Elon Musk congratulated SpaceX for an 'exciting' launch of Starship after the rocket exploded

• Elon Musk congratulated SpaceX on an "exciting" Starship launch after the prized rocket exploded.
• The mega-rocket cleared the launchpad but exploded nearly three minutes after liftoff.

Elon Musk congratulated SpaceX on an "exciting" launch after the company's Starship mega-rocket exploded soon after liftoff.

Starship and its Super Heavy booster failed to separate from each other at a critical moment of the flight, then tumbled through the air and exploded into a huge fireball around three minutes after launch.

Musk appeared stonefaced in SpaceX's control room moments after the rocket blew up, as shown on the company's livestream. "Congrats @SpaceX team on an exciting test launch of Starship!" he tweeted.

Musk was expecting the launch to be spectacular

Musk had previously hinted the launch had a one-in-two chance of ending in an explosion.

"I'm not saying it will get to orbit, but I am guaranteeing excitement," the billionaire said in an interview at the Morgan Stanley Conference on March 7, adding: "Won't be boring!"

Musk said during a Twitter Spaces session on Sunday that his biggest concern for the flight was if Starship "fireballed" on the launchpad.

Such an incident would melt the steel and destroy the launchpad, he said, adding this would take SpaceX several months to rebuild. If this happened, it would be a "very bad day," Musk said.

Overall, he estimated a 50% chance that the launch attempt would succeed.

Starship blew up but provided useful information

Musk said in a tweet Thursday that the launch had provided useful information.

"Learned a lot for next test launch in a few months," he said.

Musk's grandest plans hinge not only on Starship's unprecedented power, but also on its capacity to be fully reusable.

In 2002, Musk founded SpaceX with the goal of making spaceflight cheap enough to establish a permanent human settlement on Mars. This is the rocket that's supposed to make that happen.

NASA has also chosen Starship as its next lunar lander, to carry astronauts from an agency vehicle in lunar orbit to the moon's surface. That mission, called Artemis III, could happen sometime this decade.

The rocket is the biggest and most powerful rocket ever built. With that comes technical challenges that need to be addressed.

Up to this point, the tallest rockets were the Saturn V that launched NASA's Apollo missions, and the agency's new Space Launch System, which it developed to return astronauts to the moon again.

Once fully operational, Starship will be able to carry up to 150 metric tonnes (165 US tons) to space, per SpaceX. That jumps to 250 metric tonnes (275 tons) if the company forgoes reusability and discards the spaceship when the mission is done.

To put that in perspective, the most powerful operational rocket right now is SpaceX's Falcon Heavy, which carries up to 70 tons to low-Earth orbit.

Musk's ultimate goal is much bigger than the moon: Eventually, the billionaire has said he aims to build 1,000 Starships to fly 100,000 people to Mars per year, build a city there, and make humans the first multi-planetary species in Earth's history.