SpaceX Scrubs Launch of World's Biggest Rocket

SpaceX still plans to launch a behemoth into space—the world's largest and most powerful rocket known as Starship—but it's not happening Monday as planned. The nearly 400-foot-tall rocket was on the launch pad at the company's facility in Boca Chica, Texas, but the company called off the unmanned test flight at the last minute. In a tweet, CEO Elon Musk blamed a frozen "pressurant valve." The next attempt can't happen until at least Wednesday. The rocket was to fly from Texas to Hawaii in about 90 minutes. While Starship is designed to be reusable eventually, this test flight, whenever it happens, won't be. The first-stage booster will be discarded in the Gulf of Mexico and the spacecraft itself in the Pacific, per the AP.

The test flight is seen as a major milestone for the company, given that Musk envisions future Starships taking people to Mars. NASA already has committed to using one to land on the moon in a few years. As the Washington Post notes, Starship represents a new vision of spaceflight: It's "designed to be refueled in orbit, allowing SpaceX to hoist an unprecedented amount of cargo and potentially dozens of people to deep space. And, because it will be reusable, it is expected to be far less expensive to operate" than NASA's current moon rocket, the Space Launch System.

On Sunday night, Musk had been publicly lowering expectations, notes the Wall Street Journal. “We’re going to be pretty careful about this launch," he said in a Twitter discussion. "If it does go wrong, it’s a lot to go wrong." He likened Starship's engines to grenades. "My top hope is please, may fate smile upon us, and we clear the launchpad before anything goes wrong," he said. "That’s all I’m asking." Space.com has details on the specs of the rocket, which is fueled by methane. (More SpaceX stories.)