Watch NASA roll out its moon-bound mega-rocket for the first time on Thursday evening

• NASA’s new mega-rocket is rolling to the launchpad for the first time Thursday.
• NASA designed the Space Launch System to return astronauts to the moon and set up a base there.
• Watch the rocket roll out live, below. It’s poised to launch to the moon for the first time in June.

NASA has spent more than a decade building a new mega-rocket for its return to the moon, and the 30-story vehicle is finally ready to roll to the launchpad Thursday evening.

The Space Launch System (SLS) is composed of a massive core stage with four car-sized engines, two rocket boosters strapped on its sides, and an Orion spaceship secured to its top. It’s the cornerstone of NASA’s new Artemis moon program. SLS is slated to fly astronauts to the moon for the first time since 1972, using SpaceX’s Starship vehicle as its lunar lander. Eventually, NASA plans to set up a base on the lunar surface.

But first, NASA has to prove that SLS can fly. Now that the first iteration of the rocket, called Artemis I, is fully stacked and thoroughly tested, NASA is rolling it out of its Vehicle Assembly Building to a launchpad at the Kennedy Space Center in Cape Canaveral, Florida.

“That’s really an iconic moment for this vehicle,” Tom Whitmeyer, NASA’s associate administrator for exploration systems development, said in a press briefing on Monday.

NASA will share the sight of the towering rocket leaving its assembly building for the first time in a live broadcast starting at 5 p.m. ET, in the video embedded below. That’s when the rocket is scheduled to start moving.

A crawler transporter is ready at the Vehicle Assembly Building, which will carry the rocket upright for 4 miles to the launchpad. The crawler has been carrying rockets to the launchpad for more than 50 years, but it got major upgrades and new weight testing to ensure it could transport the behemoth Artemis I.

“It’s going to be just a wonderful, wonderful sight, when we see that amazing Artemis vehicle cross the threshold of the VAB, and we see it outside of that building for the very first time, I think it’s going to really be breathtaking,” Charlie Blackwell-Thompson, Artemis launch director, said in the briefing.

NASA expects the rollout to take six to 12 hours.

At the launchpad, the Artemis I rocket will run through a wet dress rehearsal, where launch controllers practice the eight-hour process of loading the rocket with fuel, and counting down all the way to 10 seconds before liftoff, then stopping and emptying the tanks. That test is scheduled for April 3. If it goes well, NASA plans to fire the engines and send Artemis I roaring into space for the first time as early as June.

That first mission aims to send the Orion spaceship around the moon and back to Earth without humans on board. If that goes well, the next SLS mission will carry astronauts on the same roundabout.