SpaceX rolls 29-engine Super Heavy rocket to launch site (video)

SpaceX's first true Super Heavy booster has made it to the launch site.

A few days ago, technicians installed 29 Raptor engines on a Super Heavy known as Booster 4 at SpaceX's Starbase site, near the South Texas village of Boca Chica. And today (Aug. 3), the company rolled the 230-foot-tall (70 meters) Booster 4 from its build facility to the launch site, a few kilometers down the road.

SpaceX will soon start subjecting Booster 4 to a series of pressurization and engine tests. If all goes well with those trials, the rocket will be poised for an orbital launch attempt, which could occur within the next few months. 

Related: SpaceX's Starship and Super Heavy rocket in pictures

Super Heavy is the first stage of Starship, a fully reusable, two-stage transportation system that SpaceX is developing to carry people and cargo to the moon, Mars and other distant destinations. NASA recently selected Starship as the crewed lander for its Artemis program, which aims to establish a sustainable human presence on and around the moon by the end of the 2020s.

Starship's upper stage is a 165-foot-tall (50 meters) spacecraft that is also known, somewhat confusingly, as Starship. The final Starship spacecraft will have six Raptors, and the final Super Heavy will likely be powered by 32 of the engines, SpaceX founder and CEO Elon Musk has said.

Starship spacecraft prototypes have launched before. This past May, for example, a three-engine vehicle known as SN15 ("Serial No. 15") flew to a maximum altitude of 6.2 miles (10 kilometers) and came down for a safe landing back on Earth.

SpaceX performed engine tests last month on Booster 4's predecessor, the three-Raptor Booster 3, but no Super Heavy has gotten off the ground to date. Booster 4 will change that, if all goes according to plan. SpaceX plans to launch the rocket, topped with the SN20 Starship prototype, from Starbase on an uncrewed orbital test mission

Shortly after launch, Booster 4 will splash down in the Gulf of Mexico, about 20 miles (32 km) offshore. SN20 will power itself to orbit, complete one loop around our planet and come down in the Pacific Ocean near the Hawaiian island of Kauai, about 90 minutes after liftoff.

It's unclear when Booster 4 and SN20 will fly. Even if the duo sail through all their prelaunch checkouts and tests, logistical roadblocks may yet keep them grounded. For example, the U.S. Federal Aviation Administration is performing an environmental review of Starship's launch operations, and we don't know when that will wrap up. 

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook. 

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.