uptime

When this option is executed, a new screen will appear which will display the times when the source is visible from each of the ground VLBI sites. The information is displayed in the form of green, red, and black coloured bars for each station. At times when a bar is green, the source is visible from that ground VLBI station, the satellite can point to the source, and a telemetry link is possible (i.e., the satellite-ground baseline is available). If a bar is red, the source is visible to that ground VLBI station, but the satellite cannot observe the source due to violation of some constraint. If a bar is black (i.e. no colour) then the source is below the elevation limit of that ground VLBI station. The upper-most portion of the screen shows a schematic of the satellite's altitude versus time. The altitude scale is normalized so that the range in altitude occupies the entire box with the height plotted from the lowest point (perigee) to the highest point (apogee). This option can also be enabled by pressing the `u' key. See Figure on p. .