Risk Mapping and Interaction Approach: A Special Session for HSRB Risk Custodians
No abstract available
Antonsen, Erik↗
Engineering topics
Reynolds, Robert
Publications and source records attributed to Reynolds, Robert.
Small Engine Technology (SET) - Task 4, Regional Turboprop/Turbofan Engine Advanced Combustor Study
Under the SET Program Task 4 - Regional Turboprop/Turbofan Engine Advanced Combustor Study, a total of ten low-emissions combustion system concepts were evaluated analytically for three different gas turbine engine geometries and three different levels of oxides of nitrogen (NOx) reduction technology, using an existing AlliedSignal three-dimensional (3-D) Computational Fluid Dynamics (CFD) code to predict Landing and Takeoff (LTO) engine cycle emission values. A list of potential Barrier Technologies to the successful implementation of these low-NOx combustor designs was created and assessed. A trade study was performed that ranked each of the ten study configurations on the basis of a number of manufacturing and durability factors, in addition to emissions levels. The results of the trade study identified three basic NOx-emissions reduction concepts that could be incorporated in proposed follow-on combustor technology development programs aimed at demonstrating low-NOx combustor hardware. These concepts are: high-flow swirlers and primary orifices, fuel-preparation cans, and double-dome swirlers.
Reynolds, Robert↗
NASA/JSC orbital debris models
The orbital debris models developed within the framework of the NASA Johnson Space Center's (JSC's) orbital debris program, are categorized as environment definition and risk assessment models. The EVOLVE, CHAIN and the orbital debris engineering model 1996 (ORDEM96) computer programs determine the past, present and future orbital particulate environment, while the BUMPER and debris assessment software (DAS) computer programs provide a means for evaluating the risks of specific space missions. These models are presented. To support these models and to conduct specialized analyses, NASA/JSC employs a range of auxiliary models, including explosion and collision satellite breakup models, hypervelocity impact ballistic limit models, orbit propagation and decay models, space traffic models and solid rocket motor effluent models.
Johnson, Nicholas↗
The historical contribution of solid rocket motors to the one centimeter debris population
The measured small particle population in earth orbit contains cm-sized objects that are not accounted for by breakup fragments. It was proposed that slag ejection during solid rocket motor burn is a contributor to this population. The direct evidence for such slag ejection follows from: observations of the exhausts of vehicles in flight, and engineering data from static firings. A source model is presented to account for the contribution of slag expulsion from solid rocket motors to the debris population. The mass and velocity distribution of the slag effluents are taken into account and used as a source term in the debris environment model. The model is based on the available observation data and on models for slag development and ejection.
Jackson, Albert↗
Debris environment interactions with low Earth orbit constellations
Several low earth orbit communication satellite constellations are planned. Due to their size and complexity, these constellations potentially contribute to the orbital debris environment. The results of a parametric assessment of the impact of low earth orbit constellations on the orbital debris environment are presented. The increase in loss rate of non constellation spacecraft is considered, as well as the increase in the loss rate or replacement rate of constellation satellites as a result of debris impact. Primary parameters in the analysis are the number, size and altitude of the constellation. Parameters are defined for the vulnerable area of loss of spacecraft and the disposition of constellation spacecraft at the end of its life.
Reynolds, Robert↗
An overview of revised NASA safety standard 1740.14
Following a broad review of the debris control guidelines outside of NASA and according to additional feedback on the guidelines from within NASA, revisions were made to the NASA safety standard 1740.14. The NASA policy to limit the generation of orbital debris on NASA missions, stated in the NASA management instruction 1700.8 and implemented in the form of the NASA safety standard (NSS) 1740.14 is described together with the revisions implemented. The overall direction of the guidelines is the same, but the details of many of the guidelines were changed, including: changes for tether programs and for the control of operational debris. The NASA will continue to review the guidelines as new measurements and improved models of the environment are obtained.
Reynolds, Robert↗
Orbital debris minimization and mitigation techniques
Man's activity in space has generated significant amounts of debris that remain in orbit for periods of sufficient duration to become a hazard to future space activities. Upper stages and spacecraft that have ended their functional life are the largest objects. In the past, additional debris has been generated by inadvertent explosions of upper stages and spacecraft, by intentional explosions for military reasons, and possibly by a few breakups resulting from collisions. In the future, debris can be generated by collisions among spacecraft as the number of orbital objects continues to grow at rates greater than natural forces remove them from orbit. There are design and operations practices that can minimize the inadvertent generation of debris. There are other design and operations options for removing objects from space at the end of their useful service so they are not available as a source for the generation of future debris. Those studies are the primary concern of this paper. The most economic removal of objects is achieved when those objects have the capability to execute the necessary maneuvers with their own systems and resources. The most costly option is to have some other system remove the spacecraft after it has become a derelict. Numerous options are being studied to develop systems and techniques that can remove spacecraft from useful orbits at the end of their useful life and do so for the least mass penalty and economic cost.
Loftus, Joseph P., Jr.↗