How NASA's MOXIE Made Oxygen on Mars, and Why It's Not Enough

Everything NASA has ever made on the surface of Mars, every gram of oxygen, all of it, across two and a half years... adds up to what a small dog breathes in about ten hours.

A dog. Ten hours. That's the total?

One hundred and twenty-two grams. That's NASA's own comparison, by the way, not me being mean.

So when people argue about who lands first in twenty thirty whatever...

They're all quietly assuming the breathing part is solved. Hold onto that, because there's a line in a NASA paper from this July that I want to read you at the end. It's one word in capital letters, and it tells you how late we are.

Okay. Start with the dog machine.

April, twenty twenty-one. A box the size of a car battery, bolted inside the belly of the Perseverance rover, wakes up in Jezero Crater. Two hours of warm-up. Then it starts pulling in Martian air and splitting it apart. Six grams of oxygen an hour.

Six grams means nothing to me. Translate.

About ten minutes of breathing. For one person.

We flew that across two hundred million miles... for ten minutes of air.

We did, and NASA called it a milestone, correctly. It was called MOXIE. It ran sixteen times. Last run, August seventh, twenty twenty-three, nine point eight grams. And here's the part nobody mentions when they laugh at the dog number... it beat its target. At its best, twelve grams an hour, ninety-eight percent purity or better. Double what the engineers promised.

So the physics is fine.

The physics is fine. The scale is the entire problem.

Then give me the real number. Four people, Mars. What do they actually need in a day?

Per person, per day: about two and a half kilos of water for drinking, cooking, washing. And each of them breathes out roughly a kilo of carbon dioxide. Now multiply by four. Then by months of flight, plus surface time, plus the ride home.

And you can't just... pack it on the ship.

Before the space station had recycling, water was close to half the payload on shuttle flights. Half. Water is the single heaviest thing about being alive.

Which is why we get to the famous bit. The urine.

The famous bit. Sweat, breath condensation, urine. In twenty twenty-three the station crew hit ninety-eight percent water recovery. Christopher Brown, on the life support team at Johnson Space Center, put it perfectly. Imagine you launch with a hundred pounds of water. You lose two pounds. The other ninety-eight just keeps going around and around.

Around and around for three years. And when the pump dies?

On the station, a broken part gets a resupply ship in weeks. On Mars, the next launch window is roughly twenty-six months away. Nobody is coming.

Right. So food. Everyone pictures the potato farm.

Everyone pictures the potato farm. Reality, for the first crews, is pre-packaged food from Earth, water recycled and pulled out locally. NASA rehearsed it on the ground: four volunteers, a year sealed inside a simulated Mars habitat in Houston. The CHAPEA mission, starting June twenty-fifth, twenty twenty-three. They had a crop growth station.

Which is a fancy way of saying a very serious houseplant shelf.

Lettuce, not wheat fields. Fresh nutrition, variety, and honestly morale. There's good evidence plants help people psychologically in a sealed box.

But can anything actually grow in Martian dirt? Or is that still just a movie?

It's live science right now. March of this year, two studies in Scientific Reports. One grew chickpeas in simulated lunar soil and found that treating it with symbiotic fungi and worm-produced compost significantly improved the odds the plants made it to seed.

Worm compost. We're shipping worms to Mars.

Don't rule it out. The other paper tested whether microbes could survive in a Martian soil simulant with barely any available water. But look at the photos. Yellowing leaves. Stressed plants. It's not a garden yet.

Okay. The capitalized word. What's the July paper?

Engineers writing about a Mars portable life support system, the little machine strapped to your back when you walk outside. They said development of a Mars-centred spacesuit must begin... NOW. That's this year. Twenty twenty-six. They are still choosing between schematics.

So the rockets are further along than the plumbing.

That's the honest state of play. Les Johnson, former chief technologist at Marshall Space Flight Center, told Sky at Night this summer a crew will need a full habitat comparable to the living space on the station. And a national academies report last year named the real goal: bioregenerative systems. Waste, air, water, food, all looping into each other.

Which doesn't exist.

Not at crew scale. What exists is ninety-eight percent water recovery in orbit, a dog's worth of oxygen made on Mars, and some stressed chickpeas in fake moon dirt.

So what do I watch for?

The next scaled-up oxygen demo. And whether a Mars suit ever gets funded past the paper stage. Getting to Mars is one engineering problem. Staying alive there is a thousand of them... and every single one has to keep working for twenty-six months, with nobody coming.