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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

SmallSat Ka-band Operations User Terminal (SKOUT)

SKOUT is a Ka-band communications system for future NASA mission spacecraft that operates with both NASA and commercial relay satellite constellations in GEO and potentially LEO as well as direct-to-Earth (DTE) networks. This project encompasses the development and demonstration of commercial-off-the-shelf (COTS) 5G, Ka band, phased array technologies compatible with commercial space networks, including actively phases array antennas, software defined modems, power optimization algorithms, and high data rate to ground using the DVB-S2 standard.

space communications↗
NASA NTRS1978

LSA Low-cost Solar Array project

The activities of the Low-Cost Silicon Solar Array Project during the period October through December, 1977 are reported. The LSSA Project is assigned responsibility for advancing silicon solar array technology while encouraging industry to reduce the price of arrays to a level at which photovoltaic electric power systems will be competitive with more conventional power sources early in the next decade. Set forth are the goals and plans with which the Project intends to accomplish this and the progress that was made during the quarter.

Source record↗
NASA NTRS2000

Manipulation of Liquids Using Phased Array Generation of Acoustic Radiation Pressure

A phased array of piezoelectric transducers is used to control and manipulate contained as well as uncontained fluids in space and earth applications. The transducers in the phased array are individually activated while being commonly controlled to produce acoustic radiation pressure and acoustic streaming. The phased array is activated to produce a single pulse, a pulse burst or a continuous pulse to agitate, segregate or manipulate liquids and gases. The phased array generated acoustic radiation pressure is also useful in manipulating a drop, a bubble or other object immersed in a liquid. The transducers can be arranged in any number of layouts including linear single or multi- dimensional, space curved and annular arrays. The individual transducers in the array are activated by a controller, preferably driven by a computer.

Oeftering, Richard C.↗
NASA NTRS1994

Rice cultivation and methane emission: Documentation of distributed geographic data sets

High-resolution global data bases on the geographic and seasonal distribution of rice cultivation and associated methane emission, compiled by Matthews et al., were archived for public use. In addition to the primary data sets identifying location, seasonality, and methane emission from rice cultivation, a series of supporting data sets is included, allowing users not only to replicate the work of Matthews et al. but to investigate alternative cultivation and emission scenarios. The suite of databases provided, at 1 latitude by 1 longitude resolution for the globe, includes (1) locations of rice cultivation, (2) monthly arrays of actively growing rice areas, (3) countries and political subdivisions, and (4) monthly arrays of methane emission from rice cultivation. Ancillary data include (1) a listing, by country, of harvested rice areas and seasonal distribution of crop cycles and (2) country names and codes. Summary tables of zonal/monthly distributions of actively growing rice areas and of methane emissions are presented. Users should consult original publications for complete discussion of the data bases. This short paper is designed only to document formats of the distributed information and briefly describe the contents of the data sets and their initial application to evaluating the role of rice cultivation in the methane budget.

Matthews, Elaine↗
NASA NTRS2004

Microstrip patch antenna panel for large aperture L-band phased array

This paper describes the design and development of a large, lightweight antenna panel for an active phased array operating at L-band. The panel was developed under a JPL program of technology development for space based radar. It utilizes dual-stacked patch elements that are interconnected with corporate feed manifold of striplines. This paper focuses on the electromagnetic design and performance of the radiating elements, with emphasis on scan performance, and also addresses mechanical and thermal aspects of the panel. The element in the array environment has a bandwidth of more than 80MHz centered at 1260MHz and is fed so that it can radiate orthogonal linear polarizations. The envisioned phased array, with a nominal aperture of 50m x 2m, is designed to scan +/-45 degrees in azimuth and +/-20 degrees in elevation. The panel of radiating elements has a mass density of 3.9 kg/m2, which represents approximately 50% of the target 8kg/m2 total panel mass density that includes T/R modules and feed manifolds.

T/R modules↗
NASA NTRS2004

Monte Carlo Techniques for Calculations of Charge Deposition and Displacement Damage from Protons in Visible and Infrared Sensor Arrays

This slide presentation examines motivation for Monte Carlo methods, charge deposition in sensor arrays, displacement damage calculations, and future work. The discussion of charge deposition sensor arrays includes Si active pixel sensor APS arrays and LWIR HgCdTe FPAs. The discussion of displacement damage calculations includes nonionizing energy loss (NIEL), HgCdTe NIEL calculation results including variance, and implications for damage in HgCdTe detector arrays.

Marshall, Paul↗
NASA NTRS1985

Simultaneous Solar Maximum Mission and Very Large Array (VLA) observations of solar active regions

Simultaneous observations of solar active regions with the Solar Maximum Mission (SMM) Satellite and the Very Large Array (VLA) have been obtained and analyzed. Combined results enhance the scientific return for beyond that expeted from using either SMM or VLA alone. A total of two weeks of simultaneous SMM/VLA data were obtained. The multiple wavelength VLA observations were used to determine the temperature and magnetic structure at different heights within coronal loops. These data are compared with simultaneous SMM observations. Several papers on the subject are in progress. They include VLA observations of compact, transient sources in the transition region; simultaneous SMM/VLA observations of the coronal loops in one active region and the evolution of another one; and sampling of the coronal plasma using thermal cyclotron lines (magnetic field - VLA) and soft X ray spectral lines (electron density and electron temperaure-SMM).

Lang, K. R.↗
NASA NTRS2004

T/R module development for large aperture L-band phased array

This paper describes a transmit / receive (T/R) module for a large L-band space based radar active phased array being developed at JPL. Electrical performance and construction techniques are described, with emphasis on the former. The T/R modules have a bandwidth of more than 80 MHz centered at 1260MHz and support dual, switched polarizations. Phase and amplitude are controlled by a 6-bit phase shifter and a 6-bit attenuator, respectively. The transmitter power amplifier generates 2.4 W into a nominal 50 ohm load with 36% overall efficiency. The receiver noise figure is 4.4 dB including all front-end losses. The module weighs 32 g and has a footprint of 8 cm x 4.5 cm. Fourteen of these T/R modules were fabricated at the JPL Pick-and-Place Facility and were tested using a computer-controlled measurement facility developed at JPL. Calibrated performance of this set of T/R modules is presented and shows good agreement with design predictions.

transmit / receive (T/R) module↗
NASA NTRS1974

Space satellite power system

The concept of a satellite solar power station was studied. It is shown that it offers the potential to meet a significant portion of future energy needs, is pollution free, and is sparing of irreplaceable earth resources. Solar energy is converted by photovoltaic solar cell arrays to dc energy which in turn is converted into microwave energy in a large active phased array. The microwave energy is beamed to earth with little attenuation and is converted back to dc energy on the earth. Economic factors are considered.

Glaser, P. E.↗
NASA NTRS1995

Active-Pixel Image Sensor With Analog-To-Digital Converters

Proposed single-chip integrated-circuit image sensor contains 128 x 128 array of active pixel sensors at 50-micrometer pitch. Output terminals of all pixels in each given column connected to analog-to-digital (A/D) converter located at bottom of column. Pixels scanned in semiparallel fashion, one row at time; during time allocated to scanning row, outputs of all active pixel sensors in row fed to respective A/D converters. Design of chip based on complementary metal oxide semiconductor (CMOS) technology, and individual circuit elements fabricated according to 2-micrometer CMOS design rules. Active pixel sensors designed to operate at video rate of 30 frames/second, even at low light levels. A/D scheme based on first-order Sigma-Delta modulation.

Fossum, Eric R.↗
NASA NTRS2005

A membrane array using T/R membranes

We have developed the first membrane-compatible Trasmit/Receive (T/R) module (T/R membrane). Using thse modules we developed a membrane-basede active phased array in L-band. We use phase shifters within each T/R module for electronic beam stering. In this paper we will discuss the T/R membrane design and integration with the membrane.

T/R module↗
NASA NTRS1984

Coupling mechanism of gain-guided integrated semiconductor laser arrays

It is shown that a gain-guided laser array couples via propagating fields rather than the evanescent mode coupling typically responsible for directional coupling in passive (directional couplers) and active (laser array) devices. It is shown that these phase-locked modes exhibit an interference pattern, in the junction plane, which arises from the curvature of the phase fronts of optical fields of the interacting lasers. The experimental results are interpreted with the aid of a simple theoretical model, and the effect of the observed mode pattern on the coupling of gain-guided lasers is discussed.

Kapon, E.↗
NASA NTRS1975

S-band antenna phased array communications system

The development of an S-band antenna phased array for spacecraft to spacecraft communication is discussed. The system requirements, antenna array subsystem design, and hardware implementation are examined. It is stated that the phased array approach offers the greatest simplicity and lowest cost. The objectives of the development contract are defined as: (1) design of a medium gain active phased array S-band communications antenna, (2) development and test of a model of a seven element planar array of radiating elements mounted in the appropriate cavity matrix, and (3) development and test of a breadboard transmit/receive microelectronics module.

Delzer, D. R.↗
NASA NTRS1996

Monolithic Microwave Integrated Circuit (MMIC) Phased Array Demonstrated With ACTS

Monolithic Microwave Integrated Circuit (MMIC) arrays developed by the NASA Lewis Research Center and the Air Force Rome Laboratory were demonstrated in aeronautical terminals and in mobile or fixed Earth terminals linked with NASA's Advanced Communications Technology Satellite (ACTS). Four K/Ka-band experimental arrays were demonstrated between May 1994 and May 1995. Each array had GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification. The 30-GHz transmit array used in uplinks to ACTS was developed by Lewis and Texas Instruments. The three 20-GHz receive arrays used in downlinks from ACTS were developed in cooperation with the Air Force Rome Laboratory, taking advantage of existing Air Force integrated-circuit, active-phased-array development contracts with the Boeing Company and Lockheed Martin Corporation. Four demonstrations, each related to an application of high interest to both commercial and Department of Defense organizations, were conducted. The location, type of link, and the data rate achieved for each of the applications is shown. In one demonstration-- an aeronautical terminal experiment called AERO-X--a duplex voice link between an aeronautical terminal on the Lewis Learjet and ACTS was achieved. Two others demonstrated duplex voice links (and in one case, interactive video links as well) between ACTS and an Army high-mobility, multipurpose wheeled vehicle (HMMWV, or "humvee"). In the fourth demonstration, the array was on a fixed mount and was electronically steered toward ACTS. Lewis served as project manager for all demonstrations and as overall system integrator. Lewis engineers developed the array system including a controller for open-loop tracking of ACTS during flight and HMMWV motion, as well as a laptop data display and recording system used in all demonstrations. The Jet Propulsion Laboratory supported the AERO-X program, providing elements of the ACTS Mobile Terminal. The successful performance of experimental, proof-of-concept MMIC K/Ka-band arrays developed with U.S. industry in field demonstrations with ACTS indicates that high density MMIC integration at 20 and 30 GHz is indeed feasible. The successful development and demonstration of the MMIC array systems was possible only because of significant intergovernmental and Government/industry cooperation and the high level of teamwork within Lewis. The results provide a strong incentive for continuing the focused development of MMIC-array technology for satellite communications applications, with emphasis on packaging and cost issues, and for continuing the planning and conducting of other appropriate demonstrations or experiments of phased-array technology with ACTS. Given the present pressures on reducing funding for research and development in Government and industry, the extent to which this can be continued in a cooperative manner will determine whether MMIC array technology will make the transition from the proof-of-concept level to the operational system level.

Source record↗
NASA NTRS2010

The DESDynI Synthetic Aperture Radar Array-Fed Reflector Antenna

DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a largeaperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit/ receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called 'SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.

Chamberlain, Neil↗
NASA NTRS1989

Space Station Freedom solar array panels plasma interaction test facility

The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements.

Martin, Donald F.↗
NASA NTRS2002

Electrical Performance of the International Space Station U.S. Photovoltaic Array During Bifacial Illumination

With the first United States (U.S.) photovoltaic array (PVA) activated on International Space Station (ISS) in December 2000, on-orbit data can now be compared to analytical predictions. Due to ISS operational constraints, it is not always possible to point the front side of the arrays at the Sun. Thus, in many cases, sunlight directly illuminates the backside of the PVA as well as albedo illumination on either the front or the back. During this time, appreciable power is produced since the solar cells are mounted on a thin, solar transparent substrate. It is important to present accurate predictions for both front and backside power generation for mission planning, certification of flight readiness for a given mission, and on-orbit mission support. To provide a more detailed assessment of the ISS power production capability, the authors developed a PVA electrical performance model applicable to generalized bifacial illumination conditions. On-orbit PVA performance data were also collected and analyzed. This paper describes the ISS PVA performance model, and the methods used to reduce orbital performance data. Analyses were performed using SPACE. a NASA-GRC developed computer code for the ISS program office. Results showed a excellent comparison of on-orbit performance data and analytical results.

Delleur, Ann M.↗