Several decades from now, an astronaut in a Mars colony might feel a bit hungry. Rather than reach for a vacuum-sealed food packet or cook up some simple greenhouse vegetables in a tiny kitchen, the astronaut would visit a microwave-sized box, punch a few settings, and receive a delicious and nutritious meal tailored to his or her exact tastes.

This is the promise of the rapidly maturing field of 3-D food printing, an offshoot of the revolution that uses machines to build bespoke items out of metal, plastic, and even living cells. Sooner than you think, 3-D printed designer meals may be coming to a rocketship, or a restaurant, near you.

“Right now, astronauts on the space station are eating the same seven days of food on rotations of two or three weeks,” said astronautical engineer Michelle Terfansky, who studied the potential and challenges of making 3-D printed food in space for a master’s thesis at the University of Southern California. “It gets the job done, but it’s not exactly home cooking.”

The Fab@Home 3-D food printer. Credit: Jeffrey Lipton

With 3-D printers coming of age, engineers are starting to expand the possible list of materials they might work with. The early work in food has been in making desserts – a Japanese company lets you order your sweetheart a creepy chocolate 3-D model of their head – but some researchers are already thinking of what comes next. The Fab@Home team at Cornell University has developed gel-like substances called hydrocolloids that can be extruded and built up into different shapes. By mixing in flavoring agents, they can produce a range of tastes and textures.

The ability to 3-D print meals could be particularly handy on long-duration space missions, said Terfansky. Food is a basic source of comfort to humans, who would be dealing with a high-stress environment during a trip to an asteroid or Mars. Monotony will be a major challenge for such endeavors and the ability to provide variety and change in diet could be key. Having a family member back on Earth be able to design a special meal for an astronaut, beam it to their spaceship, and have it prepared in space might help travelers deal with distance and loneliness.

A 3-D printer could mix vitamins and amino acids into a meal to provide nutrients and boost productivity. There are limitations to the types of fresh foods that can be grown in space – NASA says some of the best crops for a Mars mission are lettuce, carrots, and tomatoes. With that you could make a salad, but a 3-D printer could manufacture croutons or protein-dense supplements. The device could take up less space than a supply of packets of food and, because each item is custom built, would help cut down on waste.

Obviously, such technology would find many applications on Earth. A 3-D printer could create unique and novel foods that are impossible to produce with conventional cooking. Hot dogs could be filled with layers of ketchup or mustard and cakes could have a logo inside that appears when a slice is cut out. Likely the first people to embrace the new design possibilities will be avant-garde chefs.

But 3-D food printing systems still have a long way to go, with most of the current limitations involving the printer’s extruding system. Some items, like frosting or processed cheese, are easy to make printable. A chocolate treat, for instance, is created using a syringe filled with melted chocolate to build up a shape specified by a computer layer by layer.

But other materials – fruits, vegetables, and meats – are much more of a challenge. Even with flavored gels, printing a wide variety of foods would require figuring out how to lay down potentially dozens of different materials, each with their own characteristic viscosity or perfect temperature range, using interchangeable printer heads.

A 3-D food printer building turkey paste into blocks. Credit: Fab@Home

Of course, this is food we’re talking about, and it has to be appealing. In the earliest tests of the hydrocolloid 3-D food printer, the Cornell team produced different fake items – bananas, mushrooms, mozzarella – all with the appropriate texture and flavor.

“We quickly ran into the yuck factor,” said engineer Jeffrey Lipton, who leads Cornell’s Fab@Home lab, which makes open-source 3-D printer kits. “It was the Uncanny Valley of food,” he added. It was very close to, but still unlike, the cuisine people expected.

Terfansky understands this is an issue. At first, she said such devices would probably extrude gloppy shapes filled with chemicals that make them smell or taste like chicken (while not quite being a drumstick). Because no one wants to eat something that looks and tastes bad, Terfansky said the best thing would be to focus on making sure things are delicious and then improving the visual aesthetics.

Within five to 10 years, she said the technology might get to the point where a single printer could produce lots of different food items that are both flavorful and look like what they’re supposed to be. Terfansky sees a day further in the future when most home kitchens include a 3-D printer simple enough for a child to go up and press the “hamburger” button in order to receive a meal. Such plans may seem like the food machine from The Jetsons but other researchers say they’re not out of the realm of possibility.

“At first I thought of it being ridiculously difficult,” said engineer Boris Fritz of Northrop Grumman Aerospace Systems, who works on 3-D printers that produce extremely high-precision metallic machinery. “But this stuff doesn’t have to be precise at all. The more I thought about it, the more it seemed obvious and inevitable that within about five years something like this will be done.”

Lipton thinks the more out-there possibilities, like building up a meal of steak and potatoes from scratch, are still 15 to 20 years or more in the future. He agrees that the technology could be adopted first in places like hospitals or space stations, where people have sensitive or predictable nutritional needs.

“It’s an exciting premise it’s just a long ways away,” he said.