EUVE Satellite Communications Simulation |
This Java applet simulates some of the communications constraints that satellites like EUVE must take into account. In this example, the viewer is positioned near the Sun looking at the daylight side of the Earth. The Earth makes a complete rotation in 24 hours of simulated time. The geosynchronous satellites also make a complete revolution around the Earth in 24 hours. Meanwhile EUVE, a low-Earth-orbiting satellite, revolves around the Earth much faster than the geosynchronous satellites, completeting a revolution in 96 minutes. This simulation demonstrates when EUVE can communicate with the TDRS communications satellite. Note that the "lines of communication" are open only when the EUVE satellite has an unobstructed view of the TDRS statellite. The red line shows the line of sight communication from EUVE to TDRS. The gray line shows the line of sight communications from TDRS to the White Sands groundstation continued to Domsat 1. Finally, the green line shows the communications link from Domsat 1 to Goddard Space Flight Center, through Domsat 2 to Onizuka Air Force Base. From Onizuka AFB the link is carried by wire to CEA at UCB.