There’s so much we take for granted here on Earth. Oxygen. Gravity. Water. You know, the little things that make it possible for life to exist. But out in space, none of these things come naturally—which is why it’s so amazing that astronauts have managed to grow flowers aboard the International Space Station.

The cheerful zinnia blooms do more than just brighten up the space station, of course. They’re part of an experiment, begun in November 2015, that aims to understand how plants grow in microgravity. Astronaut Scott Kelly and his colleagues took on the role of space gardeners, working to coax their seedlings out of the soil and into bloom.

One month into the experiment, Kelly reported that the plants were struggling: 

(Mark Watney is the name of the main character in The Martian. His survival on the Red Planet depends, in part, on growing potatoes.)

NASA staff on the ground created and sent up a one-sheet space-gardening manual called “The Zinnia Care Guide for the On-Orbit Gardener.” Before long, Kelly and his fellow gardeners had their plants in fine condition. By January 12, the zinnias were sprouting, and on the 16th, they bloomed.

Kelly wasn't exactly correct. The orange zinnia might have been his first flower, but it wasn't the first. As Mika McKinnon at Gizmodo points out, astronauts have been growing plants—including flowers—in space for decades. The real first space flowers bloomed in 1993. Since then, astronauts have conducted a number of successful gardening experiments, including a memorable "talking" zucchini plant that kept a diary.