Here’s a writeup from the source for this comic:
Chris Hadfield (August 1959-) is a Canadian astronaut currently on assignment aboard the International Space Station. He will become the first Canadian Commander of the ISS when Expedition 35 takes over this March.
Hadfield has become an Internet celebrity, using social media and YouTube to share what daily life is like aboard the ISS. He regularly tweets breath-taking photos of Earth (here is a selection of his best pics) and has a YouTube channel with videos on everything from how he operates a giant robotic arm to how he eats a peanut butter and honey pita sandwich (bread isn’t used because of the crumbs). This particular quote is taken from a recent Redditt ‘Ask me anything’ session Hadfield took part in while aboard the ISS. A youngster asked if Hadfield had any advice for an aspiring astronaut, and this quote was his reply.
(Hat tip to the lovely Stephen Power for alerting me to this.)