Starship, the gargantuan rocket under development by Elon Musk’s SpaceX, is scheduled on Thursday morning to make a fourth attempt to get to space and back.

The previous three flights of the vehicle all ended in explosions, but each got farther than the last. Such progress is regarded as success in SpaceX’s break-it-then-fix-it approach to engineering and has been celebrated by some of the company’s fans. Those include Bill Nelson, the administrator of NASA, whose agency is depending on Starship to land astronauts on the moon.

Here’s what you need to know about today’s launch attempt.

The latest Starship is on the launchpad at the SpaceX site in South Texas, outside Brownsville. As with the other three flights, there are no people on board.

A two-hour launch window opens at 8 a.m. Eastern time on Thursday. SpaceX is scheduled to begin coverage of the launch at 7:30 a.m. Eastern on X, Mr. Musk’s social media service.

With the Starship spaceship on top of what SpaceX calls a Super Heavy booster, the rocket system is, by pretty much every measure, the biggest and most powerful ever.

The rocket is the tallest ever built — 397 feet tall, or about 90 feet taller than the Statue of Liberty, including the pedestal.