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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Design and Performance of a Wideband Radio Telescope

The Goldstone Apple Valley Radio Telescope (GAVRT) is an outreach project, a partnership involving NASA's Jet Propulsion Laboratory (JPL), the Lewis Center for Educational Research (LCER), and the Apple Valley Unified School District near the NASA Goldstone deep space communication complex. This educational program currently uses a 34-meter antenna, DSS12, at Goldstone for classroom radio astronomy observations via the Internet. The current program utilizes DSS12 in two narrow frequency bands around S-band (2.3 GHz) and X-band (8.45 GHz), and is used by a training program involving a large number of secondary school teachers and their classrooms. To expand the program, a joint JPL/LCER project was started in mid-2006 to retrofit an additional existing 34-meter beam-waveguide antenna, DSS28, with wideband feeds and receivers to cover the 0.5-to- 14-GHz frequency bands. The DSS28 antenna has a 34-meter diameter main reflector, a 2.54-meter subreflector, and a set of beam waveguide mirrors surrounded by a 2.43-meter tube. The antenna was designed for high power and a narrow frequency band around 7.2 GHz. The performance at the low end of the frequency band desired for the educational program would be extremely poor if the beam waveguide system was used as part of the feed system. Consequently, the 34-meter antenna was retrofitted with a tertiary offset mirror placed at the vertex of the main reflector. The tertiary mirror can be rotated to use two wideband feeds that cover the 0.5-to-14-GHz band. The earlier designs for both GAVRT and the DSN only used narrow band feeds and consequently, only covered a small part of the S- and X-band frequencies. By using both a wideband feed and wideband amplifiers, the entire band from 0.5 to 14 GHz is covered, expanding significantly the science activities that can be studied using this system.

Weinreb, Sander↗
DOE OSTI2020

Why Wideband Gap Needs Techno-Economics

The wideband gap community when discussing projects antidotally refers to the cost of the technology, frequently noting the higher wideband gap upfront cost in comparison to the incumbent state of art. Other technologies such as photovoltaics have embraced techno-economics analysis (TEA) as a method of analytically articulating the impacts of research advancements on system performance and lifetime costs. Our TEA shows the potential impact of research advancements on Gallium Oxide (Ga2O3) and Silicon Carbide (SiC) wafer manufacturing cost, the impact on the levelized cost of electricity (LCOE) when using a SiC based solar inverter, and lastly how the high cost of devices (SiC in this case) can be offset by other system cuts, such as the footprint and cooling reductions in a 1MW variable frequency motor drive. The specific goal is to show analytically the lifetime cost and performance benefits of adopting wideband gap technology whether it is at the device level or it is cumulative benefit though a simplified balance of system.

14 SOLAR ENERGY↗
NASA NTRSDate not supplied

NASA's Progress Toward Commercial Space Communications — SATCOM Demonstrations and Wideband Multilingual Terminal Development

The National Aeronautics and Space Administration (NASA) Space Communications and Navigation (SCaN) Program is continuing to forge a path toward programmatic and operational transformation enabling commercialization of communications and navigation services to the greatest extent possible for near Earth users. U.S. National Space Policy is driving government agencies to incorporate commercial offerings and services to the maximum extent possible. As such, NASA has no plans to build or deploy additional Tracking and Data Relay Satellites (TDRS), but will seek to fill NASA mission space-relay capability needs using commercial satellite communications (SATCOM) providers and services. The goal is to support an approach that is both flexible to commercial service constructs and provides continuity of support with current assets as long as required. Progress toward commercial services is advancing in two key areas: (1) awards have been made for demonstrations of SATCOM services, and (2) development of wideband and multilingual user terminals has advanced to the flight demonstration phase. The Communications Services Project (CSP) at Glenn Research Center (GRC), has awarded Funded Space Act Agreements (FSAA) to six industry vendors. Inmarsat Government Inc., Kuiper Government Solutions (KGS) LLC, SES Government Solutions, Space Exploration Technologies, Telesat U.S. Services LLC, and Viasat Incorporated will receive a combined $278.5 million to complete technology development and in-space demonstrations over the next several years. The end-to-end service capabilities being targeted are based on existing NASA mission operational needs. Accordingly, each company has proposed a technical approach to lower costs, increase flexibility, and improve performance for a broad range of missions. In the current market, industry vendors operate at a range of different frequencies and use variable, sometimes proprietary, coding and modulations schemes. As NASA strives for a network comprised of services provided by multiple distinct suppliers, interoperability is a fitting solution to unify the network. Wideband and multi-lingual user terminals are being developed to bridge differences in industry services. Building on ground demonstrations completed in 2021, the Johns Hopkins Applied Physics Lab (APL) will be flight testing a multi-lingual wideband terminal (payload) and demonstrating connectivity to both government and commercial relay services. This paper provides a discussion of the progress toward NASA’s commercial space communications goals and consideration of key challenges and next steps.

commercialization↗
NASA NTRS1991

Gaussian beam and physical optics iteration technique for wideband beam waveguide feed design

The Gaussian beam technique has become increasingly popular for wideband beam waveguide (BWG) design. However, it is observed that the Gaussian solution is less accurate for smaller mirrors (approximately less than 30 lambda in diameter). Therefore, a high-performance wideband BWG design cannot be achieved by using the Gaussian beam technique alone. This article demonstrates a new design approach by iterating Gaussian beam and BWG parameters simultaneously at various frequencies to obtain a wideband BWG. The result is further improved by comparing it with physical optics results and repeating the iteration.

Veruttipong, W.↗
NASA NTRS2019

Multiyear sea ice thickness estimation using wideband P/L-band radiometric measurements

A new wideband radiometer covering P/L-band was developed at the Jet Propulsion Laboratory for polar ocean salinity and seasonal sea-ice thickness measurements. The instrument was deployed on the US Coast Guard Cutter Healy for an Arctic Ocean research cruise from September 13, 2018 to October 20, 2018. This work shows the first results relating sea ice thickness obtained from the measurements taken with the wideband P/L-band radiometer during the campaign. Results from the Artic cruise campaign were also used to study wideband spectral properties of salinity. In addition to this paper, Salinity and wide-band calibration challenges are presented in two other companion papers.

Brown, Shannon↗
NASA NTRSDate not supplied

NASA’s Progress Toward Commercial Space Communications—SATCOM Demonstrations and Wideband Multilingual Terminal Development

The National Aeronautics and Space Administration (NASA) Space Communications and Navigation (SCaN) Program is continuing to forge a path toward programmatic and operational transformation enabling commercialization of communications and navigation services to the greatest extent possible for near Earth users. National Space Policy is driving government agencies to incorporate commercial offerings and services to the maximum extent possible. As such, NASA has no plans to build or deploy Tracking and Data Relay Satellites, but will seek to fill NASA mission space-relay capability needs using commercial satellite communications (SATCOM) providers and services. The goal is to support an approach that is both flexible to commercial service constructs and provides continuity of support with current assets as long as required. Progress toward commercialization is advancing in two key areas: (1) awards have been made for demonstrations of SATCOM services, and (2) development of wideband and multilingual user terminals has advanced to the flight demonstration phase. The Communications Services Project (CSP) at Glenn Research Center (GRC), has awarded Funded Space Act Agreements (FSAA) to six industry vendors. Inmarsat Government Inc., Kuiper Government Solutions (KGS) LLC, SES Government Solutions, Space Exploration Technologies, Telesat U.S. Services LLC, and Viasat Incorporated received a combined $278.5 million to complete technology development and in-space demonstrations over the next several years. The end-to-end service capabilities being targeted are based on existing NASA mission operational needs. Accordingly, each company has proposed a technical approach to lower costs, increase flexibility, and improve performance for a broad range of missions. In the current market, industry vendors operate at a range of different frequencies and use variable, sometime proprietary, coding and modulations schemes. As NASA strives for a network comprised of services provided by multiple distinct suppliers, interoperability is a fitting solution to unify the network. Wideband and multi-lingual user terminals are being developed to bridge differences in industry services. Building on ground demonstrations completed in 2021, the Johns Hopkins Applied Physics Lab (APL) will be flight testing a multi-lingual wideband terminal (payload) and demonstrating connectivity to both government and commercial relay services. This paper provides a discussion of the progress toward NASA’s commercial space communications goals and consideration of key challenges and next steps.

space communications↗
NASA NTRS2015

Design of an 8-40 GHz Antenna for the Wideband Instrument for Snow Measurements (WISM)

Measurement of land surface snow remains a significant challenge in the remote sensing arena. Developing the tools needed to remotely measure Snow Water Equivalent (SWE) is an important priority. The Wideband Instrument for Snow Measurements (WISM) is being developed to address this need. WISM is an airborne instrument comprised of a dual-frequency (X- and Ku-bands) Synthetic Aperture Radar (SAR) and dual-frequency (K- and Ka-bands) radiometer. A unique feature of this instrument is that all measurement bands share a common antenna aperture consisting of an array feed reflector that covers the entire bandwidth. This paper covers the design and fabrication of the wideband array feed which is based on tightly coupled dipole arrays. Implementation using a relatively new multi-layer microfabrication process results in a small, 6x6 element, dual-linear polarized array with beamformer that operates from 8 to 40 gigahertz.

8-40 GHz↗
DOE OSTI2022

Ultra-Wideband Microwave Imaging System for Root Phenotyping

The roots are a vital organ for plant growth and health. The opaque surrounding environment of the roots and the complicated growth process means that in situ and non-destructive root phenotyping face great challenges, which thus spur great research interests. The existing methods for root phenotyping are either unable to provide high-precision and high accuracy in situ detection, or they change the surrounding root environment and are destructive to root growth and health. Thus,we propose and develop an ultra-wideband microwave scanning method that uses time reversal to achieve in situ root phenotyping nondestructively. To verify the method’s feasibility, we studied an electromagnetic numerical model that simulates the transmission signal of two ultra-wideband microwave antennas. The simulated signal of roots with different shapes shows the proposed system’s capability to measure the root size in the soil. Experimental validations were conducted considering three sets of measurements with different sizes, numbers and locations, and the experimental results indicate that the developed imaging system was able to differentiate root sizes and numbers with high contrast. The reconstruction from both simulations and experimental measurements provided accurate size estimation of the carrots in the soil, which indicates the system’s potential for root imaging.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2015

Conformal and Spectrally Agile Ultra Wideband Phased Array Antenna for Communication and Sensing

There is a continuing need for reducing size and weight of satellite systems, and is also strong interest to increase the functional role of small- and nano-satellites (for instance SmallSats and CubeSats). To this end, a family of arrays is presented, demonstrating ultra-wideband operation across the numerous satellite communications and sensing frequencies up to the Ku-, Ka-, and Millimeter-Wave bands. An example design is demonstrated to operate from 3.5-18.5 GHz with VSWR2 at broadside, and validated through fabrication of an 8 x 8 prototype. This design is optimized for low cost, using Printed Circuit Board (PCB) fabrication. With the same fabrication technology, scaling is shown to be feasible up to a 9-49 GHz band. Further designs are discussed, which extend this wideband operation beyond the Ka-band, for instance from 20-80 GHz. Finally we will discuss recent efforts in the direct integration of such arrays with digital beamforming back-ends. It will be shown that using a novel on-site coding architecture, orders of magnitude reduction in hardware size, power, and cost is accomplished in this transceiver.

Ultra Wideband antenna↗
NASA NTRS2016

Wideband Instrument for Snow Measurements (WISM)

This presentation discusses current efforts to develop a Wideband Instrument for Snow Measurements (WISM). The objective of the effort are as follows: to advance the utility of a wideband active and passive instrument (8-40 gigahertz) to support the snow science community; improve snow measurements through advanced calibration and expanded frequency of active and passive sensors; demonstrate science utility through airborne retrievals of snow water equivalent (SWE); and advance the technology readiness of broadband current sheet array (CSA) antenna technology for spaceflight applications.

Radiometer↗
NASA NTRSDate not supplied

Development and Demonstration of a Wideband RF User Terminal for Roaming between Ka-band Relay Satellite Networks

The National Aeronautics and Space Administration (NASA) has provided low-latency communication relay services to science and exploration spacecraft for nearly four decades with the Tracking and Data Relay Satellite System (TDRSS). Through NASA’s Communications Services Project (CSP), the agency is pursuing a transition away from dedicated government-owned communication relay satellites and infrastructure in favour of commercially provided satellite communication (SATCOM) services. Many of these SATCOM services are offered in the K/Ka-band covering spectrum allocated to commercial, military, and civilian space operations. While these services were intended to provide broadband connectivity for terrestrial, maritime, and aviation customers, many can be tailored to support orbiting spacecraft. By introducing commercial SATCOM providers, NASA intends to create an interoperable network of networks which will enable missions to roam between multiple service providers. A key enabling technology needed for this vision is a multi-frequency (wideband), multi-waveform user terminal which can seamlessly roam between multiple providers. This paper discusses the development and ground demonstration of a new wideband RF user terminal prototype designed to roam across multiple networks over the Ka-band, allowing ubiquitous service, resiliency, and flexibility for the user.

satellite communication↗
DOE OSTI2024

Wideband Impedance Passivation of MMCs for Suppressing Harmonic Oscillations

Harmonic instability and associated oscillation events have become one of the main concerns in MMC-based HVdc systems. These oscillations can appear in the range from a few hundred hertz to several kilohertz, and the root cause is identified as delay-induced negative damping of MMC impedance appearing at the system resonance frequency. Here, this paper introduces a wideband impedance reshaping method through MMC control to eliminate such negative damping for both grid-following (GFL) and grid-forming (GFM) MMCs, which makes the MMC impedance completely passive from the second harmonic frequency upward, thus preventing all harmonic oscillations. First, simplified impedance models of MMCs are derived for the harmonic stability analysis and the impedance reshaping control design. Next, a passivity-based impedance reshaping method is presented, as well as practical considerations for its implementation. In addition, to maintain the MMC's disturbance ride-through capability, an adaptive activation scheme is developed, which enables the wideband impedance reshaping control only in the presence of harmonic oscillation events. The effectiveness of the proposed method is validated by frequency domain analysis and by electromagnetic transient (EMT) simulations of two typical MMC-based power systems.

17 WIND ENERGY↗
NASA NTRS1967

Wideband, high efficiency optical modulator requires less than 10 watts drive power

Wideband optical modulation system operates with less than 10-watts drive power. It consists of an optical modulator and transistorized driver that combines small cross-section potassium dideuterium phosphate crystals with laser beam-condensing optics. Optical modulation systems may serve importantly in future space wideband communication systems.

Becknell, W. E.↗
NASA NTRS1972

A wideband Gaussian noise generator utilizing simultaneously generated pn-sequences.

A digital system has been constructed for the generation of wideband Gaussian noise with a spectrum which is flat to within plus or minus 0.5 dB from 0 to 10 MHz. These characteristics are substantially better than those of commercially available analog noise generators, and are required in testing and simulation of wideband communications systems. The noise is generated by the analog summation of thirty essentially independent binary waveforms, clocked at 35 MHz, and low-pass filtered to 10 MHz.

Hurd, W. J.↗
NASA NTRS1972

The ERTS wideband image communication system.

The ERTS payload includes a three camera return beam vidicon (RBV) television system and a four channel multispectral scanner system (MSS). The communications system described includes spacecraft wideband equipment plus unique payload processing equipment located at three NASA tracking stations. The RBV information, transmitted as analog FM with a baseband response of dc to 3.2 MHz, is telemetered, processed and recorded on a wideband video recorder. The MSS data, consisting of 24 analog sensor outputs, is digitized and encoded as 15 megabit per second PCM. The MSS data is then transmitted as analog FM, demultiplexed, and recorded on a 25 channel recorder. It is shown that bit error rate is an excellent indicator of MSS link performance while signal-to-noise ratio and distortion vs frequency adequately define RBV link performance.

Pandelides, J.↗
NASA NTRS1974

Coding/modulation trade-offs for Shuttle wideband data links

This paper describes various modulation and coding schemes which are potentially applicable to the Shuttle wideband data relay communications link. This link will be capable of accommodating up to 50 Mbps of scientific data and will be subject to a power constraint which forces the use of channel coding. Although convolutionally encoded coherent binary PSK is the tentative signal design choice for the wideband data relay link, FM techniques are of interest because of the associated hardware simplicity and because an FM system is already planned to be available for transmission of television via relay satellite to the ground. Binary and M-ary FSK are considered as candidate modulation techniques, and both coherent and noncoherent ground station detection schemes are examined. The potential use of convolutional coding is considered in conjunction with each of the candidate modulation techniques.

Batson, B. H.↗
NASA NTRS1976

Test of the principle of operation of a wideband magnetic direction finder for lightning return strokes

The principle of operation of a wideband crossed-loop magnetic-field direction finder is studied by comparing the bearing determined from the NS and EW magnetic fields at various times up to 155 microsec after return stroke initiation with the TV-determined lightning channel base direction. For 40 lightning strokes in the 3 to 12 km range, the difference between the bearings found from magnetic fields sampled at times between 1 and 10 microsec and the TV channel-base data has a standard deviation of 3-4 deg. Included in this standard deviation is a 2-3 deg measurement error. For fields sampled at progressively later times, both the mean and the standard deviation of the difference between the direction-finder bearing and the TV bearing increase. Near 150 microsec, means are about 35 deg and standard deviations about 60 deg. The physical reasons for the late-time inaccuracies in the wideband direction finder and the occurrence of these effects in narrow-band VLF direction finders are considered.

Herrman, B. D.↗
NASA NTRS1978

Zodiacal light dynamics experiment: A wideband imaging Fabry-Perot interferometer

The Solar Probe will provide an ideal platform from which to study dynamics of dust particles near the sun by measuring the detailed character of the Fraunhofer structure of the zodiacal light. The suggested instrument is a wideband imaging Fabry-Perot interferometer with state of the art technology in both the optics and the detector. The instrument would function as a high-resolution imaging device providing wavelength resolution of 0.03 A over about a 20 A range. The wideband imaging capability would provide sky maps of the zodiacal light on a despun spacecraft without mechanical scanning. The Solar Probe mission would allow the velocity distribution of the dust to be mapped along most of the trajectory of the spacecraft.

Torr, D. G.↗