Engineers completed a final test of Starship's propulsion system with a so-called "spin prime" test Wednesday at the launch site in South Texas. Ground crews then rolled the ship back to a nearby hangar for engine inspections, touchups to its heat shield, and a handful of other chores to ready it for liftoff.

Liftoff from the company's Starbase, Texas, manufacturing and test site is expected during a launch window that begins at 7:30 p.m. EDT (2330 GMT). SpaceX announced the launch date on X Friday (Aug. 15), about one week later than SpaceX CEO Elon Musk predicted in mid-July when he estimated Starship would launch again in "about three weeks."