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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Signal Characterization for TDRSS Support of Range Safety

This work involves the analysis of signal attenuation using the NASA Tracking and Data Relay Satellite/Space Network to provide range safety and flight termination system support for expendable launch vehicles and the space shuttle. We found that at least one of the two operational TDRSS satellites could provide flight termination operating at about 250bps. Lowering the data rate could provide a larger link margin. The other satellite's signal would be attenuated below an acceptable link margin due to rocket exhaust. Lowering the data rate could provide a larger link margin.

Kozaitis, Sam↗
NASA NTRS2006

A Microstrip Patch-Fed Short Backfire Antenna for the Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) Array

Short Backfire Antennas (SBAs) are widely utilized for mobile satellite communications, tracking, telemetry, and wireless local area network (WLAN) applications due to their compact structure and excellent radiation characteristics [1-3]. Typically, these SBA s consist of an excitation element (i.e., a half-wavelength dipole), a reflective bottom plane, a planar sub-reflector located above the "exciter", and an outer circular rim. This configuration is capable of achieving gains on the order of 13-15 dBi, but with relatively narrow bandwidths (approx.3%-5%), making it incompatible with the requirements of the next generation enhanced Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) array [1]. Several attempts have been made to enhance the bandwidth performance of the common dipole-fed SBA by employing various other feeding mechanisms (e.g., waveguide, slot) with moderate success [4-5]. In this paper, a novel method of using a microstrip patch is employed for the first time to excite an SBA. The patch element is fed via two H-shaped slots electromagnetically coupled to a broadband hybrid coupler to maintain a wide bandwidth, as well as provide for dual circular polarization capabilities.

Nessel, James A.↗
NASA NTRS2006

Comparative Study of Antenna Elements for TDRSS Enhanced Multiple Access System

We compare three antennas, which are candidates for the TDRSS-Continuation enhanced MA array antenna elements. Measured and simulated data show very good agreement for all antenna elements. All of the antennas meet the specifications with the exception of the SBA isolation. However, improvements can likely be made with further design efforts.

Kory, Carol L.↗
NASA NTRS2013

GRC GSFC TDRSS Waveform Metrics Report

The report presents software metrics and porting metrics for the GGT Waveform. The porting was from a ground-based COTS SDR, the SDR-3000, to the CoNNeCT JPL SDR. The report does not address any of the Operating Environment (OE) software development, nor the original TDRSS waveform development at GSFC for the COTS SDR. With regard to STRS, the report presents compliance data and lessons learned.

Mortensen, Dale J.↗
NASA NTRS1973

Tracking and Data Relay Satellite System configuration and tradeoff study. Volume 2: Delta 2914 launched TDRSS, Configuration 2. Part 2: Final Report, 22 August 1972 - 1 April 1973

Configuration data and design information for a Delta 2914 launched configuration with greatly enhanced telecommunication service over the Part I Delta 2914 configuration is contained. The overall system definition, operations and control, and telecommunication service system, including link budgets are discussed. A brief description of the user transceiver and ground station is presented. A final section includes a summary description of the TDR spacecraft and all the subsystems. The data presented are largely in tabular form.

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NASA NTRS1973

Tracking and Data Relay Satellite System configuration and tradeoff study. Volume 3: Atlas Centaur launched TDRSS. Part 2: Final Report, 22 August 1972 - 1 April 1973

Configuration data and design information for the Atlas Centaur launched configuration are presented. Overall system definition, operations and control, and telecommunication service system, including link budgets, are discussed. A brief description of the user telecommunications equipment and ground station is presented. A summary description of the TDR spacecraft and all the subsystems is included. The data presented are largely in tabular form. A brief treatment of an optional configuration with enhanced telecommunications service is described.

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NASA NTRS1973

Tracking and Data Relay Satellite System configuration and tradeoff study. Volume 4: Space shuttle launched TDRSS. Part 2: Final Report, 22 August 1972 - 1 April 1973

Configuration data and design information for the space shuttle launched configuration is presented. The overall system definition, operations and control, and telecommunication service system including link budgets are discussed. A brief description of the user transceiver and ground station is presented. A final section includes a summary description of the TDR spacecraft and all the subsystems. The data presented are largely in tabular form.

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NASA NTRS1972

Tracking and data relay satellite system configuration and tradeoff study. Volume 3: TDRSS configuration and data summary, part 1

A reference handbook of configuration data and design information is presented. It treats the overall system definition, operations and control, and telecommunication service system including link budgets. A brief description of the user transceiver and ground station is presented. A final section includes a summary description of the TDR spacecraft and all the subsystems. The data presented are largely in tabular form for easy reference.

Source record↗
NASA NTRS1974

Preliminary assessment of RFI impacts on TDRSS in the 2- to 2.3 GHz band

A study was conducted of the radio frequency bands and radio frequency interference (RFI) impacts on the TDR satellite. Quick look evaluations were performed on RFI conditions in the 136 to 138 MHz and 400.5 to 401.5 MHz bands. An approximate chronological account of the investigations and the intermediate findings are presented. The preliminary results of RFI evaluations in the nominally 2 to 2.3 GHz band. An analysis of the time interaction of user satellites with microwave radio-relay type communications beams as a source of RFI is included.

Lyttle, J. D.↗
NASA NTRS1974

TDRSS multimode transponder program. Phase 2: Equipment development

This report contains a complete description of the TDRS Multimode Transponder and its associated ground support equipment. The transponder will demonstrate candidate modulation techniques to provide the required information for the design of an eventual VHF/UHF transponder suitable for installation in a user satellite, capable of operating as part of a Tracking and Data Relay Satellite (TDRS) systems. Use of geosynchronous TDRS which can serve both low data rate users at VHF and high data rate users at other frequencies has been considered. The effects of radio frequency interference from the earth and of multipath propagation due to reflections from the earth are expected to pose problems for the TDRS system at VHF. Investigations have suggested several modulation techniques that offer promise to overcome these problems.

Cnossen, R. S.↗
NASA NTRS1975

TDRSS multimode transponder program S-band modification

The S-Band TDRS multimode transponder and its associated ground support equipment is described. The transponder demonstrates candidate modulation techniques to provide the required information for the design of an eventual S-band transponder suitable for installation in a user satellite, capable of operating as part of a Tracking and Data Relay Satellite (TDRS) system.

Mackey, J. E.↗
NASA NTRS1979

TDRSS solar array arc discharge tests

Solar array design guidelines for immunity to the geomagnetic substorm environment at geosynchronous altitudes are summarized. The preliminary design guidelines and recommended practices based on these test results are given. It is concluded that specific design and immunity verification problems on each spacecraft program have to be solved on an individual basis until the technology matures to an adequate level.

Inouye, G. T.↗
NASA NTRS1980

Feasibility study of using a two-plate model to approximate the TDRSS solar pressure effects

An investigation was performed to determine the feasibility of using a two plate model to approximate the Tracking and Data Relay Satellite (TDRS) in orbit propagation, taking into account the effects of solar radiation pressure. The two plate model comprises one plate which always points to the Earth, and the other which is hinged to an axis normal to the orbital plane and is always rotated so that its normal makes a minimum angle with the direction of the sun. The results indicate that it is sufficient to take three parameters, the areas of the two plates and the reflectivity of the Earth pointing plate, to achieve an accuracy of one meter during a 24 hour orbit propagation.

Chan, F. K.↗
NASA NTRS1981

Tracking and Data Relay Satellite System (TDRSS) navigation with DSN radio metric data

The use of DSN radiometric data for enhancing the orbit determination capability for TDRS is examined. Results of a formal covariance analysis are presented which establish the nominal TDRS navigation performance and assess the performance improvement based on augmenting the nominal TDRS data strategy with radiometric data from DSN sites.

Ellis, J.↗
NASA NTRS1981

NASA Communications Division (NASCOM) Tracking and Data Relay Satellite System (TDRSS) shuttle multiplexer-demultiplexer data system (MDM) and supporting items

The multiplexer-demultiplexer (MDM) project included the design, documentation, manufacture, and testing of three MDM Data Systems. The equipment is contained in 59 racks, and includes more than 3,000 circuit boards and 600 microprocessors. Spares, circuit card testers, a master set of programmable integrated circuits, and a program development system were included as deliverables. All three MDM's were installed, and were operationally tested. The systems performed well with no major problems. The progress and problems analysis, addresses schedule conformance, new technology, items awaiting government approval, and project conclusions are summarized. All contract modifications are described.

New, S. R.↗
NASA NTRS1983

Ku-band system design study and TDRSS interface analysis

The capabilities of the Shuttle/TDRSS link simulation program (LinCsim) were expanded to account for radio frequency interference (RFI) effects on the Shuttle S-band links, the channel models were updated to reflect the RFI related hardware changes, the ESTL hardware modeling of the TDRS communication payload was reviewed and evaluated, in LinCsim the Shuttle/TDRSS signal acquisition was modeled, LinCsim was upgraded, and possible Shuttle on-orbit navigation techniques was evaluated.

Lindsey, W. C.↗