Flying Silo

Yesterday, SpaceX successfully flew a full-sized Starship tank-section prototype at its launch facility in Boca Chica, Texas. Standing thirty meters tall without its nosecone, weighing one to two hundred tons with methalox propellant, and made from stainless steel, Starship was powered by a single Raptor engine, the first full-flow staged-combustion engine to fly. Operational Starships will have six Raptors in two pairs of three. For this test, a single engine was necessarily installed off-center. In the photo below from a SpaceX drone, the thrust of the Raptor, traced by a standing wave of shock diamonds, passes through the tilted Starship’s center-of-mass. The heavy mass on top simulates the nosecone, minimizes the tilt, and helps land (as the Raptor can’t throttle below 50% of thrust). Note the construction tractors parked in the lower left.