Space food has gotten a lot better since the food-in-a-tube from the early days of the space program. In fact, NASA has a food lab at the Johnson Space Center in Houston, Texas, where a whole team works to create nutritious and tasty meals for American astronauts. With the arrival of fairly frequent cargo missions, crewmembers on the International Space Station do have access to fresh fruits and vegetables, but occasionally they get an extra special delivery, like the time they got space pizza delivered.
Almost 20 years ago, when the ISS was a brand new orbiting outpost, Pizza Hut delivered a space pizza to Russian cosmonaut Yuri Usachov. Because Pizza Hut didn't have their own rocket, the pizza chain hitched a ride on a Russian launch vehicle on its way to the space station.
Like other efforts to make shelf stable pizza, the space pizza had to be prepared in a particular way for the delivery, since the ride to orbit is a little longer than a normal pizza delivery time. Although the pizza had a normal crust, pizza sauce and cheese, the traditional pepperoni topping was replaced with salami because the pepperoni didn't meet the life space requirements. Since the pizza had to be reheated for eating, the space pizza was made the since of a personal pan pizza so that it would fit in the oven onboard the ISS.
The delivery was a publicity stunt, with Pizza Hut paying about a million dollars to place their logo on the Russian rocket and get a picture of Usachov floating in zero gravity with the pizza and giving a thumbs up. Because NASA is a U.S. government agency, they are prohibited from selling advertising to companies, so the American astronauts on the ISS at the time were not allowed to take part in the pizza dinner.
But because pizza is beloved by astronauts from all over the world, there have been other pizza nights on board the space station. In 2013, the space agency used a 3D printer on the ISS to test "print" a pizza. To be clear, we're not talking about a Star Trek-style replicator; the 3D printer uses macronutrients like protein and starch, fed into a 3D printer as powders where they're mixed with oil or water and liquid flavorings. For a pizza, a crust layer is printed, followed by the pizza sauce and then the toppings.
And in 2017, Italian astronaut and ISS crewmember Paolo Nespoli received a delivery of ready-made crusts, tomato sauce and all the toppings needed to build some excellent pizzas. Nespoli and the rest of Expedition 53 made their pizzas for a crew movie night and showed off their space pizza skills in a fun video from NASA.
One of the tricky things about pizza in space is that regular pizza can actually be dangerous in space. Small toppings, little bits of cheese and crumbs from the pizza crust float in microgravity and can get into the air system and computers and cause all sorts of problems. It's the same reason why astronauts use tortillas to make sandwiches instead of regular bread.
So the crew made sure to use toppings that stuck to the sauce and worked as a team to make sure flying pizza didn't make a mess (also, giving a whole new meaning to pizza tossing).
Since then, ISS crews have continued to make pizzas in space. Having access to comfort food in space is going to be incredibly important for future astronaut crews headed to Mars. Those missions are likely to last at least 18 months, and that's a long time to go without pizza, so expect to see more space pizza innovation.