The SpaceX Falcon 9 rocket slated to launch two NASA astronauts into orbit May 27 test-fired its nine Merlin booster engines Friday, May 22, on launch pad 39A at the Kennedy Space Center in Florida.

SpaceX test-fired a Falcon 9 rocket at Cape Canaveral Friday evening, igniting nine Merlin engines for several seconds while hold-down restraints kept the launcher on the ground. The company also confirmed the rocket is scheduled for takeoff Wednesday on a space station resupply mission, three days later than previously planned.

Boeing’s first Starliner spacecraft designed to fly to the International Space Station rolled out of a converted space shuttle hangar before dawn Thursday.