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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Advanced communications, tracking, robotic vision technology for space applications

Recent advancements in the areas of tracking, communications, and robotics vision sensors being pursued within NASA, as applicable to space programs, are presented. Optical and laser-based communications and tracking systems and applications to space programs are discussed. Communication systems for multiple access, broadband, high data rate, and efficient operations are given. Current efforts at 20/30 GHz and millimeter wave bands are summarized. The use of optical data processing in control system applications for rendezvous and docking is presented. Robotics vision, based on television, laser, and microwave sensors for space applications, is discussed. The fusion of these technologies for remote control, station keeping, tracking, inspection, and satellite repair is detailed.

Krishen, Kumar↗
NASA NTRSDate not supplied

System Level TVAC Functional Testing for the Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) Payload Destined for the International Space Station

The Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) Payload will be launched to the International Space Station (ISS) in 2023. ILLUMA-T is an optical communications payload that will make the ISS the first space-based user to communicate with NASA’s Laser Communications Relay Demonstration (LCRD). The system will support all-optical forward links up to 150 Mbps and return links up to 1 Gbps. The payload recently underwent system level Thermal VACuum (TVAC) functional testing at MIT Lincoln Laboratory. We present an overview of the payload’s TVAC functional tests and results.

lasercom↗
NASA NTRS1982

Single-mode fiber systems for deep space communication network

The present investigation is concerned with the development of single-mode optical fiber distribution systems. It is pointed out that single-mode fibers represent potentially a superior medium for the distribution of frequency and timing reference signals and wideband (400 MHz) IF signals. In this connection, single-mode fibers have the potential to improve the capability and precision of NASA's Deep Space Network (DSN). Attention is given to problems related to precise time synchronization throughout the DSN, questions regarding the selection of a transmission medium, and the function of the distribution systems, taking into account specific improvements possible by an employment of single-mode fibers.

Lutes, G.↗
NASA NTRS1996

Electronic-To-Optical-To-Electronic Packet-Data Conversion

Space-time multiplexer (STM) cell-based communication system designed to take advantage of both high throughput attainable in optical transmission links and flexibility and functionality of electronic processing, storage, and switching. Long packets segmented and transmitted optically by wavelength-division multiplexing. Performs optoelectronic and protocol conversion between electronic "store-and-forward" protocols and optical "hot-potato" protocols.

Monacos, Steve↗
NASA NTRS2019

Few-Mode Fiber Coupled Superconducting Nanowire Single-Photon Detectors for Photon Efficient Optical Communications

The NASA Glenn Research Center's development of a high-photon efficiency real-time optical communications ground receiver has added superconducting nanowire single-photon detectors (SNSPDs) coupled with few-mode fibers (FMF). High data rate space-to-ground optical communication links require enhanced ground receiver sensitivity to reduce spacecraft transmitter constraints, and therefore require highly efficient coupling from fiber to detector. In the presence of atmospheric turbulence the received optical wave front can be severely distorted introducing higher-order spatial mode components to the received signal. To reduce mode filtering and mismatch loss and the resulting degradations to detector coupling efficiency, we explore the use of few-mode fiber coupling to commercial single-pixel SNSPDs. Graded index 20-µm few-mode fibers allow the commercial single pixel SNSPD's active area to couple with equal efficiency as single mode fibers. Here we determine detector characteristics such as count rate, detection efficiency, dark counts, and jitter, as well as detection efficiencies for higher-order fiber spatial modes. Additionally, we assess the laboratory performance of the detectors in an optical system which emulates future deep space optical communications links.

Vyhnalek, Brian E.↗
NASA NTRS2017

Communications and Intelligent Systems Division Overview

Provides expertise, and plans, conducts and directs research and engineering development in the competency fields of advanced communications and intelligent systems technologies for applications in current and future aeronautics and space systems.Advances communication systems engineering, development and analysis needed for Glenn Research Center's leadership in communications and intelligent systems technology. Focus areas include advanced high frequency devices, components, and antennas; optical communications, health monitoring and instrumentation; digital signal processing for communications and navigation, and cognitive radios; network architectures, protocols, standards and network-based applications; intelligent controls, dynamics and diagnostics; and smart micro- and nano-sensors and harsh environment electronics. Research and discipline engineering allow for the creation of innovative concepts and designs for aerospace communication systems with reduced size and weight, increased functionality and intelligence. Performs proof-of-concept studies and analyses to assess the impact of the new technologies.

Intelligent Systems↗
NASA NTRS1996

Atmospheric Visibility Monitoring (AVM) Program

The objective of the AVM Program is to obtain atmospheric transmission statistics data to support optical communications. The AVM Program is an autonomouse system that measures ground intensity of stars through different filters. The fully autonomouse systems collect atmospheric visibility data from three sites. A database of visibility data is being created to easily extract atmospheric transmission statistics information. This presentation describes the Program, the sites chosen, and the data obtained.

optical↗
NASA NTRS1985

Wavelength division multiplexing

Wavelength division multiplexing (WDM) represents an approach for expanding the communication capacity and for implementing special data techniques in a fiber optics system. This technology is implemented by adding optical sources of different wavelengths at optical transmitting locations. The present paper is concerned with some of the current efforts in WDM. WDM applications are related to long haul communications, local area data networks, spacecraft and aircraft data systems, fault tolerant computer networks, special sensor devices, high speed data processors, closed circuit and cable television, and submarine cable systems. Attention is given to the current state of wavelength division multiplexing applications, the availability and status of WDM components semiconductor lasers/transmitters, availability and status of fiber optic detectors/receivers, optical fibers/cables/connectors/taps/star couplers, wavelength multiplexers/demultiplexers, and future WDM for local area networks.

Hendricks, H. D.↗
NASA NTRS1995

More About Beam-Steering Subsystem For Laser Communication

Two reports present additional information about developmental beam-steering subsystem of laser-communication system. Aspects of this subsystem described previously in "Beam-Steering Subsystem for Laser Communication" (NPO-19069) and "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193). Reports reiterate basic principles of operation of beam-steering subsystem and of laser-communication system as whole. Also presents some of details of optical and mechanical design of prototype of subsystem, called Optical Communication Demonstrator.

Page, Norman A.↗
NASA NTRS2013

The Architecture of the Laser Communications Relay Demonstration Ground Stations: An Overview

NASA's Laser Communication Relay Demonstration (LCRD) will be NASA's first long-duration demonstration of laser communications (lasercom) in space, providing geosynchronous-satellite-hosted bidirectional relay services between two Earth ground stations. LCRD will leverage and enhance existing ground stations. Ground Station 1 (GS-1) will leverage the Optical Communications Telescope Laboratory (OCTL) built by JPL, while Ground Station 2 (GS-2) will leverage the Lunar Laser Communications Demonstration (LLCD) Ground Terminal (LLGT) built by MIT Lincoln Laboratory. While each ground system has unique telescopes and integrated optics, many of the backend subsystems (e.g., communications, environmental monitoring, control, user simulators) will be common to both terminals. Here we provide an overview of the architecture of the LCRD ground stations, and the planned enhancements to the existing facilities.

deformable mirror↗
NASA NTRS1989

Apollo Lightcraft Project

The ultimate goal for this NASA/USRA-sponsored Apollo Lightcraft Project is to develop a revolutionary manned launch vehicle technology which can potentially reduce payload transport costs by a factor of 1000 below the Space Shuttle Orbiter. The Rensselaer design team proposes to utilize advanced, highly energetic, beamed-energy sources (laser, microwave) and innovative combined-cycle (airbreathing/rocket) engines to accomplish this goal. The research effort focuses on the concept of a 100 MW-class, laser-boosted Lightcraft Technology Demonstrator (LTD) drone. The preliminary conceptual design of this 1.4 meter diameter microspacecraft involved an analytical performance analysis of the transatmospheric engine in its two modes of operation (including an assessment of propellant and tankage requirements), and a detailed design of internal structure and external aeroshell configuration. The central theme of this advanced propulsion research was to pick a known excellent working fluid (i.e., air or LN sub 2), and then to design a combined-cycle engine concept around it. Also, a structural vibration analysis was performed on the annular shroud pulsejet engine. Finally, the sensor satellite mission was examined to identify the requisite subsystem hardware: e.g., electrical power supply, optics and sensors, communications and attitude control systems.

Myrabo, Leik N.↗
NASA NTRS1991

A plan for the development and demonstration of optical communications for deep space

A development history, current status, and prospective development account are given for deep-space optical communications, giving attention to overall systems-related activities and to the generic technology developments required for their implementation. An account is given of the progression envisioned from laboratory subsystems demonstrations to the full-scale flight experiment for the Mars Communications Relay Orbiter missions.

Lesh, James R.↗
NASA NTRS1995

Two Optical-Beam-Forming Concepts For Array Antennas

Two optical-beam-forming concepts selected for development of phased-array antennas. Involve use of novel combinations of optical and electronic techniques to distribute radio-frequency signal to or from antenna elements in array: phase and amplitude of radio-frequency signal traveling to or from each element controlled in such way to cause array as whole to transmit or receive signal in desired spatial pattern, steered, narrowed, broadened, or otherwise varied. Techniques result in compact, lightweight beam-steering antennas. Potential applications include steered-beam or quasi-optical microwave antennas in communication and radar systems, remote control of antennas in general, and photonic communication. With some modifications, transmitting and receiving configurations incorporated into single system.

Wu, Te-Kao↗
NASA NTRS2006

Polarization Loss Compensation in a Laser Transceiver System

JPL is developing a polarization-based sky tracking laser transceiver system in which some mirror coatings produce significant polarization losses that vary with tracking angle. We describe a useful method for dynamically compensating these effects.

optical systems design↗
NASA NTRS2009

Compact Deep-Space Optical Communications Transceiver

Deep space optical communication transceivers must be very efficient receivers and transmitters of optical communication signals. For deep space missions, communication systems require high performance well beyond the scope of mere power efficiency, demanding maximum performance in relation to the precious and limited mass, volume, and power allocated. This paper describes the opto-mechanical design of a compact, efficient, functional brassboard deep space transceiver that is capable of achieving megabyte-per-second rates at Mars ranges. The special features embodied to enhance the system operability and functionality, and to reduce the mass and volume of the system are detailed. System tests and performance characteristics are described in detail. Finally, lessons learned in the implementation of the brassboard design and suggestions for improvements appropriate for a flight prototype are covered.

DSOCT↗
NASA NTRS2015

Lessons Learned from Optical Payload for Lasercomm Science (OPALS) Mission Operations

This paper provides an overview of Optical Payload for Lasercomm Science (OPALS) activities and lessons learned during mission operations. Activities described cover the periods of commissioning, prime, and extended mission operations, during which primary and secondary mission objectives were achieved for demonstrating space-to-ground optical communications. Lessons learned cover Mission Operations System topics in areas of: architecture verification and validation, staffing, mission support area, workstations, workstation tools, interfaces with support services, supporting ground stations, team training, procedures, flight software upgrades, post-processing tools, and public outreach.

Sindiy, Oleg V.↗