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SpaceX to upgrade Starship with 50% more Raptor engines
SpaceX CEO Elon Musk says that future Starships – or at least certain Starship variants – are being upgraded with 50% more Raptor engines and stretched propellant tanks.
On December 17th, the CEO revealed the plans, confirming a tweet published three months prior stating that Starship was “begging for an extra 3 engines.” Musk was likely referring to the fact that a 9-engine Starship – combined with upcoming 33-engine Super Heavy boosters – would create a rocket with 42 engines, a number made famous as “the answer to the ultimate question of life [and everything]” in Hitchhiker’s Guide to the Galaxy – both of which the CEO vocally enjoys. As ever, it’s thus almost impossible to tell jokes from serious, consequential plans – as is the case with Starship.
Nonetheless, origination aside, adding another three Raptor engines to Starship – boosting the count from six to nine – and stretching its tanks could be a substantial upgrade.
According to amateur modelers, who are generally able to estimate rocket performance with enough information about its structures, shape, and engines; an optimal nine-engine Starship’s tanks would be stretched about 25% to store an additional 300 tons (650,000 lb) of cryogenic liquid oxygen and methane (LOx/LCH4). That upgraded Starship would have a liftoff mass close to 1600 tons (3.5M lb) and stand about 55 meters (~180 ft) tall – 10% taller than current ships.
At stage separation, close to vacuum, a stretched Starship with three sea-level-optimized Raptors (RCs) and six vacuum-optimized Raptors (RVacs) should produce at least 2000 tons (4.4M lbf) of thrust – and possibly more than 2250 tons (~5M lbf) depending on engine performance. At that upper level of thrust, Starship – an upper stage – would be just 10% less powerful than the first stage of Falcon Heavy, the most powerful operational rocket in the world.
Regardless of its thrust, dimensions, or weight, what matters most is how a stretched, nine-engine Starship would impact that overall rocket’s launch performance. If unofficial modelers are to be believed, the results are significant: compared to a ‘normal’ Starship with a six-engine upper stage and 33-engine booster, the stretched ship could theoretically boost the amount of payload the rocket can launch to low Earth orbit (LEO) from about 150 tons to 220 tons or more (330,000 to 485,000+ lb) – an almost 50% improvement. In fact, per another recent comment from Musk indicating that Starship – unlike almost all other rockets – won’t temporarily throttle down on ascent, the total payload performance could be a bit less than 230 tons (~500,000 lb) – more than 50% greater than a shorter six-engine Starship.
If those estimates are accurate, upgrading Starship with nine Raptors and stretching its tanks is a no-brainer. It might slow development and make all nine-engine ships cost a substantial fraction more but a 50% improvement in payload performance would significantly improve the efficiency of Starship’s more ambitious Moon and Mars launch profiles, which require numerous orbital refuelings.
In effect, a 50% payload increase would allow SpaceX to complete most refueling tasks more efficiently, quickly, and cheaply. Even if the upgrade plans mean that all Starships will be stretched and carry nine Raptors, fully refueling the new Starship variant in LEO could require 7 tanker launches instead of 8-10. If SpaceX doesn’t mind maintaining multiple distinct Starship variants, which appears to be the case, then ships that are exclusively dependent on refueling (Moon and Mars landers in particular) could stay at their current size, with ~1200 tons (~2.6M lb) of propellant storage and six Raptors. A fleet of upgraded Starships could thus refuel their smaller siblings with just 5-6 tanker launches.
However, there’s a good chance that the extra mass required to stretch Starship ~5.5m (~4 tons or ~9000 lb) is minor enough that SpaceX will instead stretch all Starship variants. In fact, for variants like NASA’s HLS Moon lander and future Marsbound Starships, which depend entirely on refueling to reach their destinations, stretched tanks and more propellant storage could increase the amount of payload they could send to the Moon, Mars, and other high-energy destinations by quite a bit. Ultimately, it will be fascinating to hear more details from SpaceX and Musk on how exactly the upgraded Starship design might benefit those operations in the coming weeks and months.
Elon Musk
Tesla shows what Roadster drivers will see on screen before thruster activation
Tesla’s Roadster video reveals a fighter jet inspired cockpit with a 5,500 PSI thruster gauge.
Tesla has given future owners their clearest look yet at the cockpit of its next generation Roadster. In a 34 second video posted to X on Friday afternoon, the company walked through the car’s touchscreen with a caption: “Inspired by fighter jet cockpits, Roadster’s interface was designed around the pilot.”
The clip opens on a black screen with red graphics and a 3D wireframe of the car, which sits beside the Roadster’s squared off yoke. Tapping parts of the model brings up controls for the rear wing, including low drag and high downforce positions, along with a charging page with a charge limit bar and a small music player. A row of tabs along the bottom reads Home, Vehicle, Listen, Climate and Navigate.
Most of the video is spent in Track Mode. The dashboard shows a live circuit map, a list of session lap times, brake and motor temperatures, and pressure and temperature readouts for each tire. A setup page lets the driver pick Auto, Low Drag, High Downforce or Custom aero modes, adjust aero balance and brake balance, and switch stability and traction control off. Along the bottom, a status bar reads “Thruster · 5,500 PSI” next to a “Boost Ready” indicator.
That gauge ties the software to the hardware Tesla showed off near Waco, Texas on October 15. The Thrust and Rocket versions use cold gas thrusters fed by carbon overwrapped pressure vessels, and Tesla lists 0 to 60 mph times of under 0.9 seconds and under 0.59 seconds for them, as Teslarati detailed in its breakdown of the three Roadster configurations. The base Performance car relies on a fan and ground sealing system for grip, and the aero settings on screen match the active wings and suction setup covered in our look at how the Roadster generates downforce.
The Roadster layout is a departure from the rest of Tesla’s lineup. Instead of a map centered screen, the Roadster puts the car itself at the center of the home page, and Tesla’s Roadster page lists two smaller forward displays alongside the main touchscreen. Tesla has not said whether any of the Track Mode telemetry will make its way to the Model 3 Performance or other vehicles.
The interface could still change before deliveries. Elon Musk said at the event that Roadster production will begin in 2028, and Tesla says the flagship Rocket version is not approved for public road use. Reservations are open with a $50,000 payment, while Thrust is listed as a limited release and Rocket is invite only.
Those who want to see the car in person will get their first chance this weekend. The Roadster goes on display in the lobby of the Petersen Automotive Museum in Los Angeles from October 24 to 27, according to Sawyer Merritt, the first time the public will be able to view it up close.
Elon Musk
Tesla reveals Optimus Academy, where robots teach themselves
Tesla has begun building production quality Optimus robots in Fremont and revealed its training plan.
Tesla has started building Optimus on the high volume line it set up inside its Fremont factory, and the company says the robots coming off it are the first that meet the bar for a real product. “The bots coming off this line are the first production-quality bots that we have manufactured,” Tesla wrote in its third quarter shareholder letter, adding that it has “proven that the current manufacturing process for Optimus is suitable for a commercial product.”
The line sits in space that built the Model S and Model X until this spring. Tesla cleared the old vehicle line in 46 days, as Teslarati reported in July, to make room for robot production sized for one million units a year. On Wednesday’s earnings call, Elon Musk said most of the equipment for that capacity is already in Fremont, with output set to climb toward roughly 20,000 robots a week as the line ramps.
Musk described the ramp as a classic S curve. “The growth of Optimus is an S curve, but the initial curve is a shallow slope,” he said. The team is now refining the robot’s AI, electromechanical design, reliability and service life, and Musk expects that work to be finished by the end of next year, when Tesla plans to start delivering Optimus to outside companies for dangerous, repetitive and around the clock jobs.
The most interesting part of the call was how Tesla plans to teach the robots. Its cars send real driving data back to the AI team from millions of vehicles, but Optimus has no fleet like that yet. “A big difference with Optimus versus the cars is we don’t have this vast fleet of cars from which we can gather training data,” Musk said. Tesla’s answer is an Optimus Academy, where 10,000 to 20,000 robots will practice a wide range of tasks and feed what they learn into the next version of the model. Every unit off the Fremont line becomes a source of that training data.
Smarter hardware is on the way too. Tesla plans to put its AI5 chip into Optimus next year, and Musk said a new Optimus video should arrive within one or two months showing the robot completing tasks driven by AI rather than preprogrammed motions. He took aim at rival humanoid demos that only run scripted routines, saying those would not hold up in the real world.
The supply chain is lining up behind the program. In September, Tesla certified Tuopu, Joyson and Sanhua as mass production partners for Optimus components. A far larger Optimus factory is also rising at Giga Texas, where drone footage from Joe Tegtmeyer showed the steel frame nearing completion, and Musk has pegged that plant’s long term target at 10 million robots a year.
Tesla executives also said Optimus production costs are trending toward the expected manufacturing cost of Cybercab, a sign the robot is being engineered for volume from the start. The hands remain the toughest piece of the design, a point Musk also made at the X Takeover event earlier this month, as Teslarati covered at the time, and that is where much of the current engineering effort is focused.
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.