The cosmic cafe

Since the dawn of the Space Age, astronauts have survived off processed, prepackaged food. From burritos to shrimp cocktails, these days, ISS is stocked with hundreds of meal options to choose from. But most fresh food remains firmly off the menu. It’s not just about satisfying the hankerings for a salad, either.

Prepackaged food has lower levels of some key nutrients, and the ones that are there can degrade over time. That means NASA will have to sort out a supply of fresh food before sending astronauts farther out into the solar system. (Interestingly, the scientists say that some space-grown lettuce actually had higher levels of potassium and minerals, but they caution that their sample size was too small to draw any sweeping conclusions.) Plants could also aid life-support systems on a space colony by sucking up carbon dioxide and pumping out oxygen.

But for all the benefits it offers, space farming presents many challenges.

To start, there’s no gravity, soil or rain, and the sun rises 16 times per day. Everything also has to be sent from Earth. In just one week, life on the ISS is hit with a year’s worth of radiation on the ground. And then there’s the less-obvious challenges.

Without tiny astronaut bees or other pollinators, humans have to take time to carefully monitor the plants and then jump in at exactly the right time to move pollen from flower to flower. Miss the pollination window and you’ve lost your next crop.

Astronaut farmers

Scientists have been studying these problems since before NASA even existed. As far back as the 1940s, rocket-borne experiments were sending seeds into space to learn how the radiation changed living tissues. That’s decades before humans would experience a microgravity environment. The first serious, long-duration studies were conducted on Russia’s Mir space station, which was humanity’s first outpost in orbit. There, scientists and cosmonauts spent years experimenting with growing and eating a variety of simple crops.

The results were often troubling.

In joint experiments with NASA, scientists attempted to grow wheat on Mir. Early on, the plants grew excessive numbers of leaves and never flowered. Later tests got the wheat to reach its seed phase, but the seeds proved sterile, perhaps due to a fungus growing on the station that emits a sterility-causing gas. Other plants ended up puny compared to ground controls.

Thanks to some extreme space farming efforts, Mir did eventually manage to grow leafy greens from seed to seed. But even then, the second-generation space crop was weak, perhaps due to disruptions after a resupply capsule collided with the space station.

Growing crops also has been a major focus of science on the ISS over the past two decades. It’s now hosted dozens of plant-growing experiments.

And the two Veggie chambers on ISS, together with a more complicated Advanced Plant Habitat, have been designed to take these studies to the next level. Legions of sensors and clearly defined protocols let researchers reduce variables and replicate their experiments. This system also allowed them to steadily build toward farming increasingly complex crops.