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Results for “maintenance simulation”

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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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Tutoring electronic troubleshooting in a simulated maintenance work environment

A series of intelligent tutoring systems, or intelligent maintenance simulators, is being developed based on expert and novice problem solving data. A graded series of authentic troubleshooting problems provides the curriculum, and adaptive instructional treatments foster active learning in trainees who engage in extensive fault isolation practice and thus in conditionalizing what they know. A proof of concept training study involving human tutoring was conducted as a precursor to the computer tutors to assess this integrated, problem based approach to task analysis and instruction. Statistically significant improvements in apprentice technicians' troubleshooting efficiency were achieved after approximately six hours of training.

Gott, Sherrie P.↗
NASA NTRS1980

Modeling a maintenance simulation of the geosynchronous platform

A modeling technique used to conduct a simulation study comparing various maintenance routines for a space platform is dicussed. A system model is described and illustrated, the basic concepts of a simulation pass are detailed, and sections on failures and maintenance are included. The operation of the system across time is best modeled by a discrete event approach with two basic events - failure and maintenance of the system. Each overall simulation run consists of introducing a particular model of the physical system, together with a maintenance policy, demand function, and mission lifetime. The system is then run through many passes, each pass corresponding to one mission and the model is re-initialized before each pass. Statistics are compiled at the end of each pass and after the last pass a report is printed. Items of interest typically include the time to first maintenance, total number of maintenance trips for each pass, average capability of the system, etc.

Kleiner, A. F., Jr.↗
NASA NTRS1986

Reliability and maintenance simulation of the Hubble Space Telescope

An analytical approach is presented which was developed and implemented at MSFC specifically for the Space Telescope Program to provide comparisons of critical item failures, system downstates, on-orbit servicing versus return for ground maintenance, overall system downtime, and to obtain a measure of expected uptime for science functions.

Pizzano, F.↗
NASA NTRS1993

RENEW v3.2 user's manual, maintenance estimation simulation for Space Station Freedom Program

RENEW is a maintenance event estimation simulation program developed in support of the Space Station Freedom Program (SSFP). This simulation uses reliability and maintainability (R&M) and logistics data to estimate both average and time dependent maintenance demands. The simulation uses Monte Carlo techniques to generate failure and repair times as a function of the R&M and logistics parameters. The estimates are generated for a single type of orbital replacement unit (ORU). The simulation has been in use by the SSFP Work Package 4 prime contractor, Rocketdyne, since January 1991. The RENEW simulation gives closer estimates of performance since it uses a time dependent approach and depicts more factors affecting ORU failure and repair than steady state average calculations. RENEW gives both average and time dependent demand values. Graphs of failures over the mission period and yearly failure occurrences are generated. The averages demand rate for the ORU over the mission period is also calculated. While RENEW displays the results in graphs, the results are also available in a data file for further use by spreadsheets or other programs. The process of using RENEW starts with keyboard entry of the R&M and operational data. Once entered, the data may be saved in a data file for later retrieval. The parameters may be viewed and changed after entry using RENEW. The simulation program runs the number of Monte Carlo simulations requested by the operator. Plots and tables of the results can be viewed on the screen or sent to a printer. The results of the simulation are saved along with the input data. Help screens are provided with each menu and data entry screen.

Bream, Bruce L.↗
NASA NTRS1975

Simulation of on-orbit maintenance cycle for LST

A maintenance simulation model of the Large Space Telescope has been developed to assess the operational cost sensitivity to system configuration options. The model lends itself to equipment-level selections for various subsystem alternatives. Maintenance decisions include considerations for LST spacecraft on-orbit service or retrieval. Tradeoffs are identified in terms of on-orbit maintenance for specific design concepts, with Space Shuttle revisit costs balanced against retrieval and ground-facility operations. Simulation output is in the form of computer plots of cost, availability, time to first maintenance, and a cost-effective Shuttle revisit frequency.

Donnelly, J. A.↗
NASA NTRS1993

Object oriented Simulation of Maintenance and Operations for Space Systems (OSMOSSYS)

This paper describes the NASA/JSC Research Technology Opportunity Program (RTOP) activity to assess the supportability of space systems throughout their life cycles. Supportability analyses for space systems present unique attributes and problems. The OSMOSSYS (Object oriented Simulation of Maintenance and Operations for Space Systems) was developed using object-oriented design concepts to provide NASA an analysis tool which addresses the question `Will a proposed space facility be able to successfully perform the missions for which it is designed?' This model integrates the complete configuration of the system including the reliability and maintainability characteristics of each component, the logistics support, and the mission operations of the facility to assess the success rate of the planned mission(s). Two parallel design processes are being utilized; developing core modules utilizing C++, and incorporating as much code and ideas as possible from existing NASA models. The space station was used as a test case to demonstrate the applicability of the model.

Doran, Linda↗
NASA NTRS1995

Estimating Maintenance Demands Of A Space Station

RENEW computer program simulates maintenance events and estimates data pertinent to maintenance demands. Developed in support of Space Station Freedom Program (SSFP) Work Package 4. Uses data on reliability and maintainability (R&M) as well as logistical data to estimate both average and time-dependent maintenance demands. Estimates failure and repair times by use of Monte Carlo simulations. Written in BASIC and Assembly language.

Bream, B. L.↗
NASA NTRS1982

Fabrication of Essex EVA ratchet wrenches

The extravehicular activity (EVA) ratchet wrench was developed. Shortly after Space Telescope (ST) maintenance simulations began, the need for a specialized maintenance tool arose. With inputs of tool requirements and design recommendations, several development model wrenches were tested in conjunction with ST neutral buoyancy simulations. The wrench design was modified and refined.

Vanvalkenburgh, C. N.↗
NASA NTRS1980

Payload maintenance cost model for the space telescope

An optimum maintenance cost model for the space telescope for a fifteen year mission cycle was developed. Various documents and subsequent updates of failure rates and configurations were made. The reliability of the space telescope for one year, two and one half years, and five years were determined using the failure rates and configurations. The failure rates and configurations were also used in the maintenance simulation computer model which simulate the failure patterns for the fifteen year mission life of the space telescope. Cost algorithms associated with the maintenance options as indicated by the failure patterns were developed and integrated into the model.

White, W. L.↗
NASA NTRS1989

Hubble Space Telescope maintenance and refurbishment planning analysis

This paper presents an updated analytical approach toward the identification of Hubble Space Telescope system failures and downstates, maintenance requirements, and overall support to maintenance mission planning. Different sparing options of Orbital Replacement Units are evaluated, and the optimum spares complement that satisfies the expected servicing requirements is identified. Specific Space Telescope Reliability and maintenance Simulation Computer Program (SPATEL) updates and refinements are reported, and input data updates relevant to failure rates, downstate ground rules, and maintenance policy are addressed. A summary of the latest SPATEL outputs is provided along with maintenance analysis results.

Pizzano, F.↗
NASA NTRS1995

O/S analysis of conceptual space vehicles

The application of recently developed computer models in determining operational capabilities and support requirements during the conceptual design of proposed space systems is discussed. The models used are the reliability and maintainability (R&M) model, the maintenance simulation model, and the operations and support (O&S) cost model. In the process of applying these models, the R&M and O&S cost models were updated. The more significant enhancements include (1) improved R&M equations for the tank subsystems, (2) the ability to allocate schedule maintenance by subsystem, (3) redefined spares calculations, (4) computing a weighted average of the working days and mission days per month, (5) the use of a position manning factor, and (6) the incorporation into the O&S model of new formulas for computing depot and organizational recurring and nonrecurring training costs and documentation costs, and depot support equipment costs. The case study used is based upon a winged, single-stage, vertical-takeoff vehicle (SSV) designed to deliver to the Space Station Freedom (SSF) a 25,000 lb payload including passengers without a crew.

Ebeling, Charles E.↗
NASA NTRS1988

Crew activities, science, and hazards of manned missions to Mars

The crew scientific and nonscientific activities that will occur at each stage of a mission to Mars are examined. Crew activities during the interplanetary flight phase will include simulations, maintenance and monitoring, communications, upgrading procedures and operations, solar activity monitoring, cross-training and sharpening of skills, physical conditioning, and free-time activities. Scientific activities will address human physiology, human psychology, sociology, astronomy, space environment effects, manufacturing, and space agriculture. Crew activities on the Martian surface will include exploration, construction, manufacturing, food production, maintenance and training, and free time. Studies of Martian geology and atmosphere, of the life forms that may exist there, and of the Martian moons will occur on the planet's surface. Crew activities and scientific studies that will occur in Mars orbit, and the hazards relevant to each stage of the mission, are also addressed.

Clark, Benton C.↗
NASA NTRS1992

Assessment of a head-mounted miniature monitor

Two experiments were conducted to assess the capabilities and limitations of the Private Eye, a miniature, head-mounted monitor. The first experiment compared the Private Eye with a cathode ray tube (CRT) and hard copy in both a constrained and unconstrained work envelope. The task was a simulated maintenance and assembly task that required frequent reference to the displayed information. A main effect of presentation media indicated faster placement times using the CRT as compared with hard copy. There were no significant differences between the Private Eye and either the CRT or hard copy for identification, placement, or total task times. The goal of the second experiment was to determine the effects of various local visual parameters on the ability of the user to accurately perceive the information of the Private Eye. The task was an interactive video game. No significant performance differences were found under either bright or dark ambient illumination environments nor with either visually simple or complex task backgrounds. Glare reflected off of the bezel surrounding the monitor did degrade performance. It was concluded that this head-mounted, miniature monitor could serve a useful role for in situ operations, especially in microgravity environments.

Hale, J. P., II↗
NASA NTRS1993

SimTool - An object based approach to simulation construction

The creation and maintenance of large complex simulations can be a difficult and error prone task. A number of interactive and automated tools have been developed to aid in simulation construction and maintenance. Many of these tools are based upon object oriented analysis and design concepts. One such tool, SimTool, is an object based integrated tool set for the development, maintenance, and operation of large, complex and long lived simulations. This paper discusses SimTool's object based approach to simulation design, construction and execution. It also discusses the services provided to various levels of SimTool users to assist them in a wide range of simulation tasks. Also, with the aid of an implemented and working simulation example, this paper discusses SimTool's key design and operational features. Finally, this paper presents a condensed discussion of SimTool's Entity-Relationship-Attribute (ERA) modeling approach.

Crues, Edwin Z.↗
NASA NTRS1990

CREW CHIEF: A computer graphics simulation of an aircraft maintenance technician

Approximately 35 percent of the lifetime cost of a military system is spent for maintenance. Excessive repair time is caused by not considering maintenance during design. Problems are usually discovered only after a mock-up has been constructed, when it is too late to make changes. CREW CHIEF will reduce the incidence of such problems by catching design defects in the early design stages. CREW CHIEF is a computer graphic human factors evaluation system interfaced to commercial computer aided design (CAD) systems. It creates a three dimensional man model, either male or female, large or small, with various types of clothing and in several postures. It can perform analyses for physical accessibility, strength capability with tools, visual access, and strength capability for manual materials handling. The designer would produce a drawing on his CAD system and introduce CREW CHIEF in it. CREW CHIEF's analyses would then indicate places where problems could be foreseen and corrected before the design is frozen.

Aume, Nilss M.↗