engine sensors to verify functioning status. Details of the inspection procedures, unscheduled maintenance, and inspection tools and instruments are provided.
Final user requirements defined for the Voice Switching and Control System (VSCS) to be implemented for ATC functions as part of the Area Control Facility (ACF) concept for the National Airspace System (NAS) are described. The VSCS will be communications equipment at operational stations, supervisory positions, and support systems, the switching system itself, and interfaces between the VSCS and other systems. Supervisory users will include the Area Manager, Traffic Management Coordinator, a Military Operations Specialists, a Weather Coordinator, a NAS manager, Maintenance, and a flight Data Communications Specialist. The VSCS will supply computerized communications capability within and among ATC centers. Details of the efforts used to define the system requirements are recounted, noting the heavy reliance on recommendations from active ATC personnel.
A space station in a crew-tended or permanently crewed configuration will provide major R&D opportunities for innovative, technology and materials development and advanced space systems testing. A space station should be designed with the basic infrastructure elements required to grow into a major systems technology testbed. This space-based technology testbed can and should be used to support the development of technologies required to expand our utilization of near-Earth space, the Moon and the Earth-to-Jupiter region of the Solar System. Space station support of advanced technology and materials development will result in new techniques for high priority scientific research and the knowledge and R&D base needed for the development of major, new commercial product thrusts. To illustrate the technology testbed potential of a space station and to point the way to a bold, innovative approach to advanced space systems' development, a hypothetical deep space transport development and test plan is described. Key deep space transport R&D activities are described would lead to the readiness certification of an advanced, reusable interplanetary transport capable of supporting eight crewmembers or more. With the support of a focused and highly motivated, multi-agency ground R&D program, a deep space transport of this type could be assembled and tested by 2010. Key R&D activities on a space station would include: (1) experimental research investigating the microgravity assisted, restructuring of micro-engineered, materials (to develop and verify the in-space and in-situ 'tuning' of materials for use in debris and radiation shielding and other protective systems), (2) exposure of microengineered materials to the space environment for passive and operational performance tests (to develop in-situ maintenance and repair techniques and to support the development, enhancement, and implementation of protective systems, data and bio-processing systems, and virtual reality and telepresence/kinetic processes), (3) subsystem tests of advanced nuclear power, nuclear propulsion and communication systems (using boom extensions, remote station-keeping platforms and mobile EVA crew and robots), and (4) logistics support (crew and equipment) and command and control of deep space transport assembly, maintenance, and refueling (using a station-keeping platform).
This paper describes vision functionalities required in future orbital laboratories; in such systems, robots will be needed in order to execute the on-board scientific experiments or servicing and maintenance tasks under the remote control of ground operators. For this sake, ESA has proposed a robotic configuration called EMATS; a testbed has been developed by ESTEC in order to evaluate the potentialities of EMATS-like robot to execute scientific tasks in automatic mode. For the same context, CNES develops the BAROCO testbed to investigate remote control and teleprogrammation, in which high level primitives like 'Pick Object A' are provided as basic primitives. In nominal situations, the system has an a priori knowledge about the position of all objects. These positions are not very accurate, but this knowledge is sufficient in order to predict the position of the object which must be grasped, with respect to the manipulator frame. Vision is required in order to insure a correct grasping and to guarantee a good accuracy for the following operations. We describe our results about a visually guided grasping of static objects. It seems to be a very classical problem, and a lot of results are available. But, in many cases, it lacks a realistic evaluation of the accuracy, because such an evaluation requires tedious experiments. We propose several results about calibration of the experimental testbed, recognition algorithms required to locate a 3D polyhedral object, and the grasping itself.
The purpose of this document is to provide experience-based guidance in implementing a software process improvement program in any NASA software development or maintenance community. This guidebook details how to define, operate, and implement a working software process improvement program. It describes the concept of the software process improvement program and its basic organizational components. It then describes the structure, organization, and operation of the software process improvement program, illustrating all these concepts with specific NASA examples. The information presented in the document is derived from the experiences of several NASA software organizations, including the SEL, the SEAL, and the SORCE. Their experiences reflect many of the elements of software process improvement within NASA. This guidebook presents lessons learned in a form usable by anyone considering establishing a software process improvement program within his or her own environment. This guidebook attempts to balance general and detailed information. It provides material general enough to be usable by NASA organizations whose characteristics do not directly match those of the sources of the information and models presented herein. It also keeps the ideas sufficiently close to the sources of the practical experiences that have generated the models and information.
The complexity of the Space Shuttle Main Engine (SSME), combined with mounting requirements to reduce operations costs have increased demands for accurate tracking, maintenance, and projections of SSME assets. The SSME Logistics Team is developing an integrated asset management process. This PC-based tool provides a user-friendly asset database for daily decision making, plus a variable-input hardware usage simulation with complex logic yielding output that addresses essential asset management issues. Cycle times on critical tasks are significantly reduced. Associated costs have decreased as asset data quality and decision-making capability has increased.
Rotor health monitoring and online damage detection are increasingly gaining the interest of the manufacturers of aircraft engines. This is primarily due to the need for improved safety during operation as well as the need for lower maintenance costs. Applied techniques for detecting damage in and monitoring the health of rotors are essential for engine safety, reliability, and life prediction. The goals of engine safety are addressed within the NASA-sponsored Aviation Safety Program (AvSP). AvSP provides research and technology products needed to help the Federal Aviation Administration and the aerospace industry improve aviation safety. The Nondestructive Evaluation Group at the NASA Glenn Research Center is addressing propulsion health management and the development of propulsion-system-specific technologies intended to detect potential failures prior to catastrophe.
System diagnosis is an integral part of any Integrated System Health Management application. Diagnostic applications make use of system information from the design phase, such as safety and mission assurance analysis, failure modes and effects analysis, hazards analysis, functional models, fault propagation models, and testability analysis. In modern process control and equipment monitoring systems, topological and analytic , models of the nominal system, derived from design documents, are also employed for fault isolation and identification. Depending on the complexity of the monitored signals from the physical system, diagnostic applications may involve straightforward trending and feature extraction techniques to retrieve the parameters of importance from the sensor streams. They also may involve very complex analysis routines, such as signal processing, learning or classification methods to derive the parameters of importance to diagnosis. The process that is used to diagnose anomalous conditions from monitored system signals varies widely across the different approaches to system diagnosis. Rule-based expert systems, case-based reasoning systems, model-based reasoning systems, learning systems, and probabilistic reasoning systems are examples of the many diverse approaches ta diagnostic reasoning. Many engineering disciplines have specific approaches to modeling, monitoring and diagnosing anomalous conditions. Therefore, there is no "one-size-fits-all" approach to building diagnostic and health monitoring capabilities for a system. For instance, the conventional approaches to diagnosing failures in rotorcraft applications are very different from those used in communications systems. Further, online and offline automated diagnostic applications are integrated into an operations framework with flight crews, flight controllers and maintenance teams. While the emphasis of this paper is automation of health management functions, striking the correct balance between automated and human-performed tasks is a vital concern.