SpaceX
SpaceX’s first Starship engine suffers “expected” damage during Raptor test fire
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.
Merlins. The max chamber pressure run damaged Raptor SN 1 (as expected). A lot of the parts are fine for reuse, but next tests will be with SN 2, which is almost done.
— Elon Musk (@elonmusk) February 21, 2019
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.
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.
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- SpaceX’s world-class rocket propulsion team has been progressing through early full-scale Raptor tests at an incredible speed. (SpaceX)
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- Full-scale Raptor’s first static fire test, February 3rd. (SpaceX)
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- Raptor’s business end with a Musk-for-scale. (Elon Musk)
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- Starship revealed a trio of Raptor mockups when SpaceX technicians moved the assembly from stand to ground. (NSF – bocachicagal)
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- A September 2018 render of Starship (then BFS) shows one of the vehicle’s two hinged wings/fins/legs. (SpaceX)
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- BFR (2018) breaks through a cloud layer shortly after launch. (SpaceX)
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.
— Elon Musk (@elonmusk) February 4, 2019
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.
SN2 has changes that should help
— Elon Musk (@elonmusk) February 21, 2019
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.
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.
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SpaceX’s Raptor engine family has steadily increased sea-level thrust while simultaneously reducing mass, turning iterative engineering gains into substantially higher performance for the Super Heavy booster. CEO Elon Musk shed more light on how powerful Raptor 4 will be, and it’s pretty crazy.
Raptor 1 delivered 185 metric tons of thrust at roughly 2,080 kilograms, while Raptor 2 raised that to 230 tons while cutting mass to about 1,630 kilograms. SpaceX data for Raptor 3 lists a target of 280 tons at 1,525 kilograms (with further reductions in associated vehicle hardware), while operational flight ratings have been cited near 250 tons.
This morning, Elon Musk stated that Raptor 4 is expected to reach 300 tons of sea-level thrust at roughly the same mass as Raptor 3. Across these versions, thrust has risen by more than 60 percent from the first engines while engine mass has fallen, producing a sharp improvement in thrust-to-weight ratio. This is a true testament to how great SpaceX engineering has been:
🚀 Elon says Raptor 4 will make 300 tons of thrust at sea level at roughly the same mass as Raptor 3.
How far Raptor has come:
Raptor 1: 185 tf, 2,080 kg
Raptor 2: 230 tf, 1,630 kg
Raptor 3: 250 tf, 1,525 kg
Raptor 4: 300 tf33 on Super Heavy = ~9,900 tf, nearly 3x Saturn V https://t.co/HQDswZhyvL
— TESLARATI (@Teslarati) October 26, 2026
With 33 engines on SuperHeavy, the jump from earlier versions to a 300-ton Raptor 4 would produce roughly 9,900 metric tons of total liftoff thrust, nearly three times the Saturn V’s approximately 3,400 metric tons from its five F-1 engines.
This is not just a larger number on a data sheet, either, as sea-level thrust is the force available the moment the vehicle leaves the pad. This is when it is heaviest and still deep in Earth’s gravity well and dense atmosphere.
Higher levels of sea-level thrust directly improves the initial thrust-to-weight ratio of the full stack. A higher ratio produces faster acceleration off the pad, which shortens the time the rocket has to spend fighting gravity, and gravity losses during the first minute or two of the flight are a major drain on total available delta-v. Every second shaved off of that early climb preserves more propellant energy for reaching orbital velocity or for carrying extra payload.
Because Super Heavy’s engine count is constrained by vehicle diameter and packing density, increasing thrust per engine is the most straightforward way to raise total liftoff performance without redesigning the booster structure or design.
The same-mass target for Raptor 4 is equally important. Holding engine mass roughly constant while raising thrust improves the engine’s own thrust-to-weight ratio and reduces the structural and propellant mass fraction that must be carried solely to support the engines.
Earlier Raptor iterations also simplified or eliminated extensive vehicle-side hardware such as heat shields. These gains compound: more force for less installed mass leaves additional capacity for propellant, payload, or operational margins such as engine-out capability.
For Starship’s architecture, the practical effects are large. Greater liftoff thrust supports heavier vehicles, larger propellant loads, and higher payloads to low Earth orbit, figures SpaceX has targeted in the 100-plus-ton reusable range. That capacity underpins orbital refueling, lunar missions, and eventual Mars cargo and crew flights.
Continued growth in sea-level thrust therefore tightens the gap between theoretical rocket performance and the high flight rates and reusability needed to make large-scale space transport practical.
Tesla expanded its Robotaxi geofence in Houston, Texas, today, enlarging the service area and drawing a new rocket-shaped boundary across the city’s northwestern and central parts.
Although CEO Elon Musk said it was just a coincidence, the expansion seems to be an ode to SpaceX and its potential merger with Tesla.
🚨 Tesla has just expanded its Robotaxi geofence in Houston
It looks a lot like a rocket — we all remember the shape in Austin 🤣 https://t.co/cFOPEuiJ4u
— TESLARATI (@Teslarati) October 26, 2026
The official Tesla Robotaxi account announced the change with the lines “Houston, we have liftoff” and “Bigger service area now live,” pairing them with a map overlay.
The prior white geofence, roughly 25 square miles covering Jersey Village, Harvest Bend, and the Willowbrook corridor along U.S. 290 and State Highway 249, now sits inside a larger blue zone that stretches southeast toward Bellair and closer to central Houston.
Houston’s Robotaxi service launched on April 18, 2026, the same day as Dallas, as Tesla’s first unsupervised public expansion beyond Austin. From the start, the vehicles were Model Ys running without anyone in the front seats, booked through the dedicated Tesla Robotaxi app and open to the public inside the geofence.
Trackers measured the initial zone at about 25 square miles; by late September it had not grown substantially. Community and registry data indicated a modest local fleet of unsupervised Model Ys, while dozens to nearly 200 Cybercabs, the purpose-built, steering-wheel-free two-seaters, have been spotted staging and testing in Houston lots, though public Cybercab rides remain limited to Austin for now.
Across the broader Robotaxi program, Tesla began public Robotaxi rides in Austin in June 2025, as a small geofence and vehicles with safety monitors became available for a ride-hailing service. Later on, Tesla removed the monitors and steadily expanded the service area until it covered most of the Austin metro area.
Unsupervised Robotaxi services now run in six cities: Austin, Dallas, Houston, Miami, Orlando, and Tampa. Cumulative driverless miles reported by the company have reached several million. The Cybercab entered public service in Austin in early September 2026 and has scaled rapidly there. The company has also said that Dallas is next for Cybercab rides in November, with further cities and 24/7 hours targeted by year-end, plus fleet-operator sales of the vehicle.
Waymo also operates a fully driverless service in Houston, which has been open to the public since August of this year.
The Houston expansion continues Tesla’s pattern of starting with tightly controlled validation zones before widening coverage as real-world data accumulates, while the rocket motif on the map underscores the company’s habit of injecting visual flair into its autonomy rollout.
Riders inside the new boundary can request unsupervised Model Y trips in the Robotaxi app; exact operating hours and further Cybercab availability remain subject to app updates and company statements.
Elon Musk
The Starship moon landing number NASA and Elon Musk can’t agree on
Musk disputes NASA estimate of 22 Starship launches for Moon landing, predicting 6 to 8.
Elon Musk is disputing a new NASA safety panel estimate of how many Starship launches it will take to put astronauts on the Moon, saying the real number will be less than half the panel’s figure.
On Thursday, NASA’s Aerospace Safety Advisory Panel held its quarterly public meeting. Panel member Charlie Precourt, a former NASA astronaut, flagged the fueling process for SpaceX’s lunar lander as a major risk for Artemis IV, the mission planned to land a crew on the Moon in 2028. “We need to keep our eyes on numerous required fuelings for the lander,” Precourt said, according to Ars Technica. “I think the last estimate is around 22 flights.”
Ars Technica’s Eric Berger posted the comment on X, and Musk replied. “That’s way too high,” Musk wrote. “Actual number will be more like 6 to 8.”
The disagreement comes down to a basic problem with sending a ship as large as Starship to the Moon. Starship burns nearly all of its propellant just reaching Earth orbit, so it cannot continue on to the Moon without stopping for a refill. SpaceX’s answer is a gas station in space. First, a Starship that works as a storage tank, called a depot, is launched into orbit. Then a series of tanker Starships launch one at a time, dock with the depot and pump their leftover propellant into it. Once the depot is full, the lunar lander version of Starship launches, docks, fills up and heads for the Moon.
Every tanker trip is its own full rocket launch, which is why the count matters. More launches mean more time, more cost and more chances for something to go wrong before astronauts ever leave Earth. Berger estimated that even if SpaceX reaches twice weekly Starship launches by the end of 2027, filling a depot at the panel’s number would still take roughly three months.
How many tankers are needed depends mostly on how much propellant each one can carry to orbit and how much is lost along the way. Starship’s fuel and oxygen are stored at extremely cold temperatures, and some of it slowly boils off while waiting in orbit. More is lost in each transfer. NASA appears to be working from what Starship can lift today, while Musk’s range assumes a more capable rocket.
Musk has pushed back on higher counts before. In 2021, after a government document suggested 16 launches, he called that “extremely unlikely” and said eight tankers would be the most required.
Much of the answer depends on hardware SpaceX has not finished flying. As Teslarati noted earlier this year, the company plans to carry out the refueling process with its upgraded V3 Starship, and Precourt described Artemis IV as carrying “a large number of firsts.” He also praised NASA Administrator Jared Isaacman’s team for working to clear obstacles for both SpaceX and Blue Origin, whose Blue Moon lander does not rely on orbital refueling for its first mission.
Tesla has a Cybercab problem nobody saw coming
How SpaceX Is raising Raptor’s sea-level thrust while holding engine mass steady
