SpaceX's Starship, a futuristic vehicle designed to eventually carry astronauts to the moon and beyond, was poised for a third uncrewed test launch on Thursday that Elon Musk's company hopes will carry it farther than before, even if it ends up exploding once again in flight.
The spacecraft, mounted atop its towering Super Heavy rocket booster, was due for liftoff as early as 8 a.m. EDT (1200 GMT) from SpaceX's Starbase launch site on the Gulf of Mexico near Boca Chica, Texas.
The U.S. Federal Aviation Administration just granted a license for the test flight on Wednesday afternoon.
Unlike the first two test flights last year, aimed mainly at demonstrating that the spacecraft's two stages can separate after launch, the third test flight will involve an attempt to open Starship's payload door and reignite one of its engines in space.
Each of the previous flights were routed toward a planned crash landing near the Hawaiian islands in the Pacific, while the latest flight is targeting a splashdown zone in the Indian Ocean.
Even if it achieves more of its test objectives than before, SpaceX acknowledges a high probability that Starship's latest flight will end up like the first two, with the vehicle blowing itself to bits before its intended trajectory is complete.
Regardless of how well it performs on Thursday, all indications are that Starship remains a considerable distance from becoming fully operational.
Musk, SpaceX's billionaire founder and CEO, has said the rocket should fly hundreds of uncrewed missions before carrying its first humans. And several other ambitious milestones overseen by NASA are needed before the craft can execute a moon landing with American astronauts.
Still, Musk is counting on Starship to fulfill his goal of producing a large, multipurpose next-generation spacecraft capable of sending people and cargo to the moon later this decade, and ultimately flying to Mars.
Closer to home, Musk also sees Starship as eventually replacing the SpaceX Falcon 9 rocket as the workhorse in company's commercial launch business that already lofts most of the world's satellites and other payloads to low-Earth orbit.
For Thursday, SpaceX is aiming to at least exceed Starship's performance with its Super Heavy booster during their inaugural test launch together last April, when the spacecraft exploded over the Gulf less than four minutes into a planned 90-minute flight.
That flight went awry from the start. Some of the Super Heavy's 33 Raptor engines malfunctioned on ascent, and the lower-stage rocket failed to separate as designed from the upper-stage Starship, leading to termination of the flight.
The second test flight in November made it farther than the first, and managed to properly achieve stage separation, but the spacecraft exploded about eight minutes after launch.
SpaceX's engineering culture, considered more risk-tolerant than many of the aerospace industry's more established players, is built on a flight-testing strategy that pushes spacecraft to the point of failure, then fine-tunes improvements through frequent repetition.
NASA, SpaceX's biggest customer, has a lot riding in the success of Starship, which the U.S. space agency is giving a central role in its Artemis program, successor to the Apollo missions that put astronauts on the moon for the first time more than 50 years ago.
While NASA Administrator chief Bill Nelson has embraced Musk's frequent flight-testing approach, agency officials in recent months have made clear their desire to see greater progress with Starship's development as the U.S. races with China to the lunar surface.
