Displays this help screen. Selects the planet that your satellite will orbit. This option sets the correct mass, spin rate, equatorial bulge, planet-Sun distance, and additional data appropriate for the planet you select. This number specifies the accuracy of the integration.
More accurate integrations take longer and are more prone to run into numerical problems.
Accordingly, you want the lowest number which gives an accurate plot. Experiment by following the same orbit at different accuracies and seeing if the output plots are similar. Here you specify how many years into the future the orbit should be followed. A good strategy is to try a short integration time first to get an idea of how fast the program is. This number determines how often a point along the orbit is saved to disk.