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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Making the Hubble Space Telescope servicing mission safe

This paper will detail how the Hubble Space Telescope (HST) system safety program is conducted. Numerous safety analyses are conducted through the various phases of design, test, and fabrication, and results are presented to NASA management for discussion during dedicated safety reviews. This paper will then address the system safety assessment and risk analysis methodologies used (i.e. hazard analysis, fault tree analysis, and failure modes and effects analysis), and how they are coupled with enginering and test analyses for a 'synergistic picture' of the system. Some preliminary safety analysis results, showing the relationship between hazard identification, control or abatement, and finally control verification, will be presented as examples of this safety process.

Bahr, N. J.↗
NASA NTRS1998

Research Lasers and Air Traffic Safety: Issues, Concerns and Responsibilities of the Research Community

The subject of outdoor use of lasers relative to air traffic has become a diverse and dynamic topic. During the past several decades, the use of lasers in outdoor research activities have increased significantly. Increases in the outdoor use of lasers and increases in air traffic densities have changed the levels of risk involved. To date there have been no documented incidents of air traffic interference from research lasers; however, incidents involving display lasers have shown a marked increase. As a result of the national response to these incidents, new concerns over lasers have arisen. Through the efforts of the SAE G-10T Laser Safety Hazards Subcommittee and the ANSI Z136.6 development committee, potential detrimental effects to air traffic beyond the traditional eye damage concerns have been identified. An increased emphasis from the Federal Aviation Administration (FAA), the Center for Devices and Radiological Hazards (CDRH), and the National Transportation Safety Board (NTSB) along with increased concern by the public have resulted in focused scrutiny of potential hazards presented by lasers. The research community needs to rethink the traditional methods of risk evaluation and application of protective measures. The best current approach to assure adequate protection of air traffic is the application of viable hazard and risk analysis and the use of validated protective measures. Standards making efforts and regulatory development must be supported by the research community to assure that reasonable measures are developed. Without input, standards and regulations can be developed that are not compatible with the needs of the research community. Finally, support is needed for the continued development and validation of protective measures.

Nessler, Phillip J., Jr.↗
NASA NTRS2000

Fault Tree Analysis: A Bibliography

Fault tree analysis is a top-down approach to the identification of process hazards. It is as one of the best methods for systematically identifying an graphically displaying the many ways some things can go wrong. This bibliography references 266 documents in the NASA STI Database that contain the major concepts. fault tree analysis, risk an probability theory, in the basic index or major subject terms. An abstract is included with most citations, followed by the applicable subject terms.

Source record↗
NASA NTRS2001

Phased Array Ultrasonic Evaluation of Space Shuttle Main Engine (SSME) Nozzle Weld

This viewgraph presentation gives an overview of the phased array ultrasonic evaluation of the Space Shuttle Main Engine (SSME) nozzle weld. Details are given on the nondestructive testing evaluation approach, conventional shear wave and phased array techniques, and an x-ray versus phased array risk analysis. The field set-up was duplicated to the greatest extent possible in the laboratory and the phased array ultrasonic technique was developed and validated prior to weld evaluation. Results are shown for the phased array ultrasonic evaluation and conventional ultrasonic evaluation results.

James, Steve↗
NASA NTRS2002

Stochastic Models of Human Errors

Humans play an important role in the overall reliability of engineering systems. More often accidents and systems failure are traced to human errors. Therefore, in order to have meaningful system risk analysis, the reliability of the human element must be taken into consideration. Describing the human error process by mathematical models is a key to analyzing contributing factors. Therefore, the objective of this research effort is to establish stochastic models substantiated by sound theoretic foundation to address the occurrence of human errors in the processing of the space shuttle.

Elshamy, Maged↗
NASA NTRS2002

Quick Fix for Managing Risks

Under a Phase II SBIR contract, Kennedy and Lumina Decision Systems, Inc., jointly developed the Schedule and Cost Risk Analysis Modeling (SCRAM) system, based on a version of Lumina's flagship software product, Analytica(R). Acclaimed as "the best single decision-analysis program yet produced" by MacWorld magazine, Analytica is a "visual" tool used in decision-making environments worldwide to build, revise, and present business models, minus the time-consuming difficulty commonly associated with spreadsheets. With Analytica as their platform, Kennedy and Lumina created the SCRAM system in response to NASA's need to identify the importance of major delays in Shuttle ground processing, a critical function in project management and process improvement. As part of the SCRAM development project, Lumina designed a version of Analytica called the Analytica Design Engine (ADE) that can be easily incorporated into larger software systems. ADE was commercialized and utilized in many other developments, including web-based decision support.

Source record↗
NASA NTRS2004

Estimating the Risk of Technology Development

This viewgraph presentation introduces a methodology for incorporating risk analysis and technology assessment in the evaluation of research and development projects.

Wilhite, Alan W.↗
NASA NTRS2007

Resilient Propulsion Control Research for the NASA Integrated Resilient Aircraft Control (IRAC) Project

Gas turbine engines are designed to provide sufficient safety margins to guarantee robust operation with an exceptionally long life. However, engine performance requirements may be drastically altered during abnormal flight conditions or emergency maneuvers. In some situations, the conservative design of the engine control system may not be in the best interest of overall aircraft safety; it may be advantageous to "sacrifice" the engine to "save" the aircraft. Motivated by this opportunity, the NASA Aviation Safety Program is conducting resilient propulsion research aimed at developing adaptive engine control methodologies to operate the engine beyond the normal domain for emergency operations to maximize the possibility of safely landing the damaged aircraft. Previous research studies and field incident reports show that the propulsion system can be an effective tool to help control and eventually land a damaged aircraft. Building upon the flight-proven Propulsion Controlled Aircraft (PCA) experience, this area of research will focus on how engine control systems can improve aircraft safe-landing probabilities under adverse conditions. This paper describes the proposed research topics in Engine System Requirements, Engine Modeling and Simulation, Engine Enhancement Research, Operational Risk Analysis and Modeling, and Integrated Flight and Propulsion Controller Designs that support the overall goal.

Guo, Ten-Huei↗
NASA NTRS2006

Mapping the Rainforest of the Sea: Global Coral Reef Maps for Global Conservation

Coral reefs are the center of marine biodiversity, yet are under threat with an estimated 60% of coral reef habitats considered at risk by the World Resources Institute. The location and extent of coral reefs in the world are the basic information required for resource management and as a baseline for monitoring change. A NASA sponsored partnership between remote sensing scientists, international agencies and NGOs, has developed a new generation of global reef maps based on data collected by satellites. The effort, dubbed the Millennium Coral Reef Map aims to develop new methods for wide distribution of voluminous satellite data of use to the conservation and management communities. We discuss the tradeoffs between remote sensing data sources, mapping objectives, and the needs for conservation and resource management. SeaWiFS data were used to produce a composite global shallow bathymetry map at 1 km resolution. Landsat 7/ETM+ data acquisition plans were modified to collect global reefs and new operational methods were designed to generate the firstever global coral reef geomorphology map. We discuss the challenges encountered to build these databases and in implementing the geospatial data distribution strategies. Conservation applications include a new assessment of the distribution of the world s marine protected areas (UNEPWCMC), improved spatial resolution in the Reefs at Risk analysis for the Caribbean (WRI), and a global basemap for the Census of Marine Life's OBIS database. The Millennium Coral Reef map and digital image archive will pay significant dividends for local and regional conservation projects around the globe. Complete details of the project are available at http://eol.jsc.nasa.gov/reefs.

Robinson, Julie A.↗
NASA NTRS2009

Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

Metallic foams are a relatively new class of materials with low density and novel physical, mechanical, thermal, electrical and acoustic properties. Although incompletely characterized, they offer comparable mechanical performance to traditional spacecraft structural materials (i.e. honeycomb sandwich panels) without detrimental through-thickness channeling cells. There are two competing types of metallic foams: open cell and closed cell. Open cell foams are considered the more promising technology due to their lower weight and higher degree of homogeneity. Leading micrometeoroid and orbital debris shields (MMOD) incorporate thin plates separated by a void space (i.e. Whipple shield). Inclusion of intermediate fabric layers, or multiple bumper plates have led to significant performance enhancements, yet these shields require additional non-ballistic mass for installation (fasteners, supports, etc.) that can consume up to 35% of the total shield weight [1]. Structural panels, such as open cell foam core sandwich panels, that are also capable of providing sufficient MMOD protection, represent a significant potential for increased efficiency in hypervelocity impact shielding from a systems perspective through a reduction in required non-ballistic mass. In this paper, the results of an extensive impact test program on aluminum foam core sandwich panels are reported. The effect of pore density, and core thickness on shielding performance have been evaluated over impact velocities ranging from 2.2 - 9.3 km/s at various angles. A number of additional tests on alternate sandwich panel configurations of comparable-weight have also been performed, including aluminum honeycomb sandwich panels (see Figure 1), Nomex honeycomb core sandwich panels, and 3D aluminum honeycomb sandwich panels. A total of 70 hypervelocity impact tests are reported, from which an empirical ballistic limit equation (BLE) has been derived. The BLE is in the standard form suitable for implementation in risk analysis software, and includes the effect of panel thickness, core density, and facesheet material properties. A comparison between the shielding performance of foam core sandwich panel structures and common MMOD shielding configurations is made for both conservative (additional 35% non-ballistic mass) and optimistic (additional mass equal to 30% of bumper mass) considerations. Suggestions to improve the shielding performance of foam core sandwich panels are made, including the use of outer mesh layers, intermediate fabric/composite layers, and varying pore density.

Ryan, Shannon↗
NASA NTRS2010

Effects of Increasing Drag on Conjunction Assessment

Conjunction Assessment Risk Analysis relies heavily on the computation of the Probability of Collision (Pc) and the understanding of the sensitivity of this calculation to the position errors as defined by the covariance. In Low Earth Orbit (LEO), covariance is predominantly driven by perturbations due to atmospheric drag. This paper describes the effects of increasing atmospheric drag through Solar Cycle 24 on Pc calculations. The process of determining these effects is found through analyzing solar flux predictions on Energy Dissipation Rate (EDR), historical relationship between EDR and covariance, and the sensitivity of Pc to covariance. It is discovered that while all LEO satellites will be affected by the increase in solar activity, the relative effect is more significant in the LEO regime around 700 kilometers in altitude compared to 400 kilometers. Furthermore, it is shown that higher Pc values can be expected at larger close approach miss distances. Understanding these counter-intuitive results is important to setting Owner/Operator expectations concerning conjunctions as solar maximum approaches.

Frigm, Ryan Clayton↗
NASA NTRS2010

Space Shuttle Probabilistic Risk Assessment (SPRA) Iteration 3.2

The Shuttle is a very reliable vehicle in comparison with other launch systems. Much of the risk posed by Shuttle operations is related to fundamental aspects of the spacecraft design and the environments in which it operates. It is unlikely that significant design improvements can be implemented to address these risks prior to the end of the Shuttle program. The model will continue to be used to identify possible emerging risk drivers and allow management to make risk-informed decisions on future missions. Potential uses of the SPRA in the future include: - Calculate risk impact of various mission contingencies (e.g. late inspection, crew rescue, etc.). - Assessing the risk impact of various trade studies (e.g. flow control valves). - Support risk analysis on mission specific events, such as in flight anomalies. - Serve as a guiding star and data source for future NASA programs.

Boyer, Roger L.↗
NASA NTRS2008

2008 NASA Range Safety Annual Report

Welcome to the 2008 edition of the NASA Range Safety Annual Report. Funded by NASA Headquarters, this report provides a NASA Range Safety overview for current and potential range users. This year, along with full length articles concerning various subject areas, we have provided updates to standard subjects with links back to the 2007 original article. Additionally, we present summaries from the various NASA Range Safety Program activities that took place throughout the year, as well as information on several special projects that may have a profound impact on the way we will do business in the future. The sections include a program overview and 2008 highlights of Range Safety Training; Range Safety Policy; Independent Assessments and Common Risk Analysis Tools Development; Support to Program Operations at all ranges conducting NASA launch operations; a continuing overview of emerging Range Safety-related technologies; Special Interests Items that include recent changes in the ELV Payload Safety Program and the VAS explosive siting study; and status reports from all of the NASA Centers that have Range Safety responsibilities. As is the case each year, contributors to this report are too numerous to mention, but we thank individuals from the NASA Centers, the Department of Defense, and civilian organizations for their contributions. We have made a great effort to include the most current information available. We recommend that this report be used only for guidance and that the validity and accuracy of all articles be verified for updates. This is the third year we have utilized this web-based format for the annual report. We continually receive positive feedback on the web-based edition, and we hope you enjoy this year's product as well. It has been a very busy and productive year on many fronts as you will note as you review this report. Thank you to everyone who contributed to make this year a successful one, and I look forward to working with all of you in the years to come.

Lamoreaux, Richard W.↗
NASA NTRS2015

NASA Conjunction Assessment Organizational Approach and the Associated Determination of Screening Volume Sizes

NASA is committed to safety of flight for all of its operational assets Performed by CARA at NASA GSFC for robotic satellites Focus of this briefing Performed by TOPO at NASA JSC for human spaceflight he Conjunction Assessment Risk Analysis (CARA) was stood up to offer this service to all NASA robotic satellites Currently provides service to 70 operational satellites NASA unmanned operational assets Other USG assets (USGS, USAF, NOAA) International partner assets Conjunction Assessment (CA) is the process of identifying close approaches between two orbiting objects; sometimes called conjunction screening The Joint Space Operations Center (JSpOC) a USAF unit at Vandenberg AFB, maintains the high accuracy catalog of space objects, screens CARA-supported assets against the catalog, performs OD tasking, and generates close approach data.

Conjunction↗
NASA NTRS2015

Trending in Probability of Collision Measurements

A simple model is proposed to predict the behavior of Probabilities of Collision (P(sub c)) for conjunction events. The model attempts to predict the location and magnitude of the peak P(sub c) value for an event by assuming the progression of P(sub c) values can be modeled to first order by a downward-opening parabola. To incorporate prior information from a large database of past conjunctions, the Bayes paradigm is utilized; and the operating characteristics of the model are established through a large simulation study. Though the model is simple, it performs well in predicting the temporal location of the peak (P(sub c)) and thus shows promise as a decision aid in operational conjunction assessment risk analysis.

Conjunction↗
NASA NTRS2016

Approaches to Evaluating Probability of Collision Uncertainty

While the two-dimensional probability of collision (Pc) calculation has served as the main input to conjunction analysis risk assessment for over a decade, it has done this mostly as a point estimate, with relatively little effort made to produce confidence intervals on the Pc value based on the uncertainties in the inputs. The present effort seeks to try to carry these uncertainties through the calculation in order to generate a probability density of Pc results rather than a single average value. Methods for assessing uncertainty in the primary and secondary objects' physical sizes and state estimate covariances, as well as a resampling approach to reveal the natural variability in the calculation, are presented; and an initial proposal for operationally-useful display and interpretation of these data for a particular conjunction is given.

PROBABILITY↗
NASA NTRS2015

2015 Occupant Protection Standing Review Panel

The 2015 Occupant Protection (OP) Risk Standing Review Panel (from here on referred to as the SRP) participated in a WebEx/teleconference with members of the Space Human Factors and Habitability (SHFH) Element, representatives from the Human Research Program (HRP), NASA Headquarters, and NASA Research and Education Support Services on November 3, 2015 (list of participants is in Section VII of this report). The SRP reviewed the updated research plans for the Risk of Injury from Dynamic Loads (OP Risk). The SRP agrees that the Gaps are relevant and appropriate to mitigate the injury risk. All the appropriate and relevant Tasks have been identified to fill the Gaps. Depending upon the findings, additional tasks may need to be identified or modified. Excellent progress has been made since the 2014 SRP meeting. Publications in peer-reviewed journals validate the scientific merit of the research findings. As detailed in this report, the SRP has specific comments, guidance, and information in the following areas: human finite element modeling, human vs. surrogate dynamic responses, chest injury risk curves, matched pair testing of Test device for Human Occupant Restraint (THOR) and Hybrid III, and disc herniation risk analysis.

Steinberg, Susan↗
NASA NTRS2016

Model Based Mission Assurance: Emerging Opportunities for Robotic Systems

The emergence of Model Based Systems Engineering (MBSE) in a Model Based Engineering framework has created new opportunities to improve effectiveness and efficiencies across the assurance functions. The MBSE environment supports not only system architecture development, but provides for support of Systems Safety, Reliability and Risk Analysis concurrently in the same framework. Linking to detailed design will further improve assurance capabilities to support failures avoidance and mitigation in flight systems. This also is leading new assurance functions including model assurance and management of uncertainty in the modeling environment. Further, the assurance cases, a structured hierarchal argument or model, are emerging as a basis for supporting a comprehensive viewpoint in which to support Model Based Mission Assurance (MBMA).

Mission Assurance↗