SpaceX fired up its SN20 Starship prototype in earnest for the first time Thursday night (Oct. 21), notching a big milestone on the vehicle's planned path to orbit.
The 165-foot-tall (50 meters) SN20, which is currently outfitted with two Raptor engines, performed a brief "static fire" test at 8:16 p.m. EDT Thursday (0016 Oct. 22 GMT) at SpaceX's Starbase facility, near the South Texas town of Boca Chica.
The test seemed to involve just one of the two Raptors, as pointed out by commentators with NASASpaceflight.com, which livestreamed the event. One of SN20's engines is a standard "sea-level" Raptor, whereas the other is a "vacuum" version, which is optimized to operate in space.
About half an hour after the test, SpaceX confirmed via Twitter that the vacuum Raptor had fired up. It was the first such trial of a vacuum Raptor integrated on a Starship vehicle, according to the company.
Then, at 9:18 p.m. EDT (0118 GMT) on Thursday, SN20 conducted a second static fire. This one looked a bit brighter and more powerful than the first and may have involved both Raptors, as a NASASpaceflight.com commentator noted.
First firing of a Raptor vacuum engine integrated onto a Starship pic.twitter.com/uCNAt8KwzoOctober 22, 2021
SpaceX is developing Starship to take people and cargo to the moon, Mars and other distant destinations. NASA has already signed on, picking Starship as the first crewed lunar landing system for its Artemis moon program.
Starship consists of two elements: a spacecraft called Starship and a giant first-stage booster known as Super Heavy. Both will be fully reusable, and both will be powered by Raptors — six for the final Starship and 29 for Super Heavy.
SN20 will eventually sport six Raptors — three standard and three vacuum. SpaceX is prepping the vehicle for an orbital flight test in the coming months, a first for the Starship program. Starship prototypes have launched before, but those were three-engine (at most) vehicles that reached a maximum altitude of about 6 miles (10 kilometers).
SN20 and a Super Heavy known as Booster 4 will launch from Starbase. The booster will make an ocean splashdown in the Gulf of Mexico, about 20 miles (32 km) from the launch site. But SN20 will go all the way to orbit, if all goes according to plan, and eventually splash down off the Hawaiian island of Kauai.
SpaceX aims to launch that landmark test flight relatively soon, but the timeline is not entirely in the company's control. The U.S. Federal Aviation Administration (FAA) is conducting an environmental assessment of Starship's orbital launch site. The FAA recently released a draft of that assessment, but more work needs to be done; the agency will accept public comments on the draft until Nov. 1, then incorporate those comments into the final report.
While today marked SN20's debut static fires, the vehicle has breathed flame before. On Monday (Oct. 18), SpaceX conducted a brief test of the vehicle's preburners, which heat and mix the Raptor engines' liquid methane and liquid oxygen propellants.
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.