Gary Zhou 
Key Points
- 🚀 SpaceX has moved Booster 9 back to the Orbital Launch Mount for additional testing before its test flight.
- 🛠️ A vented interstage was added to Booster 9, allowing for hot staging where Starship’s engines ignite before separating from the booster.
- 🚀 Booster 9 was moved to the launch site using ‘chopsticks’ and underwent a spin prime test with liquid oxygen in the engines.
- 🔥 The next step is another static fire test for Booster 9, aiming to address previous engine shutdown issues.
After a brief stint at the production site, Booster 9 has returned to the Orbital Launch Mount for further testing before its upcoming test flight.
A notable modification SpaceX implemented on Booster 9 was the addition of a vented interstage at the top of the booster. This alteration allows for the ignition of Starship’s engines before detachment from the booster, a technique referred to as hot staging.
It remains uncertain whether SpaceX replaced any Raptor engines on the booster following the previous test fire.
Initially, SpaceX intended to move the booster back to the Orbital Launch Mount earlier, but the development of Tropical Storm Harold, which was heading towards Starbase, caused a delay. Fortunately, the storm altered its course to the North, sparing Starbase from significant impacts.
Upon reaching the launch site, Booster 9 was hoisted onto the launch mount using the distinctive ‘chopsticks’ apparatus.
SpaceX wasted no time initiating this test phase, as they partially loaded the booster with liquid oxygen and executed a spin prime test on the engines. A spin prime test entails circulating super chilled liquid oxygen through the Raptor engines’ turbopumps, simulating engine firing just short of ignition.
The subsequent step in the process will involve another static fire test for Booster 9. The previous attempt was cut short, with 4 Raptor engines shutting down prematurely during a planned 5-second test, while the other 29 engines ran for 2.74 seconds.
Regarding a potential launch date, a new Notice to Mariners (NOTMAR) has been issued for September 8th. Elon Musk also recently indicated that the next Starship launch is imminent.
While optimism is present, the likelihood of a launch by September 8th is low. However, once the static fire test is successfully conducted and the FAA provides clearance, the wait is expected to be relatively short.
An unmistakable indication of the nearing second integrated test flight will be the issuance of the NOTAM (Notice to Air Missions) and the completion of the stacking process of Starship atop Booster 9, along with the installation of the flight termination system.
