Demo
    A rocket with fins is launched skyward, emitting flames and smoke from its engines against a dark, cloudy sky.
    SpaceX’s SN10 Starship prototype descends back toward Boca Chica after a 10-kilometer test flight in March 2021, the first prototype of the Starship upper stage to successfully flip and land base first as future operational Starships must. But the landing occurred at too high a speed and the prototype exploded shortly after landing.
    Close-up view of a rocket engine nozzle during a test firing, with flames and exhaust gases emanating from the engine.
    NASA cancelled the X-33 program before the wedge-shaped demonstrator ever flew, but NASA engineers conducted a handful of ground tests with the two prototypes Rocketdyne built of the plane’s linear aerospike engine design, chosen for its higher specific impulse compared to the bell-shaped rocket engine nozzle. During the 2001 ground test pictured here at NASA’s Stennis Space Center in Mississippi, one of the engines was fired for 30 seconds.