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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Program verification document for the ASTP flight program

The various segments of the Apollo Soyuz Test Project (ASTP) flight program were verified. This included checks on the following: general verification, reference systems and transformations, launch preparations, boost navigation and guidance, orbital navigation and guidance, time bases, discretes, and interrupts, launch vehicle attitude control, switch selector processing, digital command system, real time telemetry and data compression, and algorithms.

Source record↗
NASA NTRS1975

Digital command system

The correct processing of the Digital Command System (DCS), which provides a limited real-time means of controlling specific flight program functions, was verified. The ability of the flight program to correctly read and process DCS commands was verified. Tests made by the flight program after reading the contents of the command decoder register to establish the validity of the received data were verified through the following: DCS mode command verification, DCS data command verification, DCS data validation, and DCS error message. The operation of the following DCS commands accepted and processed by the flight program was tested: time base update, navigation update, generalized switch selector, memory dump, terminate, execute generalized maneuver, return to nominal timeline, ECS water control valve logic inhibit, execute maneuver, execute alternate sequence, targeting load, ladder magnitude limit, S-IVB/IU de-orbit, compressed data dump, and remove inhibit on the extraction maneuver.

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NASA NTRS1976

Fast pressure-sensor system

Miniature silicon-diaphragm sensors and signal multiplexer are mounted to ganged zero-operate-calibrate pressure selector switches. Device allows in-situ calibration, can be computer controlled, and measures at approximately 10,000 readings per second.

Gross, C.↗
NASA NTRS1976

LACIE performance predictor final operational capability program description, volume 2

Given the swath table files, the segment set for one country and cloud cover data, the SAGE program determines how many times and under what conditions each segment is accessed by satellites. The program writes a record for each segment on a data file which contains the pertinent acquisition data. The weather data file can also be generated from a NASA supplied tape. The Segment Acquisition Selector Program (SACS) selects data from the segment reference file based upon data input manually and from a crop window file. It writes the extracted data to a data acquisition file and prints two summary reports. The POUT program reads from associated LACIE files and produces printed reports. The major types of reports that can be produced are: (1) Substrate Reference Data Reports, (2) Population Mean, Standard Deviation and Histogram Reports, (3) Histograms of Monte Carlo Statistics Reports, and (4) Frequency of Sample Segment Acquisitions Reports.

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NASA NTRS1976

LACIE performance predictor FOC users manual

The LACIE Performance Predictor (LPP) is a computer simulation of the LACIE process for predicting worldwide wheat production. The simulation provides for the introduction of various errors into the system and provides estimates based on these errors, thus allowing the user to determine the impact of selected error sources. The FOC LPP simulates the acquisition of the sample segment data by the LANDSAT Satellite (DAPTS), the classification of the agricultural area within the sample segment (CAMS), the estimation of the wheat yield (YES), and the production estimation and aggregation (CAS). These elements include data acquisition characteristics, environmental conditions, classification algorithms, the LACIE aggregation and data adjustment procedures. The operational structure for simulating these elements consists of the following key programs: (1) LACIE Utility Maintenance Process, (2) System Error Executive, (3) Ephemeris Generator, (4) Access Generator, (5) Acquisition Selector, (6) LACIE Error Model (LEM), and (7) Post Processor.

Source record↗
NASA NTRS1976

NASA atomic hydrogen standards program - An update

Some of the design features of NASA hydrogen masers are discussed including the large hydrogen source bulb, the palladium purified, the state selector, the replaceable pumps, the small entrance stem, magnetic shields, the elongated storage bulb, the aluminum cavity, the electronics package, and the autotuner. Attention is also given to the reliability and operating life of these hydrogen atomic standards.

Reinhardt, V. S.↗
NASA NTRS1979

Multichannel VCO needs only one reference

Frequency stabilizing circuit controls output of multichannel microwave oscillator using passband filters and selector logic to eliminate need for separate crystal diode voltage controlled oscillator (VCO).

Masson, R. K.↗
NASA NTRS1978

New X-band microwave equipment at the DSN 64-meter stations

The performance and capabilities of the DSN 64 m antennas at X-band are considered including extensive modifications to the XRO cone assemblies. The changes include a feed assembly with a dual hybrid mode horn and orthogonal mode junction, dual traveling wave masers, and receiver mode selector.

Hartop, R.↗
NASA NTRS1979

How accurate is NETTO

The historical origin and general history of vertical current total energy variometer, including its optimum airspeed selector ring are reviewed, and some later developments of it are discussed. Polars of three sailplanes of different spans are charted for straight and circling flight, then plotted to reveal their parabolic anomaly and the effect of circling flight sink rate. These effects are further analyzed for their influence on the transient compensation of NETTO variometers as well as the speed ring. Some other disturbances due to the quality of sailplane preparation and flight dynamics are listed. Conclusions are drawn about the problems to pilots from imperfect NETTO variometer compensation and its effect on the maximization of ground speed from the speed ring. A modification for improvements to the speed ring and computer is suggested.

Dupont, S.↗
NASA NTRS1980

Optical calibrator for TDL spectrometers

Two etalons and monochromator mode selector help calibrate spectrometer in selected laser mode. Technique accurately determines free spectral range of etalon. By establishing number of fringes between two modes, both of which have been calibrated with molecular line standards, one finds free spectral range with error inversely proportional to spectral interval between calibration points. Procedure establishes free spectral range of etalon without prior knowledge of its length or refractive index.

Jennings, D. E.↗
NASA NTRS1980

Electron-beam welder circle generator

Generator rotates electron beam and performs other convenient functions during welding process. Device eliminates time-consuming techniques relying heavily on operator's skill. Welding speed is varied with frequency selector, and amplitudes of x- and y-axes are varied by adjusting phase shift. Both high and low-range adjustments are available, and each axis can be separately controlled. Crosshair is provided for set-up and beam alinements.

Burley, R. K.↗
NASA NTRS1979

Starlab ultraviolet /UV/ astronomy telescope facility

The paper describes a 1-m high-resolution wide field-of-view telescope (Starlab) to be used on board the Space Shuttle. The purpose of Starlab is to obtain optical astronomical observations in the UV domain of the spectrum. The discussion focuses on scientific programs and technical description of the Starlab. The use of photographic film and rapid reconfiguration is possible because Starlab is flown in the Shuttle-attached mode. The Starlab uses an f/15-modified Ritchey-Chretien telescope, followed by an instrument selector that gives access to the conventional Cassegrain focus or, by inserting a diagonal mirror, to a radial focal plane. Results of five critical subsystem-design studies confirm the feasibility of using state-of-the-art design practices in meeting the Starlab science and engineering requirements.

Richard, H. L.↗
NASA NTRS1980

Intermode calibration of diode-laser spectra using tandem etalons

The paper deals with an approach which can improve the accuracy of etalon calibration of tunable diode-laser (TDL) spectra in the IR and extend absolute calibration among several isolated modes. Two etalons placed in the laser beam produce a combined fringe pattern that, with the aid of a monochromator mode selector, can be used to establish the number of fringes between any two spectral points separated by a large frequency interval. This technique has been applied to several similar cases for calibration of isolated modes or verification of the identity of lines of known frequency.

Jennings, D. E.↗
NASA NTRS1981

Decommutator patchboard verifier

A system for automatically verifying the connections between terminals of a patchboard is described. The system includes a back plane having a plurality of plugs corresponding to the pins of the patchboard. A number of decoders are connected to the plugs of the back plane so that a signal can be sequentially applied to each plug of the back plane under control of a stepping register and a control circuit. A plurality of data selectors are also connected to the plugs of the back plane and under control of a second external register. This control circuit sequentially makes connections between an output circuit and the plugs of the back plane so as to patch the signal applied to a respective plug through a patch connection to the output circuit. The precise locations of the patches on the patchboard can be identified and compared with previously stored information in a memory unit.

Brunson, J. W.↗
NASA NTRS1982

Reconfiguring redundancy management

A redundancy management system is described wherein input signals from a sensor are provided redundantly in parallel so that a primary control signal may be selected. Median value signals for groups of three sensors are detected in median value selectors of selection filter. The detected median value signals are then also compared in a subtractor/comparator to determine whether any of them exceed the others by an amount greater than the signal level for a failed sensor. If so, the exceeding detected medium value signal is sent to a control computer as the primary control signal. If not, the lowest level detected medium value signal is sent as the primary control signal.

Gelderloos, H. J. C.↗
NASA NTRS1983

A compact hydrogen maser with exceptional long-term stability

A passive hydrogen maser employing a smaller microwave cavity than previous masers is described. The volume of the entire resonator package, including a conventional source, hexapole state selector, and four magnetic shields, is estimated at 20 liters. The techniques for constructing the ceramic cavity, coating it with FEP, and attaching the endcaps to achieve a stable container (to allow its use as a single vacuum system) are described in detail. Frequency stability measurements were made of four such masers, against an NBS-4 cesium primary standard, against each other, and against eight commercial cesium clocks; frequency stability level is reported as 1.7 x 10 to the -12th tau exp -1/2 from 1 to 100,000 sec, and no drift above 1 x 10 to the -15th/day was found. Pressure and temperature effects on frequency stability were found at the 1 x 10 to the -14th level. Noise behavior beyond 200,000 sec is characterized as random walk. The potential use of a compact stable maser as a clock is suggested.

Howe, D. A.↗
NASA NTRS1985

Differential Pressure Helps Seal Ball Valve

Leakage suppressed despite O-ring wear. New design eliminates leakage in vacuum selector valve on Space Shuttle waste-control subsystem. Applied to improve sealing in laboratory and industrial vacuum systems and other plumbing involving switching among lines with pressure differentials of order of 1 atmosphere (0.1 MPa).

Mangialardi, J. K.↗
NASA NTRS1985

Acoustic detection of air shower cores

At an altitude of 1890m, a pre-test with an Air shower (AS) core selector and a small acoustic array set up in an anechoic pool with a volume of 20x7x7 cu m was performed, beginning in Aug. 1984. In analyzing the waveforms recorded during the effective working time of 186 hrs, three acoustic signals which cannot be explained as from any source other than AS cores were obtained, and an estimation of related parameters was made.

Gao, X.↗