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SpaceX’s first Starship engine suffers “expected” damage during Raptor test fire

Sometimes you have to crack a few Raptor eggs to make a Starship omelette. (SpaceX)

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6 years ago

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SpaceX CEO Elon Musk says that the first full-scale Starship engine to be tested has already been pushed to the point of damage less than three weeks after the campaign began, setting the stage for the second full-scale Raptor to take over in the near future.

According to Musk, while most of the damaged pathfinder Raptor’s components should still be easily reusable, the assembly of the second finalized engine is “almost done” and that Raptor will take over near-term testing rather than waiting for repairs to the first engine. This is undoubtedly an extraordinarily aggressive test program, particularly for such a new and cutting-edge rocket propulsion system, but these latest developments are ultimately far more encouraging than they are concerning.

Although the Raptor engine family began integrated subscale static fires way back in September 2016, SpaceX’s propulsion team finalized Raptor’s baseline design and completed assembly, shipment, and an integrated static fire of the first full-scale engine on February 3rd, considerably less than three weeks before Musk took to Twitter. Aside from confirming that the new Raptor had been damaged during its most recent static fire several days prior, Musk indicated that the failure (unsurprisingly) was primarily attributed to the engine reaching the highest chamber pressures yet.

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Raptor’s main combustion chamber (the bit directly above the nozzle) has been designed to nominally operate at and reliably withstand extraordinary pressures of 250+ bar (3600+ psi), performance that demands even higher pressures in the components that feed hot methane and oxygen gas into Raptor’s combustion chamber. One prime example hinted at by Musk in a 2018 tweet is its oxygen preburner, used to convert liquid propellant into a high-velocity gas that can then feed a dedicated oxygen turbopump. Aside from the absurdly corrosive environment created by extremely hot gaseous oxygen, the preburner must also survive pressures that could peak as high as 800+ bar, or 12,000 psi.

 

A lack of technical detail means that it’s hard to know what thrust or main chamber pressure Musk had in mind when referring to exotic alloys that would be needed to survive those pressures, but the performance statistics of a Raptor with a preburner operating at 800+ bar would probably outstrip anything Musk has thus far described. In other words, it’s safe to assume that Raptor has probably not been pushed to those performance levels just yet, although it’s still a distant possibility. More likely is that 800+ bar in the oxygen preburner is an extreme stretch-goal that will take concerted research, development, and optimization to achieve, with Raptor having suffered damage somewhere below those levels while still reaching eye-watering performance figures.

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For an engine as complex as Raptor, there are countless dozens of potential failure modes the appearance of which would come as little surprise for an engine just days into full-scale testing. Above all else, the Raptor test schedule held by SpaceX’s world-class propulsion team – be it self-motivated or driven by reckless management-by-spreadsheet – has been fast-paced in the extreme, taking the first high-performance Raptor ever built from standstill to more than 90% thrust and chamber pressures of almost 270 bar (3900 psi) in – quite literally – less than one week. In the same period of time, more than half a dozen static fire tests (ranging from 1-10 seconds) were performed.

Within a few days of that February 10th milestone, in which Raptor reached chamber pressures comparable with the most advanced modern engines (namely RD-180/190/191), the engine was apparently pushed dramatically higher still, reaching a chamber pressure (and thus thrust) that wrought damage on some of the more sensitive parts of the engine’s plumbing. Despite the fact that the second production Raptor is apparently already “almost done”, Musk suggested that it would already feature changes (of unknown gravity) to mitigate the failure modes experienced by Raptor SN01.

In an industry where NASA and contractors like Aerojet-Rocketdyne will spend months between static fire tests of Space Shuttle engines that have each literally flown multiple (if not) dozens of missions to orbit and have a demonstrated performance and reliability record that is measured in the hundreds of thousands of seconds, the speed and agility of SpaceX’s Raptor development and test program is breathtaking. What remains to be seen is just how comparably reliable and successful the end results (i.e. operational Raptor) will be, but an attitude that actively accepts and even pursues testing to destruction can ultimately only serve to benefit the finished product at the cost of destroyed hardware and many on-ground lessons learned the hard ways.

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Given the immense success of SpaceX’s Merlin family of engines and the aggressive strategy of development and continuous improvement that brought it from Merlin 1A to 1D and MVacD, SpaceX is clearly not fumbling around in the dark when it comes to Raptor R&D.

Check out Teslarati’s newsletters for prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket launch and recovery processes!

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Elon Musk reveals SpaceX’s target for Starship’s 10th launch

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

Published

2 weeks ago

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July 16, 2025

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Credit: SpaceX

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

Musk says SpaceX is aiming for a timeline of roughly three weeks from now, which would come about ten weeks after the previous launch.

Coincidentally, it would bring the two launches 69 days apart, and if you know anything about Elon Musk, that would be an ideal timeline between two launches.

SpaceX is coming off a test flight in which it lost both the Super Heavy Booster and the Upper Stage in the previous launch. The Super Heavy Booster was lost six minutes and sixteen seconds into the flight, while SpaceX lost communication with the Ship at 46 minutes and 48 seconds.

Musk is aiming for the tenth test flight to take place in early August, he revealed on X:

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This will be SpaceX’s fourth test flight of the Starship program in 2025, with each of the previous three flights bringing varying results.

IFT-7 in January brought SpaceX its second successful catch of the Super Heavy Booster in the chopstick arms of the launch tower. The ship was lost after exploding during its ascent over the Turks and Caicos Islands.

IFT-8 was on March 6, and SpaceX caught the booster once again, but the Upper Stage was once again lost.

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The most recent flight, IFT-9, took place on May 27 and featured the first reused Super Heavy Booster. However, both the Booster and Upper Stage were lost.

The Federal Aviation Administration (FAA) hit SpaceX with a mishap investigation for Flight 9 on May 30.

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SpaceX’s Crew-11 mission targets July 31 launch amid tight ISS schedule

The flight will lift off from Launch Complex 39A at Kennedy Space Center in Florida.

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3 weeks ago

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July 12, 2025

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spacex-dragon-axiom-ax-4-mission-iss
(Credit: SpaceX)

NASA and SpaceX are targeting July 31 for the launch of Crew-11, the next crewed mission to the International Space Station (ISS). The flight will lift off from Launch Complex 39A at Kennedy Space Center in Florida, using the Crew Dragon Endeavour and a Falcon 9 booster.

Crew Dragon Endeavour returns

Crew-11 will be the sixth flight for Endeavour, making it SpaceX’s most experienced crew vehicle to date. According to SpaceX’s director of Dragon mission management, Sarah Walker, Endeavour has already carried 18 astronauts representing eight countries since its first mission with NASA’s Bob Behnken and Doug Hurley in 2020, as noted in an MSN report.

“This Dragon spacecraft has successfully flown 18 crew members representing eight countries to space already, starting with (NASA astronauts) Bob (Behnken) and Doug (Hurley) in 2020, when it returned human spaceflight capabilities to the United States for the first time since the shuttle retired in July of 2011,” Walker said.

For this mission, Endeavour will debut SpaceX’s upgraded drogue 3.1 parachutes, designed to further enhance reentry safety. The parachutes are part of SpaceX’s ongoing improvements to its human-rated spacecraft, and Crew-11 will serve as their first operational test.

The Falcon 9 booster supporting this launch is core B1094, which has launched in two previous Starlink missions, as well as the private Ax-4 mission on June 25, as noted in a Space.com report.

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The four-members of Crew-11 are NASA astronauts Zena Cardman and Mike Fincke, as well as Japan’s Kimiya Yui and Russia’s Oleg Platonov.

Tight launch timing

Crew-11 is slated to arrive at the ISS just as NASA coordinates a sequence of missions, including the departure of Crew-10 and the arrival of SpaceX’s CRS-33 mission. NASA’s Bill Spetch emphasized the need for careful planning amid limited launch resources, noting the importance of maintaining station altitude and resupply cadence.

“Providing multiple methods for us to maintain the station altitude is critically important as we continue to operate and get the most use out of our limited launch resources that we do have. We’re really looking forward to demonstrating that capability with (CRS-33) showing up after we get through the Crew-11 and Crew-10 handover,” Spetch stated.

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SpaceX launches Ax-4 mission to the ISS with international crew

The SpaceX Falcon 9 launched Axiom’s Ax-4 mission to ISS. Ax-4 crew will conduct 60+ science experiments during a 14-day stay on the ISS.

Published

1 month ago

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June 25, 2025

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spacex-ax-4-mission-iss
(Credit: SpaceX)

SpaceX launched the Falcon 9 rocket kickstarting Axiom Space’s Ax-4 mission to the International Space Station (ISS). Axiom’s Ax-4 mission is led by a historic international crew and lifted off from Kennedy Space Center’s Launch Complex 39A at 2:31 a.m. ET on June 25, 2025.

The Ax-4 crew is set to dock with the ISS around 7 a.m. ET on Thursday, June 26, 2025. Axiom Space, a Houston-based commercial space company, coordinated the mission with SpaceX for transportation and NASA for ISS access, with support from the European Space Agency and the astronauts’ governments.

The Ax-4 mission marks a milestone in global space collaboration. The Ax-4 crew, commanded by U.S. astronaut Peggy Whitson, includes Shubhanshu Shukla from India as the pilot, alongside mission specialists Sławosz Uznański-Wiśniewski from Poland and Tibor Kapu from Hungary.

“The trip marks the return to human spaceflight for those countries — their first government-sponsored flights in more than 40 years,” Axiom noted.

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Shukla’s participation aligns with India’s Gaganyaan program planned for 2027. He is the first Indian astronaut to visit the ISS since Rakesh Sharma in 1984.

Axiom’s Ax-4 mission marks SpaceX’s 18th human spaceflight. The mission employs a Crew Dragon capsule atop a Falcon 9 rocket, designed with a launch escape system and “two-fault tolerant” for enhanced safety. The Axiom mission faced a few delays due to weather, a Falcon 9 leak, and an ISS Zvezda module leak investigation by NASA and Roscosmos before the recent successful launch.

As the crew prepares to execute its scientific objectives, SpaceX’s Ax-4 mission paves the way for a new era of inclusive space research, inspiring future generations and solidifying collaborative ties in the cosmos. During the Ax-4 crew’s 14-day stay in the ISS, the astronauts will conduct nearly 60 experiments.

“We’ll be conducting research that spans biology, material, and physical sciences as well as technology demonstrations,” said Whitson. “We’ll also be engaging with students around the world, sharing our experience and inspiring the next generation of explorers.”

SpaceX’s Ax-4 mission highlights Axiom’s role in advancing commercial spaceflight and fostering international partnerships. The mission strengthens global space exploration efforts by enabling historic spaceflight returns for India, Poland, and Hungary.

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