This model illustrates the concept of interplanetary travel.
Press "Run" button. The rocket will power its engines and enter the intermediate elliptic orbit (Homan ellipse). The engines will start again upon the rocket's arrival at the aphelion, and the spacecraft will move to Mars' orbit. The experts should be able to calculate the time of departure with astounding precision, since the planet and the rocket must be are at their exact respective positions - as predicted - when the interplanetary station moves into another planet's orbit.
"Stop" and "Reset" buttons suspend the model and return it to its initial state, respectively.
Select a space flight from Mars to the Earth, and observe the sequence of events in reverse. While it is in the Martian orbit, the spacecraft receives a braking pulse, and moves to the intermediate elliptical orbit. The second braking pulse in perihelion of the intermediate orbit will propel the spacecraft to the Earth's orbit.