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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 NTRS1988

Development and verification of NASA Standard Initiator-2 (NSI-2): Appendix

This is the Appendix to the Final Report on the results of verification testing on NASA Contract NAS9-17249. The test results are presented graphically in the Appendix. The Final Report is a brief discussion of design elements, test results, and a discussion of the latter. The contract was awarded for development and demonstration of design modifications to the NASA Standard Initiator-1 (NSI-1), resulting in the development of NSI-2. The intent of the project was to develop and prove the following design features: (1) Protection from premature detonation due to electrostatic potential by means other than a spark gap; (2) Development of an integral insulated charge cup for use with a zirconium/potassium perchlorate type mixture; (3) Improved cost and reliability figures by the use of a deposited bridge; and (4) Elimination of dudding as a result of the pyrotechnic shock effect, the movement of the primer composition away from the bridge circuit.

Source record↗
NASA NTRS1987

Spacecraft technology trends - A view from the past

Future spacecraft will be sent on missions to complete the exploration of the solar system, to return samples from celestial bodies, record the process of creation of stars, galaxies, and the universe itself, to provide a continuous record of earth processes, and to maintain vital space communications. A key ingredient to projecting the future is to comprehend the historic record and to understand the significance of trends. This paper focuses on spacecraft cost and life trends, as well as those of the major subsystems. Throughout the history of the 'space age' there has been significant progress in the performance of spacecraft and their subsystems. However, various aspects of spacecraft performance lag behind what is technically feasible by a considerable margin. In addition, examination of the historical trend implies that future spacecraft will likely continue to be relatively unique in their design features. This is in contrast to the technically realizable future attributes such as large space platforms, modularity, system autonomy and on-orbit repair and servicing.

Hudson, Wayne R.↗
NASA NTRS1986

Performance characterization of the Hubble Space Telescope Rate Gyro Assembly

An account is given of the design features and performance characteristics of the Rate Gyro Assembly employed by the Hubble Space Telescope's Pointing Control System to effect accurate spacecraft maneuvers and support fine pointing telescope operation, in conjunction with the fine guidance sensors. The rate sensor attitude quantization is 0.00025 arcsec. Fine-pointing stability is the driver for gyro noise performance, while spacecraft-pointing accuracy requirements at the end of maneuvers has driven the gyro scale factor and mechanical alignment stability performance.

Dougherty, H.↗
NASA NTRS1986

Seam bonding of graphite reinforced composite panels

An account is given of the design features and operating characteristics of a method for the joining of composite parts, at a rate of 2 to 6 inches/min, in which the heating process responsible for adhesive flow at 800 F is focused upon the overlapped seam. The heating element is a self-tuning solid state power oscillator whose ferrite's toroid geometry generates a uniform, concentrated magnetic flux in the component to be bonded. Specimens cut from graphite/epoxy panels bonded with epoxy-phenolic adhesive by this process have exhibited average lap-shear strengths of the order of 3400 lbs/sq in.

Buckley, John D.↗
NASA NTRS1987

S-Band ranging system for NASA mission support

The NASA Ground Network (GN) provides range and Doppler data for orbit determination of Space Shuttle and scientific missions from the Merritt Island, FL, Bermuda, and Wallops Island, VA, tracking stations. This paper describes a new generation of S-Band tone ranging equipment developed under the Goddard Space Flight Center, System Utilization Enhancement (SUE) Project. The Ranging Equipment incorporates several novel design features, emphasizing reliability and maintainability for support of NASA missions during the next decade.

Zilliig, David J.↗
NASA NTRS1987

Technological status and future challenges of deep space optical communication

An account is given of the concepts, techniques, and system design features that may be used to realize an optical communications link for future planetary missions. Such a spacecraft subsystem would encompass a 10-30 cm aperture optical telescope for both transmitting and receiving. Uplink from a laser, in the form of pulsed ranging signals or command information, will be extracted by a tracking detector; downlink data, as well as detected ranging pulses, will be properly formatted and used to modulate the downlink laser. The optical receiving station may be either on the ground or in earth orbit.

Lesh, James R.↗
NASA NTRS1987

Implementation and flight-test of a multi-mode rotorcraft flight-control system for single-pilot use in poor visibility

A flight investigation was conducted to evaluate a multi-mode flight control system designed according to the most recent recommendations for handling qualities criteria for new military helicopters. The modes and capabilities that were included in the system are those considered necessary to permit divided-attention (single-pilot) lowspeed and hover operations near the ground in poor visibility conditions. Design features included mode-selection and mode-blending logic, the use of an automatic position-hold mode that employed precision measurements of aircraft position, and a hover display which permitted manually-controlled hover flight tasks in simulated instrument conditions. Pilot evaluations of the system were conducted using a multi-segment evaluation task. Pilot comments concerning the use of the system are provided, and flight-test data are presented to show system performance.

Hindson, William S.↗
NASA NTRS1988

Numerical and experimental evaluation of a new low-leakage labyrinth seal

The effectiveness of a recently developed leakage model for evaluating new design features of most seals is demonstrated. A preliminary assessment of the present stator groove feature shows that it gives approximately a 20 percent leakage reduction with no shaft speed effects. Also, detailed distributions of predicted streamlines, axial velocity, relative pressure and turbulence energy enhance one's physical insight. In addition, the interesting measured effect of axial position of the rotor/stator pair on leakage rate and stator wall axial pressure distribution is examined.

Rhode, D. L.↗
NASA NTRS1988

The Hubble Space Telescope high speed photometer

The Hubble Space Telescope will provide the opportunity to perform precise astronomical photometry above the disturbing effects of the atmosphere. The High Speed Photometer is designed to provide the observatory with a stable, precise photometer with wide dynamic range, broad wavelenth coverage, time resolution in the microsecond region, and polarimetric capability. Here, the scientific requirements for the instrument are examined, the unique design features of the photometer are explored, and the improvements to be expected over the performance of ground-based instruments are projected.

Vancitters, G. W., Jr.↗
NASA NTRS1988

An experimental and analytical evaluation of the tapered tension-torsion strap concept

A new free-tip rotor moment controller designed to increase torque output (a restoring moment) was proposed. The controller would be used as a retention device for the freely pitching tip of a helicopter rotor. The new design featured a tapered tension-torsion strap instead of the previously used parellel strap. A tapered strap has a larger separation between the tension wires at the retention end than at the oscillating end; separation is equal at both ends for a parallel strap. A simple dynamic analysis was developed and an experiment performed to evaluate this tapered strap concept. The test results indicated that the torsional spring stiffness of the strap, represented by a torsional pendulum, increased with the amount of taper. The predicted dynamic characteristics of the pendulum also confirmed this observation and correlated reasonably well with the experimental results. It could be concluded from the experimental and analytical results that the tapered strap accomplished increased torque output when compared to the parellel strap.

Louie, Alexander↗
NASA NTRS1988

The human factors of color in environmental design: A critical review

The literature on environmental color to enhance habitability in the design of Space Station interiors is reviewed. Some 200 studies were examined to determine the relative contributions of the three dimensions of color (hue, saturation, and brightness or lightness) to responses to environmental colorations. Implications of the study for color usage in novel settings and locales include: (1) There are no hard-wired linkages between environmental colors and particular judgmental or emotional states; (2) Perceptual impressions of color applications can, however, affect experiences and performances in settings; (3) Color behavior studies cannot yet specify an optimal color scheme, but instead must consider differing objectives, the relative importance of each, and design features such as the coordination of geometry, color, texture, etc.; (4) Some color-behavior effects are governed by low-level retinal and limbal mechanisms as well as by cognitive processes; and (5) Colors should first be specified in terms of what they are to do instead of what they are. Some exercise of choice is therefore needed to establish a sense of personal competence in the setting, since color must be ultimately be accepted by the people who are to live with it.

Wise, Barbara K.↗
NASA NTRS1987

Design improvement of a pump wear ring labyrinth seal

The investigation was successful in obtaining two improved designs for the impeller wear ring seal of the liquid hydrogen turbopump of interest. A finite difference computer code was extensively used in a parametric computational study in determining a cavity configuration with high flow resistance due to turbulence dissipation. These two designs, along with that currently used, were fabricated and tested. The improved designs were denoted Type O and Type S. The measurements showed that Type O and Type S given 67 and 30 percent reduction in leakage over the current design, respectively. It was found that the number of cavities, the step height and the presence of a small stator groove are quite important design features. Also, the tooth thickness is of some significance. Finally, the tooth height and an additional large cavity cut out from the stator (upstream of the step) are of negligible importance.

Rhode, David L.↗
NASA NTRS1987

A strategy for space biology and medical science for the 1980s and 1990s

A guideline is provided for developing NASA's long-term mission plans and a rational, coherent research program. Ten topical areas for research are addressed: developmental biology, gravitropism in plants, sensorimotor integration, bone and mineral metabolism, cardiovascular/pulmonary function, muscle remodeling, nutrition, human reproduction, space anemia, and human behavior. Scientific goals, objectives, and required measurements and facilities for each of the major areas of space biology and medicine are identified and described along with primary goals and objectives for each of these disciplines. Proposals are made concerning the use of scientific panels to oversee the implementation of the strategy, life sciences' need for continuous access to spaceflight opportunities, the advantages of a focused mission strategy, certain design features that will enhance spaceflight experimentation, and general facilities. Other topics that are considered include mission planning, crew selection and training, and interagency and international cooperation.

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NASA NTRS1989

Fuzzy set applications in engineering optimization: Multilevel fuzzy optimization

A formulation for multilevel optimization with fuzzy objective functions is presented. With few exceptions, formulations for fuzzy optimization have dealt with a one-level problem in which the objective is the membership function of a fuzzy set formed by the fuzzy intersection of other sets. In the problem examined here, the goal set G is defined in a more general way, using an aggregation operator H that allows arbitrary combinations of set operations (union, intersection, addition) on the individual sets Gi. This is a straightforward extension of the standard form, but one that makes possible the modeling of interesting evaluation strategies. A second, more important departure from the standard form will be the construction of a multilevel problem analogous to the design decomposition problem in optimization. This arrangement facilitates the simulation of a system design process in which different components of the system are designed by different teams, and different levels of design detail become relevant at different time stages in the process: global design features early, local features later in the process.

Diaz, Alejandro R.↗
NASA NTRS1989

Thermal Protection System of the Space Shuttle

The Thermal Protection System (TPS), introduced by NASA, continues to incorporate many of the advances in materials over the past two decades. A comprehensive, single-volume summary of the TPS, including system design rationales, key design features, and broad descriptions of the subsystems of TPS (E.g., reusable surface insulation, leading edge structural, and penetration subsystems) is provided. Details of all elements of TPS development and application are covered (materials properties, manufacturing, modeling, testing, installation, and inspection). Disclosures and inventions are listed and potential commercial application of TPS-related technology is discussed.

Cleland, John↗
NASA NTRS1989

A corner-reflector mixer mount for far infrared wavelengths

A new type of corner-reflector mixer mount, which has the advantages of ease of fabrication and assembly as well as frequency versatility, has been designed and constructed. The predicted response patterns have been experimentally verified for various antenna lengths and operating frequencies between 800 and 2000 GHz. An important design feature is the incorporation of a microstrip matching network which eliminates IF impedance mismatch and provides mechanical isolation for the whisker antenna.

Zmuidzinas, J.↗
NASA NTRS1989

Design of a spanloader cargo aircraft

The design features of an aircraft capable of fulfilling a long haul, high capacity cargo mission are described. This span-loading aircraft, or flying wing, is capable of carrying extremely large payloads and is expected to be in demand to replace the slow-moving cargo ships currently in use. The spanloader seeks to reduce empty weight by eliminating the aircraft fuselage. Disadvantages are the thickness of the cargo-containing wing, and resulting stability and control problems. The spanloader presented here has a small fuselage, low-aspect ratio wings, winglets, and uses six turbofan engines for propulsion. It will have a payload capacity of 300,000 pounds plus 30 first class passengers and 6 crew members. Its projected market is transportation of freight from Europe and the U.S.A. to countries in the Pacific Basin. Cost estimates support its economic feasibility.

Weisshaar, Terrence A.↗
NASA NTRS1989

Introduction to D-He(3) fusion reactors

A review and evaluation of D-He(3) fusion reactor technology is presented. The advantages and disadvantages of the D-He(3) and D-T reactor cycles are outlined and compared. In addition, the general design features of D-He(3) tokamaks and field reversed configuration (FRC) reactors are described and the relative merits of each are compared. It is concluded that both tokamaks and FRC's offer certain advantages, and that the ultimate decision as to which to persue for terrestrial power generation will depend heavily on how the physics performance of each of them develops over the next few years. It is clear that the D-He(3) fuel cycle offers marked advantages over the D-T cycle. Although the physics requirements for D-He(3) are more demanding, the overwhelming advantages resulting from the two order of magnitude reduction of neutron flux are expected to lead to a shorter time to commercialization than for the D-T cycle.

Vlases, G. C.↗