Blue Origin’s New Glenn rocket exploded on Thursday night during a hotfire test on the launch pad, lighting up the skies around the launch site in Cape Canaveral, Florida. In a post on X, Blue Origin founder Jeff Bezos said that all personnel had been accounted for.

“It’s too early to know the root cause but we’re already working to find it,” Bezos wrote. “Very rough day, but we’ll rebuild whatever needs rebuilding and get back to flying. It’s worth it.”

What Is a Hotfire Test?

The test during which Blue Origin’s rocket—a vehicle that, at 98 meters tall, is one of the largest ever built—exploded is known as a hotfire test, or static fire test. Essentially, it is a standard procedure carried out on the engines of a rocket, spacecraft, or prototype, in which the engines are ignited for a very short period of time and then shut down while the vehicle remains secured to the launch pad. The purpose of this test is to verify that the systems are functioning correctly before an actual launch.

Blue Origin’s Rocket

This would have been the fourth mission of the New Glenn rocket, which was slated to carry 48 satellites, destined to become part of Amazon Leo’s satellite Internet network, as soon as next week. “NASA is aware of the anomaly that occurred tonight at Launch Complex 36 involving Blue Origin’s New Glenn rocket at Cape Canaveral Space Force Station,” said NASA administrator Jared Isaacman in a post on X. “Spaceflight is unforgiving, and developing new heavy-lift launch capability is extraordinarily difficult. We will work with our partners to support a thorough investigation of this anomaly, assess near-term mission impacts, and get back to launching rockets.”

Isaacman further said that NASA would provide updates on any potential impacts to the Artemis and Moon Base missions when they were available; the agency has contracted with both Blue Origin and SpaceX for various aspects of its plans for a lunar return.

This explosion represents the latest setback for Bezos’s company. On April 19, a failure occurred during the rocket’s third flight that prompted a Federal Aviation Administration (FAA) investigation. During that mission, the rocket’s first stage had successfully landed on a floating platform, but the upper, or second stage, had failed to carry its payload—AST SpaceMobile’s BlueBird 7 satellite— into a safe orbit. That investigation was just completed on May 22.

This story originally appeared in WIRED Italia and has been translated from Italian.