There are rumors that some astronauts wear diapers when they are in outer space because there are no toilet for them.
The Astronaut Diapers (MAG)
The true name of NASA's astronaut diaper is the maximum absorbency Garment (MAG) which is piece of clothing astronauts wear during liftoff, landing, spacewalks, and other extra-vehicular activities to absorb urine and feces. The MAG is used because astronauts cannot remove their spacesuits during long operations, so the MAG is worn in case of an emission.
Nobody has gone to another planet at all, in or out of diapers. The farthest we've gone is the Moon. Though if we get to Mars (I'm optimistic about it happening in my lifetime), they'll probably be padded.