Next-level astronaut food

While astronaut cuisine has come a long way since John Glenn sustained himself on toothpaste-shaped tubes of applesauce and beef puree, the struggle of menu fatigue in outer space is still real. That’s partly why NASA launched its Deep Space Food Challenge in January 2021. Over 300 teams from 32 countries accepted the challenge to develop novel food technologies for long-term space travel. Eight teams, announced on May 19, will continue into the third and final phase of the competition.

With missions to Mars on the horizon, NASA realized that the International Space Station model of constant food shipments wouldn’t work for deep space travel. Grace Douglas, lead scientist for advanced food technology at the Johnson Space Center, co-authored a September 2020 Journal of Nutrition paper outlining food system criteria for extended missions. They include stability for up to five years, resource minimization, and nutrients that maintain their quality beyond low-Earth orbit. But taste is king. If a team produces an unpalatable product, meeting the other requirements becomes irrelevant.

In phase one, teams were evaluated based on their design concepts, while in phase two they were tasked with building small-scale prototypes that could grow or make food. For phase three, the eight remaining teams each received $150,000 to scale up their systems.

Jim Sears developed SATED, a space cooking appliance, in his garage. An electrical engineer with experience in the aerospace industry, Sears started tinkering with boiling water, simulating the low gravity conditions found in space. Bubbles formed when boiling water on Earth are lighter than water and are pushed off the water’s surface through buoyancy. But bubbles formed in near-zero gravity are not lighter than the water and merge into amorphous blobs or stick to surfaces. “And so you get what’s called [boiling] surface dry out, where you can’t get any energy into the water because you can never get water to touch the surface,” explained Sears.

Sears designed a rotating heated cylinder that uses centrifugal force to keep water pressed against the cooking surface and pushes the bubbles toward the center. Sears next worked with his business partner, George Abuhamad, to develop SATED. The size of a toaster, SATED uses Sears’ cylindrical rotor technology to keep food adhered to the hot cooking surface in space. SATED consists of a Teflon-coated aluminum rotor resembling a kitchen pot that rests beside a control panel. Any food ingredients can be cooked with the device, but Abuhamad’s recent focus is pizzas. He outlined a pizza-making process using a Bisquick-type mix to form the dough, injecting tomato sauce with a syringe, and adding cheese and vegetable toppings in less than 20 minutes.

Nolux, the brainchild of researchers at the University of California, Riverside, uses artificial photosynthesis to grow plant- and fungal-based foods more efficiently. “What plants do is actually very energy inefficient,” said team leader Robert Jinkerson, a chemical and environmental engineering professor. “If you take sunlight, the plants waste 99 percent of that energy. Only about 1 percent makes it into the plant’s biomass.” Nolux replaces sunlight with “carbon dioxide electrocatalysis,” in which water, electricity, and carbon dioxide are converted into oxygen and acetate. The acetate is an energy source for plants, replacing the glucose produced via photosynthesis. Jinkerson’s team demonstrated 4 percent efficiency, a whopping 300-percent improvement upon photosynthesis when growing algae. Currently, the Nolux system consists of several shoebox-sized growth chambers fueled by an electrolyzer.

A significant advantage of Nolux is that it requires only electricity and water. No additional raw inputs are needed. Jinkerson said Nolux can produce yeast, algae, and fungi, but they’d like to expand its output to include fruit and vegetable crops. Annie Shelton, a researcher in Jinkerson’s lab, described Nolux’s mushroom product as a “mycelium mat” resembling a block of tofu. Mycelium makes up the root structure of mushrooms. Shelton claims the edible mat tastes like a regular mushroom with a more robust umami flavor. “You could not only put this mycelium mat in your salad; you could also turn it into powder and have supplements which would offer every aspect of nutrition that you would need,” said Shelton.

Kernel Deltech, the space division of Eternal Bioworks in Cape Canaveral, Fla., also created a fungi-producing system. A mini fridge–sized bioreactor adapted to work in space rapidly converts the organism Fusarium venenatum into mycoprotein, an edible fungus. Mycoprotein boasts an excellent nutritional profile, high in protein and fiber and low in saturated fats. Kernel Deltech’s CEO, Miguel Neumann, said the flavor is versatile. His team incorporated mycoprotein into ice cream, hamburgers, protein shakes, yogurt, and cheese.

Kernel Deltech hopes to use its technology alongside other Deep Space Food Challenge winners’ technologies, said Newmann. They want to use Nolux’s acetate substrate to feed their Fusarium organism in space. Ultimately, Neumann envisions coupling Kernel Deltech’s bioreactor with a 3D food printer to allow users to make complete meals with the press of a button.