Growing vegetables in space is one thing, but it’s no place for the animals that most of us still rely on for key nutrients.
Will space-faring humans be forever denied the joy of a bacon sandwich? Is the true cosmic horror a solar system populated by evangelising veganauts?
I never thought I’d be pondering these questions when I began to write a story about human expansion and rebellious AIs in the 22nd century.
Meat vs protein
The same questions also bother space agencies around the world. Rather than ensuring my unhealthy diet is still available somewhere near Saturn in 2120, their goal is providing a healthy diet for astronauts.
When NASA announced the finalists of its Deep Space Food Challenge in May 2023, it was impossible to ignore the focus on providing meat substitutes as well as vegetables. Animals provide not only protein, but fats, iron, vitamins, micronutrients and amino acids. It’s a lot to replace.
As with veggies, the key challenge today is reducing the weight — and cost — of anything you take into space. The most efficient rocket today, SpaceX’s semi-reusable Falcon 9 Heavy, costs about €1,400 to send a kilogram into low Earth orbit. The fully reusable SpaceX Starship could cut that to below €100/kg by the 2030s. A century of development might see something like a space elevator that costs a few Euros per kilo, but no-one’s holding their breath for that to happen.
A fungi to feed you
As with plants, the lightest option is to take the ingredients and grow your own protein in space. Plant-based meat substitutes are a common sight on supermarket shelves and look certain to feature in space diets too.
Mushrooms have the advantage of being ready to cook, or eat, in their natural form. Only one of the DSFC finalists — Interstellar Lab — is actually growing edible fungi, but several are making mycoprotein using fungi. That sounds unappetising, but mycoprotein is already a household foodstuff through brands like Quorn.
Single-celled organisms like yeasts, algae and bacteria can also make edible protein. Like mycoprotein, it has to be processed before we can eat it, but its nutritional value can also be tailored to replace everything that we’re used to getting from meat.
Another bonus is that you can use the carbon dioxide breathed out by astronauts. The process makes alcohols that feed the protein-producing organisms, and oxygen to breathe. Very likely, some of the alcohol also makes its way to your space travellers in liquid form.
DSFC finalist Air Company already makes carbon neutral vodka, eau de parfum, hand sanitiser and aviation fuel (be careful not mix them up). Methanol also powers fuel cells for electricity and Starship uses its precursor — methane — as a rocket fuel.
Mushrooms and soy protein feature in White Kibble, a food from The Expanse that’s a staple of asteroid-dwelling Belters. Cheese powder and spices give it a warm and peppery taste and a cheesy aftertaste, but kibble-based foods are mentioned several times in the series.
Meat without the moo
If you want real meat without animals, then cultured meat can be grown from animal cells in a feed solution.
NASA has been working on it as an option for spaceflight since 2001. Aleph Farms has flown two missions to the International Space Station to grow cultured meat in microgravity. It’s yet to feed any astronauts, mainly because the ISS doesn’t yet have an oven that’s hot enough to cook meat.
The first lab-grown hamburger was served in 2013 in London, but cultured meat has had a long journey to win approval for human consumption. However, in 2023 the USA, Israel and Singapore all approved lab-grown meat products for public sale.
The biggest problem for cultivated meat as a space food is also a challenge on Earth. It’s grown using fetal bovine serum as food (yep, that’s blood product extracted from fetal cows). Solutions include using stem cells that can grow in something else and using plants or bacteria to produce a feedstock that mimics the serum. In zero-g, it’s also harder to keep the cells immersed in the growth medium, just as it is with plants in hydroponic systems.
As for the texture question hanging over meat substitutes, that’s a challenge for both mycoprotein, yeast-grown protein and cultured meat. In the next instalment, we’ll look at 3D bio-printing that combines different ingredients to mimic the structure of meat.
Cattle on the high frontier
One of the fun things about early visions of life in space is that diets without meat were still unusual in the West.
T. A. Heppenheimer’s 1977 Colonies In Space ponders chickens, pigs, rabbits and goats — even cows — in vast spinning orbital habitats. The livestock would eat waste from hydroponic greens and grain from fields of space wheat. Looking back, it’s science fiction unburdened by significant research.
Habitats on that scale are at least fifty years away, but animals still aren’t an absurd proposition for smaller spacecraft. As for the Moon, Mars and beyond, no-one knows how much gravity is enough to keep us healthy. Fifty years of manned space travel have only seen a few small-scale experiments on animals in microgravity.
The results aren’t encouraging. NASA provided mice with cages where they could grip the walls at feeding time, and they adapted quickly to floating, grooming themselves and eating. However, baby mammals can’t huddle together for warmth as they do on Earth, and it’s hard to nurse if they can’t find their mother’s nipple.
Fish and tadpoles swim in loops rather than straight lines, although fish will orient towards a light if it’s provided. Tilapia — a fast-growing white fish — could be a productive food source in zero gravity. As for birds, the USSR hatched Japanese quail chicks on a Salyut space station in the 1980s. They were hopelessly confused. I find it hard to care about birds, but I felt sorry for the chicks in this footage.
Various insects have thrived in space, and future food entusiasts often tout invertebrates as a protein source of the future. Once you get past the ick factor, the big problem is what happens when they escape, because they will get out.
The egg dilemma
Animals provide two things that we take for granted in Earth-based kitchens: milk and eggs. Milk is an emulsion of protein and fats that’s relatively easy to synthesise. It’s also the starting point for butter, cheese and yoghurt, but the right bacteria can be used to make these from many milk substitutes. In both cases, making it and making it taste good are very different challenges.
Eggs, however, need chickens or another farm-friendly bird, and Russia’s quail experiments rule out zero-g egg production. People do eat crocodile and snake eggs, but that sounds too much like the opening of a space horror story.
Fortunately, eggs can be replaced, at least in part. Solar Foods claims that its Solein protein powder can replace egg yolks in foods like pasta and noodles. It’s no runny egg on toast, but it’s a start.
Next course: cosmic cooking
We’ve got plenty of vegetables and some kind of protein, but how do you turn them into a meal? Everyday Earthside activities like food preparation, boiling, steaming, frying and baking are the cutting edge of space science, many of them pioneered in astronauts’ spare time.
I will also write about baking bread in space. Possibly too much.
* Congratulations if you recognised one of my favourites lines from Douglas Adams’s The Restaurant At The End Of The Universe.
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