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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

The University of Hawaii Institute for Astronomy CCD camera control system

The University of Hawaii Institute for Astronomy CCD Camera Control System consists of a NeXT workstation, a graphical user interface, and a fiber optics communications interface which is connected to a San Diego State University CCD controller. The UH system employs the NeXT-resident Motorola DSP 56001 as a real time hardware controller. The DSP 56001 is interfaced to the Mach-based UNIX of the NeXT workstation by DMA and multithreading. Since the SDSU controller also uses the DPS 56001, the NeXT is used as a development platform for the embedded control software. The fiber optic interface links the two DSP 56001's through their Synchronous Serial Interfaces. The user interface is based on the NeXTStep windowing system. It is easy to use and features real-time display of image data and control over all camera functions. Both Loral and Tektronix 2048 x 2048 CCD's have been driven at full readout speeds, and the system is intended to be capable of simultaneous readout of four such CCD's. The total hardware package is compact enough to be quite portable and has been used on five different telescopes on Mauna Kea. The complete CCD control system can be assembled for a very low cost. The hardware and software of the control system has proven to be quite reliable, well adapted to the needs of astronomers, and extensible to increasingly complicated control requirements.

Jim, K. T. C.↗
NASA NTRS1993

Study of LEO-SAT microwave link for broad-band mobile satellite communication system

In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

Fujise, Masayuki↗
NASA NTRS1992

Electronic Subsystems For Laser Communication System

Electronic subsystems of free-space laser communication system carry digital signals at 650 Mb/s over long distances. Applicable to general optical communications involving transfer of great quantities of data, and transmission and reception of video images of high definition.

Long, Catherine↗
NASA NTRS2012

Evaluation of Deep-Space Laser Communication under Different Mission Scenarios

A number of space agencies, including NASA, are considering free-space laser communications as a means for returning higher data-rates from future space missions. In this paper, potential deep-space missions are evaluated to show that with optical communication a 10x increase relative to state-of-the art telecommunication systems could be achieved. The maximum deep-space distance where ground transmitted laser beacons could assist acquisition and tracking; and operating points where optical communication performance degrades faster than the inverse square distance are also discussed.

mission scenarios↗
DOE OSTI2025

Long-range optical coupling with epsilon-near-zero materials

Long-range resonant quantum tunneling of electrons happens across potential barriers when the wavefunction interferes constructively outside the barrier. Here we demonstrate an analogy in optical systems based on epsilon-near-zero materials, achieving phase-modulated, long-range optical interactions between transparent semiconducting oxide layers beyond the evanescent photonic coupling. Distinct from weak thin-film interference, intense electromagnetic fields confined within the epsilon-near-zero thin films show anti-correlated intensity oscillations as a function of interlayer separation up to hundreds of microns. The oscillatory, anti-correlated electromagnetic field intensities were probed by second harmonic generation from wedged indium tin oxide multilayers. Such a system that hosts subwavelength mode footprint and simultaneously long-range radiative coupling offers prospects for long-distance optical communication, large-scale photonic circuits, and hybrid quantum photonic systems.

Wang, Danqing [Fudan University, Shanghai (China);↗
NASA NTRS1995

Laser Communication Demonstration System (LCDS) and future mobile satellite services

The Laser Communications Demonstration System (LCDS) is a proposed in-orbit demonstration of high data rate laser communications technology conceived jointly by NASA and U.S. industry. The program objectives are to stimulate industry development and to demonstrate the readiness of high data rate optical communications in Earth orbit. For future global satellite communication systems using intersatellite links, laser communications technology can offer reduced mass and power requirements and higher channel bandwidths without regulatory constraints. As currently envisioned, LCDS will consist of one or two orbiting laser communications terminals capable of demonstrating high data rate (greater than 750Mbps) transmission in a dynamic space environment. Two study teams led by Motorola and Ball Aerospace are currently in the process of conducting a Phase A/B mission definition study of LCDS under contracts with JPL/NASA. The studies consist of future application survey, concept and requirements definition, and a point design of the laser communications flight demonstration. It is planned that a single demonstration system will be developed based on the study results. The Phase A/B study is expected to be completed by the coming June, and the current results of the study are presented in this paper.

Chien-Chung Chen↗
NASA NTRS1995

Laser Communication Demonstration System (LSCS) and Future Mobile Satellite Services

The Laser Communications Demonstration System (LCDS) is a proposed in-orbit demonstration of high data rate laser communications technology conceived jointly by NASA and U.S. industry. The program objectives are to stimulate industry development and to demonstrate the readiness of high data rate optical communications in Earth Orbit. For future global satellite communication systems using intersatellite links (ISLs), laser communications technology can offer reduced mass , reduced power requirements, and increased channel bandwidths without regulatory restraint. This paper provides comparisons with radio systems and status of the program.

laser communications intersatellite links↗
NASA NTRS1996

Optical Communications for Extreme Deep Space Missions

A recent study of deep space telecommunications systems was performed in support of NASA's Mission to the Solar System planing activity. The results show that high bandwidth communications (greater than 1Mbps) are feasible at high-value planetary targets provided there are investments in the ground and spacecraft communication infrastructure.

Optical Communications laser communications deep s↗
DOE OSTI2021

(Paper) TRIPWIRE: Multi-modal Distributed Sensing For Repository Verification

Underground geological repositories for storing used nuclear fuel are being planned and developed around the world. Research is being performed to understand technical aspects of sealing entombed materials and underground repositories to ensure the radiological and nuclear materials remain contained. To support safeguards verification for these facilities research at Idaho National Laboratory (INL) is underway to develop and demonstrate a multi-modal sensor system, TRIPWIRE, for containment verification in inaccessible radiological and nuclear waste repositories. The TRIPWIRE system will continuously monitor ionizing radiation and electromagnetic fields in the vicinity of emplaced nuclear materials buried in a repository, reporting on disturbances with a real-time alarm control station. The system will use long-length scintillating fiber bundles (SFBs) to perform area radiation monitoring; these will be coupled to kilometer-scale multimodal optical communication fibers – all light sensors and electronic components used with this system will be located above ground. Electromagnetic fields, and changes in local dielectric conditions caused by intrusion and soil movement, will be monitored using commercial grade, ported "leaky" coaxial cables (PCCs), with control electronics also located above ground. Tamper-indicating self-diagnostic assessments will be done using optical and electronic time domain reflectometry in the SFBs and PCCs, respectively. The result will be a long, kilometer-scale multi-modal SFB-PCC system. Simulation and modeling are being used to inform the work and a demonstration of the system's utility is planned at a nuclear storage facility in the future.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗
NASA NTRS1991

Optoelectronics research for communication programs at the Goddard Space Flight Center

Current optoelectronics research and development of high-power, high-bandwidth laser transmitters, high-bandwidth, high-sensitivity optical receivers, pointing, acquisition and tracking components, and experimental and theoretical system modeling at the NASA Goddard Space Flight Center is reviewed. Program hardware and space flight milestones are presented. It is believed that these experiments will pave the way for intersatellite optical communications links for both the NASA Advanced Tracking and Data Relay Satellite System and commercial users in the 21st century.

Krainak, Michael A.↗
NASA NTRS1991

Reduced electrical bandwidth receivers for direct detection 4-ary PPM optical communication intersatellite links

This interim progress report consists of copies of three reports written for NASA's Flight System Development and Demonstration (FSDD) project on optical intersatellite links. The first report, 'Test results of the PlessCor avalanche photodiode (APD) preamplifier for use in the 50 Mbps quaternary pulse position modulator (QPPM) receiver,' was prepared for NASA Goddard Space Flight Center. The second, 'Performance of Q-ary PPM receiver under additive white Gaussian noise,' was prepared at the request of NASA Lewis Research Center for testing the electronic systems for the FSDD project. The third, 'Use of a Bessel lowpass filter as an approximate raised cosine filter,' was written for raised cosine filter implementation in the FSDD QPPM receiver.

Davidson, Frederic M.↗
NASA NTRS1985

Semiconductor Laser Phased Array

Oscillations synchronized and modulated individually for beam steering. Phased array of GaAs infrared lasers put out powerful electronically-steerable coherent beam. Fabricated as integrated circuit on GaAs chip, new device particularly suited to optical communications, optical data processing and optical detection and ranging systems.

Katz, J.↗
NASA NTRSDate not supplied

Coherent Architectures for Free-Space Optical Communications

Custom coherent architectures can provide many advantages for FSO communications systems through co-development of integrated photonics, ASIC-or FPGA-based DSP algorithms, and system design to mitigate atmospheric turbulence and reduce pointing requirements.

David J Geisler↗
DOE OSTI2022

Progress of Tripwire: Multi-Modal Distributed Sensing for Repository Verification

This project is developing and demonstrating a multi-modal sensor system, TRIPWIRE, for containment verification in inaccessible radiological and nuclear waste repositories. The TRIPWIRE system will continuously monitor ionizing radiation and electromagnetic fields in the vicinity of emplaced nuclear materials buried in a repository, reporting on disturbances with a real-time alarm control station. The system will use long-length scintillating fiber bundles (SFBs) to perform area radiation monitoring; these will be coupled to kilometer-scale multimodal optical communication fibers – all light sensors and electronic components used with this system will be located above ground. Electromagnetic fields, and changes in local dielectric conditions caused by intrusion and soil movement, will be monitored using commercial grade, ported "leaky" coaxial cables (PCCs), with control electronics also located above ground. This paper documents the results of the simulations and modeling efforts that have helped identify the optimal placement of the SFBs. Additionally, the paper includes the current progress on the multi-modal SFB-PCC system, including the fabrication of long-length (>3-m) fibers and their coupling to optical fibers.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗
DOE OSTI2022

Progress of Tripwire: Multi-modal Distributed Sensing for Repository Verification

This project is developing and demonstrating a multi-modal sensor system, TRIPWIRE, for containment verification in inaccessible radiological and nuclear waste repositories. The TRIPWIRE system will continuously monitor ionizing radiation and electromagnetic fields in the vicinity of emplaced nuclear materials buried in a repository, reporting on disturbances with a real-time alarm control station. The system will use long-length scintillating fiber bundles (SFBs) to perform area radiation monitoring; these will be coupled to kilometer-scale multimodal optical communication fibers – all light sensors and electronic components used with this system will be located above ground. Electromagnetic fields, and changes in local dielectric conditions caused by intrusion and soil movement, will be monitored using commercial grade, ported "leaky" coaxial cables (PCCs), with control electronics also located above ground. This paper documents the results of the simulations and modeling efforts that have helped identify the optimal placement of the SFBs. Additionally, the paper includes the current progress on the multi-modal SFB-PCC system, including the fabrication of long-length (>3-m) fibers and their coupling to optical fibers.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗
NASA NTRS1986

Optical technologies for communication satellite applications; Proceedings of the Meeting, Los Angeles, CA, Jan. 21, 22, 1986

The present conference considers topics encompassing the fields of satellite communications technology, optical subsystems, transmitters and receivers, subsystems for pointing and tracking, onboard processing- and component-related technologies, fiber-optic distribution networks, and reliability-related considerations. Attention is given to lightwave technology in microwave systems, the status of CO2 laser technology and homodyne receiver concepts for communication satellite optical links, laser Doppler measurement techniques for spacecraft, fiber-optic gyros for space applications, integrated acoustooptic device modules for communication, signal processing and computing, radiation-hardened optoelectronic components, and radiation effects on fiber-optics.

Bhasin, Kul↗