3.1NASA’S GROUND COMMUNICATIONSMANAGEMENT NETWORKFOCUSNASA’s communications network is extensivebecause its operations are spread out around theworld and into space. The main Deep Space Network is controlled out of the Jet Propulsion Laboratory (JPL) in California. JPL is connected to thehree main Deep Space Communications CentersDSCCs) that communicate with NASA spacecraft.The three DSCCs are spread out equidistantlyaround the world so that one will always be ableo communicate with spacecraft no matter wherehey are in relation to the earth: Canberra, Ausralia; Madrid, Spain; and Goldstone, California.Figure 3.7 shows the JPL network. Each DSCChas four large-dish antennas ranging in size from85 to 230 feet (26 to 70 meters) that communicate with the spacecraft. These send and receiveoperational data such as telemetry, commands,tracking, and radio signals. Each DSCC also sendsand receives administrative data such as email,reports, and Web pages, as well as telephonecalls and video.The three DSCCs and JPL use Ethernet localarea networks (LANs) that are connected to multiplexers that integrate the data, voice, and videosignals for transmission. Satellite circuits are usedbetween Canberra and JPL and Madrid and JPL.Fiber-optic circuits are used between JPL andGoldstone.
đang được dịch, vui lòng đợi..
![](//viimg.ilovetranslation.com/pic/loading_3.gif?v=b9814dd30c1d7c59_8619)