Last month, SpaceX pulled off an incredible feat. On the fifth test flight of its enormous Starship rocket, the booster stage returned to the launchpad and was caught in midair by two large mechanical arms on the launch tower.

Starship’s sixth test flight will try to repeat that feat and accomplish some other goals, too. The president-elect, Donald J. Trump, is also expected to be in attendance. Here’s what you need to know about Tuesday’s launch.

When is the test flight, and how can I watch it?

The launch may occur as early as Tuesday during a 30-minute time slot starting at 5 p.m. Eastern time. SpaceX will stream coverage of the test flight beginning about 30 minutes before liftoff from SpaceX’s site in South Texas near the city of Brownsville.

What is Starship?

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

And it has the most engines ever in a rocket booster: The Super Heavy booster — the bottom part of the rocket — has 33 of SpaceX’s powerful Raptor engines sticking out of its bottom. As those engines lift Starship off the launchpad in South Texas, they will generate 16 million pounds of thrust at full throttle.

The upper part, also called Starship or Ship for short, looks like a shiny rocket from science fiction movies of the 1950s, made of stainless steel with large fins. This is the upper stage that will head toward orbit, and ultimately could carry people to the moon or even Mars.