The NASA System Safety Program
NASA aerospace system safety program implementation and supporting organization with emphasis on background, concepts, constraints, methods and results
Harris, R. E.↗
SEARCH · Engineering Papers
Results for “program implementation”
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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Space station design
Space station design, discussing existing technology base for earth orbital operations program implementation
Berglund, R. A.↗
CIRCAL-2 - General-purpose on-line circuit design.
CIRCAL-2 is a second-generation general-purpose on-line circuit-design program with the following main features: (1) multiple-analysis capability; (2) uniform and general data structures for handling text editing, network representations, and output results, regardless of analysis; (3) special techniques and structures for minimizing and controlling user-program interaction; (4) use of functionals for the description of hysteresis and heat effects; and (5) ability to define optimization procedures that 'replace' the user. The paper discusses the organization of CIRCAL-2, the aforementioned main features, and their consequences, such as a set of network elements and models general enough for most analyses and a set of functions tailored to circuit-design requirements. The presentation is descriptive, concentrating on conceptual rather than on program implementation details.
Dertouzos, M. L.↗
Dynamic verification of a digital flight control system.
Development of a digital control system dynamic variation technique which accounts for the limitation of available frequency response analyzers. Digital control system theory is briefly reviewed, and generation of the necessary theoretical frequency responses is discussed. Results of the dynamic verification of a digital control system for a Saturn V launch vehicle are presented, and attention is given to the limitations of this technique along with its applicability to other types of digital control systems. A technique for performing open-loop frequency response analyses of a flight program implemented in a 'flight-type' digital computer and interface hardware with vehicle dynamics simulated on an analog computer is described.
Nabers, J. P., Jr.↗
Evaluation of human operator visual performance capability for teleoperator missions.
Investigation of the human operator visual performance demands of teleoperator system applications to earth-orbital missions involving visual system requirements for satellite retrieval and satellite servicing functions. The first phase of an experimental program implementing this investigation is described in terms of the overall test apparatus and procedures used, the specific tests performed, and the test results obtained.
Huggins, C. T.↗
Medical operations: Crew surgeon's report
To assure the safety and well being of the Skylab environment simulation crewmembers it was necessary to develop a medical safety plan with emergency procedures. All medical and nonmedical test and operations personnel, except those specifically exempted, were required to meet the medical standards and proficiency levels as established. Implemented programs included health care of the test crew and their families, occupational medical services for chamber operating personnel, clinical laboratory support and hypobaric and other emergency support.
Ross, C. E.↗
Reliability model derivation of a fault-tolerant, dual, spare-switching, digital computer system
A computer based reliability projection aid, tailored specifically for application in the design of fault-tolerant computer systems, is described. Its more pronounced characteristics include the facility for modeling systems with two distinct operational modes, measuring the effect of both permanent and transient faults, and calculating conditional system coverage factors. The underlying conceptual principles, mathematical models, and computer program implementation are presented.
Source record↗
Safety management of a complex R&D ground operating system
Report discusses safety program implementation for large R&D operating system. Analytical techniques are defined and suggested as tools for identifying potential hazards and determining means to effectively control or eliminate hazards.
Connors, J.↗
Gate-controlled-diodes in silicon-on-sapphire: A computer simulation
The computer simulation of the electrical behavior of a Gate-Controlled Diode (GCD) fabricated in Silicon-On-Sapphire (SOS) was described. A procedure for determining lifetime profiles from capacitance and reverse current measurements on the GCD was established. Chapter 1 discusses the SOS structure and points out the need of lifetime profiles to assist in device design for GCD's and bipolar transistors. Chapter 2 presents the one-dimensional analytical formula for electrostatic analysis of the SOS-GCD which are useful for data interpretation and setting boundary conditions on a simplified two-dimensional analysis. Chapter 3 gives the results of a two-dimensional analysis which treats the field as one-dimensional until the silicon film is depleted and the field penetrates the sapphire substrate. Chapter 4 describes a more complete two-dimensional model and gives results of programs implementing the model.
Gassaway, J. D.↗
On the computation and updating of the modified Cholesky decomposition of a covariance matrix
Methods for obtaining and updating the modified Cholesky decomposition (MCD) for the particular case of a covariance matrix when one is given only the original data are described. These methods are the standard method of forming the covariance matrix K then solving for the MCD, L and D (where K=LDLT); a method based on Householder reflections; and lastly, a method employing the composite-t algorithm. For many cases in the analysis of remotely sensed data, the composite-t method is the superior method despite the fact that it is the slowest one, since (1) the relative amount of time computing MCD's is often quite small, (2) the stability properties of it are the best of the three, and (3) it affords an efficient and numerically stable procedure for updating the MCD. The properties of these methods are discussed and FORTRAN programs implementing these algorithms are listed.
Vanrooy, D. L.↗
A quasi-Newton approach to optimization problems with probability density constraints
A quasi-Newton method is presented for minimizing a nonlinear function while constraining the variables to be nonnegative and sum to one. The nonnegativity constraints were eliminated by working with the squares of the variables and the resulting problem was solved using Tapia's general theory of quasi-Newton methods for constrained optimization. A user's guide for a computer program implementing this algorithm is provided.
Tapia, R. A.↗
Early space station user accommodations
The requirements for extended-duration space missions in earth orbit beyond those anticipated for the 7- to 30-day Shuttle Spacelab system have been examined. It has been determined that a continuously manned, free-flying orbital facility provides a realistic and cost-effective space platform for multidiscipline payloads designed to support research, applications, and system implementation programs such as the assembly of large space structures, and on-orbit space manufacturing. A conceptual description of such a manned facility (early Space Station) and the accommodations that it can provide using agencies and organizations is presented in this paper.
Saxton, D. R.↗
Operational plans for life science payloads - From experiment selection through postflight reporting
Key features of operational plans developed in a study of the Space Shuttle era life science payloads program are presented. The data describes the overall acquisition, staging, and integration of payload elements, as well as program implementation methods and mission support requirements. Five configurations were selected as representative payloads: (a) carry-on laboratories - medical emphasis experiments, (b) mini-laboratories - medical/biology experiments, (c) seven-day dedicated laboratories - medical/biology experiments, (d) 30-day dedicated laboratories - Regenerative Life Support Evaluation (RLSE) with selected life science experiments, and (e) Biomedical Experiments Scientific Satellite (BESS) - extended duration primate (Type I) and small vertebrate (Type II) missions. The recommended operational methods described in the paper are compared to the fundamental data which has been developed in the life science Spacelab Mission Simulation (SMS) test series. Areas assessed include crew training, experiment development and integration, testing, data-dissemination, organization interfaces, and principal investigator working relationships.
Mccollum, G. W.↗
Lightning strike experience
A program implemented to report various lightning-strike incidents was reviewed. Strike incidence data was summarized according to aircraft altitude, flight path, meteorological conditions and atmospheric air temperature. Data was given indicating the incidence of reported lightning strikes to commercial and U.S. Air Force aircraft and an outline of pilot opinion in lightning avoidance was given.
Franklin A Fisher↗
SEAHT: A computer program for the use of intersecting arcs of altimeter data for sea surface height refinement
The SEAHT program is designed to process multiple passes of altimeter data with intersecting ground tracks, with the estimation of corrections for orbital errors to each pass such that the data has the best overall agreement at the crossover points. Orbit error for each pass is modeled as a polynomial in time, with optional orders of 0, 1, or 2. One or more passes may be constrained in the adjustment process, thus allowing passes with the best orbits to provide the overall level and orientation of the estimated sea surface heights. Intersections which disagree by more than an input edit level are not used in the error parameter estimation. In the program implementation, passes are grouped into South-North passes and North-South passes, with the North-South passes partitioned out for the estimation of orbit error parameters. Computer core utilization is thus dependent on the number of parameters estimated for the set of South-North arcs, but is independent on the number of North-South passes. Estimated corrections for each pass are applied to the data at its input data rate and an output tape is written which contains the corrected data.
Allen, C. P.↗
Space industrialization. Volume 1: Executive summary
Potential goals for space industrialization were identified, and evolutionary program options for the realization of those goals were developed and assessed. Program support demands were defined, and recommendations were made in relation to program implementation.
Source record↗
Description and texts for the auxiliary programs for processing video information on the YeS computer. Part 3: Test program 2
The functions were discribed and the operating instructions, the block diagram and the proposed versions are given for modifying the program in order to obtain the statistical characteristics of multi-channel video information. The program implements certain man-machine methods for investigating video information. It permits representation of the material and its statistical characteristics in a form which is convenient for the user.
Borisenko, V. I., G.g.↗
Atmospheric lidar multi-user instrument system definition study
A spaceborne lidar system for atmospheric studies was defined. The primary input was the Science Objectives Experiment Description and Evolutionary Flow Document. The first task of the study was to perform an experiment evolutionary analysis of the SEED. The second task was the system definition effort of the instrument system. The third task was the generation of a program plan for the hardware phase. The fourth task was the supporting studies which included a Shuttle deficiency analysis, a preliminary safety hazard analysis, the identification of long lead items, and development studies required. As a result of the study an evolutionary Lidar Multi-User Instrument System (MUIS) was defined. The MUIS occupies a full Spacelab pallet and has a weight of 1300 kg. The Lidar MUIS laser provides a 2 joule frequency doubled Nd:YAG laser that can also pump a tuneable dye laser wide frequency range and bandwidth. The MUIS includes a 1.25 meter diameter aperture Cassegrain receiver, with a moveable secondary mirror to provide precise alignment with the laser. The receiver can transmit the return signal to three single and multiple photomultiple tube detectors by use of a rotating fold mirror. It is concluded that the Lidar MUIS proceed to program implementation.
Greco, R. V.↗