SpaceX demonstrated Thursday that its towering Super Heavy booster and Starship rocket might one day soon be recovered and reused in the manner Elon Musk has envisioned for the future of space exploration.
For the first time, both elements of the nearly 400-foot-tall (121-meter) rocket not only launched successfully from SpaceX’s Starbase facility near Brownsville, Texas, but also came back to Earth for controlled splashdowns at sea. This demonstration is a forerunner to future Starship test flights that will bring the booster, and eventually the upper stage, back to land for reuse again and again.
The two-stage rocket took off from Starbase at 7:50 am CDT (12:50 UTC) and headed east over the Gulf of Mexico with more than 15 million pounds of thrust, roughly twice the power of NASA’s Saturn V rocket from the Apollo lunar program of the 1960s and 1970s.
Checking all the boxes
Starship, the largest and powerful launch vehicle ever built, is key to the future of SpaceX. NASA also has an interest in Starship’s success because the agency selected it to fill the role of human-rated lunar lander for the Artemis program to ferry astronauts to and from the surface of the Moon.
There will be dozens more Starship flights before anyone actually climbs inside the Starship lander, and this probably won’t happen sooner than the latter part of this decade. But some of the other goals for Starship, such as recovering and reusing the entire rocket, appear within reach.
“The fourth flight of Starship made major strides to bring us closer to a rapidly reusable future,” SpaceX said in an update on its website. “Its accomplishments will provide data to drive improvements as we continue rapidly developing Starship into a fully reusable transportation system designed to carry crew and cargo to Earth orbit, the Moon, Mars, and beyond.”
Thursday’s test flight was the fourth launch of a full-size Starship rocket and was the first to end with the booster and ship reaching Earth’s surface in one piece. The results matched the best of all possible scenarios leading up to Thursday’s flight.
It fell short of total perfection, but you can’t describe the flight as anything but a success. “The payload for this test was the data,” SpaceX said. “Starship delivered.”
Two of the 33 methane-fueled Raptor engines on the Super Heavy booster failed on Thursday’s test flight—one on the ascent and one during the booster’s final braking burn just before splashdown in the Gulf of Mexico. Still, the remaining engines guided the booster to a relatively gentle splashdown in the ocean after a vertical descent just off the coast of Starbase about seven-and-a-half minutes after liftoff. SpaceX got close to accomplishing this milestone on the third Starship flight in March but lost contact when most of its landing engines failed to reignite.
Engineers blamed filter blockage in the lines feeding liquid oxygen propellant into the Raptor engines for the landing failure in March. This didn’t appear to be a major problem on Thursday. SpaceX also made another change to the booster’s descent with the jettison during the descent of the rocket’s hot-staging ring, where the Starship upper stage attaches to Super Heavy for launch.
Meanwhile, six Raptor engines on the Starship upper stage burned a few seconds longer than planned to make up for the performance shortfall on the booster. This put the ship on the proper suborbital trajectory to reach a peak altitude of 132 miles (213 km) before Earth’s gravity pulled the 165-foot-long (50-meter) vehicle back into the atmosphere around 47 minutes after launch.
The flight up to this point was just a prelude to the grand finale.
On SpaceX’s third Starship test flight in March, the scorching heat of reentry destroyed the rocket as it descended into the upper atmosphere over the Indian Ocean. SpaceX said clogged thrusters caused the ship to lose the ability to control its orientation in space. This caused the Starship to fall into the atmosphere in the wrong orientation, subjecting unprotected parts of the vehicle to the extreme heat of reentry.
Stephen Clark/Ars Technica
This time, Starship maintained control throughout the flight. Dazzling live views from cameras aboard the rocket, relayed to the ground through SpaceX’s Starlink broadband network, showed purple and orange plasma pouring over the vehicle as it glided through the atmosphere over the Indian Ocean.
A few moments later, one camera showed pieces of the rocket, presumably ceramic thermal protection tiles, peeling away. There appeared to be damage to the hinge joint connecting one of the ship’s control flaps to the main body. Nevertheless, the damaged flap could still move and help control the ship using aerodynamic forces as it dived belly-first deeper into the atmosphere.
“Starship made a controlled reentry, successfully making it through the phases of peak heating and max aerodynamic pressure and demonstrating the ability to control the vehicle using its flaps while descending through the atmosphere at hypersonic speeds,” SpaceX said. These were the mission’s main objectives outlined by Musk before the launch.
Finally, three of the Raptor engines on Starship reignited, and the rocket flipped from a belly-down orientation to a vertical position a few hundred feet over the middle of the Indian Ocean, according to SpaceX. It was difficult to make sense of what the live camera views were showing because the splashdown happened at night halfway around the world from Texas.
But live telemetry data indicated the rocket slowed to a near stop as it reached the sea, then the communication feed cut off about 1 hour and 6 minutes into the mission.
“Despite loss of many tiles and a damaged flap, Starship made it all the way to a soft landing in the ocean!” Musk posted on X, his social media platform. “Congratulations SpaceX team on an epic achievement.”