Half the medicines on the International Space Station expire before astronauts can use them. Now, scientists have figured out how to grow fresh drugs in space — using plants.Here is a problem nobody thinks about when they dream of sending humans to Mars: what happens when an astronaut gets sick 100 million kilometres from the nearest pharmacy?
It turns out, the medicines they carry may not even work by the time they need them.
Even aboard the International Space Station — just 400 kilometres above Earth — more than half the medications stocked there have been found to expire within three years. A trip to Mars takes around 200 days each way. Do the math, and the situation looks alarming. Carry enough medicines for a three-year Mars mission, and you are essentially packing boxes of drugs that will be useless before you get home.
Resupplying from Earth? Not an option when you are millions of miles away.
Now, engineers at the University of California San Diego think they have cracked the problem — with plants.
The Idea: Turn Plants Into Drug Factories
The UC San Diego team developed a simple method to grow and repeatedly harvest pharmaceuticals from plants under space-like conditions, without destroying the plants or generating large amounts of waste. Think of it as a mini pharmaceutical factory that runs on sunlight, water, and soil — and fits inside a spacecraft.
“With plants, you can grow complex therapeutic compounds using light, water and soil,” said study senior author Nicole Steinmetz. That is a massive advantage over conventional drug manufacturing, which requires giant sterile tanks, complex equipment, and supply chains that simply cannot follow you to another planet.
The findings were published on June 5 in the journal npj Science of Plants.
The Drug: A Cancer-Fighting Virus From a Bean Plant
The compound the team chose to demonstrate this idea sounds almost absurd at first — a plant virus called cowpea mosaic virus, or CPMV, grown from black-eyed pea plants and Nicotiana benthamiana, a relative of tobacco.
But here is the twist: while CPMV is more commonly known for infecting legumes, Steinmetz’s team has spent more than a decade studying its ability to stimulate the immune system to attack cancer cells. The compound has shown strong anti-tumor effects in preclinical mouse models and in clinical studies in canine cancer patients.
In short, a humble bean plant virus could one day be medicine’s answer to cancer — grown fresh, on demand, aboard a spacecraft hurtling toward Mars.
The Biggest Problem They Solved
Growing the compound in plants was not the hard part. Getting it out was.
Extracting pharmaceuticals from plants typically involves picking leaves and grinding them up. “You end up with something that looks like a smoothie, and you can imagine getting your product out of that smoothie is challenging,” said study first author Patrick Opdensteinen. “The equipment that we use to do this fills our entire lab. You can’t fit all that on a spacecraft.”
The team solved this with an elegantly simple method. The leaves are submerged in a buffer solution, placed in a sealed vessel, and a vacuum is applied — which floods the interior spaces of the leaf with fluid. The saturated leaves are then gently spun in a centrifuge to draw the liquid back out, and the resulting extract is filtered to isolate the pharmaceutical particles.
The leaves survive the process entirely intact. The plant keeps growing. The same plant can be harvested again and again.
Researchers were able to harvest and purify the compound from more than 50 plants in under two hours.
Tested Under Space-Like Conditions
The team did not just test this on Earth. To simulate microgravity, they built a custom random positioning machine — a device that continually rotates the plants to effectively cancel out gravity. The plants were also exposed to temperature fluctuations and oxidative stress to mimic the effects of space radiation.
The results were surprising. In some cases, the stress of simulated space conditions actually increased the yields of the compound. The researchers hypothesise this may be because plants become more susceptible to viral infection when stressed — and since their product is derived from a plant virus, that stress response works in their favour.
Space, it turns out, might actually make the medicine stronger.
The Road to Mars — and the Clinic
The team’s ultimate goal is to test this method on actual space missions. There is still work to be done — understanding how rocket launches affect seeds, how plants absorb water in zero gravity, and whether the process can be scaled up further.
But the implications stretch well beyond space travel. The method could also bring low-cost pharmaceutical production to resource-limited areas on Earth — remote villages, disaster zones, or parts of the world where a cold supply chain simply does not exist.
From a bean field to a spacecraft to a cancer ward, the humble plant may be about to become medicine’s most unexpected frontier.
-Rashmi Kumari
