Space Network
Space Network (SN) is a NASA program that combines space and ground elements to support spacecraft communications in Earth vicinity. The SN Project Office at Goddard Space Flight Center (GSFC) manages the SN, which consists of: Satellite generations. Tracking and Data Relay Satellite (TDRS) currently consists of first-generation (F1–F7), and second-generation (F8–F10) satellites. The space segment of the SN consists of up to six operational relay satellites in geosynchronous orbit. These communications satellites are allocated longitudes for relaying forward and return service signals to and from customers, any entity with an Earth-orbiting satellite  that has an agreement with SN to use its communications services, for data transfer and tracking. An additional TDRS, F1, provides dedicated support to the National Science Foundation (NSF) through the use of the WSC Alternate Relay Terminal (WART). Additional spare TDRSs may be in geosynchronous orbit. All first-generation TDRSs (F1–F7, also known as TDRS A–G) carry functionally identical payloads and all second-generation TDRSs (F8–F10, also known as TDRS H–J) carry functionally identical payloads. A third generation, TDRS K, L, and M were launched between 2013–2017. The figures identify the pertinent communications components and  associated parameters of the orbiting relay platforms. Coverage. For spacecraft operating in a low Earth orbit (LEO) 73 km to 3000 km altitude, the SN is capable of providing tracking and data acquisition services over 100% of the spacecraft's orbit. Spacecraft sent to more distant or exotic destinations rely on either Deep Space Network or their own custom, dedicated networks.