SpaceX scrubbed its first attempt today to launch its super heavy Starship rocket from the company’s Texas launchpad. Instead, the SpaceX team used the attempt as a “wet rehearsal” for a launch.

A “pressure issue” caused the cancellation, but there was no further word immediately from the launch site.

“I guess I’d like to just set expectations low,” SpaceX CEO Elon Musk said during a Twitter “Spaces” event for his subscribers Sunday evening. “If we get far enough away from launch pad before something goes wrong, then I think I would consider that to be a success. Just don’t blow up the pad.”

The rocket is designed to be reusable and big enough to carry cargo and astronauts to the moon and the International Space Station. It will also lift next generation of the company’s Starlink satellites providing broadband Internet coverage to remote areas of the Earth.