It’s not rocket science, but growing plants in space may finally be down to a science. As part of an effort to feed themselves on journeys to Mars—or elsewhere—astronauts on the International Space Station have spent years dealing with the difficulties of growing plants in space, The Scientist reports. They started with zinnias, which were often waterlogged or dried out, thanks in part to how microgravity affected water uptake. However, astronauts eventually found the perfect solution: watering them as if they were on Earth. Because of the zinnia’s success, astronauts began growing cabbage, lettuce, and other small greens. The greenhouse where they are raised, known as the Veggie, is a model for bigger greenhouses that may feed astronauts on their way to the Red Planet, making it possible for them to venture into new territories without worrying about starvation.