NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsDirect Data Distribution From Low-Earth OrbitNASA Lewis Research Center (LeRC) is developing the space and ground segment technologies necessary to demonstrate a direct data distribution (1)3) system for use in space-to-ground communication links from spacecraft in low-Earth orbit (LEO) to strategically located tracking ground terminals. The key space segment technologies include a K-band (19 GHz) MMIC-based transmit phased array antenna, and a multichannel bandwidth- and power-efficient digital encoder/modulate with an aggregate data rate of 622 Mb/s. Along with small (1.8 meter), low-cost tracking terminals on the ground, the D3 system enables affordable distribution of data to the end user or archive facility through interoperability with commercial terrestrial telecommunications networks. The D3 system is applicable to both government and commercial science and communications spacecraft in LEO. The features and benefits of the D3 system concept are described. Starting with typical orbital characteristics, a set of baseline requirements for representative applications is developed, including requirements for onboard storage and tracking terminals, and sample link budgets are presented. Characteristics of the transmit array antenna and digital encoder/modulator are described. The architecture and components of the tracking terminal are described, including technologies for the next generation terminal. Candidate flights of opportunity for risk mitigation and space demonstration of the D3 features are identified.Document ID19970017397Acquisition SourceLegacy CDMSDocument TypeConference PaperAuthorsBudinger, James M.*(NASA Lewis Research Center Cleveland, OH United States)*Fujikawa, Gene*(NASA Lewis Research Center Cleveland, OH United States)*Kunath, Richard R.*(NASA Lewis Research Center Cleveland, OH United States)*Nguyen, Nam T.*(NASA Lewis Research Center Cleveland, OH United States)*Romanofsky, Robert R.*(NASA Lewis Research Center Cleveland, OH United States)*Spence, Rodney L.*(NASA Lewis Research Center Cleveland, OH United States)*Date AcquiredSeptember 6, 2013Publication DateApril 1, 1997Subject CategorySpace Communications, Spacecraft Communications, Command And TrackingReport/Patent NumberNAS 1.15:107438E-10703NASA-TM-107438Meeting InformationMeeting: International Conference on CommunicationsLocation: MontrealCountry: CanadaStart Date: June 8, 1997End Date: June 12, 1997Sponsors:Institute of Electrical and Electronics EngineersAccession Number97N19676Funding Number(s)PROJECT: RTOP 315-90-2GDistribution LimitsPublicCopyrightWork of the US Gov. Public Use Permitted.Available DownloadsNameType19970017397.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsThere are no records associated with this record.visibility_offNo Preview Available
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