Live Video: Watch Launch of Starship on 4th Test Flight

SpaceX’s launch of its giant Starship rocket accomplished a set of ambitious goals on Thursday that Elon Musk, the company’s chief executive, set out before the test flight, its fourth.

The flight, while not a perfect success, offered a sign that Mr. Musk’s vision of building the most powerful rocket ever and making it reusable could again transform a global space launch industry that his company already dominates. It is most likely encouraging for officials at NASA, which will use a version of Starship to take astronauts to the surface of the moon during its Artemis III mission, currently scheduled for late 2026.

Bill Nelson, the administrator of NASA, offered his congratulations on X, the social media site that Mr. Musk owns.

“We are another step closer to returning humanity to the Moon through #Artemis—then looking onward to Mars,” he wrote.

The upper-stage Starship vehicle was lifted into space, coasted halfway around the world, survived the searing heat of re-entry and then made a water landing in the Indian Ocean, as planned.

During the descent, cameras on the spacecraft captured the colorful glow of gases heating up below it, At an altitude of above 30 miles, part of one of the steering flaps started falling apart, but it still held together. The view then became obstructed when debris cracked the camera lens.

“The question is how much of the ship is left,” Kate Tice, one of the hosts of the SpaceX broadcast said.

But real-time data continued to stream back, via SpaceX’s Starlink internet satellites, to company’s headquarters in Hawthorne, Calif., all the way until the altitude was reported at 0 — back to the surface of the Indian Ocean.

A final maneuver to flip Starship to a vertical position just before landing was commande.

“Despite loss of many tiles and a damaged flap, Starship made it all the way to a soft landing in the ocean!” Mr. Musk wrote on X.

A crowd of onlooking SpaceX employees outside mission control, cheered wildly, seeing the outcome as a validation of the company’s break-it-then-fix-it approach to engineering.

Earlier in the flight, the rocket’s first stage, the giant Super Heavy booster with 33 engines, was also able to perform maneuvers that in the future would take it back to the launch site. For this flight, it made a simulated landing in the Gulf of the Mexico.

What is Starship and why is it important?

With the Starship spaceship on top of what SpaceX calls a Super Heavy booster, the rocket system is, by pretty much every measure, the biggest and most powerful ever.

The rocket is the tallest ever built — 397 feet tall, or about 90 feet taller than the Statue of Liberty, including the pedestal.

The rocket also has the most engines ever in a booster: The Super Heavy has 33 of SpaceX’s powerful Raptor engines sticking out of its bottom. As those engines lift Starship off the launchpad, they will generate 16 million pounds of thrust at full throttle.

For Mr. Musk, Starship is really a Mars ship. He envisions a fleet of Starships carrying settlers to the Red Planet.

For NASA, the vehicle is to be a lunar lander, carrying astronauts to the surface of the moon for the first time since 1972.

In the near term, SpaceX also plans to use Starship to deploy the next generation of Starlink internet communication satellites.

An even more transformative feature of Starship is that it is designed to be entirely reusable. That capability has the potential to cut the cost of sending payloads into orbit — such that sending 100 tons to space one day might cost less than $10 million, Mr. Musk has predicted.

What was SpaceX trying to accomplish with this flight?

A couple of weeks ago, after a successful launch rehearsal, Mr. Musk wrote on X that for this flight, “Primary goal is getting through max re-entry heating.”

In other words, he did not want the vehicle to burn up.

During launch, Starship reaches orbital speeds of more than 17,000 miles per hour while reaching an altitude of 145 miles. As the spacecraft belly-flops back into the atmosphere, it experiences temperatures up to 2,600 degrees Fahrenheit.

On Thursday, Starship endured that heat, then landed in a remote part of the Indian Ocean. Another goal was to softly land the first stage, the Super Heavy booster, in the Gulf of Mexico.

During future operational flights, both vehicles are to return to the launch site and to be caught in one piece by the launch tower. Those attempts are still in the future.

What happened during the last flight?

The previous launch in March for the first time reached speeds that were fast enough for Starship to enter orbit. The ascent included a successful new twist: hot-staging separation, when some of the second-stage engines ignited before the Super Heavy booster, or first stage, separated and dropped away.

The second-stage part of Starship accomplished some of its goals as it coasted in space, including opening and closing the spacecraft’s payload door and a demonstration of moving propellant between two tanks inside the vehicle.

But while coasting at the highest point of its trajectory, Starship began rolling out of control. Cameras on board captured the orange glow of hot plasma beneath the spacecraft. Some 49 minutes after launching, it disintegrated, with communications lost at an altitude of 40 miles.

Earlier in the flight, the Super Heavy booster was to simulate a landing over the Gulf of Mexico. But six of 13 engines used for that maneuver shut down early.

SpaceX blamed blockages in the flow of propellants as the most likely cause for losses of the Starship and the Super Heavy booster. The company said it had made changes to address those problems.