SpaceX got its massive Starship rocket off the Texas launchpad shortly after 8:30 a.m. CDT today but it exploded high over the ocean in a failed separation from the booster. No one was aboard or injured on the ground in the first test launch of the rocket.

A “rapid unplanned disassembly,” one SpaceX commenter said quoting a phrase coined by SpaceX founder Elon Musk following an earlier explosion.

The launch goals were to clear the launch tower and gather flight data, a SpaceX commenter said, and those goals were successful. But commenters noted at 3 minutes and 50 seconds after launch that separation from the booster should have occurred. It did not separate and the rocket appeared to tumble before exploding.

Starship is designed to be the most powerful launch vehicle ever built, and it is designed to be reusable spreading the cost of space travel over multiple launches. Ultimately, it is to carry humans to Mars.