WASHINGTON (Reuters) -SpaceX postponed its second attempt to launch the company's Starship rocket system into space by a day to Saturday, Chief Executive Elon Musk said, citing a piece of flight control hardware that needed replacing.

"We need to replace a grid fin actuator, so launch is postponed to Saturday," Musk wrote on messaging platform X.

The launch is set to take place at the company's Starbase site on the Gulf of Mexico near Boca Chica, Texas.

SpaceX is aiming to make a second attempt at launching its 400-foot-tall (122 meters) Starship rocket system into space for the first time, following an April test flight in which the rocket exploded roughly four minutes after lifting off from Texas.

Company officials have said the rocket has been ready to fly for months, pending approval of a license by the U.S. Federal Aviation Administration, which the company obtained on Wednesday.

The upcoming flight is one of many crucial tests in SpaceX's development campaign to build a fully reusable rocket capable of sending some 150 tons of satellites into space, as well as humans to the moon and eventually Mars.

(Reporting by Joey Roulette; Editing by Chris Reese and Will Dunham)