Some astronauts are able to walk around in Earth gravity immediately after getting back, though with some difficulty. Valeri Polyakov walked out of his space ca

Some astronauts are able to walk around in Earth gravity immediately after getting back, though with some difficulty. Valeri Polyakov walked out of his space capsule after his 2 year stint in the Russian space station. And then there's the fact that Mars has only half the gravity. I think gravity won't be a showstopper when arriving at Mars.