On Monday, Aug. 29, NASA’s Space Launch System—the rocket that will return American astronauts to the moon in this decade—is set to take off on its first uncrewed test flight, with liftoff scheduled for 8:33 AM ET. The mission will send an Orion crew capsule on a 42-day mission that will see it making two giant loops around the moon before heading home for a Pacific Ocean splashdown in mid-October. | TIME