Starship to launch 'soon' as SpaceX shows off modifications

Both Super Heavy and Starship are designed to be fully reusable so as to drastically reduce the cost of successive missions — a move designed to make human spaceflight to Mars and beyond economically feasible.

The full Starship launch system has only flown once before. Its first test flight on April 20 this year ended with the rocket spinning out of control at high altitude after the two stages failed to separate. This led to ground control manually triggering a termination — or explosion.

Since then, SpaceX has been preparing for the second test flight of Starship. The company is known for its fail fast, learn fast mantra — several of its Falcon 9 boosters exploded on landing attempts, for example, before the first successful landing in 2015.

Starship's hot-staging modifications explained

Back in June, Musk noted that SpaceX had made "well over a thousand" changes to Starship ahead of the second test flight. One of the key changes the company has made is to modify Booster 9 to allow for a hot-staging separation shortly after launch.

Hot-staging involves igniting the engines on the upper stage of the rocket while it's still attached to the lower stage. To make this possible, SpaceX installed a "vented interstage" and a heat shield on the top of Booster 9, which it recently showed off in a Twitter post.

Vented interstage and heat shield installed atop Booster 9. Starship and Super Heavy are being upgraded to use a separation method called hot-staging, where Starship’s second stage engines will ignite to push the ship away from the booster pic.twitter.com/UbMpciGJqd

— SpaceX (@SpaceX) August 18, 2023

Those two additions will essentially protect Booster 9 from the Raptor engine flames coming from the Starship's upper stage during the separation process.

The heat shield will protect the top of Booster 9, while the vented interstage will allow the engine flames to escape while the upper stage is still attached to the Super Heavy prototype.

During an online discussion on Twitter in June with Bloomberg journalist Ashlee Vance, Musk explained the benefit of hot-staging separation: "There’s a meaningful payload-to-orbit advantage with hot-staging that is conservatively about a 10% increase," he said, adding that Starship will avoid losing thrust during separation by using this method.

When will we see Starship's next flight?

SpaceX seems to be fast approaching the second test flight of Starship; the company has conducted static fire engine tests on Ship 25 and Booster 9, the Starship upper stage prototype and Super Heavy prototype that will be used for the launch.

However, Starship is still the subject of an ongoing environmental lawsuit levied against the Federal Aviation Administration (FAA).

NASA has also recently expressed concern over a timeline it received for the development of the modified Starship lunar lander it will use to send astronauts back to the lunar surface as part of its Artemis III mission.

The FAA has yet to greenlight the second test flight of Starship, and though Musk has mentioned on more than one occasion that Starship could fly within eight weeks, he's been known to exaggerate his companies' progress in the past.

Starship's second flight may liftoff soon, but it might just not be as soon as SpaceX's CEO would have you believe.