A successful static-fire engine test shortly after 4 p.m. Wednesday clears the way for a high-altitude launch from Boca Chica Beach of SpaceX’s Starship SN9 prototype, possibly as early as Friday.

SpaceX founder and CEO Elon Musk, meanwhile, has teased the possibility of launching two Starships simultaneously from Boca Chica in the near future.

The SN9 was rolled to the launch pad on Dec. 22, following the Dec. 9 high-altitude flight of the SN8, which flew to 41,000 feet before making a controlled, free-fall descent that was a first for a Starship prototype. Although the SN8, the first multi-engine Starship prototype, came in too fast and disintegrated upon landing, SpaceX heralded the test as a major success.

Testing leading up the SN9’s launch, including pressurization testing, has moved at a much faster clip than testing for the SN8. Cameron County ordered closures of Boca Chica Beach and S.H. 4 from the beach F.M. 1419 (Oklahoma Avenue) from 8 a.m. to 5 p.m. on Jan. 6 in advance of Wednesday’s expected test of three engines fitted in the SN9. The Federal Aviation Administration issued Temporary Flight Restrictions for the area around the launch site for Jan. 6-10 in expectation of an impending launch.

A SN9 launch would be the fifth flight of a Starship prototype at Boca Chica, the second high-altitude flight and second flight of a prototype with more than one engine. SN10 and SN11 are nearing completion in SpaceX’s production complex. The company has also started building the first Super Heavy, a 28-engine, 230-foot-tall booster rocket designed to help propel Starship into orbit and beyond.

The Starship development program is aimed at eventual mass production of a vehicle capable of ferrying cargo and people to the Moon and Mars as well as Earth destinations. SpaceX in 2019 concentrated its Starship program at Boca Chica. Prototype development had been previously been taking place in Florida as well.

“Production is hard, prototypes are easy,” Musk tweeted on Dec. 30. “Building ~1000 Starships to create a self-sustaining city on Mars is our mission.”

And a dual launch at Boca Chica could be coming soon, he suggested. In response to a Photoshopped image posted to Twitter by RGV Aerial Photography showing two gleaming silver prototypes at the launch site, Musk tweeted, “It will be real soon.” In response to a question this month about whether a double launch could take place in the next few weeks, Musk tweeted simply, “Yes.”