SEARCH · Search NASA

Results for “POPS”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7

All sources NASA NTRS DOE OSTI

NASA NTRS1987

U.S. Space Station platform - Configuration technology for customer servicing

Features of the Space Station coorbiting and polar orbiting platforms (COP and POP, respectively) are described that will allow them to be configured optimally to meet mission requirements and to be assembled, serviced, and modified on-orbit. Both of these platforms were designed to permit servicing at the Shuttle using the remote manipulator system with teleoperated end effectors; EVA was planned as a backup and for unplanned payload failure modes. Station-based servicing is discussed as well as expendable launch vehicle-based servicing concepts.

Dezio, Joseph A.↗

NASA NTRS1989

Mobile, high-wind, balloon-launching apparatus

In order to place instruments for measuring meteorological and electrical parameters into thunderstorms, an inexpensive apparatus has been developed which makes it possible to inflate, transport, and launch balloons in high winds. The launching apparatus is a cylinder of bubble plastic that is made by joining the sides of the cylinder together with a velcro rip strip. A balloon is launched by pulling the rip strip rapidly. This allows the balloon to pop upward into the ambient low-level wind and carry its instrumentation aloft. Different-sized launch tubes are constructed to accommodate particular sizes of balloons. Balloons have been launched in winds of about 20 m/s.

Rust, W. David↗

NASA NTRS1989

Knowledge representation in space flight operations

In space flight operations rapid understanding of the state of the space vehicle is essential. Representation of knowledge depicting space vehicle status in a dynamic environment presents a difficult challenge. The NASA Jet Propulsion Laboratory has pursued areas of technology associated with the advancement of spacecraft operations environment. This has led to the development of several advanced mission systems which incorporate enhanced graphics capabilities. These systems include: (1) Spacecraft Health Automated Reasoning Prototype (SHARP); (2) Spacecraft Monitoring Environment (SME); (3) Electrical Power Data Monitor (EPDM); (4) Generic Payload Operations Control Center (GPOCC); and (5) Telemetry System Monitor Prototype (TSM). Knowledge representation in these systems provides a direct representation of the intrinsic images associated with the instrument and satellite telemetry and telecommunications systems. The man-machine interface includes easily interpreted contextual graphic displays. These interactive video displays contain multiple display screens with pop-up windows and intelligent, high resolution graphics linked through context and mouse-sensitive icons and text.

Busse, Carl↗

NASA NTRS1990

A test matrix sequencer for research test facility automation

The hardware and software configuration of a Test Matrix Sequencer, a general purpose test matrix profiler that was developed for research test facility automation at the NASA Lewis Research Center, is described. The system provides set points to controllers and contact closures to data systems during the course of a test. The Test Matrix Sequencer consists of a microprocessor controlled system which is operated from a personal computer. The software program, which is the main element of the overall system is interactive and menu driven with pop-up windows and help screens. Analog and digital input/output channels can be controlled from a personal computer using the software program. The Test Matrix Sequencer provides more efficient use of aeronautics test facilities by automating repetitive tasks that were once done manually.

Mccartney, Timothy P.↗

NASA NTRS1989

Size-frequency distributions of chondrules in CO3 chondrites

The size-frequency distributions of chondrules were determined for eleven CO3 chondrites (including ALHA77003, ALHA77307, ALH82101, ALH85003, Colony, Felix, Isna, Kainsaz, Lance, Ornans, and Warrenton), using the results of petrographic analyses of thin sections. The mean proportion of different chondrule types in CO3 chondrites were estimated to be 69 percent POP, 18 percent PP, 8 percent PO, 2 percent BO, 2 percent RP, 1 percent C, and less than 0.1 percent GOP. These proportions are very different from those in ordinary or EH and CV chondrites, with the smaller proportion of nonporphyritic chondrules than EH chondrites, but a larger proportion than CV chondrites. Relative proportions of chondrule types vary with size interval; thus, with decreasing chondrule size, PO chondrules decrease fairly regularly in abundance, while RP chondrules are most abundant in the smallest size intervals.

Rubin, Alan E.↗

NASA NTRS1990

A test matrix sequencer for research test facility automation

Mccartney, Timothy P.↗

NASA NTRS1991

Software For Integration Of EVA And Telerobotics

Telerobotics/EVA Joint Analysis Systems (TEJAS) computer program is hypermedia information software system using object-oriented programming to bridge gap between crew-EVA and telerobotics activities. TEJAS Version 1.0 contains 20 HyperCard stacks using visual, customizable interface of icon buttons, pop-up menus, and relational commands to store, link, and standardize related information about primitives, technologies, tasks, assumptions, and open issues involved in space-telerobot or crew-EVA tasks. Runs on any Apple MacIntosh personal computer.

Drews, Michael L.↗

NASA NTRS1990

Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2

This report summarizes and documents the results of the 12-month phase 1 work effort. The objective of phase 1 was to establish the conceptional definition of the laser atmospheric wind sounder (LAWS) sensor system, including accommodations analyses to ensure compatibility with the Space Station Freedom (SSF) and the Earth Observing System (EOS) Polar Orbiting Platform (POP). Various concepts were investigated with trade studies performed to select the configuration to be carried forward to the phase 2 Preliminary Design Definition. A summary of the LAWS system and subsystem trade studies that were performed leading to the baseline design configuration is presented in the appendix. The overall objective of the LAWS Project is to define, design, and implement an operational space based facility, LAWS, for accurate measurement of Earth wind profiles. Phase 1 addressed three major areas: (1) requirements definition; (2) instrument concepts and configurations; and (3) performance analysis. For the LAWS instrument concepts and configurations, the issues which press the technological state of the art are reliable detector lifetime and laser performance and lifetime. Lag angle compensation, pointing accuracy, satellite navigation, and telescope design are significant technical issues, but they are considered to be currently state of the art. The primary issues for performance analysis concern interaction with the atmosphere in terms of backscatter and attenuation, wind variance, and cloud blockage. The phase 1 tasks were formulated to address these significant technical issues and demonstrate the technical feasibility of the LAWS concept. Primary emphasis was placed on analysis/trade and identification of candidate concepts. Promising configurations were evaluated for performance, sensitivities, risks, and budgetary costs. Lockheed's baseline LAWS configuration is presented.

Source record↗

NASA NTRS1991

Development and evaluation of an inverse solution technique for studying helicopter maneuverability and agility

An inverse solution technique for determining the maximum maneuvering performance of a helicopter using smooth, pilotlike control inputs is presented. Also described is a pilot simulation experiment performed to investigate the accuracy of the solution resulting from this technique. The maneuverability and agility capability of the helicopter math model was varied by varying the pitch and roll damping, the maximum pitch and roll rate, and the maximum load-factor capability. Three maneuvers were investigated: a 180-deg turn, a longitudinal pop-up, and a lateral jink. The inverse solution technique yielded accurate predictions of pilot-in-the-loop maneuvering performance for two of the three maneuvers.

Whalley, Matthew S.↗

NASA NTRS1992

TIGER: Turbomachinery interactive grid generation

A three dimensional, interactive grid generation code, TIGER, is being developed for analysis of flows around ducted or unducted propellers. TIGER is a customized grid generator that combines new technology with methods from general grid generation codes. The code generates multiple block, structured grids around multiple blade rows with a hub and shroud for either C grid or H grid topologies. The code is intended for use with a Euler/Navier-Stokes solver also being developed, but is general enough for use with other flow solvers. TIGER features a silicon graphics interactive graphics environment that displays a pop-up window, graphics window, and text window. The geometry is read as a discrete set of points with options for several industrial standard formats and NASA standard formats. Various splines are available for defining the surface geometries. Grid generation is done either interactively or through a batch mode operation using history files from a previously generated grid. The batch mode operation can be done either with a graphical display of the interactive session or with no graphics so that the code can be run on another computer system. Run time can be significantly reduced by running on a Cray-YMP.

Soni, Bharat K.↗

NASA NTRS1992

EnviroNET: An on-line environment data base for LDEF data

EnviroNET is an on-line, free form data base intended to provide a centralized depository for a wide range of technical information on environmentally induced interactions of use to Space Shuttle customers and spacecraft designers. It provides a user friendly, menu driven format on networks that are connected globally and is available twenty-four hours a day, every day. The information updated regularly, includes expository text, tabular numerical data, charts and graphs, and models. The system pools space data collected over the years by NASA, USAF, other government facilities, industry, universities, and ESA. The models accept parameter input from the user and calculate and display the derived values corresponding to that input. In addition to the archive, interactive graphics programs are also available on space debris, the neutral atmosphere, radiation, magnetic field, and ionosphere. A user friendly informative interface is standard for all the models with a pop-up window, help window with information on inputs, outputs, and caveats. The system will eventually simplify mission analysis with analytical tools and deliver solution for computational intense graphical applications to do 'What if' scenarios. A proposed plan for developing a repository of LDEF information for a user group concludes the presentation.

Lauriente, Michael↗

NASA NTRS1992

Some observations on spin detector response during Galileo high gain antenna deployment

This paper summarizes a dynamic analysis conducted in support of the investigation of the anomalous deployment of the Galileo High Gain Antenna on April 11, 1991. The work was focused on modeling the spacecraft spin dynamics to predict and compare the spin detector telemetry during the antenna deployment for possible cause scenarios. The effects of analog and digital low-pass filtering, digitization, and telemetry on the reported spin rate were studied as well. The high frequency phenomena in the spin detector response are masked by the filtering and sampling of the telemetry data. However, the observed spin detector telemetery is consistent with a single rib popping free, and is most likely associated with a rib near the spin detector, or 180 deg opposite.

Peng, Chia-Yen↗

NASA NTRS1992

Analysis of precracking parameters and fracture toughness for ceramic single-edge-precracked-beam specimens

The single-edge-precracked-beam (SEPB) method involves creation of a straight-through crack from an indentation crack. The straight-through crack is developed by applying a controlled bending load to a specimen via a precracking fixture. The fixture induces the following sequence: (1) stable growth of the indentation crack; (2) pop-in; and finally, (3) arrest-thereby forming a straight-through precrack. The effects of indentation load on precracking load as well as precrack size were studied for experimental variables such as specimen width, fixture span, and material. Finite element analysis was used to obtain the stress distribution and stress intensity factor, thus providing a quantitative prediction of the precracking load and precrack size for silicon nitride, alumina, silicon cabide, and two SiC whisker-reinforced silicon nitrides. Fracture toughness values obtained from the SEPB method were compared with those obtained from other methods.

Choi, Sung R.↗

NASA NTRS1993

Vibration Pattern Imager (VPI): A control and data acquisition system for scanning laser vibrometers

The Vibration Pattern Imager (VPI) system was designed to control and acquire data from scanning laser vibrometer sensors. The PC computer based system uses a digital signal processing (DSP) board and an analog I/O board to control the sensor and to process the data. The VPI system was originally developed for use with the Ometron VPI Sensor, but can be readily adapted to any commercially available sensor which provides an analog output signal and requires analog inputs for control of mirror positioning. The sensor itself is not part of the VPI system. A graphical interface program, which runs on a PC under the MS-DOS operating system, functions in an interactive mode and communicates with the DSP and I/O boards in a user-friendly fashion through the aid of pop-up menus. Two types of data may be acquired with the VPI system: single point or 'full field.' In the single point mode, time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and is stored by the PC. The position of the measuring point (adjusted by mirrors in the sensor) is controlled via a mouse input. The mouse input is translated to output voltages by the D/A converter on the I/O board to control the mirror servos. In the 'full field' mode, the measurement point is moved over a user-selectable rectangular area. The time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and converted to a root-mean-square (rms) value by the DSP board. The rms 'full field' velocity distribution is then uploaded for display and storage on the PC.

Rizzi, Stephen A.↗

NASA NTRS1993

Numerical modeling of the interstellar medium in galactic disks

We have been developing detailed hydrodynamic models of the global interstellar medium in the hope of understanding the mass and volume occupied by various phases, as well as their structure and kinematics. In our model, the gas is modeled by one fluid while representative Pop 1 stars are modeled by a second fluid. The two fluids are coupled in that the gas forms into stars at a rate given by a Schmidt law while stellar mass loss returns matter into the gas phase (on a time scale of 100 Myr). Also, the stars heat the gas through stellar winds and the gas cools through optically thin radiation. The time behavior of these two fluids is studied in two spatial dimensions with the Eulerian finite difference numerical hydrodynamic code Zen. The two spatial dimensions are along the plane of a disk (x, total length of 2 kpc) and perpendicular to the disk (z, total height of +/- 15 kpc) and a galactic gravitational field in the z direction, typical of that at the solar circle, is imposed upon the simulation; self-gravity and rotation are absent. For the boundary conditions, outflow is permitted at the top and bottom of the grid (z = +/- 15 kpc) while periodic boundary conditions are imposed upon left and right sides of the grid. As initial conditions, we assumed a gaseous distribution like that seen for the H1 by earlier researchers, although the results are insensitive to the initial conditions. We have run simulations in which the heating due to stars, parameterized as a stellar wind velocity, a, is varied from low (a = 150 km/s), to intermediate (a = 300 km/s), to high (a = 600 km/s). Since the intermediate case is roughly equivalent to the Galactic energy injection rate from supernovae, this summary will concentrate on results from this simulation.

Rosen, A.↗

NASA NTRS1993

EnviroNET: On-line information for LDEF

EnviroNET is an on-line, free-form database intended to provide a centralized repository for a wide range of technical information on environmentally induced interactions of use to Space Shuttle customers and spacecraft designers. It provides a user-friendly, menu-driven format on networks that are connected globally and is available twenty-four hours a day - every day. The information, updated regularly, includes expository text, tabular numerical data, charts and graphs, and models. The system pools space data collected over the years by NASA, USAF, other government research facilities, industry, universities, and the European Space Agency. The models accept parameter input from the user, then calculate and display the derived values corresponding to that input. In addition to the archive, interactive graphics programs are also available on space debris, the neutral atmosphere, radiation, magnetic fields, and the ionosphere. A user-friendly, informative interface is standard for all the models and includes a pop-up help window with information on inputs, outputs, and caveats. The system will eventually simplify mission analysis with analytical tools and deliver solutions for computationally intense graphical applications to do 'What if...' scenarios. A proposed plan for developing a repository of information from the Long Duration Exposure Facility (LDEF) for a user group is presented.

Lauriente, Michael↗

NASA NTRS1993

An interactive tool for design and support of lunar, gravity assist, and libration point trajectories

The 'Swingby' interactive tool for design, analysis, and support of maneuver planning for missions that involve transfers to the moon, the lunar orbits, multiple-gravity assists, and the libration-point orbits, runs on a PC and uses pull-down and pop-up menus to allow users to change physical constants and select perturbations for inclusion. Swingby can also target by ascertain parameters, or allow the computer to generate goals on the basis of mission requirements. Rapid mission analyses, operational maneuvers, and contingency plans are thereby obtainable.

Carrico, J.↗

NASA NTRS1992

Analysis of precracking parameters for ceramic single-edge-precracked-beam specimens

The single-edge-precracked-beam (SEPB) method involves creation of a straight-through crack from an indentation crack. The straight-through crack is developed by applying a controlled bending load to a specimen via a precracking fixture. The fixture induces the following sequence: (1) stable growth of the indentation crack; (2) pop-in; and finally, (3) arrest - thereby forming a straight-through precrack. The effects of indentation load on precracking load as well as precrack size were studied for experimental variables such as specimen width, fixture span, and material. Finite element analysis was used to obtain the stress distribution and stress intensity factor, thus providing a quantitative prediction of the precracking load and precrack size for silicon nitride, alumina, silicon carbide, and two SiC whisker-reinforced silicon nitrides. Fracture toughness values obtained from the SEPB method were compared with those obtained from other methods.

Choi, Sung R.↗