Your Future Mars Protein Shake Is Made From Air… and Pee

Did you know the European Space Agency has finally answered the question nobody sane ever asked: what if we could turn astronaut breath and astronaut piss into lunch? This is not satire. This is not Black Mirror. This is the HOBI-WAN programme, ESA’s straight-faced attempt to solve the eternal human problem of “what do we eat when we’ve flown so far from Earth that even freeze-dried lasagne becomes a luxury item?”

The recipe feels almost insultingly crude. You take the CO₂ the crew breathe out, generate hydrogen with electrolysis, blend in carefully rationed oxygen so nothing catches fire, and round it all off with nitrogen stripped from astronaut urine. The final ingredient is always urine. Space never lets you forget that.

Feed all of this into a bioreactor full of hydrogen-oxidising bacteria, tiny chemoautotrophic organisms that neither know nor care they’re holding the nutritional future of our species together. They simply consume gases, ignore the existential nightmare that is microgravity, and turn everything into a protein-dense microbial flour called Solein, the same stuff Solar Foods cultivates on Earth using chemoautotrophic industrial alchemy.

Solein itself is weirdly respectable for something born in a gas fermenter. It tastes faintly umami, has all the essential amino acids, and even provides vitamin B12, which plants famously refuse to help with. It is, in biochemical terms, a gift. In psychological terms, it’s a trust exercise.

The “eew” factor isn’t a bug; it’s the entire foundation of life-support economics. Space doesn’t have spare mass for comforting illusions. Everything you exhale, sweat, or flush eventually comes back in another form. HOBI-WAN leans into this reality with eerie confidence, siphoning nutrients from urea and folding them back into tomorrow’s breakfast. It’s grotesque, but it solves the most expensive part of interplanetary life: moving food around.

The engineering case behind the whole thing is brutally pragmatic. The Equivalent System Mass, the sacred metric, determines whether a technology flies or gets buried in a PowerPoint graveyard. And by that measure, HOBI-WAN wins. It beats hydroponics, beats microalgae vats, beats shipping crates of food across millions of kilometres. According to ESA’s own trade studies, the Equivalent System Mass of this microbial approach is so low that refusing it would be the space-economics equivalent of choosing a horse over a rocket.

The real complications live in the physics, because microgravity is where sensible engineering goes to lose its grip on reality. Bubbles don’t rise. Liquids don’t settle. Anything that depends on gravity, which is, inconveniently, most things, must be redesigned from scratch. Mixing the gases becomes a nightmare, separating them even worse, and the constant risk of accidental hydrogen-oxygen intimacy sits in the background like a quiet threat. The bioreactor has to keep everything agitated, oxygenated, stable and non-explosive, all while orbiting Earth at 17,000 mph.

And once the microbes have done their job, astronauts must deal with the final form of their own metabolic recycling. On Earth, Solein is spray-dried into a powder and blended into foods. In space, drying is a thermal luxury no mission designer will approve, so the crew get it in its natural state, a thick beige “space paste” with a texture best described as “optimistically edible.” It isn’t meant to be beautiful. It’s meant to keep you alive long enough to resent it.

Yet despite all this, there’s a strange beauty in the loop. Future astronauts will step onto Mars carrying inside them a blend of microbial protein derived from their own recycled breath and the filtered remains of yesterday’s toilet visit. The first human to walk across the red dust may do so powered by an unholy marriage of efficiency, necessity, and bacteria that have no concept of heroism.

There’s something strangely fitting about that. For all our talk of rockets and dreams, the thing that truly enables deep space travel isn’t glamour; it’s a closed-loop system quietly turning human waste into nutrition. If civilisation ever collapses, archaeologists won’t marvel at the rockets, they’ll marvel that humanity learned to feed itself using little more than air, microbes, electricity, and the unwavering consistency of the human bladder.

A perfect loop.

A self-sustaining cycle.

Humanity, running on its own fumes, and calling it progress.