The star of NASA's megarocket reveal isn't the big rocket

They call it the crawlers.

On March 17th, NASA will send its new moon-bound megarocket to the Kennedy Space Center. It is a dress rehearsal for a real show when an uncrewed spaceship blasts off and travels around the moon. In the open Florida air for the first time, the space agency will eventually load the completed 322-foot-tall rocket with super-cold propellant and practice a nail-biting countdown.

All the subsequent launches to the moon and beyond depend on a renovated relic from the historic Apollo missions. NASA built two huge tank-like vehicles to carry its legendary Saturn V rocket to the launch stage. The most powerful rocket ever built, the SLS, will be transported by the Crawler-transporter 2.

The only way for an SLS launch to happen is on our back, according to John Giles, the engineering operations manager.

NASA will broadcast live coverage of the launch between 5 and 6 p.m. On March 17. The rocket is expected to arrive at the launchpad in the early hours of March 18. On April 3, the actual fueling will take place.

The renovated crawlers can carry 18 million pounds, six million more than during the Apollo years. The machine will carry the loads of both the rocket and the mobile launcher as it rumbles across a four-mile road of pebbles on its way to the coast. The journey from where the rocket is built to the launchpad can take up to eight hours.

The machine is large. It is 131 feet long and 114 feet wide. Its surface is larger than a baseball infield. A person looks small next to the tracks.

Unless you have been next to it, you have no idea how big it is.

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The crawler was not built for speed. Tammy Long, a public affairs officer supporting NASA's SLS launch, said that its purpose is to safely get a giant, expensive rocket to its coastal launch pad.

The crawler will start rolling at just 0.05 mph once it moves under the mobile launching tower. It will top out at 0.85 mph, never reaching 1 mph. Near the end of the journey, the crawler will climb a slope to the pad.

Modifications to the historic crawler were made by NASA. New brakes, generators, engine parts, structural support, and beyond were added to support NASA's looming SLS missions. If NASA succeeds in sending a crew to Mars for a month in the 20th century, that deep space mission will begin with the crawler.

The crawler moving the Mobile Launch Platform during a test. Credit: NASA / KSP

In the 1960s, the crawler hauled the legendary Saturn V rocket to the launchpad at the Kennedy Space Center. Credit: NASA

NASA's engineers have practiced driving their retrofit crawler to prepare them for the Artemis 1 uncrewed launch in 2022. They have lifted and moved heavy launch platforms for half a decade.

Twelve years have passed since the rocket will be revealed to the world. NASA decided to use an old Apollo-era crawler to move its new megarocket.

The engineers of the crawler will watch from Florida as the SLS goes through the atmosphere at 17,500 mph. Without the slow tank inching toward the Florida coast, that rocket isn't going anywhere.

Giles said that this is a huge mission.