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At least 397 records · Page 22

Safety status of space radioisotope and reactor power sources

The current overall safety criterion for both radioisotope and reactor power sources is containment or immobilization in the case of a reentry accident. In addition, reactors are designed to remain subcritical under conditions of land impact or water immersion. A very extensive safety test and analysis program was completed on the radioisotope thermoelectric generators (RTGs) in use on the Galileo spacecraft and planned for use on the Ulysses spacecraft. The results of this work show that the RTGs will pose little or no risk for any credible accident. The SP-100 space nuclear reactor program has begun addressing its safety criteria, and the design is planned to be such as to ensure meeting the various safety criteria. Preliminary mission risk analyses on SP-100 show the expected value population dose from postulated accidents on the reference mission to be very small. It is concluded that the current US nuclear power sources are the safest flown.

Bennett, Gary L.↗

Aerospace Safety Advisory Panel

The results of the Panel's activities are presented in a set of findings and recommendations. Highlighted here are both improvements in NASA's safety and reliability activities and specific areas where additional gains might be realized. One area of particular concern involves the curtailment or elimination of Space Shuttle safety and reliability enhancements. Several findings and recommendations address this area of concern, reflecting the opinion that safety and reliability enhancements are essential to the continued successful operation of the Space Shuttle. It is recommended that a comprehensive and continuing program of safety and reliability improvements in all areas of Space Shuttle hardware/software be considered an inherent component of ongoing Space Shuttle operations.

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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.↗

Achievements and challenges of Space Station Freedom's safety review process

The most complex space vehicle in history, Space Station Freedom, is well underway to completion, and System Safety is a vital part of the program. The purpose is to summarize and illustrate the progress that over one-hundred System Safety engineers have made in identifying, documenting, and controlling the hazards inherent in the space station. To date, Space Station Freedom has been reviewed by NASA's safety panels through the first six assembly flights, when Freedom achieves a configuration known as Man Tended Capability. During the eight weeks of safety reviews spread out over a year and a half, over 200 preliminary hazard reports were presented. Along the way NASA and its contractors faced many challenges, made much progress, and even learned a few lessons.

Robinson, David W.↗

New health and safety initiatives at the Department of Energy (DOE)

This document touches on some of the more important lessons learned and the more noteworthy initiatives DOE has put into motion in the last three years to protect the health and safety of our contractor employees. What we have learned in the process should come as no surprise to those of you who have been working in the field: (1) that management commitment to safety and health is critical to a successful program; (2) that meaningful employee participation in all aspects of the program enhances its effectiveness at every level; and (3) that the dedication and expertise of medical and occupational safety and health professionals are needed if the challenging problems presented by the complex and technologically advanced environment at DOE facilities are to be overcome. I believe that we have made a good beginning in the long and arduous task of building an Occupational Safety and Health Program that will serve as a model for others, and I can assure you that we intend to continue our efforts to protect every worker within the complex from occupational injury and disease.

Ziemer, Paul L.↗

HFE safety reviews of advanced nuclear power plant control rooms

Advanced control rooms (ACR's) will utilize human-system interface (HSI) technologies that may have significant implications for plant safety in that they will affect the operator's overall role and means of interacting with the system. The Nuclear Regulatory Commission (NRC) reviews the human factors engineering (HFE) aspects of HSI's to ensure that they are designed to good HFE principles and support performance and reliability in order to protect public health and safety. However, the only available NRC guidance was developed more than ten years ago, and does not adequately address the human performance issues and technology changes associated with ACR's. Accordingly, a new approach to ACR safety reviews was developed based upon the concept of 'convergent validity'. This approach to ACR safety reviews is described.

Ohara, John↗

Aerospace Safety Advisory Panel

The Aerospace Safety Advisory Panel (ASAP) provided oversight on the safety aspects of many NASA programs. In addition, ASAP undertook three special studies. At the request of the Administrator, the panel assessed the requirements for an assured crew return vehicle (ACRV) for the space station and reviewed the organization of the safety and mission quality function within NASA. At the behest of Congress, the panel formed an independent, ad hoc working group to examine the safety and reliability of the space shuttle main engine. Section 2 presents findings and recommendations. Section 3 consists of information in support of these findings and recommendations. Appendices A, B, C, and D, respectively, cover the panel membership, the NASA response to the findings and recommendations in the March 1992 report, a chronology of the panel's activities during the reporting period, and the entire ACRV study report.

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Software development for safety-critical medical applications

There are many computer-based medical applications in which safety and not reliability is the overriding concern. Reduced, altered, or no functionality of such systems is acceptable as long as no harm is done. A precise, formal definition of what software safety means is essential, however, before any attempt can be made to achieve it. Without this definition, it is not possible to determine whether a specific software entity is safe. A set of definitions pertaining to software safety will be presented and a case study involving an experimental medical device will be described. Some new techniques aimed at improving software safety will also be discussed.

Knight, John C.↗

Aerospace safety advisory panel

The Aerospace Safety Advisory Panel (ASAP) monitored NASA's activities and provided feedback to the NASA Administrator, other NASA officials and Congress throughout the year. Particular attention was paid to the Space Shuttle, its launch processing and planned and potential safety improvements. The Panel monitored Space Shuttle processing at the Kennedy Space Center (KSC) and will continue to follow it as personnel reductions are implemented. There is particular concern that upgrades in hardware, software, and operations with the potential for significant risk reduction not be overlooked due to the extraordinary budget pressures facing the agency. The authorization of all of the Space Shuttle Main Engine (SSME) Block II components portends future Space Shuttle operations at lower risk levels and with greater margins for handling unplanned ascent events. Throughout the year, the Panel attempted to monitor the safety activities related to the Russian involvement in both space and aeronautics programs. This proved difficult as the working relationships between NASA and the Russians were still being defined as the year unfolded. NASA's concern for the unique safety problems inherent in a multi-national endeavor appears appropriate. Actions are underway or contemplated which should be capable of identifying and rectifying problem areas. The balance of this report presents 'Findings and Recommendations' (Section 2), 'Information in Support of Findings and Recommendations' (Section 3) and Appendices describing Panel membership, the NASA response to the March 1994 ASAP report, and a chronology of the panel's activities during the reporting period (Section 4).

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Generalized implementation of software safety policies

As part of a research program in the engineering of software for safety-critical systems, we are performing two case studies. The first case study, which is well underway, is a safety-critical medical application. The second, which is just starting, is a digital control system for a nuclear research reactor. Our goal is to use these case studies to permit us to obtain a better understanding of the issues facing developers of safety-critical systems, and to provide a vehicle for the assessment of research ideas. The case studies are not based on the analysis of existing software development by others. Instead, we are attempting to create software for new and novel systems in a process that ultimately will involve all phases of the software lifecycle. In this abstract, we summarize our results to date in a small part of this project, namely the determination and classification of policies related to software safety that must be enforced to ensure safe operation. We hypothesize that this classification will permit a general approach to the implementation of a policy enforcement mechanism.

Knight, John C.↗

An Innovative Multimedia Approach to Laboratory Safety

A new approach for teaching safe laboratory practices has been developed for materials science laboratories at Iowa State university. Students are required to complete a computerized safety tutorial and pass an exam before working in the laboratory. The safety tutorial includes sections on chemical, electrical, radiation, and high temperature safety. The tutorial makes use of a variety of interactions, including 'assembly' interactions where a student is asked to drag and drop items with the mouse (either labels or pictures) to an appropriate place on the screen (sometimes in a specific order). This is extremely useful for demonstrating safe lab practices and disaster scenarios. Built into the software is a record tracking scheme so that a professor can access a file that records which students have completed the tutorial and their scores on the exam. This paper will describe the development and assessment of the safety tutorials.

Anderson, M. B.↗

The NASA Aviation Safety Program: Overview

In 1997, the United States set a national goal to reduce the fatal accident rate for aviation by 80% within ten years based on the recommendations by the Presidential Commission on Aviation Safety and Security. Achieving this goal will require the combined efforts of government, industry, and academia in the areas of technology research and development, implementation, and operations. To respond to the national goal, the National Aeronautics and Space Administration (NASA) has developed a program that will focus resources over a five year period on performing research and developing technologies that will enable improvements in many areas of aviation safety. The NASA Aviation Safety Program (AvSP) is organized into six research areas: Aviation System Modeling and Monitoring, System Wide Accident Prevention, Single Aircraft Accident Prevention, Weather Accident Prevention, Accident Mitigation, and Synthetic Vision. Specific project areas include Turbulence Detection and Mitigation, Aviation Weather Information, Weather Information Communications, Propulsion Systems Health Management, Control Upset Management, Human Error Modeling, Maintenance Human Factors, Fire Prevention, and Synthetic Vision Systems for Commercial, Business, and General Aviation aircraft. Research will be performed at all four NASA aeronautics centers and will be closely coordinated with Federal Aviation Administration (FAA) and other government agencies, industry, academia, as well as the aviation user community. This paper provides an overview of the NASA Aviation Safety Program goals, structure, and integration with the rest of the aviation community.

Shin, Jaiwon↗

Alaska Humans Factors Safety Study: The Northern Area

At the request of the Alaska Air Carriers Association, researchers from the NASA Aviation Safety Reporting System, at NASA Ames Research Center, conducted a study on aspects of safety in Alaskan Part 135 air taxi operations. An interview form on human factors safety issues was created by a representative team from the FAA-Alaska, NTSB-Alaska, NASAASRS, and representatives of the Alaska Air Carriers Association which was subsequently used in the interviews of pilots and managers. Because of the climate and operational differences, the study was broken into two geographical areas, the southern coastal areas and the northern portion of the state. This presentation addresses the northern area, specifically: Bethel, Fairbanks, Nome, Kotzebue, and Barrow. The interview questions dealt with many of the potential pressures on pilots and managers associated with the daily air taxi operations in Alaska. The impact of the environmental factors such as the lack of available communication, navigation and weather information systems was evaluated. The results of this study will be used by government and industry working in Alaska. These findings will contribute important information on specific Alaska safety issues for eventual incorporation into training materials and policies that will help to assure the safe conduct of air taxi flights in Alaska.

Connell, Linda↗

Alaska Humans Factors Safety Study: The Southern Coastal Area

At the request of the Alaska Air Carriers Association, researchers from the NASA Aviation Safety Reporting System, at NASA Ames Research Center, conducted a study on aspects of safety in Alaskan Part 135 air taxi operations. An interview form on human factors safety issues was created by a representative team from the FAA-Alaska, NTSB-Alaska, NASA-ASRS, and representatives of the Alaska Air Carriers Association which was subsequently used in the interviews of pilots and managers. Because of the climate and operational differences, the study was broken into two geographical areas, the southern coastal areas and the northern portion of the state. This presentation addresses the southern coastal areas, specifically: Anchorage, Dillingham, King Salmon, Kodiak, Cold Bay, Juneau, and Ketchikan. The interview questions dealt with many of the potential pressures on pilots and managers associated with the daily air taxi operations in Alaska. The impact of the environmental factors such as the lack of available communication, navigation and weather information systems was evaluated. The results of this study will be used by government and industry working in Alaska. These findings will contribute important information on specific Alaska safety issues for eventual incorporation into training materials and policies that will help to assure the safe conduct of air taxi flights in Alaska.

Chappell, Sheryl L.↗

Helicopter Safety Research

In response to the President's challenge to reduce civil aviation accidents by a factor of 10 by the year 2022, NASA has embarked on an ambitious safety program in partnership with other government agencies and industry. The helicopter element of the NASA initiative has been guided by a series of accident analyses aimed at identifying the most frequent causes and consequences and initiating research to prevent or mitigate these factors. This talk will summarize the key findings of three of the accident analyses, the major elements of the safety program, and how helicopter safety research relates to the safety program.

Hart, Sandra G.↗

Safety on Earth From MARSS

ENSCO, Inc., developed the Meteorological and Atmospheric Real-time Safety Support (MARSS) system for real-time assessment of meteorological data displays and toxic material spills. MARSS also provides mock scenarios to guide preparations for emergencies involving meteorological hazards and toxic substances. Developed under a Small Business Innovation Research (SBIR) contract with Kennedy Space Center, MARSS was designed to measure how safe NASA and Air Force range safety personnel are while performing weather sensitive operations around launch pads. The system augments a ground operations safety plan that limits certain work operations to very specific weather conditions. It also provides toxic hazard prediction models to assist safety managers in planning for and reacting to releases of hazardous materials. MARSS can be used in agricultural, industrial, and scientific applications that require weather forecasts and predictions of toxic smoke movement. MARSS is also designed to protect urban areas, seaports, rail facilities, and airports from airborne releases of hazardous chemical substances. The system can integrate with local facility protection units and provide instant threat detection and assessment data that is reportable for local and national distribution.

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Organizational Culture and Safety

'..only a fool perseveres in error.' Cicero. Humans will break the most advanced technological devices and override safety and security systems if they are given the latitude. Within the workplace, the operator may be just one of several factors in causing accidents or making risky decisions. Other variables considered for their involvement in the negative and often catastrophic outcomes include the organizational context and culture. Many organizations have constructed and implemented safety programs to be assimilated into their culture to assure employee commitment and understanding of the importance of everyday safety. The purpose of this paper is to examine literature on organizational safety cultures and programs that attempt to combat vulnerability, risk taking behavior and decisions and identify the role of training in attempting to mitigate unsafe acts.

Adams, Catherine A.↗

Propulsion Health Monitoring for Enhanced Safety

This report presents the results of the NASA contract Propulsion System Health Management for Enhanced Safety performed by General Electric Aircraft Engines (GE AE), General Electric Global Research (GE GR), and Pennsylvania State University Applied Research Laboratory (PSU ARL) under the NASA Aviation Safety Program. This activity supports the overall goal of enhanced civil aviation safety through a reduction in the occurrence of safety-significant propulsion system malfunctions. Specific objectives are to develop and demonstrate vibration diagnostics techniques for the on-line detection of turbine rotor disk cracks, and model-based fault tolerant control techniques for the prevention and mitigation of in-flight engine shutdown, surge/stall, and flameout events. The disk crack detection work was performed by GE GR which focused on a radial-mode vibration monitoring technique, and PSU ARL which focused on a torsional-mode vibration monitoring technique. GE AE performed the Model-Based Fault Tolerant Control work which focused on the development of analytical techniques for detecting, isolating, and accommodating gas-path faults.

Butz, Mark G.↗