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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 631 records · Page 35

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NASA NTRS1990

Civil air transport - A fresh look at power-by-wire and fly-by-light

Power-by-wire (PBW) is a key element under subsonic transport flight systems technology, with potential savings of over 10 percent in gross take off weight and in fuel consumption compared to today's transport aircraft. The PBW technology substitutes electrical actuation in place of centralized hydraulics, uses internal starter-motor/generators, and eliminates the need for variable engine bleed air to supply cabin comfort. The application of advanced fiber optics to the electrical power system controls, to built-in-test (BITE) equipment, and to fly-by-light (FBL) flight controls provides additional benefits in lightning and high-energy radio frequency (HERF) immunity over existing mechanical or even fly-by-wire controls. The program plan is reviewed and a snapshot is given of the key technologies and their benefits to future aircraft, both civil and military.

Sundberg, Gale R.↗

NASA NTRS1990

Surface radiation budget - Current perspective

The surface radiation budget of the earth is important in climate research because it gives an understanding of the distribution of solar and IR radiation exchanges at the surface. Data on the distribution and exchange of these surface radiations are needed over the entire earth on a long-term basis. Global satellite data, coupled with highly developed models, now provide estimates of the surface radiation budget which are near the accuracy required for climate research. A description of surface radiation research, its current state, and planned programs are presented.

Darnell, Wayne L.↗

NASA NTRS1990

Latest developments in the Advanced Photovoltaic Solar Array Program

In 1985, the Advanced Photovoltaic Solar Array (APSA) Program was established to demonstrate a producible array system with a specific power greater than 130 W/kg at a 10-kW (BOL) power level. The latest program phase completed fabrication and initial functional testing of a prototype wing representative of a full-scale 5-kW (BOL) wing (except truncated in length to about 1 kW), with weight characteristics that could meet the 130-W/kg (BOL) specific power goal using thin silicon solar cell modules and weight-efficient structural components. The wing configuration and key design details are reviewed, along with results from key component-level and wing-level tests. Projections for future enhancements that may be expected through the use of advanced solar cells and structural components are shown. Performance estimates are given for solar electric propulsion orbital transfer missions through the Van Allen radiation belts. The latest APSA program plans are presented.

Stella, Paul M.↗

NASA NTRS1991

Environmental interactions of the Space Station Freedom electric power system

The Space Station Freedom will be operating in the Low Earth Orbit (LEO) environment. LEO environment operation results in different potential interactions with the Space Station systems including the Electric Power Systems (EPS). These potential interactions result in environmental effects which include neutral species effects such as atomic oxygen erosion, effects of micrometeroid and orbital debris impacts, plasma effects, ionizing radiation effects, and induced contamination degradation effects. The EPS design and its interactions with the LEO environment are described. The results of analyses and testing programs planned and performed thus far to resolve the environmental concerns related to the EPS and its function in the LEO environment are discussed.

Nahra, Henry K.↗

NASA NTRS1991

Space system production cost benefits from contemporary philosophies in management and manufacturing

The cost of manufacturing space system hardware has always been expensive. The Engineering Cost Group of the Program Planning office at Marshall is attempting to account for cost savings that result from new technologies in manufacturing and management. The objective is to identify and define contemporary philosophies in manufacturing and management. The seven broad categories that make up the areas where technological advances can assist in reducing space system costs are illustrated. Included within these broad categories is a list of the processes or techniques that specifically provide the cost savings within todays design, test, production and operations environments. The processes and techniques listed achieve savings in the following manner: increased productivity; reduced down time; reduced scrap; reduced rework; reduced man hours; and reduced material costs. In addition, it should be noted that cost savings from production and processing improvements effect 20 to 40 pct. of production costs whereas savings from management improvements effects 60 to 80 of production cost. This is important because most efforts in reducing costs are spent trying to reduce cost in the production.

Rosmait, Russell L.↗

NASA NTRS1992

A survey of instabilities within centrifugal pumps and concepts for improving the flow range of pumps in rocket engines

Design features and concepts that have primary influence on the stable operating flow range of propellant-feed centrifugal turbopumps in a rocket engine are discussed. One of the throttling limitations of a pump-fed rocket engine is the stable operating range of the pump. Several varieties of pump hydraulic instabilities are mentioned. Some pump design criteria are summarized and a qualitative correlation of key parameters to pump stall and surge are referenced. Some of the design criteria were taken from the literature on high pressure ratio centrifugal compressors. Therefore, these have yet to be validated for extending the stable operating flow range of high-head pumps. Casing treatment devices, dynamic fluid-damping plenums, backflow-stabilizing vanes and flow-reinjection techniques are summarized. A planned program was undertaken at LeRC to validate these concepts. Technologies developed by this program will be available for the design of turbopumps for advanced space rocket engines for use by NASA in future space missions where throttling is essential.

Veres, Joseph P.↗

NASA NTRS1992

NASA Workshop on future directions in surface modeling and grid generation

Given here is a summary of the paper sessions and panel discussions of the NASA Workshop on Future Directions in Surface Modeling and Grid Generation held a NASA Ames Research Center, Moffett Field, California, December 5-7, 1989. The purpose was to assess U.S. capabilities in surface modeling and grid generation and take steps to improve the focus and pace of these disciplines within NASA. The organization of the workshop centered around overviews from NASA centers and expert presentations from U.S. corporations and universities. Small discussion groups were held and summarized by group leaders. Brief overviews and a panel discussion by representatives from the DoD were held, and a NASA-only session concluded the meeting. In the NASA Program Planning Session summary there are five recommended steps for NASA to take to improve the development and application of surface modeling and grid generation.

Vandalsem, W. R.↗

NASA NTRS1992

High-speed civil transport issues and technology program

A strawman program plan is presented, consisting of technology developments and demonstrations required to support the construction of a high-speed civil transport. The plan includes a compilation of technology issues related to the development of a transport. The issues represent technical areas in which research and development are required to allow airframe manufacturers to pursue an HSCT development. The vast majority of technical issues presented require flight demonstrated and validated solutions before a transport development will be undertaken by the industry. The author believes that NASA is the agency best suited to address flight demonstration issues in a concentrated effort. The new Integrated Test Facility at NASA Dryden Flight Research Facility is considered ideally suited to the task of supporting ground validations of proof-of-concept and prototype system demonstrations before night demonstrations. An elaborate ground hardware-in-the-loop (iron bird) simulation supported in this facility provides a viable alternative to developing an expensive fill-scale prototype transport technology demonstrator. Drygen's SR-71 assets, modified appropriately, are a suitable test-bed for supporting flight demonstrations and validations of certain transport technology solutions. A subscale, manned or unmanned flight demonstrator is suitable for flight validation of transport technology solutions, if appropriate structural similarity relationships can be established. The author contends that developing a full-scale prototype transport technology demonstrator is the best alternative to ensuring that a positive decision to develop a transport is reached by the United States aerospace industry.

Hewett, Marle D.↗

NASA NTRS1989

Risk analysis of space transportation during the space station era

This study addresses the operational risks of manned space transportation during the era of space station deployment along with alternative launch vehicle architectures to reduce the risks. Vehicle architectures considered included shuttle only, an additional unmanned launch vehicle, and a second manned/unmanned launch vehicle. Projections are made for the operational parameters and flight event probabilities. Using these projections and Space Station era mission models, the operability of alternative vehicle architectures are examined, and implications to future manned space program plans are summarized.

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NASA NTRS1990

Slush hydrogen (SLH2) technology development for application to the National Aerospace Plane (NASP)

The National Aerospae Plane (NASP) program is giving us the opportunity to reach new unique answers in a number of engineering categories. The answers are considered enhancing technology or enabling technology. Airframe materials and densified propellants are examples of enabling technology. The National Aeronautics and Space Administration's Lewis Research Center has the task of providing the technology data which will be used as the basis to decide if slush hydrogen (SLH2) will be the fuel of choice for the NASP. The objectives of this NASA Lewis program are: (1) to provide, where possible, verified numerical models of fluid production, storage, transfer, and feed systems, and (2) to provide verified design criteria for other engineered aspects of SLH2 systems germane to an NASP. This program is a multiyear multimillion dollar effort. The present pursuit of the above listed objectives is multidimensional, covers a range of problem areas, works these to different levels of depth, and takes advantage of the resources available in private industry, academia, and the U.S. Government. The NASA Lewis overall program plan is summarized. The initial implementation of the plan will be unfolded and the present level of efforts in each of the resource areas will be discussed. Results already in hand will be pointed out. A description of additionally planned near-term experimental and analytical work is described.

Dewitt, Richard L.↗

NASA NTRS1991

Lunar base as a precursor to Mars exploration and settlement

A well planned program of human exploration of the moon is suggested which would provide a base for increasing human capabilities and experience to levels required for Mars exploration. A strategy intended for immediate Mars exploration and settlement is considered to incur serious programmatic risks from current lack of knowledge on human performance on long-duration deep space missions and lack of experience in designing human space systems. The lunar program provides an opportunity to build up space capability in an evolutionary way and to broaden the participation of the educational system in the space exploration.

Mendell, Wendell W.↗

NASA NTRS1992

Lunar stepping stones to a manned Mars exploration scenario

The initial trips to Mars by humans will be the first real severing of our dependence on Earth's environment. Common sense dictates that a human departure from Earth measured in years, to explore a distant planet, requires systems, techniques, and operations that have solid credibility proven with space experience. The space test and verification experience must occur with Mars-like conditions but under proving-ground conditions with good instrumentation, close monitoring, and fast emergency recovery capabilities. The lunar environment is the only arena that satisfies the requirements of a space recovery capabilities. The lunar environment is the only arena that satisfies the requirements of a space planetary proving-ground. The objective of this scenario is to demonstrate a program planning approach that has human presence at Mars as the goal but, prudently, capitalizes on manned lunar project facilities, operations, and experience to enable a safe journey for the first Mars crews. The emphasis in lunar application objectives is to perform productive science and resources exploitation missions. Most of the Mars mission aspects can be proven in the lunar environment providing 'stepping stones' to conducting the first human mission to travel to Mars and return safely to Earth.

Davidson, W. L.↗

NASA NTRS1992

Remote Assessment of Lunar Resource Potential

Assessing the resource potential of the lunar surface requires a well-planned program to determine the chemical and mineralogical composition of the Moon's surface at a range of scales. The exploration program must include remote sensing measurements (from both Earth's surface and lunar orbit), robotic in situ analysis of specific places, and eventually, human field work by trained geologists. Remote sensing data is discussed. Resource assessment requires some idea of what resources will be needed. Studies thus far have concentrated on oxygen and hydrogen production for propellant and life support, He-3 for export as fuel for nuclear fusion reactors, and use of bulk regolith for shielding and construction materials. The measurement requirements for assessing these resources are given and discussed briefly.

Taylor, G. Jeffrey↗

NASA NTRS1992

Developing a safe on-orbit cryogenic depot

New U.S. space initiatives will require technology to realize planned programs such as piloted lunar and Mars missions. Key to the optimal execution of such missions are high performance orbit transfer vehicles and propellant storage facilities. Large amounts of liquid hydrogen and oxygen demand a uniquely designed on-orbit cryogenic propellant depot. Because of the inherent dangers in propellant storage and handling, a comprehensive system safety program must be established. This paper shows how the myriad and complex hazards demonstrate the need for an integrated safety effort to be applied from program conception through operational use. Even though the cryogenic depot is still in the conceptual stage, many of the hazards have been identified, including fatigue due to heavy thermal loading from environmental and operating temperature extremes, micrometeoroid and/or depot ancillary equipment impact (this is an important problem due to the large surface area needed to house the large quantities of propellant), docking and maintenance hazards, and hazards associated with extended extravehicular activity. Various safety analysis techniques were presented for each program phase. Specific system safety implementation steps were also listed. Enhanced risk assessment was demonstrated through the incorporation of these methods.

Bahr, Nicholas J.↗

NASA NTRS1991

Autonomous Guidance, Navigation and Control

The NASA Autonomous Guidance, Navigation and Control (GN&C) Bridging program is reviewed to demonstrate the program plan and GN&C systems for the Space Shuttle. The ascent CN&C system is described in terms of elements such as the general-purpose digital computers, sensors for the navigation subsystem, the guidance-system software, and the flight-control subsystem. Balloon-based and lidar wind soundings are used for operations assessment on the day of launch, and the guidance software is based on dedicated units for atmospheric powered flight, vacuum powered flight, and abort-specific situations. Optimization of the flight trajectories is discussed, and flight-control responses are illustrated for wavelengths of 500-6000 m. Alternate sensors are used for load relief, and adaptive GN&C systems based on alternate gain synthesis are used for systems failures.

Bordano, A. J.↗

NASA NTRS1992

NASA's commercial space program

This paper will review the goals, status and progress of NASA's commercial space development program administered by the Office of Commercial Programs (OCP). The technologies and flight programs underway by NASA's Centers for Commercial Development (CCDS), NASA's field centers, and the NASA/Industry Joint Endeavor Programs will be summarized. A summary of completed and upcoming commercial payload activities on Shuttle, suborbital rockets, and orbital ELV's will be provided. The new commercial infrastructure and transportation initiatives will be discussed including the Wake Shield Facility, Consort and Joust suborbital rocket programs, the COMET orbital and recovery program, and the Commercial Middeck Accommodation Module Program with Spacehab Inc. Finally, the Commercial Space Station Freedom Program planned by OCP will be reviewed.

Ott, Richard H.↗

NASA NTRS1987

Maintainability Program Requirements for Space Systems

This document is established to provide common general requirements for all NASA programs to: design maintainability into all systems where maintenance is a factor in system operation and mission success; and ensure that maintainability characteristics are developed through the systems engineering process. These requirements are not new. Design for ease of maintenance and minimization of repair time have always been fundamental requirements of the systems engineering process. However, new or reusable orbital manned and in-flight maintainable unmanned space systems demand special emphasis on maintainability, and this document has been prepared to meet that need. Maintainability requirements on many NASA programs differ in phasing and task emphasis from requirements promulgated by other Government agencies. This difference is due to the research and development nature of NASA programs where quantities produced are generally small; therefore, the depth of logistics support typical of many programs is generally not warranted. The cost of excessive maintenance is very high due to the logistics problems associated with the space environment. The ability to provide timely maintenance often involves safety considerations for manned space flight applications. This document represents a basic set of requirements that will achieve a design for maintenance. These requirements are directed primarily at manned and unmanned orbital space systems. To be effective, maintainability requirements should be tailored to meet specific NASA program and project needs and constraints. NASA activities shall invoke the requirements of this document consistent with program planning in procurements or on inhouse development efforts.

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NASA NTRS1988

NASA specification for manufacturing and performance requirements of NASA standard aerospace nickel-cadmium cells

On November 25, 1985, the NASA Chief Engineer established a NASA-wide policy to maintain and to require the use of the NASA standard for aerospace nickel-cadmium cells and batteries. The Associate Administrator for Safety, Reliability, Maintainability, and Quality Assurance stated on December 29, 1986, the intent to retain the NASA standard cell usage policy established by the Office of the Chief Engineer. The current NASA policy is also to incorporate technological advances as they are tested and proven for spaceflight applications. This policy will be implemented by modifying the existing standard cells or by developing new NASA standards and their specifications in accordance with the NASA's Aerospace Battery Systems Program Plan. This NASA Specification for Manufacturing and Performance Requirements of NASA Standard Aerospace Nickel-Cadmium Cells is prepared to provide requirements for the NASA standard nickel-cadmium cell. It is an interim specification pending resolution of the separator material availability. This specification has evolved from over 15 years of nickel-cadmium cell experience by NASA. Consequently, considerable experience has been collected and cell performance has been well characterized from many years of ground testing and from in-flight operations in both geosynchronous (GEO) and low earth orbit (LEO) applications. NASA has developed and successfully used two standard flight qualified cell designs.

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