In this lecture Ir. R. Noomen talks about interplanetary flight. He start off by talking about transfer orbits, reaching the Hohmann transfer. Hohmann transfers for interplanetary flight are different however from those just in earth orbit. He then talkt about the different escape velocities needed in order to travel to different planets in our solar system. When transfering to a different planet, timing is essential due to the different periods which planets orbit the sun. The next subject is a fast trajectory, this would mean expending more energy to reach a destination faster. Finally the time it takes to make a round trip to another planet is explained.