SpaceX launches its mega Starship rocket on second test flight

SpaceX on Saturday carried out the second test launch of Starship, the largest rocket ever built that Elon Musk hopes will one day colonize Mars, while NASA awaits a modified version to land humans on the Moon.

It comes after a first attempt to fly the spaceship in its fully-stacked configuration back in April ended in a spectacular explosion over the Gulf of Mexico.

The rocket blasted off from the company's Starbase in Boca Chica, Texas shortly after 7:00 am local time (1300 GMT).

The booster successfully separated from the ship, but blew up shortly after, while the ship continued on track.

"As you could see, the super heavy booster has just experienced a rapid unscheduled disassembly however, our ship is still underway," an announcer said.

When the two stages of Starship are combined, the rocket stands 397 feet (121 meters) tall — beating the Statue of Liberty by a comfortable 90 feet.

Its Super Heavy booster produces 16.7 million pounds (74.3 Meganewtons) of thrust, almost double that of the world's second most powerful rocket, NASA's Space Launch System (SLS) — though the latter is now fully operational.

Both systems are designed to be fully reusable, a key element of SpaceX's design meant to greatly reduce costs.

The booster that blew up had been due to land in the Gulf of Mexico a few minutes after launch, while the upper stage started a partial trip around the Earth, almost obtaining orbital velocity, before being scheduled to belly flopping into the Pacific Ocean near Hawaii after 90 minutes.

Design changes

SpaceX was forced to blow up Starship during its first test flight four minutes after launch on April 20, because the two stages failed to separate. The rocket disintegrated into a ball of fire and crashed into the Gulf of Mexico, sending a dust cloud over a town several miles (kilometers) away.

After a months long investigation, the Federal Aviation Administration on Wednesday finally cleared SpaceX to try again, despite objections by conservation groups, who are suing the regulator claiming it failed to comply with environmental law.

SpaceX has insisted that explosions during the early stages of rocket development are welcome and help inform design choices faster than ground tests — though time is ticking down for a modified Starship to be ready for a planned lunar landing in 2025.

The biggest change since the first launch relates to how the spaceship separates from the booster.

Starship has been modified to use "hot staging," which means the upper stage engines will ignite while it is still attached to the booster, an approach that is commonly used in Russian rockets and could unlock far greater power.

Other changes include improvements to vents to decrease the likelihood of an explosion.

The first launch also caused massive damage to the company's launchpad at Starbase, and this has now been reinforced with high-strength concrete and a system that will jet water to protect against the enormous heat and force generated by launch.