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Results for “Accelerator Design”

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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Acceleration environment of payloads while being handled by the Shuttle Remote Manipulator System

Described in this paper is the method used in the Draper Remote Manipulator System (RMS) Simulation to compute linear accelerations at the point on the SPAS01 payload where its accelerometers are mounted. Simulated accelerometer output for representative on-orbit activities is presented. The objectives of post-flight analysis of SPAS01 data are discussed. Finally, the point is made that designers of acceleration-dependent payloads may have an interest in the capability of simulating the acceleration environment of payloads while under the control of the overall Payload Deployment and retrieval System (PDRS) that includes the Orbiter and its attitude control system as well as the Remote Manipulator Arm.

Turnbull, J. F.↗
NASA NTRS2005

Large-Scale NASA Science Applications on the Columbia Supercluster

Columbia, NASA's newest 61 teraflops supercomputer that became operational late last year, is a highly integrated Altix cluster of 10,240 processors, and was named to honor the crew of the Space Shuttle lost in early 2003. Constructed in just four months, Columbia increased NASA's computing capability ten-fold, and revitalized the Agency's high-end computing efforts. Significant cutting-edge science and engineering simulations in the areas of space and Earth sciences, as well as aeronautics and space operations, are already occurring on this largest operational Linux supercomputer, demonstrating its capacity and capability to accelerate NASA's space exploration vision. The presentation will describe how an integrated environment consisting not only of next-generation systems, but also modeling and simulation, high-speed networking, parallel performance optimization, and advanced data analysis and visualization, is being used to reduce design cycle time, accelerate scientific discovery, conduct parametric analysis of multiple scenarios, and enhance safety during the life cycle of NASA missions. The talk will conclude by discussing how NAS partnered with various NASA centers, other government agencies, computer industry, and academia, to create a national resource in large-scale modeling and simulation.

Brooks, Walter↗
NASA NTRS1992

Microgravity acceleration measurement and environment characterization science (17-IML-1)

The Space Acceleration Measurement System (SAMS) is a general purpose instrumentation system designed to measure the accelerations onboard the Shuttle Orbiter and Shuttle/Spacelab vehicles. These measurements are used to support microgravity experiments and investigation into the microgravity environment of the vehicle. Acceleration measurements can be made at locations remote from the SAMS main instrumentation unit by the use of up to three remote triaxial sensor heads. The prime objective for SAMS on the International Microgravity Lab (IML-1) mission will be to measure the accelerations experienced by the Fluid Experiment System (FES). The SAMS acceleration measurements for FES will be complemented by low level, low frequency acceleration measurements made by the Orbital Acceleration Research Experiment (OARE) installed on the shuttle. Secondary objectives for SAMS will be to measure accelerations at several specific locations to enable the acceleration transfer function of the Spacelab module to be analyzed. This analysis effort will be in conjunction with similar measurements analyses on other Spacelab missions.

Source record↗
NASA NTRS1979

Development of a portable, high-energy radiographic source

A two-year program has been undertaken to develop a portable high-energy (3-4 MeV) radiographic system for in-service and repair inspections of components at nuclear power stations. The basic design concept uses a lightweight portable linear accelerator. This paper describes the design objectives, concepts employed, and progress to date. Specific potential applications and accompanying radiographic techniques are discussed, along with novel beam-angulation devices that permit utilization in areas of highly restricted access.

Reinhart, E. R.↗
NASA NTRS2004

Test of the Equivalence Principle in an Einstein Elevator

The scientific goal of the experiment is to test the equality of gravitational and inertial mass (i.e., to test the Principle of Equivalence) by measuring the independence of the rate of fall of bodies from the composition of the falling body. The measurement is accomplished by measuring the relative displacement (or equivalently acceleration) of two falling bodies of different materials which are the proof masses of a differential accelerometer. The goal of the experiment is to measure the Eoetvoes ratio sigma g/g (differential acceleration/common acceleration) with an accuracy goal of several parts in 10(exp 15). The estimated accuracy is about two orders of magnitude better than the present state of the art. The main goal of the study to be carried out under this grant is part of the flight definition of the experiment and laboratory testing of key components. The project involves an international cooperation in which the responsibility of the US side is the flight definition of the experimental facility while the responsibility of the non-US partners is the flight definition and laboratory prototyping of the differential acceleration detector.In summary, the experiment to be designed is for taking differential acceleration measurements with a high-sensitivity detector (the sensor) during free fall conditions lasting up to 30 s in a disturbance-free acceleration environment. The experiment strategy consists in letting the sensor free fall inside a few meters long (in the vertical direction) evacuated capsule that is falling simultaneously in the rarefied atmosphere after release from a helium balloon flying at a stratospheric altitude.

Shapiro, Irwin I.↗
NASA NTRS1993

Microgravity acceleration measurement environment characterization

The Space Acceleration Measurement System (SAMS) is a general-purpose instrumentation system designed to measure the accelerations onboard the shuttle Orbiter and shuttle/Spacelab vehicles. These measurements are used to support microgravity experiments and investigations into the microgravity environment of the vehicle. Acceleration measurement can be made at locations remote from the SAMS main instrumentation unit by the use of up to three remote triaxial sensor heads. The SAMS was developed by NASA's Lewis Research Center (LeRC) in support of NASA's microgravity science programs. In the past, numerous acceleration measurement systems have flown on various space missions. These systems were tailored to measure accelerations for a narrow set of requirements and were limited in bandwidth, dynamic range, and recording capability. In addition, these systems were mission-peculiar and not easily modified for other applications or missions. The result has been an inability to accurately assess the expected microgravity environment prior to a mission for a particular experiment and/or location. The prime science objective for SAMS on the SL-J mission will be to measure the accelerations experienced by a multitude of experiments in the two racks of the Japanese First Materials Processing Test (FMPT). The FMPT consists of a variety of materials science and life science experiments contained in racks no. 7 and no. 10. The SAMS data will be made available to the FMPT principal investigators after the mission for their analysis with the FMPT data. A secondary science objective for SAMS will be the characterization of the acceleration environment of the Spacelab module. This will include an analysis of the acceleration transfer function of the Spacelab module which will utilize the FMPT acceleration measurement along with measurements at the rack no. 9 structure. Another analytical effort to be undertaken is a general characterization of the acceleration environment of the Spacelab as an orbiting laboratory. These analysis efforts will be in conjunction with similar measurements and analyses on other SAMS Spacelab missions.

Delombard, Richard↗
NASA NTRS1993

Acceleration-Augmented LQG Control of an Active Magnetic Bearing

A linear-quadratic-gaussian (LQG) regulator controller design for an acceleration-augmented active magnetic bearing (AMB) is outlined. Acceleration augmentation is a key feature in providing improved dynamic performance of the controller. The optimal control formulation provides a convenient method of trading-off fast transient response and force attenuation as control objectives.

Feeley, Joseph J.↗
NASA NTRS1976

Results of the Low Speed Aeroelastic Buffet Test with a 0.046-scale Model (747-ax1322-d-3/orbiter 8-0) of the 747 Cam/orbiter in the University of Washington Wind Tunnel (CS 3)

A series of wind tunnel studies designed to assess the potential buffet problems resulting from orbiter wake characteristics with its tailcone removed are presented to provide design loads and acceleration environments, and to develop data on buffet sensitivity to various aerodynamic configurations and flight parameters. Data are intended to support subsequent analyses of structural fatigue life, crew efficiency, and equipment vibrations.

Gillins, R. L.↗
NASA NTRS1977

Lithium cell tests at Marshall Space Flight Center

Three 18 AH Li-CF batteries with a polypropylene separator and using dimethyl sulfite in Li as F6 for the electrolyte will be placed in each shuttle solid rocket booster for range safety and frustrum location aid. Mechanical vibration, acceleration, random and design vibration, and discharge evaluation tests are discussed.

Paschal, L. E.↗
NASA NTRS1979

Ion propulsion and Comet Halley rendezvous

Cometary rendezvous missions using ion propulsion is considered. The characteristics of the ion engine are discussed including the fuel efficiency and acceleration, and the design of the ion engine is described. The operation of the ion drive engine and an overview of its applications are presented.

Atkins, K. L.↗
NASA NTRS1981

The influence of environmental effects on the mechanical properties of graphite/epoxy laminates

The time dependent deformational and creep rupture processes in graphite/epoxy laminates are examined as a function of temperature and stress level. The role of accelerated characterization of design materials is discussed, and the use of a nonlinear time-temperature-stress-superposition principle in the determination of compliance master curves as a function of stress and temperature is considered. Creep rupture analytical models are discussed as applied to polymer-matrix composites, and the data is shown to be in general agreement with a logarithmic stress and temperature-dependent delayed fracture model. Comparisons between creep and rupture experiments and phenomenological models are presented.

Brinson, H. F.↗
NASA NTRS1984

Preliminary analysis of space mission applications for electromagnetic launchers

The technical and economic feasibility of using electromagnetically launched EML payloads propelled from the Earth's surface to LEO, GEO, lunar orbit, or to interplanetary space was assessed. Analyses of the designs of rail accelerators and coaxial magnetic accelerators show that each is capable of launching to space payloads of 800 KG or more. A hybrid launcher in which EML is used for the first 2 KM/sec followed by chemical rocket stages was also tested. A cost estimates study shows that one to two EML launches per day are needed to break even, compared to a four-stage rocket. Development models are discussed for: (1) Earth orbital missions; (2) lunar base supply mission; (3) solar system escape mission; (4) Earth escape missions; (5) suborbital missions; (6) electromagnetic boost missions; and (7) space-based missions. Safety factors, environmental impacts, and EML systems analysis are discussed. Alternate systems examined include electrothermal thrustors, an EML rocket gun; an EML theta gun, and Soviet electromagnetic accelerators.

Miller, L. A.↗
NASA NTRS1987

Electron-cyclotron-resonance (ECR) plasma acceleration

A research effort directed at analytically and experimentally investigating electron-cyclotron-resonance (ECR) plasma acceleration is outlined. In addition, relevant past research is reviewed. Also, the prospects for application of ECR plasma acceleration to spacecraft propulsion are described. It is shown that previously unexplained losses in converting microwave power to directed kinetic power via ECR plasma acceleration can be understood in terms of diffusion of energized plasma to the physical walls of the accelerator. It is also argued that line radiation losses due to electron-ion and electron-atom inelastic collisions should be less than estimated in past research. Based on this new understanding, the expectation now exists that very efficient ECR plasma accelerators can be designed for application to high-specific-impulse spacecraft propulsion.

Sercel, Joel C.↗
NASA NTRS1987

Radio emission from coronal and interplanetary shocks

Observational data on coronal and interplanetary (IP) type II burst events associated with shock-wave propagation are reviewed, with a focus on the past and potential future contributions of space-based observatories. The evidence presented by Cane (1983 and 1984) in support of the hypothesis that the coronal (metric) and IP (kilometric) bursts are due to different shocks is summarized, and the fast-drift kilometric events seen at the same time as metric type II bursts (and designated shock-accelerated or shock-associated events) are characterized. The need for further observations at 0.5-20 MHz is indicated.

Cane, H. V.↗
NASA NTRS1988

Proposed acceptance, qualification, and characterization tests for thin-film PV modules

Details of a proposed test program for PV thin-film modules which the Department of Energy has directed the Solar Energy Research Institute (SERI) to prepare are presented. Results of one of the characterization tests that SERI has performed are also presented. The objective is to establish a common approach to testing modules that will be acceptable to both users and manufacturers. The tests include acceptance, qualification, and characterization tests. Acceptance tests verify that randomly selected modules have similar characteristics. Qualification tests are based on accelerated test methods designed to simulate adverse conditions. Characterization tests provide data on performance in a predefined environment.

Waddington, D.↗
NASA NTRS1993

Engine/airframe integration for waverider cruise vehicles

Engine-airframe integrated hypersonic waveriders have been optimized previously for both cruising flight and accelerators using inverse design flowfields to provide desirable aerodynamic performance and inlet properties. With engine installation, cruisers retain the high L/D advantages of the basic waverider form. To provide an understanding of waverider optimizer trends, an analytical development is presented which includes the presentation of a simplified model of a generic waverider shape. The model is shown to have good agreement with computational results, and it is used to demonstrate engineering tradeoffs in L/D, volume, and volume efficiency. Based on the demonstrated performance trends, and considering the desirability of uniform inlet flow, an improved waverider shape for engine-airframe integration is proposed using a hybrid cone-wedge generating flowfield.

Lewis, Mark J.↗