SpaceX was supposed to make history with NASA astronauts on Wednesday, but due to threatening weather conditions in Florida, the launch has been called off. Another attempt will be made on Saturday, May 30, at 3:22 p.m. ET, weather permitting.

The mission, called Demo-2, is the first crewed launch in the history of Elon Musk’s company. It’s also NASA’s first time sending astronauts into space since 2011.

President Donald Trump and vice president Mike Pence were among the VIPs in attendance at Thursday’s launch at NASA’s Kennedy Space Center.