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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Microwave systems applications in deep space telecommunications and navigation - Space Exploration Initiative architectures

The general support requirements of a typical SEI mission set, along with the mission operations objectives and related telecommunications, navigation, and information management (TNIM) support infrastructure options are described. Responsive system architectures and designs are proposed, including a Mars orbiting communications relay satellite system and a Mars-centered navigation capability for servicing all Mars missions. With the TNIM architecture as a basis, key elements of the microwave link design are proposed. The needed new technologies which enable these designs are identified, and current maturity is assessed.

Hall, Justin R.↗
NASA NTRS1992

Nuclear thermal rockets - Key to moon-Mars exploration

The Space Exploration Initiative (SEI) calls for lunar and Martian exploration missions for which solid-core nuclear thermal rockets (NTRs), in virtue of their single-stage, fully-reusable nature, are ideally suited. NTRs promise double the specific impulse of chemical propulsion. A lunar mission employing a reusable NTR is currently being conducted by NASA. The NTR would be assembled in LEO in such a way that it remained 'radioactively cold' during earth-to-orbit deployment by a heavy-lift chemical booster, and therefore presented no radioactive hazard. Also under consideration is a particle-bed reactor in which the hydrogen propulsive fluid directly cools coated-particle fuel spheres.

Borowski, Stanley K.↗
NASA NTRS1992

In-space operations for lunar and Mars space transfer vehicles

The in-space operations required to process the lunar and Mars mission vehicles foreseen in early studies for the SEI are discussed. Those studies that have examined the degree to which on-orbit operations alter as a function of the earth-to-orbit launch vehicle size, identified a common set of on-orbit vehicle processing tasks, and generated functional requirements for in-space processing nodes, are summarized. Attention is focused on the amount of time these processing operations might necessitate and how this time duration changes as a result of how the operation is executed and how the hardware is designed.

Raper, James L., Sr.↗
NASA NTRS1991

Nuclear rocket propulsion: NASA plans and progress - FY 1991

NASA has initiated planning for a technology development project for nuclear rocket propulsion systems for space exploration initiative (SEI) human and robotic missions to the Moon and to Mars. An interagency project is underway that includes the Department of Energy National Laboratories for nuclear technology development. The activities of the project planning team in FY 1990 and 1991 are summarized. The progress to date is discussed, and the project plan is reviewed. Critical technology issues were identified and include: (1) nuclear fuel temperature, life, and reliability; (2) nuclear system ground test; (3) safety; (4) autonomous system operation and health monitoring; and (5) minimum mass and high specific impulse.

Clark, John S.↗
NASA NTRS1992

Health-risk based approach to setting drinking water standards for long-term space missions

In order to develop plausible and appropriate drinking water contaminant standards for longer-term NASA space missions, such as those planned for the Space Exploration Initiative, a human health risk characterization was performed using toxicological and exposure values typical of space operations and crew. This risk characterization showed that the greatest acute waterborne health concern was from microbial infection leading to incapacitating gastrointestinal illness. Ingestion exposure pathways for toxic materials yielded de minimus acute health risks unlikely to affect SEI space missions. Risks of chronic health problems were within acceptable public health limits. Our analysis indicates that current Space Station Freedom maximum contamination levels may be unnecessarily strict. We propose alternative environmental contaminant values consistent with both acceptable short and long-term crew health safety.

Macler, Bruce A.↗
NASA NTRS1992

Requirements for on-orbit operations

Consideration is given to the impact of on-orbit operations during the assembly and checkout of potential piloted Mars spacecraft, and the development of the requirements for those operations. An operational scenario is developed based on assumed earth-to-orbit capability, a ground based support capability, and a baseline Mars Space Transfer Vehicle. The scenarios developed define each of the operations that must transpire at the system level, thus expanding the planning horizon for the SEI.

Cockrell, Charles E.↗
NASA NTRS1992

System model development for nuclear thermal propulsion

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown, and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, and cost and time required for the technology to reach flight-ready status. Since Oct. 1991, the U.S. Department of Energy (DOE), Department of Defense (DOD), and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. The first level will provide rapid, parameterized calculations of overall system performance. Succeeding computer programs will provide analysis of each component in sufficient detail to guide the design teams and experimental efforts. The computer programs will allow simulation of the entire system to allow prediction of the integrated performance. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review.

Walton, James T.↗
NASA NTRS1992

Decision rules for spaceborne operations planning

Recent study of Space Station Freedom requirements for extravehicular activity (EVA) to perform external maintenance tasks emphasize an oversubscription of resources for performing on-orbit tasks. Extravehicular robotics (EVR) and cooperative EVA combined with EVR (using crew and robots synergistically to perform tasks) have been suggested as a part of the solution to reduce EVA. The question remains however, 'Under what conditions is it cost-effective to use the EVA and/or EVR resource.' The answer to such a question also has implications for the Space Station Freedom and its external maintenance as well as the Space Exploration Initiative (SEI) where the issue of work-system allocation is magnified by the long distances and scope of EVA work. This paper describes a simple technique of interest to operational planners and robot technology planners for determining in an economic context whether to use EVA alone, EVR alone, or Cooperative EVA. It is also shown that given: (1) the task times for these alternatives; and (2) the marginal costs of EVA, EVR, and IVA, the appropriate work system for performing the task can be identified. The paper illustrates how the work system choice is based on the ratio of costs. An example using Space Station Freedom data is presented to illustrate the trade-offs among alternative work-systems.

Smith, Jeffrey H.↗
NASA NTRS1992

Lunar PMAD technology assessment

This report documents an initial set of power conditioning models created to generate 'ballpark' power management and distribution (PMAD) component mass and size estimates. It contains converter, rectifier, inverter, transformer, remote bus isolator (RBI), and remote power controller (RPC) models. These models allow certain studies to be performed; however, additional models are required to assess a full range of PMAD alternatives. The intent is to eventually form a library of PMAD models that will allow system designers to evaluate various power system architectures and distribution techniques quickly and consistently. The models in this report are designed primarily for space exploration initiative (SEI) missions requiring continuous power and supporting manned operations. The mass estimates were developed by identifying the stages in a component and obtaining mass breakdowns for these stages from near term electronic hardware elements. Technology advances were then incorporated to generate hardware masses consistent with the 2000 to 2010 time period. The mass of a complete component is computed by algorithms that calculate the masses of the component stages, control and monitoring, enclosure, and thermal management subsystem.

Metcalf, Kenneth J.↗
NASA NTRS1991

A voyage to Mars: A challenge to collaboration between man and machines

A speech addressing the design of man machine systems for exploration of space beyond Earth orbit from the human factors perspective is presented. Concerns relative to the design of automated and intelligent systems for the NASA Space Exploration Initiative (SEI) missions are largely based on experiences with integrating humans and comparable systems in aviation. The history, present status, and future prospect, of human factors in machine design are discussed in relation to a manned voyage to Mars. Three different cases for design philosophy are presented. The use of simulation is discussed. Recommendations for required research are given.

Statler, Irving C.↗
NASA NTRS1992

Workshop on Innovative Instrumentation for the In Situ Study of Atmosphere-Surface Interactions on Mars

The speakers in the first session of the workshop addressed some of the continuing enigmas regarding the atmospheric composition, surface composition, and atmosphere-surface interactions on Mars; provided a description of a database of proposed payloads and instruments for SEI missions that is scheduled to be accessible in 1993; discussed potential uses of atmospheric imaging from landed stations on Mars; and advocated the collection and employment of high-spectral-resolution reflectance and emission data.

Fegley, Bruce, Jr.↗
NASA NTRS1991

Space transfer vehicle concepts and requirements. Volume 1: Executive summary

The objectives of the Space Transfer Vehicle (STV) Concepts and Requirements studies were to provide sensitivity data on usage, economics, and technology associated with new space transportation systems. The study was structured to utilize data on the emerging launch vehicles, the latest mission scenarios, and Space Exploration Initiative (SEI) payload manifesting and schedules, to define a flexible, high performance, cost effective, evolutionary space transportation system for NASA. Initial activities were to support the MSFC effort in the preparation of inputs to the 90 Day Report to the National Space Council (NSC). With the results of this study establishing a point-of-departure for continuing the STV studies in 1990, additional options and mission architectures were defined. The continuing studies will update and expand the parametrics, assess new cargo and manned ETO vehicles, determine impacts on the redefined Phase 0 Space Station Freedom, and to develop a design that encompasses adequate configuration flexibility to ensure compliance with on-going NASA study recommendations with major system disconnects. In terms of general requirements, the objectives of the STV system and its mission profiles will address crew safety and mission success through a failure-tolerant and forgiving design approach. These objectives were addressed through the following: engine-out capability for all mission phases; built-in-test for vehicle health monitoring to allow testing of all critical functions such as, verification of lunar landing and ascent engines before initiating the landing sequence; critical subsystems will have multiple strings for redundancy plus adequate supplies of onboard spares for removal and replacement of failed items; crew radiation protection; and trajectories that optimize lunar and Mars performance and flyby abort capabilities.

Source record↗
NASA NTRS1992

Hybrid rocket performance

A hybrid rocket is a system consisting of a solid fuel grain and a gaseous or liquid oxidizer. Figure 1 shows three popular hybrid propulsion cycles that are under current consideration. NASA MSFC has teamed with industry to test two hybrid propulsion systems that will allow scaling to motors of potential interest for Titan and Atlas systems, as well as encompassing the range of interest for SEI lunar ascent stages and National Launch System Cargo Transfer Vehicle (NLS CTV) and NLS deorbit systems. Hybrid systems also offer advantages as moderate-cost, environmentally acceptable propulsion system. The objective of this work was to recommend a performance prediction methodology for hybrid rocket motors. The scope included completion of: a literature review, a general methodology, and a simplified performance model.

Frederick, Robert A., Jr.↗
NASA NTRS1992

Industry survey of space system cost benefits from New Ways Of Doing Business

The cost of designing, building and operating space system hardware has always been expensive. Small quantities of specialty parts escalate engineering design, production and operations cost. Funding cutbacks and shrinking revenues dictate aggressive cost saving programs. NASA's highest priority is providing economical transportation to and from space. Over the past three decades NASA has seen technological advances that provide grater efficiencies in designing, building, and operating of space system hardware. As future programs such as NLS, LUTE and SEI begin, these greater efficiencies and cost savings should be reflected in the cost models. There are several New Ways Of Doing Business (NWODB) which, when fully implemented will reduce space system costs. These philosophies and/or culture changes are integrated in five areas: (1) More Extensive Pre-Phase C/D & E, (2) Multi Year Funding Stability, (3) Improved Quality, Management and Procurement Processes, (4) Advanced Design Methods, and (5) Advanced Production Methods. Following is an overview of NWODB and the Cost Quantification Analysis results using an industry survey, one of the four quantification techniques used in the study. The NWODB Cost Quantification Analysis is a study performed at Marshall Space Flight Center by the Engineering Cost Group, Applied Research Incorporated and Pittsburg State University. This study took place over a period of four months in mid 1992. The purpose of the study was to identify potential NWODB which could lead to improved cost effectiveness within NASA and to quantify potential cost benefits that might accrue if these NWODB were implemented.

Rosmait, Russell L.↗
NASA NTRS1992

Modeling software systems by domains

The Software Architectures Engineering (SAE) Project at the Software Engineering Institute (SEI) has developed engineering modeling techniques that both reduce the complexity of software for domain-specific computer systems and result in systems that are easier to build and maintain. These techniques allow maximum freedom for system developers to apply their domain expertise to software. We have applied these techniques to several types of applications, including training simulators operating in real time, engineering simulators operating in non-real time, and real-time embedded computer systems. Our modeling techniques result in software that mirrors both the complexity of the application and the domain knowledge requirements. We submit that the proper measure of software complexity reflects neither the number of software component units nor the code count, but the locus of and amount of domain knowledge. As a result of using these techniques, domain knowledge is isolated by fields of engineering expertise and removed from the concern of the software engineer. In this paper, we will describe kinds of domain expertise, describe engineering by domains, and provide relevant examples of software developed for simulator applications using the techniques.

Dippolito, Richard↗
NASA NTRS1991

Nuclear safety for the space exploration initiative

The results of a study to identify potential hazards arising from nuclear reactor power systems for use on the lunar and Martian surfaces, related safety issues, and resolutions of such issues by system design changes, operating procedures, and other means are presented. All safety aspects of nuclear reactor power systems from prelaunch ground handling to eventual disposal were examined consistent with the level of detail for SP-100 reactor design at the 1988 System Design Review and for launch vehicle and space transport vehicle designs and mission descriptions as defined in the 90-day Space Exploration Initiative (SEI) study. Information from previous aerospace nuclear safety studies was used where appropriate. Safety requirements for the SP-100 space nuclear reactor system were compiled. Mission profiles were defined with emphasis on activities after low earth orbit insertion. Accident scenarios were then qualitatively defined for each mission phase. Safety issues were identified for all mission phases with the aid of simplified event trees. Safety issue resolution approaches of the SP-100 program were compiled. Resolution approaches for those safety issues not covered by the SP-100 program were identified. Additionally, the resolution approaches of the SP-100 program were examined in light of the moon and Mars missions.

Dix, Terry E.↗
NASA NTRS1993

Thermal protection materials at NASA Ames Research Center

The topics addressed are: (1) Space Exploration Initiative (SEI); (2) Aeroassist Flight Experiment (AFE); (3) Mars Environmental Survey (MESUR); (4) National Aero-space Plan (NASP); (5) Pegasus and Pegasus/SWERVE Hypersonic Testing; and (6) Personnel Launch System TPS evaluation.

Rasky, Daniel J.↗
NASA NTRS1991

The role of smart systems in rendezvous, close proximity operations and docking maneuvers

Various missions scenarios (Space Station logistics, LEO and GEO services, and SEI operation) will involve flexibility in mission management. This means operations will be one or a combination of the following: autonomous, supervised autonomous, and machine aided manual control. Smart Systems will likely play a significant role in making these missions successful from a safety/reliability perspective and less costly from an operations perspective. This does not imply that Smart Systems need to be super sophisticated. On the contrary, Smart Systems have been described as automated intelligence that if a person had done it wrong, it would be considered stupid. The first part of this paper will describe the types of Smart System techniques involved in AR and CC, their specifications, duties, and interactions. Next will be a discussion of the work performed under the auspice of the ALS Program to further Expert Systems applications imbedded in the control process, NASA/JSC CRAD, and other related IRAD projects. This will include issues pertaining to the following: integration, speed, knowledge encapsulation, and cooperative systems. Finally, a brief description will be offered to outline the major obstacles for the acceptance of Smart Systems in critical applications.

Szatkowski, Gerard P.↗