Why have they not yet commissioned a manned flight and landing on Mars? They clearly have the technology and know how to do it? Also due to the atmosphere and composition Jupiter, could you physically land on it ignoring how far away it is?
Beso, Assuming the space craft has the same mass as when it left the Earth's orbit around the sun, it will need as much energy to return from mars as it took to get there. That is why the planets don't all fall into the sun.