And it turns out that the microbes on board the International Space Station look more like what you'd find in your living room than what you would find on a human body. He mentioned that he was really missing his favourite food Pizza, so NASA made a decision to send him up the ingredients.
NASA's ISS Program manager Kirk Shireman came through for the crew, sending up the pizza components with a recent supply ship.
Included on the craft were prepackaged crusts, a squeeze bottle full of pizza sauce, spreadable cheese and toppings including olives and pepperoni.
Because everything in microgravity floats, the astronauts were careful to tether things down while slapping ingredients onto their pizza.
After craving for his much-loved pizza slices for past 100 days, Paolo Nespoli finally declared the pizza "unexpectedly delicious".
Incredible footage taken from space shows a timelapse of an aurora. But space pizza? Well, just see for yourself.
"When you really, really miss pizza..." Despite its remote location, thousands of species live on the space station.
According to the crew, they "had a blast channeling our inner chef by building tasty pizzas for movie night". For that study, people around the USA were asked to send in samples of the bacteria found in their homes, and they were then sent up to the International Space Station - the new research reverses that, bringing samples back down from space and exploring them.