Starship brought the thunder as it climbed into space for the first time

Enlarge / SpaceX’s Starship rocket took off from South Texas at 7:03 am CST (13:03 UTC) Saturday.

BOCA CHICA BEACH, Texas—SpaceX’s Starship mega-rocket reached space for the first time Saturday, flying straight and true for more than eight minutes before exploding nearly 100 miles over the Gulf of Mexico downrange from the company’s South Texas launch base.

With this test flight, SpaceX made important steps forward with Starship, the largest rocket ever built. This is the fully reusable launch vehicle Elon Musk, SpaceX’s founder and CEO, says is crucial to his vision of establishing a settlement on Mars. In the nearer term, once Starship is flight proven, SpaceX plans to use the rocket to launch massive payloads of numerous Starlink Internet satellites. NASA has a pair of contracts with SpaceX worth more than $4 billion to use a variant of Starship to land astronauts on the Moon. Private space travelers have also signed up to fly on Starship.

But those ambitions hinge on getting Starship into orbit, which hasn’t happened yet. The flight profile for Saturday’s test launch, designated Orbital Flight Test-2 (OFT-2), should have taken the unpiloted Starship on a trajectory to fly most of the way around the world before a targeted reentry and splashdown in the Pacific Ocean near Hawaii. In the end, the rocket didn’t reach this objective, but the results Saturday were promising.

“We got the hot staging, the thing that we really wanted to see and test,” said John Insprucker, a senior SpaceX engineer providing commentary not he company’s official live broadcast of the test flight. “We saw the separation, we saw the flip maneuver, we saw the light-up of the six Raptor engines on Starship.”

Musk called the giant launcher a “magnificent machine” in a post on his social media site, X.

“Congrats to the teams who made progress on today’s flight test,” NASA Administrator Bill Nelson wrote on X. “Spaceflight is a bold adventure demanding a can-do spirit and daring innovation. Today’s test is an opportunity to learn—then fly again.”

The rocket is divided into two segments. A booster stage called Super Heavy with 33 Raptor engines is designed to power the vehicle through Earth’s atmosphere, then an upper stage with six engines—known simply as Starship—takes over to accelerate to orbital velocity. On operational missions, the Starship upper stage could serve as a propellant tanker, depot, payload deployer, or a crew and passenger cabin.

The first full-scale Starship test launch in April revealed several shortcomings in SpaceX’s design, including fuel leaks, engine failures, and extensive damage to the launch pad. This wouldn’t be a surprise for the first test flight of any new rocket, but SpaceX’s preference to learn this way—through rapid-fire flight demonstrations and iteration—is intended to help engineers identify problems earlier in development than if they followed a development approach used by the traditional aerospace industry. This usually results in a faster path from concept to operations.

In the seven months since the first Starship test flight, SpaceX redesigned and rebuilt part of the launch pad, introduced a new stage separation method to separate the rocket’s Super Heavy booster from its upper stage, and made reliability improvements to Starship’s methane-fueled Raptor engines.

The booster and ship both had a chance to shine Saturday. The rocket took off from SpaceX’s privately-owned launch site on the Texas Gulf Coast, just north of the US-Mexico border, after a brief hold in the countdown. The 397-foot-tall (121-meter) stainless steel launch vehicle ignited its 33 engines and climbed off the launch pad at 7:03 am CST (13:03 UTC).

Burning blue

SpaceX had never before successfully ignited all 33 Raptor engines at once on a Super Heavy booster stage. At least five engines failed on the first Starship test launch in April, and multiple engines misfired on this Super Heavy booster during hold-down test-firings in August.

The simultaneous ignition of all 33 engines was something SpaceX engineers were certainly elated to see. No rocket has ever fired so many engines together. The 33 Raptors put on a show, consuming more than 40,000 pounds of propellant per second and generating nearly 17 million pounds of thrust. A 1,000-foot tongue of fiery blue-orange exhaust trailed behind Starship as it rocketed into a clear sky just after sunrise.

Moments later, a deep rumble reached onlookers, including this Ars reporter, perched less than 4 miles from the launch pad. The rumble grew into a crackling thunder a few moments later. It’s no surprise the world’s largest rocket is also the loudest.

Thirty-three engines fired to power the Super Heavy booster and Starship rocket into the sky.
Enlarge / Thirty-three engines fired to power the Super Heavy booster and Starship rocket into the sky.

Stephen Clark / Ars Technica

In the first minute of flight, Starship surpassed the speed of sound and started heading downrange east from SpaceX’s Texas launch facility, known as Starbase. All 33 engines continued firing until the command to shut down all but three Raptors a little more than two-and-a-half minutes into the flight.

SpaceX has invested in upgrades and extensive ground testing to improve the reliability of the Raptor engine. Second-generation versions of the Raptor engine flew on Saturday’s launch, replacing the less reliable first-gen Raptor, called Raptor 1. SpaceX is developing a Raptor 3 engine variant to fly on future Starship missions.

Accomplishing a full-duration Super Heavy burn without any engine failures is a significant step forward for the Starship program. Engine reliability was one of top concerns identified by NASA’s lunar lander program manager, Lisa Watson-Morgan, in an interview with Ars earlier this week. She manages NASA’s contract with SpaceX to turn Starship into a human-rated Moon lander for the agency’s Artemis program.

The Raptor engine is a beast. Each one can produce a half-million pounds of thrust, about the same as one of the main engines on NASA’s retired space shuttle or the Space Launch System rocket. Raptor uses a full flow staged combustion engine cycle, which comes with higher complexity but has benefits, such as higher efficiency and lower operating temperatures. This means an engine like Raptor, theoretically, is easier to reuse than any other large rocket engine.

A new steering system also appeared to function as designed on the Super Heavy booster. Since the April test flight, SpaceX has replaced a hydraulic thrust vector control mechanism with engine gimbals driven by electric actuators.

Staging achievement unlocked

Then came the moment everyone was waiting for: Hot staging.

This maneuver was untried before Saturday’s test flight. Most rockets disconnect their boosters from their upper stages without any engines firing. The first stage shuts down its booster engines for a few seconds, the stages release from one another, and then the upper stage ignites to continue accelerating into orbit.

SpaceX settled on a new staging sequence, called hot staging, for the second full-scale Starship test flight. Russia uses hot staging for some of its rockets, but before Starship, there were no US rockets currently using it. The Super Heavy booster turned off all but three of its engines, then the Starship upper stage fired its six Raptors at the same time the booster stage separated to begin a descent into the Gulf of Mexico.

The transition to hot staging on Starship will increase the rocket’s payload capacity, according to SpaceX.

In order to make this possible, SpaceX added a 6-foot-tall vented structure in between the Super Heavy booster and Starship upper stage. This allows super-hot exhaust from the upper stage engines to escape the confined compartment between the stages, reducing the risk of damaging the booster, which SpaceX wants to eventually reuse many times.

A long-range tracking camera captured this stunning view of Starship hot staging, with the upper stage engines firing at the same time of booster separation.
Enlarge / A long-range tracking camera captured this stunning view of Starship hot staging, with the upper stage engines firing at the same time of booster separation.

Hot staging appeared to be a success. Insprucker said the hot staging result was “exactly what we were looking for.”

Remarkably, the hot staging maneuver was visible from the ground Saturday. Suddenly, a bubble of orange flashed around the rocket, which was, by this point, barely a star-like speck in the sky. SpaceX later released dazzling zoomed-in shots of stage separation taken by a long-range tracker.

The Super Heavy booster, itself as tall as an entire Falcon 9 rocket, used its three still-burning Raptor engines to turn around and fly tail first, then ignited additional engines to begin boosting back toward the Texas coastline.

The booster was supposed to descend into the Gulf of Mexico for a controlled low-speed splashdown, but the Super Heavy disintegrated in the upper atmosphere moments after stage separation. Eventually, SpaceX wants to land Super Heavy boosters back on the launch pad for quick inspections and refueling for another flight.

The April test flight ended before SpaceX could try out the Starship upper stage. On Saturday, SpaceX engineers had their first opportunity to watch their new ship fly in space.

The upper stage lit its six Raptor engines and continued flying east from Starbase, eventually accelerating to a speed of nearly 15,000 mph (about 24,100 kilometers per hour). Starship soared above the von Kármán line, the 100-kilometer-high internationally-recognized boundary of space, and kept climbing, eventually peaking at an altitude of 92 miles (149 kilometers), according to a real-time data display on SpaceX’s live launch broadcast.

Less than 30 seconds before the point at which the six Starship engines were supposed to cut off, SpaceX lost telemetry from the rocket. In the company’s live video feed, it looked like the ship exploded as it was about to pass below the horizon from the viewpoint of the Starbase launch site.

A few minutes later, Insprucker reported Starship’s automated flight termination system apparently triggered late in the upper stage’s engine burn over the Gulf of Mexico. A weather radar in Puerto Rico detected what was probably Starship debris falling back into the atmosphere over the Atlantic Ocean.

Had the engines completed their burn, Starship would have gained enough speed to circle the Earth for nearly one full orbit, before falling back to the planet over the Pacific Ocean for a targeted splashdown.

Launch pad looks clean

SpaceX’s upgrades at the Starship launch pad were also put to the test Saturday. The rocket made a big mess when it launched on its first test flight in April, when the blast from the Raptor engines blew a hole in the concrete underneath the pedestal where the rocket sits before launch. Massive chunks of concrete were strewn across hundreds of acres around the launch pad, denting tanks and carving craters in the surrounding mud flats. Clouds of dust and sand fell on communities several miles away.

SpaceX upgraded the Starship launch pad with a new water deluge system after the April test flight.
Enlarge / SpaceX upgraded the Starship launch pad with a new water deluge system after the April test flight.

Stephen Clark/Ars Technica

This is something SpaceX didn’t want to repeat with the second test flight, so engineers installed a water deluge system at the pad to protect it from similar damage again. In the final seconds of the countdown, the deluge system released more than 100,000 gallons of fresh water through channels built into a steel plate installed underneath the pad’s circular launch mount. The fountain-like flow of water was supposed to absorb the heat and acoustic energy from the Super Heavy engines.

By all early accounts, the deluge system worked as it should. There were no chunks of large debris around the launch pad after Saturday’s liftoff. This will reduce the cleanup SpaceX has to do before moving the booster and upper stage to the pad for the next Starship test flight, preserving an opportunity for another Starship launch within the next few months.

A few things left undone

Ultimately, though, SpaceX didn’t hit all of its objectives Saturday.

The booster blew up soon after detaching from the Starship upper stage, and it wasn’t clear whether it malfunctioned on its own, or if it might have been damaged from getting blasted by super-heated exhaust from the upper stage engines, a potential risk of the hot staging maneuver Musk identified before the test launch.

The destruction of the Starship upper stage in the final seconds of its engine burn also eliminated a chance to test the ship’s heat shield. If the mission went perfectly, the flight would have ended about an hour-and-a-half after liftoff with splashdown of Starship in the Pacific Ocean.

The spacecraft was covered in thousands of ceramic tiles to protect its stainless steel structure from the heat of reentry. Some of the tiles appeared to fall off the ship during the climb into space, but SpaceX didn’t immediately confirm video indications of this. SpaceX needs to safely recover the Starship upper stage on future test flights to meet the company’s goal of developing a fully reusable rocket, but that will have to wait a little longer after the outcome of Saturday’s mission.

A cloud of propellant and debris lingers high in the sky over South Texas after the explosion of the Super Heavy booster.
Enlarge / A cloud of propellant and debris lingers high in the sky over South Texas after the explosion of the Super Heavy booster.

Stephen Clark/Ars Technica

As with all commercial launches by US companies, the Federal Aviation Administration will oversee the investigation into what went wrong with Saturday’s Starship test. SpaceX blamed sluggishness at the FAA’s commercial space office for delays in launching the second Starship rocket.

Because both elements of the rocket were lost in Saturday’s test, the FAA declared a mishap had occurred. “The anomaly resulted in a loss of the vehicle. No injuries or public property damage have been reported,” the FAA said.

The FAA is responsible for ensuring commercial space launches don’t endanger the public, assessing their environmental impacts, and making sure they comply with US national security and foreign policy priorities.

As it did after the April test flight, SpaceX will create a list of corrective actions to fix the problems observed on Saturday’s launch. The FAA will approve the list and ensure SpaceX completes all of the actions relevant to public safety before issuing a new commercial launch license for the third Starship test flight.

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