A SpaceX Starship prototype blasted off Tuesday for a planned up-and-down test flight, climbing to about 6.2 miles above the Texas Gulf Coast before flipping over on its side and plunging back toward Earth, disappearing in heavy fog as it neared the ground.
As the rocket began reigniting its three engines to flip upright for landing, it apparently exploded, the fourth Starship test flight in a row to end with a "rapid unscheduled disassembly," jokingly referred to as a RUD.
"At least the crater is in the right place," SpaceX founder Elon Musk tweeted.
Providing a more serious explanation, he added: "Looks like engine 2 had issues on ascent & didn't reach operating chamber pressure during landing burn, but, in theory, it wasn't needed. Something significant happened shortly after landing burn start. Should know what it was once we can examine the bits later today."
The prototype, known as SN11, was a stand-in for the gargantuan Starship rocket system's second stage, a next-generation super-heavy-lift rocket. Using three methane-burning Raptor engines, the prototype blasted off from SpaceX's Boca Chica, Texas, test facility on the Gulf Coast near Brownsville at 9 a.m. EDT, climbing straight up through thick fog.
Liftoff came less than a month after another prototype, SN10, exploded a few moments after an apparently successful touchdown.
As with the, SN11 appeared to climb smoothly away, although the fog blocked the view from ground cameras. But a camera on board the rocket provided crystal-clear shots of the engine nozzles and long jets of fiery exhaust as the vehicle gained altitude.
First one engine, then another shut down as planned as the Starship neared its planned high point, or apogee, of about 6.2 miles (10 kilometers).
The third engine then shut down, the rocket tipped over on its side and began falling back toward the launch site in a now-familiar "belly flop" maneuver, using computer-controlled nose and tail fins to maintain the proper orientation. About a half mile above the surface, the computer began restarting the engines to flip upright for a tail-first touchdown on stubby landing legs.
But the image suddenly froze at the 5-minute, 49-second mark and the sound of an apparent explosion could be heard. After that, silence.
"Looks like we've had another exciting test of Starship number 11," SpaceX commentator John Insprucker wryly observed during a SpaceX webcast. A few moments later, he explained that a frozen image of the rocket's engines did not mean SpaceX expected to regain data.
"Starship 11 is not coming back, don't wait for the landing," Insprucker said. "We do appear to have lost all the data from the vehicle and the team, of course, is away from the landing pad. So we'll be out there seeing what we had. ... But with that, we are going to bring the webcast to a close. Interesting flight and as always with Starship, an exciting time on our webcast."
The Starship system features a 230-foot-tall "Super Heavy" first stage generating 16 million pounds of thrust with 28 Raptor engines, more than twice the power of NASA's legendary Saturn 5 moon rocket. A first-stage prototype has not yet been launched.
The rocket's 160-foot second stage, also confusingly known as Starship, will use a half-dozen Raptor engines capable of boosting 100 tons of payload to low-Earth orbit. The prototypes launched to date on high-altitude test flights have featured just three Raptors.
Musk said Starship prototype 15 will be moved to the launch pad in a few days with "hundreds of design improvements across structures, avionics/software & engine."
"Hopefully, one of those improvements covers this problem. If not, then retrofit will add a few more days."