Starship flight 15 reaches orbit and sets up a possible booster-style catch

Starship flight 15 lifts off in ideal conditions

Starship rose from Starbase in South Texas on schedule on Friday evening, marking the vehicle's 15th test flight in a little over three years, according to Ars Technica. The rocket climbed as the Sun set, and the air was so still that its white plume hung visible for many minutes.

The booster's ascent went cleanly, and the upper stage separated above the Gulf of Mexico. Its Raptor engines then fired and carried the ship into a planned orbit. This was only the second time SpaceX has sent Starship into low-Earth orbit.

26 Starlink V3 satellites reach orbit

The main goal of the mission was to release 26 Starlink V3 satellites from a door near the base of the spacecraft. This happened roughly 40 minutes after launch, and all of the satellites reached orbit safely.

Each satellite carries solar panels that will stretch 60 metres across once fully extended. They will now use their own propulsion to climb to a higher altitude. Ars Technica notes that with this success, Starship has effectively become an operational orbital rocket, and the largest and most powerful machine ever launched.

Booster diverted into the Gulf

The launch was not flawless. When the first stage came back, ground controllers ordered it away from the launch site because of an unspecified problem, and it fell into the Gulf of Mexico instead of returning for a tower catch. The impact produced an explosion that was clearly visible and audible to observers more than 10 miles away.

SpaceX had hoped to recover the booster, refurbish it and fly it again. The company has landed and reflown earlier Starship boosters, but it has not yet done so with the latest version 3 of the vehicle.

A possible first catch of the upper stage on Saturday

Attention now turns to the ship itself. SpaceX has never tried to catch the Starship upper stage with its launch tower, and Saturday could bring the first attempt. The vehicle must first pass a series of health checks in orbit and during its descent.

Those checks matter because the ship will fly over populated parts of Mexico and the United States before it reaches Texas, and SpaceX wants no risk to people on the ground or to its launch towers. According to Ars Technica, if the vehicle is judged healthy, the catch would happen at about 21:15 UTC on Saturday. If not, SpaceX has earlier opportunities to steer it to an ocean splashdown.

The heat shield remains the key challenge

A successful return would also yield valuable data on reentry, which Ars Technica describes as one of the hardest remaining problems in Starship's development. The heat shield must protect the ship during its fall through the atmosphere.

SpaceX wants the vehicle to be rapidly reusable, so the tiles on its belly must be light, durable and easy to service. The company has refined tile designs since the programme began. For this flight it added extra retention devices to tiles in the areas most likely to shed during ascent, and sealed paths where hot plasma could slip behind the tiles. A large part of the shield also uses a curved tile design that SpaceX says reduces heating in the gaps between tiles.