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A ground segment consists of all the ground-based elements of a spacecraft system, as opposed to the space segment.〔〔 Ground segment elements may be located together or separately, and may be operated by different parties.〔〔 Primary elements of a ground segment include: * Mission (or flight) control (or operations) centers (often at a prime site and one or more backup sites), which receive and process telemetry and issue commands, data uploads, and software updates to the spacecraft. Control centers use received telemetry to determine the state of health of a spacecraft and its systems. * Ground (or earth) stations〔 (generally with backups), which provide radio interfaces to the spacecraft for telemetry, tracking, and control (TT&C) and payload data transmission.〔〔〔 Tracking networks, such as NASA's Near Earth Network and Space Network (which includes space-based assets) may handle communications with multiple spacecraft through time-sharing. * User terminals,〔 which may be accessed by flight controllers, support personnel, and stakeholders (including science teams or telecommunication customers such as ISPs and individual users) * Integration and test facilities, where vehicles and their interfaces are assembled and tested prior to launch * Launch sites, from which vehicles are launched into space * Network components, which provide for communication and data transfer between ground segment elements〔〔 Mission control centers may rely on offline data processing subsystems to handle tasks such as orbit determination and maneuver planning, attitude control, conjunction assessment, on-board memory management, mission planning and scheduling, and long-term trend analysis. Control centers may be continuously or periodically monitored, or (increasingly commonly) they may be set up for "lights-out", or automated, operation. Monitoring is typically greatest during the early phases of a mission, and during critical procedures and periods. Flight control software will typically generate alerts regarding significant events, both planned and unplanned, in the ground or space segment that may require operator action. File:GSFC SpaceTelescopeOperationsControl.jpg|Space Telescope Operations Control Center at Goddard Space Flight Center, during servicing of the Hubble Space Telescope File:Rio antennas.jpg|Radio dishes at an Embratel earth station in Tanguá, Brazil File:Tsukuba.jpg|Integration of flight hardware at a JAXA facility in Tsukuba, Japan File:CSG Ariane 4 Launch Site.JPG|Decommissioned launch site at the Guiana Space Centre ==See also== *Consultative Committee for Space Data Systems, which maintains standards for telemetry and command formatting 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ground segment」の詳細全文を読む スポンサード リンク
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