SpaceX Prepares Starship to Fly Again

Saturday - August 26 2023, 09:38 UTC - 1 year ago

SpaceX is preparing for its second test flight of its fully-integrated Starship launch system. This system contains two separate elements - Super Heavy and the 165-foot-tall (50-meter) Starship upper stage prototype - which has been designed to be fully reusable. SpaceX has made modifications to Booster 9 to enable hot-staging separation shortly after launch, and it has also conducted static fire engine tests at its South Texas test site to evaluate the system's performance during launch.

SpaceX is edging closer to the second flight test of its fully-integrated Starship launch system.

SpaceX CEO Elon Musk wrote on Twitter on Tuesday, August 22, that the "next Starship launch [is happening] soon." His post was a reply to a SpaceX post showing four photos of Super Heavy prototype Booster 9 being transported to the orbital launch mount for preflight testing.

Just a few days before, SpaceX shared a pair of images showcasing its modifications to Booster 9 to allow it to perform a hot-staging separation method while flying to orbit.

The fully-integrated Starship launch system is comprised of two separate elements: Super Heavy and the 165-foot-tall (50-meter) upper stage called Starship that will eventually carry passengers. The fully-stacked Starship is 394 feet tall (120 meters).

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.

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.

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.

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 protottype respectively, at its South Texas test site in recent weeks.

The static fire tests help the company evaluate how its Starship system performs during launch — checking for propellant leaks, gauging engine thrust levels, and other vital functions.