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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

DSN Microwave Antenna Holography

The DSN microwave antenna holography project will obtain three-dimensional pictures of the large DSN antenna surfaces. These pictures must be of suffi icient resolution to allow adjustment of the reflector panels to an rms surface of 0.5 mm (0.25 mm, goal). The major parameters and equations needed to define a holographic measurement system are outlined and then the proof of concept demonstration measurement that was made at DSS-43 (Australia) that resulted in contour maps with spatial resolution of 7 m in the aperture plane and resolution orthogonal to the aperture plane of 0.7 mm was discussed.

Rochblatt, D. J.↗
NASA NTRS1985

Space shuttle program solid rocket booster decelerator subsystem

The recovery of the Solid Rocket Boosters presented a major challenge. The SRB represents the largest payload ever recovered and presents the added complication that it is continually emitting hot gases and burning particles of insulation and other debris. Some items, such as portions of the nozzle, are large enough to burn through the nylon parachute material. The SRB Decelerator Subsystem program was highly successful in that no SRB has been lost as a result of inadequate performance of the DSS.

Barnard, J. W.↗
NASA NTRS1986

A conceptual 34-meter antenna feed configuration for joint DSN/SETI use from 1 to 10 GHz

The very satisfactory performance of a conceptual 34-m DSS-12 type HA-Dec antenna feed sysem over the frequency range of 1 to 10 GHz is demonstrated. A seven-feedhorn baseline design is developed which will allow Search for Extra-Terrestrial Intelligence (SETI) investigations using each horn over a 1.4:1 frequency range. A gain/system noise temperature (G/T) figure of merit is calculated for the frequency range of each horn; it is found that system performance down to 20 deg elevation is possible with a G/T degradation of less than 3 dB at every frequency. The design presented here will allow shared but independent antenna use by the Deep Space Network (DSN) and SETI with a minimum of operational impacts to DSN functions and no intrusions into the DSN microwave equipment configuration.

Slobin, S. D.↗
NASA NTRS1986

Unattended deep space station tracking station development: Monitor and control technology

The major developments leading to successful demonstration of fully unattended operation of a Deep Space Network (DSN) station (DSS 13) are reviewed. Unattended operation was demonstrated by reliably tracking, commanding, and delivering telemetry from the Pioneer 8 spacecraft. Transfer of automated monitor and control technology to DSN implementation is summarized, along with related accomplishments.

Foster, C.↗
NASA NTRS1986

DSN microwave antenna holography. Part 2: Data processing and display of high-resolution effective maps

The results of a recently completed computer graphic package for the process and display of holographically recorded data into effective aperture maps are presented. The term effective maps (labelled provisional on the holograms) signifies that the maps include contributions of surface mechanical errors as well as other electromagnetic factors (phase error due to feed/subreflector misalignment, linear phase error contribution due to pointing errors, subreflector flange diffraction effects, and strut diffraction shadows). While these maps do not show the true mechanical surface errors, they nevertheless show the equivalent errors, which are effective in determining overall antenna performance. Final steps to remove electromagnetic pointing and misalignment factors are now in progress. The processing and display of high-resolution effective maps of a 64m antenna (DSS 63) are presented.

Rochblatt, D. J.↗
NASA NTRS1986

Rivited panel surface measurement using photogrammetry

Two riveted antenna panels on rings number 3 and 9 were removed from the 34m antenna at DSS-15, fixed in the leveled position and the surface was photographed indoors. The results from this pilot photogrammetric demonstration and diagnostics of panel surface contours, are presented. The photogrammetric network for each panel incorporated eight photographs, two from each of four camera stations and observed over 200 targets. The accuracy (1 sigma) of the XYZ coordinates for the error ellipsoids was + or - 0.013 mm (0.0005 inch). This level of precision relative to the object size corresponds roughly to 1 part in 250,000 which is superior to conventional dial sweep-arm template techniques by at least a factor of 4.

Merrick, W. D.↗
NASA NTRS1987

Proposed upgrade of the Deep Space Network research and development station

Continued exploration of the solar system will require continued evolution of capabilities to support deep space communication and navigation. That evolution will rely, as it has in the past, on the development, demonstration, and field testing of communication and navigation technologies. The existing Deep Space Network (DSN) research and development station, DSS 13, at the Venus site, Goldstone, California was instrumental in those prior developments. However, the present antenna is no longer able to provide the necessary support for technology. The 26 meter antenna has good performance at S-band, fair performance at X-band, but is unusable at the anticipated Ka-band. It is not suitable for conversion to beam waveguides, and is not usable as a test bed for demonstrating high efficiency because of structural pliancy. Additionally, its size and age are increasingly a liability in demonstrations. A 34 meter beam waveguide version of the existing DSN high efficiency (HEF) antennas was proposed for FY-88 Construction of Facilities budget. The antenna is to be built at the Venus site, adjacent to the old antenna, and serve as the DSN research and development antenna through the end of the century.

Smith, Joel G.↗
NASA NTRS1987

DSN advanced receiver: Breadboard description and test results

A breadboard Advanced Receiver for use in the Deep Space Network was designed, built, and tested in the laboratory. Field testing was also performed during Voyager Uranus encounter at DSS-13. The development of the breadboard is intended to lead towards implementation of the new receiver throughout the network. The receiver is described on a functional level and then in terms of more specific hardware and software architecture. The results of performance tests in the laboratory and in the field are given. Finally, there is a discussion of suggested improvements for the next phase of development.

Brown, D. H.↗
NASA NTRS1987

Dual-polarization 8.45 GHz traveling-wave maser

An 8.5 GHz dual-channel, dual-polarization traveling-wave maser (TWM) amplifier was installed in the XKR solar system radar cone at DSS 14. The TWM is based on the Blk IIA 8.45 GHz maser structure, with two of the four maser stages being used for each channel, and each maser half then followed by a high-performance GaAs FET amplifier to achieve the desired net gain. A shortened low-noise input waveguide and an orthogonal-mode junction which is cooled to 4.5 K feeds each amplifier chain. The rotation of an external polarizer permits the polarization of each channel to be defined as either linear or circular. A circular waveguide switch was also developed to provide for noise calibration and to protect the maser from incident transmitter power.

Quinn, R. B.↗
NASA NTRS1986

A search for narrow band signals with Serendip II - A progress report

Commensal programs for SETI, carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. An automated commensal system, Serendip II, searches for 0.49-Hz signals in sequential 64,700 Hz bands of the IF of a radio telescope being used for an astronomical observation. Upon detection of a signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85-ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64-m telescope.

Werthimer, D.↗
NASA NTRS1987

Auxiliary propulsion system flight package

Hughes Aircraft Company developed qualified and integrated flight, a flight test Ion Auxiliary Propulsion System (IAPS), on an Air Force technology satellite. The IAPS Flight Package consists of two identical Thruster Subsystems and a Diagnostic Subsystem. Each thruster subsystem (TSS) is comprised of an 8-cm ion Thruster-Gimbal-Beam Shield Unit (TGBSU); Power Electronics Unit; Digital Controller and Interface Unit (DCIU); and Propellant Tank, Valve and Feed Unit (PTVFU) plus the requisite cables. The Diagnostic Subsystem (DSS) includes four types of sensors for measuring the effect of the ion thrusters on the spacecraft and the surrounding plasma. Flight qualifications of IAPS, prior to installation on the spacecraft, consisted of performance, vibration and thermal-vacuum testing at the unit level, and thermal-vacuum testing at the subsystem level. Mutual compatibility between IAPS and the host spacecraft was demonstrated during a series of performance and environmental tests after the IAPS Flight Package was installed on the spacecraft. After a spacecraft acoustic test, performance of the ion thrusters was reverified by removing the TGBSUs for a thorough performance test at Hughes Research Laboratories (HRL). The TGBSUs were then reinstalled on the spacecraft. The IAPS Flight Package is ready for flight testing when Shuttle flights are resumed.

Collett, C. R.↗
NASA NTRS1987

Non-linearity in measurement systems: Evaluation method and application to microwave radiometers

A simple method for determination and correction of nonlinaearity in measurement systems is presented. The technique is applicable to a wide range of measuring systems. The basic concept, an analysis, and a sample application are given. Nonlinearity of the Goldstone DSS 13 low noise HEMT 2.3 GHz (S-band) radiometer system results in noise temperature measurement errors. These errors are successfully correct with this method.

Stelzried, C. T.↗
NASA NTRS1988

An optimal structure for a 34-meter millimeter-wave center-fed BWG antenna: The Cross-Box concept

An approach to the design of the planned NASA/JPL 34 m elevation-over-azimuth (Az-El) antenna structure at the Venus site (DSS-13) is presented. The antenna structural configuration accommodates a large (2.44 m) beam waveguide (BWG) tube centrally routed through the reflector-alidade structure, an elevation wheel design, and an optimal structural geometry. The design encompasses a cross-box elevation wheel-reflector base substructure that preserves homology while satisfying many constraints, such as structure weight, surface tolerance, stresses, natural frequency, and various functional constraints. The functional requirements are set to ensure that microwave performance at millimeter wavelengths is adequate. The cross-box configuration was modeled, optimized, and found to satisfy all DSN HEF baseline antenna specifications. In addition, the structure design was conceptualized and analyzed with an emphasis on preserving the structure envelope and keeping modifications relative to the HEF antennas to a minimum, thus enabling the transferability of the BWG technology for future retrofitting. Good performance results were obtained.

Chuang, K. L.↗
NASA NTRS1988

SETI data controllers

Three data controllers developed for the SETI project are described. Two are used primarily for recording and playback of SETI data from the Radio Science Surveillance System (RSSS). The third is used as a SETI station controller for DSS 13.

Gosline, R. M.↗
NASA NTRS1988

X-band noise temperature near the Sun at a 34-meter high efficiency antenna

The X-band system noise temperature near the Sun was measured at the DSS 15, a 34 meter high efficiency (HEF) antenna, in November 1987. Data was taken at angles off the center of the Sun from 0 to 4 degrees. At angles greater than 0.5 degree, the measured results agree with Voyager tracking data taken at solar conjunction in late December 1987. Within the solar disk, at angles lower than 0.27 degree, the temperature measured was lower than the prediction of a model by 30 percent, after adjusting for known receiver nonlinearities. The discrepancy in this extreme case is probably caused by unknown nonlinearities in the receiver, uncertainties in the model, or both. The measurement is nevertheless credible for practically all Sun-Earth-probe angles of interest to deep space missions.

Rebold, T. A.↗
NASA NTRS1988

Spain 31-GHz observations of sky brightness temperatures

A water vapor radiometer was deployed at DSS 63 for 3 months of sky brightness temperature measurements at 31 GHz. An exceedance plot was derived from this data showing the fraction of time that 31 GHz 30 degree elevation angle brightness temperature exceeds specified values. The 5 percent exceedance statistics occurs at 75 K, compared with 70 K in Australia.

Gary, B. L.↗
NASA NTRS1988

Australia 31-GHz brightness temperature exceedance statistics

Water vapor radiometer measurements were made at DSS 43 during an 18 month period. Brightness temperatures at 31 GHz were subjected to a statistical analysis which included correction for the effects of occasional water on the radiometer radome. An exceedance plot was constructed, and the 1 percent exceedance statistics occurs at 120 K. The 5 percent exceedance statistics occurs at 70 K, compared with 75 K in Spain. These values are valid for all of the three month groupings that were studied.

Gary, B. L.↗