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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 487 records · Page 27

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NASA NTRS1991

Development Of Composite Panels For Telescope Mirrors

Report describes continuing program for development of lightweight hexagonal graphite/epoxy composite panels intended to support precisely curved mirror surfaces assembled into large telescope mirror. Discusses development requirements, technical decisions, fabrication methods, measurements of properties of materials, analytical simulation, and thermal vacuum testing. Telescope flown in orbit around Earth to observe at wavelengths down to 30 micrometers.

Freeland, Robert E.↗

NASA NTRS1991

A superconducting large-angle magnetic suspension

The component technologies were developed required for an advanced control moment gyro (CMG) type of slewing actuator for large payloads. The key component of the CMG is a large-angle magnetic suspension (LAMS). The LAMS combines the functions of the gimbal structure, torque motors, and rotor bearings of a CMG. The LAMS uses a single superconducting source coil and an array of cryoresistive control coils to produce a specific output torque more than an order of magnitude greater than conventional devices. The designed and tested LAMS system is based around an available superconducting solenoid, an array of twelve room-temperature normal control coils, and a multi-input, multi-output control system. The control laws were demonstrated for stabilizing and controlling the LAMS system.

Downer, James↗

NASA NTRS1990

Design strategies for the International Space University's variable gravity research facility

A variable gravity research facility named 'Newton' was designed by 58 students from 13 countries at the International Space University's 1989 summer session at the Universite Louis Pasteur, Strasbourge, France. The project was comprehensive in scope, including a political and legal foundation for international cooperation, development and financing; technical, science and engineering issues; architectural design; plausible schedules; and operations, crew issues and maintenance. Since log-term exposure to zero gravity is known to be harmful to the human body, the main goal was to design a unique variable gravity research facility which would find a practical solution to this problem, permitting a manned mission to Mars. The facility would not duplicate other space-based facilities and would provide the flexibility for examining a number of gravity levels, including lunar and Martian gravities. Major design alternatives included a truss versus a tether based system which also involved the question of docking while spinning or despinning to dock. These design issues are described. The relative advantages or disadvantages are discussed, including comments on the necessary research and technology development required for each.

Bailey, Sheila G.↗

NASA NTRS1990

Rationale and requirements for lunar exploration

The moon has had a complex and geologically fascinating history. It is a natural laboratory in which to study planetary processes and is readily accessible, only 2.5 days away. The moon is the only planetary object from which there are samples of known geologic context, and its history is understood well enough to permit the posing and answering of sophisticated scientific questions. The moon also preserves information about the earth's early history and cratering record, and about the sun's history. To retrieve all this information, it is necessary to return to the moon and study it from orbit, establish surface geophysical networks, obtain reconnaissance samples, and perform field work. These ventures will require development of interesting technological systems, such as a robotic field geologist, automated roving vehicles (both pressurized for humans and unpressurized for robotic devices), a host of sampling tools, automated sample-return spacecraft, and all of the associated navigation, communication, and power systems.

Spudis, Paul D.↗

NASA NTRS1990

Technology needs of the Exploration Initiative

An overview of the U.S. Space Exploration Initiative (SEI) is presented. The two primary objectives of the initiative are a return to the moon to create a permanent lunar base and a human mission to Mars. Even though mission architectural concepts are not yet defined, previous studies indicate that the SEI will require developments in numerous areas, including advanced engines for space transportation, in-space assembly and construction to support permanent basing of exploration systems in space, and advanced surface operations capabilities including satisfactory levels of power and surface roving vehicles, and technologies to safely support human space operations of long duration. The process of mission definition has begun and it is shown that it is possible to identify a family of fundamental functional building blocks from which all SEI mission architectures will be constructed.

Aldrich, Arnold↗

NASA NTRS1989

The CELSS research program - A brief review of recent activities

The history of the Controlled Ecological Life Support System program, initiated by NASA in the late 1970s to explore the use of bioregenerative methods of life support, is reviewed. The project focused on examining the process involved in converting inorganic minerals and gases into life support materials using sunlight as the primary energy source. The research, planning, and technological development required by the CELSS program and conducted at NASA field centers, at various universities, and by commercial organizations are reviewed. Research activities at universities have focused upon exploring methods of reducing the size of the system, reducing system power requirements, understanding issues that are associated with its long-term stability, and identifying new technologies that might be useful in improving its efficiency. Research activities at Ames research center have focused on the use of common duckweed as a high biomass-producing plant, which is high in protein and on waste processing.

Macelroy, R. D.↗

NASA NTRS1990

Imaging MAMA detector systems

Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

Slater, David C.↗

NASA NTRS1991

Nuclear thermal/nuclear electric hybrids

A description is given of the nuclear thermal and nuclear electric hybrid. The specifications are described along with its mission performance. Next, the technical status, development requirements, and some cost estimates are provided.

Reid, B. D.↗

NASA NTRS1991

Spinoff, 1991

This is an instrument of the Technology Utilization Program and is designed to heighten awareness of the technology available for transfer and its potential for public benefit. NASA's mainline programs, whose objectives require development of new technology and therefore expand the bank of technology available for transfer in future years, are summarized. Focus is on the representative sampling of spinoffs (spinoff, in this context, means products and processes developed as secondary applications of existing NASA technology) that resulted from NASA's mainline programs. The various mechanisms NASA employs to stimulate technology transfer are described and contact sources are listed in the appendix for further information about the Technology Utilization Program.

Haggerty, James J.↗

NASA NTRS1992

Pressure fed thrust chamber technology program

This is the final report for the Pressure Fed Technology Program. It details the design, fabrication, and testing of subscale hardware which successfully characterized Liquid Oxygen Rocket Propulsion (LOX/RP) combustion for low cost pressure fed design. The innovative modular injector design is described in detail as well as hot-fire test results which showed excellent performance. The program summary identifies critical LOX/RP design issues that have been resolved in this testing, and details the low risk development requirements for low cost engines for future Expandable Launch Vehicles (ELV).

Dunn, Glen M.↗

NASA NTRS1992

From a lunar outpost to Mars - Science, policy and the U.S. Space Exploration Initiative

The technological developments required for the Space Exploration Initiative (SEI) objectives are discussed in terms of scientific investigation and present U.S. space policy. The results of the 90-Day Study are listed which include explicit suggestions for the successful exploration of the moon and Mars. The Outreach/Synthesis program is described which provides four methods for eliciting ideas, technologies, and research venues for lunar and Martian missions. The results of the studies include 5 scientific objectives such as the relationship between the sun, planetary atmospheres, and climate. The protection of human life from potential extraterrestrial hazards such as radiation is also found to be a key objective of SEI as are the theoretical and practical issues of scientific research.

Pilcher, Carl B.↗

NASA NTRS1991

Real-time in situ sensors and control integration for life support systems

The limitations of the state-of-the-art for in situ sensors are discussed and a program of adaptation and enhancement of off-the-shelf sensor technologies and of innovation and research to develop more appropriate sensor technologies for life support systems is offered. By critically assessing the state-of-the-art in multifunctional sensors and smart sensors, research and development requirements for life support systems can be defined. Consideration is given to the desirable characteristics of smart sensors for life support applications, and some preliminary concepts for hierarchical integration of in situ sensors and control elements are presented.

Voecks, G. E.↗

NASA NTRS1992

An advanced manned launch system concept

A two-stage fully reusable rocked powered concept is defined and analyzed in detail for the Advanced Manned Launch System missions. The concept elements include a Mach 3 staging unmanned glideback booster and a 149-ft long winged orbiter with an external payload canister with a 15-ft diameter and 30-ft long payload bay. The booster and orbiter main propulsion system is a lightweight derivative of the current Space Shuttle Main Engine. The primary mission is the Space Station Freedom logistics mission, 40,000-lb payload with two crew members and eight passengers. The structural design and material selection, the thermal protection system, the integral cryogenic tanks and insulation, the propulsion system, and the modular payload canister system are described. The ground and flight operations approach analysis, the manufacturing and certification plan, and the technology development requirements are also discussed.

Stone, H. W.↗

NASA NTRS1993

Chemical Vapor Deposition Of Silicon Carbide

Large single-crystal SiC boules from which wafers of large area cut now being produced commerically. Availability of wafers opens door for development of SiC semiconductor devices. Recently developed chemical vapor deposition (CVD) process produces thin single-crystal SiC films on SiC wafers. Essential step in sequence of steps used to fabricate semiconductor devices. Further development required for specific devices. Some potential high-temperature applications include sensors and control electronics for advanced turbine engines and automobile engines, power electronics for electromechanical actuators for advanced aircraft and for space power systems, and equipment used in drilling of deep wells. High-frequency applications include communication systems, high-speed computers, and microwave power transistors. High-radiation applications include sensors and controls for nuclear reactors.

Powell, J. Anthony↗

NASA NTRS1992

LDEF materials: An overview of the interim findings

The flight and retrieval of the National Aeronautics and Space Administration's Long Duration Exposure Facility (LDEF) provided an opportunity for the study of the low-Earth orbit (LEO) environment and long-duration space environmental effect (SEE) on materials that are unparalleled in the history of the U.S. space program. The 5.8-year flight of LDEF greatly enhanced the potential value of materials data from LDEF to the international SEE community, compared to that of the original 1-year flight plan. The remarkable flight attitude stability of LDEF enables specific analyses of various individual and combined effects of LEO environmental parameters on identical materials of the same space vehicle. NASA recognized the potential by forming the LDEF Space Environmental Effects on Materials Special Investigation Group (MSIG) to address the greatly expanded materials and LEO space environment parameter analysis opportunities available in the LDEF structure, experiment trays, and corollary measurements, so that the combined value of all LDEF materials data to current and future space missions will be assessed and documented. This paper provides an overview of the interim LDEF materials findings of the Principal Investigators and the Materials Special Investigation Group. These revelations are based on observations of LEO environmental effects on materials made in-space during LDEF retrieval and during LDEF tray deintegration at the Kennedy Space Center, and on findings of approximately 1.5 years of laboratory analyses of LDEF materials by the LDEF materials scientists. These findings were extensively reviewed and discussed at the MSIG-sponsored LDEF Materials Workshop '91. The results are presented in a format which categorizes the revelations as 'clear findings' or 'confusing/unexplained findings' and resultant needs for new space materials developments and ground simulation testing/analytical modeling in seven categories: environmental parameters and data bases; LDEF contamination; thermal control coatings and protective treatments; polymers and films; polymer-matrix composites; metals, ceramics, and optical materials; and systems-related materials. General outlines of findings of the other LDEF Special Investigation Groups (Ionizing Radiation, Meteoroid and Debris, and Systems) are also included. The utilization of LDEF materials data for future low-earth orbit missions is also discussed, concentrating on Space Station Freedom. Some directions for continuing studies of LDEF materials are outlined. In general, the LDEF data is remarkable consistent; LDEF will provide a 'benchmark' for materials design data bases for satellites in low-Earth orbit. Some materials were identified to be encouragingly resistant to LEO SEE for 5.8-years; other 'space qualified' materials displayed significant environmental degradation. Molecular contamination was widespread; LDEF offers an unprecedented opportunity to provide a unified perspective of unmanned LEO spacecraft contamination mechanisms. New material development requirements for long-term LEO missions have been identified and current ground simulation testing methods/data for new, durable materials concepts can be validated with LDEF results. LDEF findings are already being integrated into the design of Space Station Freedom.

Stein, Bland A.↗

NASA NTRS1992

Pressure fed thrust chamber technology program

This is the final report for the Pressure Fed Technology Program. It details the design, fabrication and testing of subscale hardware which successfully characterized LOX/RP combustion for a low cost pressure fed design. The innovative modular injector design is described in detail as well as hot-fire test results which showed excellent performance. The program summary identifies critical LOX/RP design issues that have been resolved by this testing, and details the low risk development requirements for a low cost engine for future Expendable Launch Vehicles (ELVi).

Dunn, Glenn M.↗

NASA NTRS1992

An interim overview of LDEF materials findings

Stein, Brad A.↗

NASA NTRS1993

Fluctuations at the blue edge of saturated wind lines in IUE spectra of O-type stars

We examine basic issues involved in synthesizing resonance-line profiles from 1-D, dynamical models of highly structured hot-star winds. Although these models exhibit extensive variations in density as well as velocity, the density scale length is still typically much greater than the Sobolev length. The line transfer is thus treated using a Sobolev approach, as generalized by Rybicki & Hummer (1978) to take proper account of the multiple Sobolev resonances arising from the nonmonotonic velocity field. The resulting reduced-Lambda-matrix equation describing nonlocal coupling of the source function is solved by iteration, and line profiles and then derived from formal solution integration using this source function. The more appropriate methods that instead use either a stationary or a structured, local source function yield qualitatively similar line-profiles, but are found to violate photon conservation by 10 percent or more. The full results suggest that such models may indeed be able to reproduce naturally some of the qualitative properties long noted in observed UV line profiles, such as discrete absorption components in unsaturated lines, or the blue-edge variability in saturated lines. However, these particular models do not yet produce the black absorption troughs commonly observed in saturated lines, and it seems that this and other important discrepancies (e.g., in acceleration time scale of absorption components) may require development of more complete models that include rotation and other 2-D and/or 3-D effects.

Owocki, Stanley P.↗