Humans

Requiring breathing and heat management apparatuses to survive in space, it is a wonder that the Human race has not given up in the first several weeks of space exploration. Yuri Gagarin, the first human in space, made it look easy so they figured, what the hell, let's do it. Valentina Tereshkova has proven that females of the species could likewise survive the vacuum and Alexei Leonov has proven that you don't need a fancy spacecraft and can hitchhike all the way.

It was all easy from then on and the dream on landing on other astral bodies was then possible. Humans even made movies about it, most notorious one showed what a hypothetical landing on the Earth's moon would look like.