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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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At least 271 records · Page 15

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NASA NTRS1982

Health and safety evaluation of a modified tunnel borer design for application to single entry coal mine development

A health and safety analysis of a single entry coal tunnel borer system is given. The results of the health analysis indicated that while the tunnel borer design offered improvements in dust control through the use of water sprays, a higher face ventilation rule, and the application of spalling rather than the conventional grinding process, it interjected an additional mutagen and toxic compound into the environment through the use of shotcrete. The tunnel borer system easily conformed with the prescribed fatality limit, but exceeded the required limits for disabling and overall injuries. It also exhibited projected disabling and overall injury rates considerably higher than existing continuous mining injury rates. Consequently, the tunnel borer system was not considered an advanced system.

Zimmerman, W. F.↗

NASA NTRS1982

Automotive Stirling Engine Mod 1 Design Review, Volume 1

Risk assessment, safety analysis of the automotive stirling engine (ASE) mod I, design criteria and materials properties for the ASE mod I and reference engines, combustion are flower development, and the mod I engine starter motor are discussed. The stirling engine system, external heat system, hot engine system, cold engine system, and engine drive system are also discussed.

Source record↗

NASA NTRS1982

Preliminary design of flight hardware for two-phase fluid research

This study defined the preliminary designs of flight software for the Space Shuttle Orbiter for three two-phase fluid research experiments: (1) liquid reorientation - to study the motion of liquid in tanks subjected to small accelerations; (2) pool boiling - to study low-gravity boiling from horizontal cylinders; and (3) flow boiling - to study low-gravity forced flow boiling heat transfer and flow phenomena in a heated horizontal tube. The study consisted of eight major tasks: reassessment of the existing experiment designs, assessment of the Spacelab facility approach, assessment of the individual carry-on approach, selection of the preferred approach, preliminary design of flight hardware, safety analysis, preparation of a development plan, estimates of detailed design, fabrication and ground testing costs. The most cost effective design approach for the experiments is individual carry-ons in the Orbiter middeck. The experiments were designed to fit into one or two middeck lockers. Development schedules for the detailed design, fabrication and ground testing ranged from 15 1/2 to 18 months. Minimum costs (in 1981 dollars) ranged from $463K for the liquid reorientation experiment to $998K for the pool boiling experiment.

Hustvedt, D. C.↗

NASA NTRS1984

Preliminary engineering report for design of a subscale ejector/diffuser system for high expansion ratio space engine testing

The design of a subscale jet engine driven ejector/diffuser system is examined. Analytical results and preliminary design drawings and plans are included. Previously developed performance prediction techniques are verified. A safety analysis is performed to determine the mechanism for detonation suppression.

Wojciechowski, C. J.↗

NASA NTRS1991

How Safe Is Control Software

Paper examines issue of software safety. Presents four case histories of software-safety analysis. Concludes that, to be safe, software, for all practical purposes, must be free of errors. Backup systems still needed to prevent catastrophic software failures.

Dunn, William R.↗

NASA NTRS1987

Software safety

Software safety and its relationship to other qualities are discussed. It is shown that standard reliability and fault tolerance techniques will not solve the safety problem for the present. A new attitude requires: looking at what you do NOT want software to do along with what you want it to do; and assuming things will go wrong. New procedures and changes to entire software development process are necessary: special software safety analysis techniques are needed; and design techniques, especially eliminating complexity, can be very helpful.

Leveson, Nancy↗

NASA NTRS1990

Technical challenges involved in supporting the Lambda Point Experiment

The Lambda Point Experiment (LPE) is one of the instruments included in the U.S. Microgravity Payload Mission 1 planned for one of the Space Shuttle flights in 1992. The objective of the experiment is to measure the heat capacity of liquid helium within a narrow interval around the transition between superfluid and normal helium (the lambda point) with an unprecedented temperature resolution of about 10 to the -10th. Multiple technical challenges are presented in the areas of structural support, safety analysis, and modal frequency tests. This paper describes the technical challenges of JPL's multidisciplinary involvement in support of these experiments in microgravity.

Petrac, D.↗

NASA NTRS1992

Buffet test in the National Transonic Facility

Young, Clarence P., Jr.↗

NASA NTRS1992

Buffet test in the National Transonic Facility

A buffet test of a commercial transport model was accomplished in the National Transonic Facility at the NASA Langley Research Center. This aeroelastic test was unprecedented for this wind tunnel and posed a high risk to the facility. This paper presents the test results from a structural dynamics and aeroelastic response point of view and describes the activities required for the safety analysis and risk assessment. The test was conducted in the same manner as a flutter test and employed onboard dynamic instrumentation, real time dynamic data monitoring, automatic, and manual tunnel interlock systems for protecting the model. The procedures and test techniques employed for this test are expected to serve as the basis for future aeroelastic testing in the National Transonic Facility. This test program was a cooperative effort between the Boeing Commercial Airplane Company and the NASA Langley Research Center.

Young, Clarence P., Jr.↗

NASA NTRS1992

Update to the safety program for the general-purpose heat source radioisotope thermoelectric generators for the Galileo and Ulysses missions

With the rescheduling of the Galileo and Ulysses launches and the use of new upper stages following the Challenger accident, the aerospace nuclear safety program for the general-purpose heat source radioisotope thermoelectric generators (GPHS-RTGs) was extended to accommodate the new mission scenarios. As in the original safety program, the objectives were to determine the response of the GPHS-RTG to the various postulated accident environments and to determine the risk (if any) associated with these postulated accidents. The extended GPHS-RTG safety program was successfully completed in sufficient time to prepare an updated Final Safety Analysis Report (FSAR) with revisions for the October 1989 launch of the Galileo spacecraft.

Bennett, Gary L.↗

NASA NTRS1996

Applications of Formal Methods to Specification and Safety of Avionics Software

This report treats several topics in applications of formal methods to avionics software development. Most of these topics concern decision tables, an orderly, easy-to-understand format for formally specifying complex choices among alternative courses of action. The topics relating to decision tables include: generalizations fo decision tables that are more concise and support the use of decision tables in a refinement-based formal software development process; a formalism for systems of decision tables with behaviors; an exposition of Parnas tables for users of decision tables; and test coverage criteria and decision tables. We outline features of a revised version of ORA's decision table tool, Tablewise, which will support many of the new ideas described in this report. We also survey formal safety analysis of specifications and software.

Hoover, D. N.↗

NASA NTRS1999

A System for Integrated Reliability and Safety Analyses

We present an integrated reliability and aviation safety analysis tool. The reliability models for selected infrastructure components of the air traffic control system are described. The results of this model are used to evaluate the likelihood of seeing outcomes predicted by simulations with failures injected. We discuss the design of the simulation model, and the user interface to the integrated toolset.

Kostiuk, Peter↗

NASA NTRS1994

Reliability-Based Design of a Safety-Critical Automation System: A Case Study

In 1986, NASA funded a project to modernize the NASA Ames Research Center Unitary Plan Wind Tunnels, including the replacement of obsolescent controls with a modern, automated distributed control system (DCS). The project effort on this system included an independent safety analysis (ISA) of the automation system. The purpose of the ISA was to evaluate the completeness of the hazard analyses which had already been performed on the Modernization Project. The ISA approach followed a tailoring of the risk assessment approach widely used on existing nuclear power plants. The tailoring of the nuclear industry oriented risk assessment approach to the automation system and its role in reliability-based design of the automation system is the subject of this paper.

Carroll, Carol W.↗

NASA NTRS2002

The Integrated Air Transportation System Evaluation Tool

Throughout U.S. history, our nation has generally enjoyed exceptional economic growth, driven in part by transportation advancements. Looking forward 25 years, when the national highway and skyway systems are saturated, the nation faces new challenges in creating transportation-driven economic growth and wealth. To meet the national requirement for an improved air traffic management system, NASA developed the goal of tripling throughput over the next 20 years, in all weather conditions while maintaining safety. Analysis of the throughput goal has primarily focused on major airline operations, primarily through the hub and spoke system.However, many suggested concepts to increase throughput may operate outside the hub and spoke system. Examples of such concepts include the Small Aircraft Transportation System, civil tiltrotor, and improved rotorcraft. Proper assessment of the potential contribution of these technologies to the domestic air transportation system requires a modeling capability that includes the country's numerous smaller airports, acting as a fundamental component of the National Air space System, and the demand for such concepts and technologies. Under this task for NASA, the Logistics Management Institute developed higher fidelity demand models that capture the interdependence of short-haul air travel with other transportation modes and explicitly consider the costs of commercial air and other transport modes. To accomplish this work, we generated forecasts of the distribution of general aviation based aircraft and GA itinerant operations at each of nearly 3.000 airport based on changes in economic conditions and demographic trends. We also built modules that estimate the demand for travel by different modes, particularly auto, commercial air, and GA. We examined GA demand from two perspectives: top-down and bottom-up, described in detail.

Wingrove, Earl R., III↗

NASA NTRS2003

Flight Guidance System Requirements Specification

This report describes a requirements specification written in the RSML-e language for the mode logic of a Flight Guidance System of a typical regional jet aircraft. This model was created as one of the first steps in a five-year project sponsored by the NASA Langley Research Center, Rockwell Collins Inc., and the Critical Systems Research Group of the University of Minnesota to develop new methods and tools to improve the safety of avionics designs. This model will be used to demonstrate the application of a variety of methods and techniques, including safety analysis of system and subsystem requirements, verification of key properties using theorem provers and model checkers, identification of potential sources mode confusion in system designs, partitioning of applications based on the criticality of system hazards, and autogeneration of avionics quality code. While this model is representative of the mode logic of a typical regional jet aircraft, it does not describe an actual or planned product. Several aspects of a full Flight Guidance System, such as recovery from failed sensors, have been omitted, and no claims are made regarding the accuracy or completeness of this specification.

Miller, Steven P.↗

NASA NTRS2008

Operational Experience with Long Duration Wildfire Mapping: UAS Missions Over the Western United States

The National Aeronautics and Space Administration, United States Forest Service, and National Interagency Fire Center have developed a partnership to develop and demonstrate technology to improve airborne wildfire imaging and data dissemination. In the summer of 2007, a multi-spectral infrared scanner was integrated into NASA's Ikhana Unmanned Aircraft System (UAS) (a General Atomics Predator-B) and launched on four long duration wildfire mapping demonstration missions covering eight western states. Extensive safety analysis, contingency planning, and mission coordination were key to securing an FAA certificate of authorization (COA) to operate in the national airspace. Infrared images were autonomously geo-rectified, transmitted to the ground station by satellite communications, and networked to fire incident commanders within 15 minutes of acquisition. Close coordination with air traffic control ensured a safe operation, and allowed real-time redirection around inclement weather and other minor changes to the flight plan. All objectives of the mission demonstrations were achieved. In late October, wind-driven wildfires erupted in five southern California counties. State and national emergency operations agencies requested Ikhana to help assess and manage the wildfires. Four additional missions were launched over a 5-day period, with near realtime images delivered to multiple emergency operations centers and fire incident commands managing 10 fires.

Hall, Philip↗

NASA NTRS2008

FootFall: A Ground Based Operations Toolset Enabling Walking for the ATHLETE Rover

The ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) vehicle consists of six identical, six degree of freedom limbs. FootFall is a ground tool for ATHLETE intended to provide an operator with integrated situational awareness, terrain reconstruction, stability and safety analysis, motion planning, and decision support capabilities to enable the efficient generation of flight software command sequences for walking. FootFall has been under development at NASA Ames for the last year, and having accomplished the initial integration, it is being used to generate command sequences for single footfalls. In this paper, the architecture of FootFall in its current state will be presented, results from the recent Human Robotic Systems Project?s Integrated Field Test (Moses Lake, Washington, June, 2008) will be discussed, and future plans for extending the capabilities of FootFall to enable ATHLETE to walk across a boulder field in real time will be described.

SunSpiral, Vytas↗

NASA NTRS2011

Safety and Mission Assurance for In-House Design Lessons Learned from Ares I Upper Stage

This viewgraph presentation identifies lessons learned in the course of the Ares I Upper Stage design and in-house development effort. The contents include: 1) Constellation Organization; 2) Upper Stage Organization; 3) Presentation Structure; 4) Lesson-Importance of Systems Engineering/Integration; 5) Lesson-Importance of Early S&MA Involvement; 6) Lesson-Importance of Appropriate Staffing Levels; 7) Lesson-Importance S&MA Team Deployment; 8) Lesson-Understanding of S&MA In-Line Engineering versus Assurance; 9) Lesson-Importance of Close Coordination between Supportability and Reliability/Maintainability; 10) Lesson-Importance of Engineering Data Systems; 11) Lesson-Importance of Early Development of Supporting Databases; 12) Lesson-Importance of Coordination with Safety Assessment/Review Panels; 13) Lesson-Implementation of Software Reliability; 14) Lesson-Implementation of S&MA Technical Authority/Chief S&MA Officer; 15) Lesson-Importance of S&MA Evaluation of Project Risks; 16) Lesson-Implementation of Critical Items List and Government Mandatory Inspections; 17) Lesson-Implementation of Critical Items List Mandatory Inspections; 18) Lesson-Implementation of Test Article Safety Analysis; and 19) Lesson-Importance of Procurement Quality.

Anderson, Joel M.↗