There are three physically impossible events in the plot. Stopping on the way to Mars, getting back to his spacecraft from his father's ship and riding a shockwave back to earth.
There are also four completely pointless events...the fall from the absurd tower, the journey across the neutral zone on the moon, the fight with the gorillas (!) and the swim through the underground lake on Mars. All of these are totally unbelievable and are unimportant to anything else in the plot. We are also expected to believe that a man going on a mission that is crucial to the planet's survival would start by taking a commercial flight to the moon which terminates in a place where the only option is to cross a zone full of pirates in a moon buggy. The only possible reason for that is to get some cash into the film from Virgin.