SpaceX
SpaceX CEO Elon Musk says that BFR could cost less to build than Falcon 9
SpaceX CEO Elon Musk believes that there may be a path for the company to ultimately build the massive Starship spacecraft and Super Heavy booster (formerly BFR) for less than Falcon 9/Falcon Heavy, a rocket 3-9 times smaller than BFR.
While it certainly ranks high on the list of wild and wacky things the CEO has said over the years, there may be a few ways – albeit with healthy qualifications – that Starship/Super Heavy production costs could ultimately compare favorably with SpaceX’s Falcon family of launch vehicles. Nevertheless, there are at least as many ways in which the next-gen rocket can (or should) never be able to beat the production cost of what is effectively a far simpler rocket.
This will sound implausible, but I think there’s a path to build Starship / Super Heavy for less than Falcon 9
— Elon Musk (@elonmusk) February 11, 2019
Dirty boosters done dirt cheap
On the one hand, Musk might not necessarily be wrong, especially if one throws the CEO several bones in the interpretation of his brief tweet. BFR at its simplest is going to require a full 38 main rocket engines to achieve its nominal performance goals, 7 on Starship and 31 on Super Heavy. As a dramatically more advanced, larger, and far more complex engine, Raptor will (with very little doubt) cost far more per engine than the relatively simple Merlin 1D. BFR avionics (flight computers, electronics, wiring, harnesses) are likely to be more of a known quantity, meaning that costs will probably be comparable or even lower than Falcon 9’s when measured as a proportion of overall vehicle cost. Assuming that BFR can use the exact same cold gas thruster assemblies currently flying on Falcon 9, that cost should only grow proportionally with vehicle size. Finally, Starship will not require a deployable payload fairing (~10% of Falcon 9’s production cost).
All of those things mean that Starship/Super Heavy will probably be starting off with far better cost efficiency than Falcon 9 was able to, thanks to almost a decade of interim experience both building, flying, and refurbishing the rocket since its 2010 debut. Still, BFR will have to account for entirely new structures like six large tripod fins/wings and their actuators, wholly new thrust structures (akin to Falcon 9’s octaweb) for both stages, and more. Considering Starship on its own, the production of a human-rated spacecraft capable of safely housing dozens of people in space for weeks or months will almost without a doubt rival the cost of airliner production, where a 737 – with almost half a century of production and flight heritage – still holds a price tag of $100-130+ million.
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- BFR shown to scale with Falcon 1, 9, and Heavy. (SpaceX)
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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’s booster, now known as Super Heavy. (SpaceX)
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- Sadly, this is a not a sight that will greet Falcon 9 booster B1046’s fourth launch – Crew Dragon’s critical In-Flight Abort test. (SpaceX)
Adding one more assumption, the most lenient interpretation of Musk’s tweet assumes that he is really only subjecting the overall structure (sans engines and any crew-relevant hardware) of BFR relative to Falcon 9. In other words, could a ~300-ton stainless steel rocket structure (BFR) cost the same amount or less to fabricate than a ~30-ton aluminum-lithium alloy rocket structure (Falcon 9/Heavy)? From the very roughest of numerical comparisons, Musk estimated the cost of the stainless steel alloys (300-series) to be used for BFR at around $3 per pound ($6.60/kg), while aluminum-lithium alloys used in aerospace (and on Falcon 9) are sold for around $20/lb ($44/kg)*. As such, simply buying the materials to build the basic structures of BFR and Falcon 9 would cost around and $7.5M and $5M, respectively.
Assuming that the process of assembling, welding, and integrating Starship and Super Heavy structures is somehow 5-10 times cheaper, easier, and less labor-intensive, it’s actually not inconceivable that the cost of building BFR’s structure could ultimately compete with Falcon 9 after production has stabilized after the new rocket’s prototyping phase is over and manufacturing processes are mature.
*Very rough estimate, difficult to find a public cost per unit mass from modern Al-Li suppliers
Costs vs. benefits
On the opposite hand, stainless steel rockets do not have a history of being uniquely cost-effective relative to vehicles using alternative materials. The only orbital-class launch vehicles to use stainless steel (and balloon) tanks are the Atlas booster and the Centaur upper stage, with Atlas dating back to the late 1950s and Centaur beginning launches in the early ’60s. Stainless steel Atlas launches ended in 2005 with the final Atlas III mission, while multiple forms of Centaur continue to fly regularly on ULA’s Atlas V and Delta IV.
Based on a 1966 contract between NASA and General Dynamics placed shortly after Centaur’s tortured development had largely been completed, Centaur upper stages were priced around $25M apiece (2018 USD). In 1980, the hardware for a dedicated Atlas-Centaur launch of a ~1500 kg Comstar I satellite to GTO cost the US the 2018 equivalent of a bit less than $40M ($71M including miscellaneous administrative costs) – $22.4M for Centaur and $17.6M for Atlas. For Atlas, the rocket’s airframe (tanks and general structure) was purchased for around $8.5M. That version of Atlas-Centaur (Atlas-SLV3D Centaur-D1A) was capable of lifting around 5100 kg (11,250 lb) into Low Earth Orbit (LEO) and 1800 kg (~4000 lb) to geostationary transfer orbit (GTO), while it stood around 40m (130 ft) tall, had a tank diameter of 3.05m (10 ft), and weighed ~150t (330,000 lb) fully fueled.
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- Atlas shows off its shiny steel balloon tanks. (SDASM)
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- The original space-faring Atlas, known as SM-65, seen here with a Mercury space capsule. (NASA)
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- A Centaur upper stage is pictured here in 1964. (NASA)
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- Atlas SLV3D is pictured here launching a Comstar I satellite.
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- A Falcon 9 booster is seen here near the end of its tank welding, just prior to painting. (SpaceX)
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- An overview of SpaceX’s Hawthorne factory floor in early 2018. (SpaceX)
In a very loose sense, that particular stainless steel Atlas variant was about half as large and half as capable as the first flight-worthy version of Falcon 9 at roughly the same price at launch ($60-70M). What does this jaunt through the history books tell us about the prospects of a stainless steel Starship and Super Heavy? Well, not much. The problem with trying to understand and pick apart official claims about SpaceX’s next-generation launch architecture is quite simple: only one family of rockets in the history of the industry (Atlas) regularly flew with stainless steel propellant tanks, a half-century lineage that completed its final launch in 2005.
Generally speaking, an industrial sample size of more or less one makes it far from easy to come to any particular conclusions about a given technology or practice, and SpaceX – according to CEO Elon Musk – fully intends to push past the state of the art of stainless steel rocket tankage with BFR. Ultimately, American Marietta/Martin Marietta/Lockheed Martin was never able to produce launch vehicle variants of the stainless steel Atlas family at a cost more than marginally competitive with Falcon 9, despite the latter rocket’s use of a far more expensive metal alloy throughout its primary tanks and structure.
At least 10X cheaper
— Elon Musk (@elonmusk) February 11, 2019
At some point, it’s even worth asking whether the per-unit cost of Starship and Super Heavy should be relevant at all to their design and construction, at least within reason. If the goal of BFR is to drastically lower the cost of launch by radically improving the ease of reuse, it would be truly bizarre (and utterly unintuitive) if those goals could somehow be achieved without dramatically raising the cost of initial hardware procurement. Perhaps the best close comparison to BFR’s goals, modern airliners are eyewateringly expensive ($100-500M apiece) as a consequence of the extraordinary reliability, performance, efficiency, and longevity customers and regulatory agencies demand from them, although those costs are admittedly not the absolute lowest they could be in a perfect manufacturing scenario.
At the end of the day, it appears that Musk is increasingly of the opinion that the pivot to stainless steel could ultimately make BFR simultaneously “better, faster, [&] cheaper”. However improbable that may be, if it does turn out to be the case, Starship and Super Heavy could be an unfathomable leap ahead for reliable and affordable access to space. It could also be another case of Musk’s excitement and optimism getting the better of him and hyping a given product well beyond what it ultimately is able to achieve. Time will tell!
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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.
How SpaceX Is raising Raptor’s sea-level thrust while holding engine mass steady
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