Holy mother of God this is one awful movie. They try to get you emotionally involved in the father-son drama but have one preposterous plot line after another.
In order to get to Mars you have fly to the light side of the moon and then drive a car to the dark side of the moon where you are attacked by moon pirates. Moon pirates?
On the way to Mars, you stop to answer a distress call, kind of like stopping to help someone with a flat tire. Of course you easily enter the distressed ship from the outside. And when you enter you are attacked by a rabid Rafiki from Lion King.
Once on Mars, you are able to sneak into the rocket to Neptune when you were under the rocket engines when the count down was at 10. And by the way, you had to swim underwater quite a ways to get to the rocket.
When you get to Neptune, you. park your rocket, and I mean park, on the opposite side of the rings so you have to go through the rings on the way down to loony pops and come back through the rings with a makeshift shield that you removed from the outside of the spacecraft with no tools while wearing a spacesuit.
To get back home from Neptune to Earth you are propelled the whole way by the nuclear bomb that you used to destroy loony pops' ship. The ship that was, by the way, somehow destroying the known universe.
The moral of all of this is that we may be alone in the universe so we should all love each other.
The End.