http://bear.ras.ucalgary.ca/glen_home_page/radast/user/node12.html (Einblicke ins Internet, ~06/1995)
The Solve command is activated by pressing Enter when Solve is highlighted or by pressing the `s' key. This starts the calculation of the visible ground tracks. Some important characteristics of the orbit are also displayed at the bottom of the screen by this command. These include the orbital period in hours, and the apogee and perigee distance (from earth center) and velocity. The total number of hours the spacecraft is visible from some available telemetry station, as well as the percentage of the orbit that this represents, are displayed when the calculation is completed.
Normally the ground track is displayed in two different colours, green when the satellite is visible from a telemetry ground station and red when it is not. However, if you so desire, by pressing the `c' key you can toggle on/off the red track. That is, with the `c' key you can decide whether or not the points at which the satellite is not visible will be plotted to the screen. This is useful for monochrome screens and for printing the screen to a monochrome printer.
The Quit command allows the user to exit from the program and is activated by highlighting Quit and pressing Enter or by pressing the `q' key.