Humans could discover the source of the methane on Mars and discover who is farting on Mars.
Also robots are very limited, especially so far from Earth. Humans would be on Mars for 1,5 years and if they had vehicles they could cover hundreds of kilometers and could look for fossils - something that is very hard for robots.
There is some talk about it in this somewhat realistic documentary on human exploration of Mars at minute 57
Also robots are very limited, especially so far from Earth. Humans would be on Mars for 1,5 years and if they had vehicles they could cover hundreds of kilometers and could look for fossils - something that is very hard for robots.
There is some talk about it in this somewhat realistic documentary on human exploration of Mars at minute 57