NASA says its Perseverance rover has successfully turned carbon dioxide on Mars into oxygen. The rover used a toaster-sized piece of equipment nicknamed MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) to produce 5.4 grams of oxygen—enough to sustain an astronaut for about 10 minutes. “This is a critical first step at converting carbon dioxide to oxygen on Mars,” said Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate. “Oxygen isn’t just the stuff we breathe. Rocket propellant depends on oxygen, and future explorers will depend on producing propellant on Mars to make the trip home.” NASA intends to scale up production: a future version of MOXIE will weigh about a ton, researchers say.