Late on Sunday night, SpaceX completed a critical cryogenic test of a Starship prototype at its launch site in South Texas. The successful test, during which chilled nitrogen was loaded into pressurized fuel tanks, was reported on Twitter by SpaceX founder Elon Musk.
The vehicle, dubbed SN4—which stands for Serial Number 4—was pressurized to 4.9 bar, or 4.9 times the atmospheric pressure at the surface of the Earth. This pressure is not as high as Starship’s fuel tanks and plumbing system are designed to withstand, but it is enough for a basic flight.
This marks an important moment in the Starship program. Since November 2019, the company has lost three full-scale Starship prototypes during cryogenic and pressure tests. The most recent failure came on April 3. This is the first time a vehicle has survived pressure testing to advance to further work. Such tests are designed to ensure the integrity of a rocket’s fueling system prior to lighting an engine.