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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
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.↗
NASA NTRS1989

NASA/GSFC split-rail parallel gripper

The current state of development of the NASA/GSFC (Goddard Space Flight Center) Split-Rail Parallel Gripper (SRPG) is described. The SPRG has been shown to be a high performance gripper for industrial robots. It has a precise wide throw and at the same time, it is light, simple, compact, rugged, and jam-proof against side loads. Originated at the National Bureau of Standards (NBS), this gripper is undergoing further development at NASA/GSFC in pursuit of two goals: as a potential gripper for robots in space and as the basis for sensory-interactive industrial gripper as part of NASA's technology utilization program. The gripper design features, its principles of operation and how it is constructed are described. Test results are included.

Vranish, John M.↗
NASA NTRS1990

A compact, rugged, high repetition rate CO2 laser incorporating catalyst

The principal design features and operating characteristics of a high repetition rate CO2 laser are outlined. The laser is a compact, rugged unit, completely sealed and incorporating an unheated solid catalyst. Stable operation has been successfully demonstrated over a temperature range of -35 C to 65 C.

Schwarzenberger, P. M.↗
NASA NTRS1990

Laboratory Simulation of the Effect of Rocket Thrust on a Precessing Space Vehicle

Ground tests of solid propellant rocket motors have shown that metal-containing propellants produce various amounts of slag (primarily aluminum oxide) which is trapped in the motor case, causing a loss of specific impulse. Although not yet definitely established, the presence of a liquid pool of slag also may contribute to nutational instabilities that have been observed with certain spin-stabilized, upper-stage vehicles. Because of the rocket's axial acceleration, absent in the ground tests, estimates of in-flight slag mass have been very uncertain. Yet such estimates are needed to determine the magnitude of the control authority of the systems required for eliminating the instability. A test rig with an eccentrically mounted hemispherical bowl was designed and built which incorporates a follower force that properly aligns the thrust vector along the axis of spin. A program that computes the motion of a point mass in the spinning and precessing bowl was written. Using various RPMs, friction factors, and initial starting conditions, plots were generated showing the trace of the point mass around the inside of the fuel tank. The apparatus will incorporate future design features such as a variable nutation angle and a film height measuring instrument. Data obtained on the nutational instability characteristics will be used to determine order of magnitude estimates of control authority needed to minimize the sloshing effect.

Alvarez, Oscar↗
NASA NTRS1989

Centaur upper stage

An account is given of the design features of the LOX/LH2-fueled Centaur upper stage engine and fuel cryotankage, in order to serve as a basis for understanding the Main Engine Cut Off (MECO) system instituted. MECO follows the instant of spacecraft separation from the upper stage. The planetary launch program during 1966-1978 involved 23 Centaur launches and led to no upper stage reentry; LEO missions for HEAO and OAO satellite lofting in 1963-1979 involved nine Centaur launches and led to five reentries. GEO satellite launches in 1969-1986 saw 32 launches and three known reentries.

Groesbeck, W.↗
NASA NTRS1989

Photovoltaic array environmental protection program

During the photovoltaic array environmental protection program, a coating material, application technique, and design approach intended to protect flexible solar array blankets during a nominal fifteen-year operating lifetime were developed. Numerous thin-film coatings for protecting the Kapton polyimide material used in the construction of the Space Station Freedom flexible solar array blanket were evaluated. The critical solar array design features and protection measures are discussed with special emphasis on the effects of solar array fabrication and flexible printed circuit manufacturing processes on coating durability. The results of the mechanical and environmental test evaluation, including oxygen plasma, neutral oxygen beam, and UV/charged-particle combined exposure, are discussed. These results led to the selection of a silicon dioxide thin-film coating to protect the solar array blanket from the low-earth-orbit atomic oxygen environment.

Bilger, Kevin M.↗
NASA NTRS1989

Characterizations of the Earth Radiation Budget Experiment (ERBE) scanning radiometers

NASA's Earth Radiation Budget Experiment employs the Earth Radiation Budget Satellite and the NOAA 9 and 10 spacecraft to obtain absolute measurements of incoming solar radiation, shortwave earth-reflected solar radiation, and longwave earth-emitted radiation, using both scanning and nonscanning radiometers. Each of the three remote-sensing spacecraft carry narrow FOV scanning radiometers whose detection sensors are thermistor bolometers. Attention is presently given to the calibration models and methods employed in characterizing the scanning radiometers' output signals; the design features of the scanners and flight calibration systems are presented.

Lee, Robert B., III↗
NASA NTRS1989

Optical materials for space based laser systems

The design features and performance characteristics of a sensitized holmium laser applicable to differential lidar and Doppler windshear measurements are presented, giving attention to the optimal choice of sensitizing/activating dopant ions. This development of a 2-micron region eye-safe laser, where holmium is sensitized by either hulium or erbium, has called for interionic energy transfer processes whose rate will not result in gain-switched pulses that are excessively long for atmospheric lidar and Doppler windshear detection. The application of diamond films for optical component hardening is noted.

Buoncristiani, A. M.↗
NASA NTRS1990

Laboratory simulation of the rocket motor thrust as a follower force

Ground tests of solid propellant rocket motors have shown that metal-containing propellants produce various amounts of slag (primarily aluminum oxide), which is trapped in the motor case causing a loss of specific impulse. Although not yet definitely established, the presence of a liquid pool of slag also may contribute to nutational instabilities that have been observed with certain spin-stabilized, upper-stage vehicles. Because of the rocket's axial acceleration - absent in the ground tests - estimates of in-flight slag mass have been very uncertain. Yet such estimates are needed to determine the magnitude of the control authority of the systems required for eliminating the instability. A test rig with an eccentrically mounted hemispherical bowl was designed and built that incorporates a follower force that properly aligns the thrust vector along the axis of spin. A program that computes the motion of a point mass in the spinning and precessing bowl was written. Using various rpm, friction factors, and initial starting conditions, plots were generated showing the trace of the point mass around the inside of the fuel tank. The apparatus will be used extensively during the 1990 to 1991 academic year and incorporate future design features such as a variable nutation angle and a film height measuring instrument. Data obtained on the nutational instability characteristics will be used to determine order-of-magnitude estimates of control authority needed to minimize the sloshing effect.

Source record↗
NASA NTRS1991

Near-term lunar nuclear thermal rocket engine options

The Nuclear Thermal Rocket (NTR) is an attractive candidate propulsion system option for manned planetary missions. Its high performance capability for such missions translates into a substantial reduction in low-earth-orbit (LEO) required mass and trip times with increased operational flexibility. This study examined NTR engine options that could support near-term lunar mission operations. Expander and gas generator cycle, solid-core NERVA derivative reactor-based NTR engines were investigated. Weight, size, operational characteristics, and design features for representative NTR engine concepts are presented. The impact of using these NTR engines for a typical lunar mission scenario is also examined.

Pelaccio, Dennis G.↗
NASA NTRS1991

Materials and light thermal structures research for advanced space exploration

The Light Thermal Structures Center at the University of Virginia sponsors educational and research programs focused on the development of reliable, lightweight structures to function in hostile thermal environments. Technology advances in materials and design methodology for light thermal structures will contribute to improved space vehicle design concepts with attendant weight savings. This paper highlights current research activities in three areas relevant to space exploration: low density, high temperature aluminum alloys, composite materials, and structures with thermal gradients. Advances in the development of new aluminum-lithium alloys and mechanically alloyed aluminum alloys are described. Material properties and design features of advanced composites are highlighted. Research studies in thermal structures with temperature gradients include inelastic panel buckling and thermally induced unstable oscillations. Current and future research is focused on the integration of new materials with applications to structural components with thermal gradients.

Thornton, Earl A.↗
NASA NTRS1991

Updated solid-core nuclear thermal propulsion engine trades

This study examined the application of state-of-the-art propulsion and reactor technologies to a near-term solid-core NERVA-based nuclear thermal propulsion system. Updated reactor performance and weight scaling laws were initially derived and input into a nuclear rocket engine system cycle design analysis code. Nuclear Thermal Propulsion (NTP) engine system weight, size, and performance are presented here for a large range of chamber pressures, nozzle area ratios, and thrust levels for three reactor fuel types operating at their corresponding temperatures. Operational characteristics and design features of representative NTP engine concepts are also presented.

Pelaccio, Dennis G.↗
NASA NTRS1992

Improved Raman-Emission Detector

Improved apparatus excites and detects Raman emissions in sample gas mixture to measure concentration of species. Sensitivity increased by novel design features as increasing collection of emissions using paraboloidal reflector and collecting lens coaxial with beam instead of spherical reflector and condensing lens on axis perpendicular to illuminating beam.

Mckinney, Gary N.↗
NASA NTRS1991

Space Station Freedom/lunar transfer vehicle propellant operation hazard analysis

Space Station Freedom (SSF), as a transportation node for Space Exploration Initiative missions, would involve the assembly and refurbishing of lunar and Mars transfer vehicles. This includes operations involving cryogenic propellants (LH2 7 LO2) such as storing and handling of loaded propellant tanks, assembly onto the vehicle, and propellant transfer. Cryogenic propellants dictate rigorous safety precautions and impose unique requirements to ensure flight safety to both personnel and SSF elements. The objective of this study is to identify potential hazards and risks associated with cryogenic propellants. This involves identification of pertinent system design features and operational procedures. Criticality of identified risks/hazards shall be assessed and those that fall in the catastrophic and critical categories shall include mitigating solutions.

Dominick, Sam↗
NASA NTRS1992

Visually Coupled Systems (VCS): The Virtual Panoramic Display (VPD) System

The development and impact is described of new visually coupled system (VCS) equipment designed to support engineering and human factors research in the military aircraft cockpit environment. VCS represents an advanced man-machine interface (MMI). Its potential to improve aircrew situational awareness seems enormous, but its superiority over the conventional cockpit MMI has not been established in a conclusive and rigorous fashion. What has been missing is a 'systems' approach to technology advancement that is comprehensive enough to produce conclusive results concerning the operational viability of the VCS concept and verify any risk factors that might be involved with its general use in the cockpit. The advanced VCS configuration described here, was ruggedized for use in military aircraft environments and was dubbed the Virtual Panoramic Display (VPD). It was designed to answer the VCS portion of the systems problem, and is implemented as a modular system whose performance can be tailored to specific application requirements. The overall system concept and the design of the two most important electronic subsystems that support the helmet mounted parts, a new militarized version of the magnetic helmet mounted sight and correspondingly similar helmet display electronics, are discussed in detail. Significant emphasis is given to illustrating how particular design features in the hardware improve overall system performance and support research activities.

Kocian, Dean F.↗