SpaceX plans to launch its giant Starship into space for the second time on Thursday, April 20. In an updated release from SpaceX, the 62-minute launch window opens at 09:28 ET (1:28 pm GMT) on Thursday. The long-awaited test mission.

The flight will be the first fully assembled Starship, the giant vehicle SpaceX has developed to take humans and cargo to the moon, Mars and beyond. The launch will take place from Starbase, SpaceX’s facility in South Texas.

SpaceX attempted to launch the mission today (April 17), but canceled the attempt less than nine minutes before its scheduled launch due to a problem with the sealing system in Starship’s first stage, a massive rocket booster called the Super Heavy.

The future flight plan calls for the Super Heavy to make a hard landing in the Gulf of Mexico about eight minutes after takeoff. Meanwhile, the Starship booster spacecraft will make a partial orbit around Earth and land in the Pacific Ocean near Hawaii about 90 minutes after launch.

But SpaceX doesn’t necessarily expect all of this to happen. This will be the first flight of a powerful and complex vehicle into space, so it wouldn’t be surprising if something goes wrong.

“Success with a test like this is measured by how much we can learn, which will inform and increase the likelihood of future success as SpaceX rapidly advances the development of the Starship,” SpaceX said in its mission statement.