The Raptor engines operate at extremely high pressures, and managing these extraordinary operating conditions has been a challenge for SpaceX. Over the past year, the company has lost several Starship prototypes during static fires, a type of test during which the engine is fired while the rocket is bolted to the ground. The rocket explosions—or “rapid unscheduled disassembly,” as Musk puts it—were a setback, but SpaceX technicians have managed to crank out new rockets at a breakneck pace. In fact, by the time the Starship prototype launched on Wednesday, there was another already waiting in the wings in case this version didn’t make it back to earth in one piece. Even Musk only gave it about a “1/3 chance” of surviving its maiden journey. “Lot of things need to go right, but that’s why we have SN9 and SN10,” Musk tweeted, referring to the next Starship prototypes to fly.

While SpaceX has perfected the art of landing its Falcon 9 rockets, its Starship vehicle has a very different and highly challenging flight profile. Whereas Falcon 9 boosters fall back to earth vertically, with their engines down and noses up, Starship is designed to fall broadside through the atmosphere and flip to a vertical posture shortly before landing. This unusual reentry is all about aerodynamics. By executing a belly flop, Starship can more accurately control its landing using its fins. But this type of landing maneuver is also unprecedented, which means that it carries a lot of risk until SpaceX gets a better idea of how Starship reacts while it’s returning to earth.

Now that the first test flight is out of the way, SpaceX engineers have a wealth of data that will help them figure out how to stick the landing and push Starship to higher altitudes. While its first jaunts to orbit will be uncrewed, Starship is destined to carry astronauts beyond low earth orbit. Musk already sold Starship’s first crewed flight around the moon to the Japanese billionaire Yusaku Maezawa, who pledged to bring a handful of artists along for the ride. The leaders of NASA’s human spaceflight program are also interested in leveraging Starship for their own lunar ambitions. Earlier this year, the agency tapped SpaceX to develop a version of the rocket that is capable of landing astronauts on the moon’s surface.

But the real reason SpaceX is developing Starship—and the whole reason Musk got into the space business to begin with—is to get boot prints on the Red Planet. If Musk wants to settle Mars in a reasonable amount of time, he’s going to need a large interplanetary transport system that can carry hundreds of tons of cargo and dozens of passengers at a time. Earlier this month, Musk predicted that Starship might carry the first astronauts to Mars as early as 2026, an incredibly aggressive timeline that only a few months ago would have seemed delusional. But now that Starship has taken to the skies, Mars really does feel closer than ever.


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