On the eve of the launch Starship Flight 9, company SpaceX published the results of the investigation into the causes of the explosion of the upper stage of the rocket during the previous flight Flight 8, which took place 6 March from Starbase in Texas.
As during Flight 7, the rocket's first stage, the Super Heavy, successfully returned to the Mechazilla landing complex, however, the upper degree (Ship) exploded again over the Atlantic Ocean. Both explosions were so powerful, that were observed from the coast of Florida, Bahamas and Turks and Caicos Islands.
What went wrong?
The investigation established, that an "explosion" occurred near one of the Raptor's central marine engines during operation. This caused uncontrolled mixing of fuel components, which led to the explosion.
This "flash" caused the engine to stall, and two more sea-level engines and one vacuum engine stopped working immediately after that. The rocket lost stability and began to rotate, and two minutes later, SpaceX lost contact with her. As a result, the self-destruct system was activated automatically.
SpaceX called the most likely cause a hardware failure in one of the engines, which led to accidental ignition of the fuel mixture.
What about Super Heavy?
First degree, although he landed successfully, was also not without problems. Only 11 from 13 engines started during the reverse maneuver, but 12 from 13 — during landing. The cause turned out to be overheating in the area of the igniters, that SpaceX plans to solve with additional thermal insulation.
How to fix the situation?
To increase reliability, SpaceX implemented a number of improvements in the design of the rocket, in particular:
- Reinforced fastening of key joints
- New nitrogen purging system
- Improvement of the fuel drain system
- Will also appear on future flights Raptor engine 3 — with additional security measures.
The company spent more than 100 long tests of the Raptor at the test site in Texas. The investigation was overseen by the FAA, NASA, NTSB and US Space Force.
Permission to return to flights
22 In May, the FAA officially allowed SpaceX to return to test launches, By confirming, that all problems, discovered after Flight 8, eliminated.
On the same day, the company announced the date of the next launch: Starship Flight 9 starts no earlier than 27 May from the launch pad in Texas. First step will be reused for the first time, who had already flown in Flight 7.