From pureed food in aluminum tubes to fresh lettuce growing in a microgravity environment, what astronauts eat in space is constantly changing. Today, astronauts can enjoy a shrimp cocktail on the International Space Station or request extra hot sauce for their meals – and space food will continue to evolve as technology improves.

Space food has to be compact, easy to preserve and nutritious. During the 1960s, astronauts ate pureed food in aluminum tubes, such as beef and vegetables. According to the National Air and Space Museum, they had to eat the meals through a straw, and the food was not delicious. For later missions in the 1960s, the National Aeronautics and Space Administration (NASA) provided freeze-dried and dehydrated foods that required astronauts to add water. Many of the meals were bite-sized or cube-shaped.

By the late 1960s and 1970s, rehydrated foods became popular. The spoon-bowl pack let an astronaut take a dehydrated meal and rehydrate it in space with hot water. From stew to spaghetti, space travelers started to receive more options during their missions. Popular foods included cereal, brownies and shrimp cocktails.

Today, astronauts have about 70 meal and 20 beverage options. Before their flights, they visit the Space Food Systems Laboratory at Houston’s Johnson Space Center to taste the food and pick out dishes. Most of the dishes require adding water, and some resemble the military's MREs (Meals Ready to Eat). Beverages are in bags and require straws for drinking. Although many items are still dehydrated, there is a push to provide better options.

One of the biggest struggles for astronauts in space is the lack of fresh vegetables and fruit. However, in recent years, the crew on the International Space Station has grown its own romaine lettuce. The plants grow inside the Vegetable Production System (Veggie) unit on the station that resembles a small greenhouse.

During the initial experiment, it took more than 30 days for the lettuce to be ready for harvest. Nevertheless, this is a positive step toward providing the crew with fresh produce during long missions. In the future, astronauts may be able to supplement their diets with a variety of vegetables and fruit in space.

When 7,400 pounds of supplies went to the International Space Station in 2017, the astronauts received a special treat of pizza and ice cream – items they requested because they missed some of the comforts of home. But these delicious treats aren't a normal part of the menu in space; NASA's food scientist Takiyah Sirmons explained that ice cream is rare because it requires refrigeration and freezers.

It's important to note that the "astronaut ice cream" seen in grocery stores never makes it to space. The freeze-dried dessert is a fun novelty, but CNET reports that flight crews did not get the chance to sample it on their missions. One of the reasons why astronaut ice cream stays on Earth may be because it creates dangerous crumbs that can affect the equipment and the people. Instead, the crew occasionally gets to enjoy regular ice cream that does not carry the risk of crumbs destroying a machine or getting in their eyes.

Although astronauts can eat, chew and drink many things in space, Sirmons shares that their perception of taste changes. The microgravity causes fluid changes and gives them congestion. This affects the crew's ability to smell and taste, so the flavor of food is different. In general, they prefer spicier food in space to compensate for the loss of taste.

Astronauts have access to a variety of condiments and spices, including hot sauce, in space. The crew gets a variety of products, like Louisiana hot sauce, salt, pepper, wasabi and Tabasco. Shrimp cocktail is a beloved dish among astronauts, despite being freeze-dried, because it is spicy.

From growing fresh produce to 3-D printing meals, space food will continue to change in the future. Advances in technology may make it possible to do long-term and large-scale space farming, so crews will have an ongoing supply of food. Looking beyond the International Space Station and other missions, the ability to grow and harvest food is a crucial part of space exploration and may determine the viability of colonizing other planets.

According to the University of Hawaii, a mission to Mars may take two and a half years, so growing food on the flight will be necessary. Farming would provide all the necessary nutrients and give them variety. It would also boost morale because caring for living things is important to humans.

3-D printing food is another option. Futurism reports that the startup BeeHex has used a 3-D printer robot to make pizza. The process takes about six minutes and produces a pizza that looks like what we'd expect. A computer controls the dough, shape and toppings, and tubes with nozzles push out all the ingredients in the right order. For astronauts who miss cooking at home, this type of machine would be an easy way to make their own meals.

You don't have to travel to the International Space Station to eat like an astronaut. Lufthansa airlines will give business class passengers on its flights the chance to eat some of the same things that the crew on the International Space Station enjoys. The menu includes chicken ragout with mushrooms, maultaschen (meat-filled dumplings) and four other special meals.

Part of Lufthansa, the LSG Group developed the six bonus meals for German astronaut Alexander Gerst and the rest of the crew on the International Space Station. All of the dishes are low in sodium and shelf stable for up to two years. Considering that passengers on an airline experience some of the same taste problems as astronauts because they are high off the ground, you may want to give the bonus meals a chance.