WASHINGTON — Space Exploration Technologies Corp. (SpaceX) confirmed May 21 that its second attempt to launch a cargo-delivery demonstration mission to the international space station (ISS) will take place in the early morning hours of May 22.

SpaceX now plans to launch at 3:44 a.m. local time from Launch Complex 40 at the Cape Canaveral Air Force Station in Florida. The company scrubbed its first launch attempt May 19 at the last second when a flight computer on its Falcon 9 rocket detected higher-than-expected pressure in the combustion chamber of one of its nine core-stage engines.

SpaceX traced the problem to a faulty check valve on the rocket’s fifth core-stage engine. SpaceX has since replaced the valve.

“The failed valve was replaced on Saturday and after thorough analysis the vehicle has been cleared for launch,” SpaceX spokeswoman Kirstin Grantham said in a May 21 statement.

If the launch succeeds, Falcon 9 will loft SpaceX’s uncrewed Dragon spacecraft into orbit, where it will attempt four days of automated maneuvers. If these succeed, Dragon will be berthed to ISS and become the first privately operated vessel to visit the orbital outpost.

If SpaceX can then detach Dragon from station and recover the spacecraft back on Earth, it will be cleared to begin regular ISS cargo shipments later this year under a $1.6 billion contract the company signed with NASA in 2008.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.