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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Space VLBI telecommunication characteristics, protection criteria, and frequency sharing

A brief description of the technical characteristics of space VLBI is made, emphasizing the VLBI cross-correlation process. The signal-to-noise ratio of the cross-correlation process should be maintained as large as possible for the duration of the observation. Protection of this process from unwanted interference is a primary objective. The telecommunication radio links required in a space VLBI system are identified and characterized. Maximum bandwidths are suggested, as well as the minimum carrier frequencies required for the telemetering and the phase-transfer radio links. Planned space VLBI system models-Radioastron (Russia), VLBI Space Observatory Project (VSOP) (Japan), and the DSN orbiting VLBI subnet. (United States)--are taken as a baseline to determine the interference criteria. It is concluded that existing interference criteria for near-Earth research satellites are suitable for the protection of the space VLBI systems planned.

Gutierrez-Luaces, B. O.↗
NASA NTRS1995

The Telecommunications and Data Acquisition Report

This quarterly publiction provides archival reports on developments in programs managed by JPL Telecommunications and Mission Operations Directorate (TMOD), which now includes the former communications and Data Acquisition (TDA) Office. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The Orbital Debris Radar Program, funded by the Office of Space Systems Development, makes use of the planetary radar capability when the antennas are configured at science instruments making direct observations of planets, their satellites, and asteroids of our solar system.

Yuen, Joseph H.↗
NASA NTRS1995

The Telecommunications and Data Acquisition Progress Report 42-123

The progress of research programs monitored by the Jet Propulsion Laboratory's Telecommunications and Mission Operations Directorate (TMOD) are presented in this quarterly document. Areas monitored include space communications, radio navigation, radio science, ground-based radio and radar astronomy, information systems, and all other communication and research technology activities for the Deep Space Network (DSN).

Yuen, Joseph H.↗
NASA NTRS1996

SPACEWAY(TM) Providing Afordable and Versatile Telecommunication Solutions

This paper presents a summary description of SPACEWAY(TM), a network of Ka band geostationary satellites being developed by Hughes Communications, Inc. to provide worldwide interactive telecommunications services to small, low cost user terminals. By the end of this decade SPACEWAY(TM), using relatively few satellites and tightly focused spot beams, will provide affordable interactive 'bandwidth on demand' communication services on a global basis to consumer and commercial end users. This paper describes the system concept, details the space and ground segment characteristics, and discusses communication links.

Fitzpatrick, Edward James↗
NASA NTRS1996

Earth-Mars Telecommunications and Information Management System (TIMS): Antenna Visibility Determination, Network Simulation, and Management Models

This report presents the results of our research on Earth-Mars Telecommunications and Information Management System (TIMS) network modeling and unattended network operations. The primary focus of our research is to investigate the feasibility of the TIMS architecture, which links the Earth-based Mars Operations Control Center, Science Data Processing Facility, Mars Network Management Center, and the Deep Space Network of antennae to the relay satellites and other communication network elements based in the Mars region. The investigation was enhanced by developing Build 3 of the TIMS network modeling and simulation model. The results of several 'what-if' scenarios are reported along with reports on upgraded antenna visibility determination software and unattended network management prototype.

Odubiyi, Jide↗
NASA NTRS1998

Satellite Telemetry and Command using Big LEO Mobile Telecommunications Systems

Various issues associated with satellite telemetry and command using Big LEO mobile telecommunications systems are presented in viewgraph form. Specific topics include: 1) Commercial Satellite system overviews: Globalstar, ICO, and Iridium; 2) System capabilities and cost reduction; 3) Satellite constellations and contact limitations; 4) Capabilities of Globalstar, ICO and Iridium with emphasis on Globalstar; and 5) Flight transceiver issues and security.

Huegel, Fred↗
NASA NTRS1998

A Flexible System for Simulating Aeronautical Telecommunication Network

At Old Dominion University, we have built Aeronautical Telecommunication Network (ATN) Simulator with NASA being the fund provider. It provides a means to evaluate the impact of modified router scheduling algorithms on the network efficiency, to perform capacity studies on various network topologies and to monitor and study various aspects of ATN through graphical user interface (GUI). In this paper we describe briefly about the proposed ATN model and our abstraction of this model. Later we describe our simulator architecture highlighting some of the design specifications, scheduling algorithms and user interface. At the end, we have provided the results of performance studies on this simulator.

Maly, Kurt↗
NASA NTRS2000

Deep Space Telecommunications

The increasing load on NASA's deep Space Network, the new capabilities for deep space missions inherent in a next-generation radio telescope, and the potential of new telescope technology for reducing construction and operation costs suggest a natural marriage between radio astronomy and deep space telecommunications in developing advanced radio telescope concepts.

Kuiper, T. B. H.↗
NASA NTRS2001

Achieving QoS for Aeronautical Telecommunication Networks Over Differentiated Services

Aeronautical Telecommunication Network (ATN) has been developed by the International Civil Aviation Organization to integrate Air-Ground and Ground-Ground data communication for aeronautical applications into a single network serving Air Traffic Control and Aeronautical Operational Communications. To carry time critical information required for aeronautical applications, ATN provides different Quality of Services (QoS) to applications. ATN has therefore, been designed as a stand alone network which implies building an expensive separate network for ATN However, the cost of operating ATN can be reduced if it can be run over a public network such as the Internet. Although the current Internet does not provide QoS the next generation Internet is expected to provide QoS to applications. The objective of this paper is to investigate the possibility of providing QoS to ATN applications when it is run over the next generation Internet. Differentiated Services (DiffServ), one of the protocols proposed for the next generation Internet, will allow network service providers to offer different QoS to customers. Our results show that it is possible to provide QoS to ATN applications when they run over a DiffServ backbone.

Bai, Haowei↗
NASA NTRS2002

Center for Space Telemetering and Telecommunications Systems, New Mexico State University

This viewgraph presentation gives an overview of the Center for Space Telemetering and Telecommunications Systems activities at New Mexico State University. Presentations cover the following topics: (1) small satellite communications, including nanosatellite radio and virtual satellite development; (2) modulation and detection studies, including details on smooth phase interpolated keying (SPIK) spectra and highlights of an adaptive turbo multiuser detector; (3) decoupled approaches to nonlinear ISI compensation; (4) space internet testing; (4) optical communication; (5) Linux-based receiver for lightweight optical communications without a laser in space, including software design, performance analysis, and the receiver algorithm; (6) carrier tracking hardware; and (7) subband transforms for adaptive direct sequence spread spectrum receivers.

Horan, Stephen↗
NASA NTRS2003

The Center for Space Telemetering and Telecommunications Systems

This report comprises the final technical report for the research grant 'Center for Space Telemetering and Telecommunications Systems' sponsored by the National Aeronautics and Space Administration's Goddard Space Flight Center. The grant activities are broken down into the following technology areas: (1) Space Protocol Testing; (2) Autonomous Reconfiguration of Ground Station Receivers; (3) Satellite Cluster Communications; and (4) Bandwidth Efficient Modulation. The grant activity produced a number of technical reports and papers that were communicated to NASA as they were generated. This final report contains the final summary papers or final technical report conclusions for each of the project areas. Additionally, the grant supported students who made progress towards their degrees while working on the research.

Horan, S.↗
NASA NTRS2003

A TDMA Broadcast Satellite/Ground Architecture for the Aeronautical Telecommunications Network

An initial evaluation of a TDMA satellite broadcast architecture with an integrated ground network is proposed in this study as one option for the Aeronautical Telecommunications Network (ATN). The architecture proposed consists of a ground based network that is dedicated to the reception and transmissions of Automatic Dependent Surveillance Broadcast (ADS-B) messages from Mode-S or UAT type systems, along with tracks from primary and secondary surveillance radars. Additionally, the ground network could contain VHF Digital Link Mode 2, 3 or 4 transceivers for the reception and transmissions of Controller-Pilot Data Link Communications (CPDLC) messages and for voice. The second part of the ATN network consists of a broadcast satellite based system that is mainly dedicated for the transmission of surveillance data as well as En-route Flight Information Service Broadcast (FIS-B) to all aircraft. The system proposed integrates those two network to provide a nation wide comprehensive service utilizing near term or existing technologies and hence keeping the economic factor in prospective. The next few sections include a background introduction, the ground subnetwork, the satellite subnetwork, modeling and simulations, and conclusion and recommendations.

Shamma, Mohammed A.↗
NASA NTRS2001

Medicine in long duration space exploration: the role of virtual reality and broad bandwidth telecommunications networks

Safety of astronauts during long-term space exploration is a priority for NASA. This paper describes efforts to produce Earth-based models for providing expert medical advice when unforeseen medical emergencies occur on spacecraft. These models are Virtual Collaborative Clinics that reach into remote sites using telecommunications and emerging stereo-imaging and sensor technologies. c 2001. Elsevier Science Ltd. All rights reserved.

Non-NASA Center↗
NASA NTRS2001

Achieving QoS for Aeronautical Telecommunication Networks over Differentiated Services

Aeronautical Telecommunication Network (ATN) has been developed by the International Civil Aviation Organization to integrate Air-Ground and Ground-Ground data communication for aeronautical applications into a single network serving Air Traffic Control and Aeronautical Operational Communications. To carry time critical information required for aeronautical applications, ATN provides different Quality of Services (QoS) to applications. ATN has therefore, been designed as a standalone network which implies building an expensive separate network for ATN. However, the cost of operating ATN can be reduced if it can be run over a public network such as the Internet. Although the current Internet does not provide QoS, the next generation Internet is expected to provide QoS to applications. The objective of this paper is to investigate the possibility of providing QoS to ATN applications when it is run over the next generation Internet. Differentiated Services (DiffServ), one of the protocols proposed for the next generation Internet, will allow network service providers to offer different QoS to customers. Our results show that it is possible to provide QoS to ATN applications when they run over a DiffServ backbone.

Bai, Haowei↗
NASA NTRS2001

Sub-microradian pointing for deep space optical telecommunications network

This presentation will cover innovative hardware, algorithms, architectures, techniques and recent laboratory results that are applicable to all deep space optical communication links, such as the Mars Telecommunication Network to future interstellar missions.

deep-space optical communication tracking pointing↗
NASA NTRS1995

Lunar Telecommunications

This paper reviews the telecommunications needs of future lunar orbiters and rovers and considers ways in which these needs can be met with ground-based tracking resources.

Lunar Prospector↗