Earlier this week, SpaceX representatives shared new details about Starship's third test flight, after which SpaceX CEO Elon Musk revealed the reason why SpaceX's second-stage Starship exploded during its second test flight last month.
During the launch of Starship, the world's largest rocket, in December, the second stage successfully separated from the first stage's thermal stage and entered space. However, its mission was not a complete success as the second stage exploded some time after ignition.
According to Musk, the explosion occurred because SpaceX had to remove excess oxygen from the spacecraft. When testing new rockets, companies typically use mass simulators to simulate the payload's flight conditions, and Musk added that the explosion could have been avoided if SpaceX had used actual payloads for orbital delivery.
Musk revealed the reason behind the anomaly during a talk at SpaceX. Just over a third of the conversations SpaceX shared on its X page involved Starship. SpaceX's future depends on Starship, as the rocket will not only be key to the company building the Starlink internet satellite constellation, but will also carry out missions to the moon for NASA and eventually enable crewed flights to Mars.
SpaceX's most recent Starship test was conducted in December, and although the rocket successfully lifted off and completed interstage separation, the first and second stages exploded at different times and far apart during the remainder of the test.
Musk shared the details of the second-stage rocket explosion and revealed that the cause of the abnormality lay with SpaceX itself. He outlined that SpaceX fully injects liquid oxygen and methane into the Starship's second stage during liftoff. The executive explained that once the company tried to expel this liquid oxygen during flight, Starship's second stage would explode.
According to Musk:
"Flight 2 actually almost made it to orbit, the reason it didn't actually make it all the way to orbit was because we vented liquid oxygen. That caused a fire and explosion, and if we had put a payload on it, there normally wouldn't be liquid oxygen. So, ironically, if we had put a payload on, the spacecraft would have gone into orbit. So, I think we have a chance of getting into orbit on Flight 3 and then achieving full and rapid reuse very quickly."
During SpaceX's second Starship test flight in December, it was necessary to have Starship's second stage carry a weight representative of the payload because it had to test the correct thrust specifications for liftoff and stage separation. As far as engines are concerned, lighter rockets require less power. When test-firing, it must be matched to flight specifications, depending on the target, to ensure performance meets the correct requirements.
While SpaceX is launching "Starship", the company has sent 42 astronauts into space through the "Dragon" program. Musk also revealed during his speech that SpaceX currently serves 2.3 million customers around the world, and the executive also said that Starlink connections will enter more countries later this year.
As for the future, Musk said that SpaceX’s goal is to save time, go hardware-free, and speed up the development of interstellar spacecraft. He thanked the National Aeronautics and Space Administration (NASA) for entrusting SpaceX to send crews to the moon, and said that SpaceX's ultimate goal is to use Starship to regularly send 200-ton spacecraft into orbit.
Musk reiterated that SpaceX plans to conduct multiple tests for the "Artemis" moon landing program. The tests included space engine burns from the Starship's nose tank and propellant transfer from the nose tank to the main tank. The starship's second-stage canopy fuel tank is located in its nose cone, one each for fuel and oxidizer. They are crucial in orienting the spacecraft for landing and providing a steady flow of propellant to the engines during the dangerous descent.