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SpaceX Starship booster survives record-breaking 31-engine static fire
SpaceX’s Starship rocket has survived a record-breaking engine test – potentially the most powerful static fire in the history of rocketry.
According to CEO Elon Musk, Super Heavy Booster 7 (B7) ultimately ignited 31 of its 33 Raptor engines. One engine was manually disabled “just before” the static fire, while the other faulty engine automatically shut down while attempting to ignite. The other 31 Raptors, however, completed a “full duration” static fire that lasted about five seconds. Musk says that even with two engines disabled, those that remained were “still enough…to reach orbit” – an excellent result despite the static fire’s imperfections.
Most importantly, Super Heavy Booster 7 survived the test without catching fire, exploding, or popping its tanks. To partially counteract the thrust of its Raptor engines, the rocket’s tanks were filled with some 3000 tons (6.6M lbs) of liquid oxygen and methane propellant. The stool-like orbital launch mount (OLM), which also survived the test in one piece, held Starship down with 20 clamps to counteract any remaining thrust. From SpaceX’s perspective, the fact alone that its only orbital-class Starship launch site survived the ordeal is likely enough for it to consider the static fire a success. But the test was much more than that.
The update that's rolling out to the fleet makes full use of the front and rear steering travel to minimize turning circle. In this case a reduction of 1.6 feet just over the air— Wes (@wmorrill3) April 16, 2024
Incinerating rocket records
Despite losing two Raptors, SpaceX still broke the all-time record for the number of rocket engines ignited simultaneously. That record was held by the Soviet N1 rocket, which launched four times with 30 NK-15 engines in the late 1960s and early 1970s. None of its test flights were successful, but N1 still set the record for the most thrust produced by a single rocket, generating up to 4500 tons (9.9M lbf) of thrust at liftoff.
Neither SpaceX nor CEO Elon Musk has confirmed it, reducing the odds that Super Heavy Booster 7 broke that historic thrust record. But it certainly could have. Each Raptor 2 engine can generate up to 230 tons (507,000 lbf) of thrust at sea level. Raptor is theoretically designed to throttle as low as 40%, or 92 tons (~200,000 lbf) of thrust. With 33 engines operating nominally at their minimum throttle setting, Super Heavy would have produced 3036 tons (~6.7M lbf) of thrust during today’s static fire – not a record.
For 31 Raptors to break N1’s thrust record, the average throttle setting would have had to be around 64% or higher – far from unreasonable. From a data-gathering perspective, a full-thrust static fire would be the most valuable 33-engine test SpaceX could attempt, but it would also be the riskiest and most stressful for the rocket and pad.
Former SpaceX executive Tom Mueller says that SpaceX broke N1’s record. Mueller is effectively the father of the Raptor engine, and likely still gets information straight from SpaceX engineers he used to work with. Still, one would expect SpaceX itself to proudly confirm as much if a rocket it built became the most powerful in history.
The most powerful rocket test in history?
Whether or not Starship became the most powerful rocket in history, it has likely become the most powerful rocket ever tested on the ground. The first stage of Saturn V produced around 3400 tons (7.5M lbf) of thrust during its first sea-level static fire in 1965. Likely contributing to its failure, N1’s booster was never static-fired. Other powerful rockets like the Space Shuttle and SLS use or used a combination of solid rocket boosters and liquid engines that cannot be tested together on the ground.
Unless SpaceX’s goal was a minimum-throttle static fire, Starship’s 31-Raptor static fire likely beat Saturn V’s record to become the most powerful ground test in the history of rocketry.
SpaceX’s next steps
While the 31 that did ignite appeared to perform about as well as SpaceX could have hoped, the two engines missing from February 9th’s historic Starship static fire have probably complicated the company’s next steps. To be fully confident in Starship’s ability to launch and fly a safe distance away from the launch site, SpaceX would likely need to complete a full 33-engine test. Meanwhile, Starship can’t fly until the Federal Aviation Administration approves a launch license, and the FAA could be stodgy enough to deny SpaceX a license without a perfect 33-engine static fire.
Alternatively, the FAA may accept that Starship could still safely launch and reach orbit while missing several Raptors. SpaceX could also guarantee that it will only allow Starship to lift off if all 33 engines are active, in which case a second 33-engine static fire attempt may not be necessary.
If SpaceX is happy with Booster 7’s 31-engine test results and isn’t too put off by any pad damage the test may or may not have caused, it will likely focus on finishing Starship 24. Ship 24 will then be transported back to the pad and reinstalled on top of Booster 7. SpaceX may choose to conduct another wet dress rehearsal or a static fire with the fully-stacked Starship, but it may also deem additional testing unnecessary.
Once all those tasks are completed, Ship 24 and Booster 7 will be ready to support Starship’s first orbital launch attempt. Prior to February 9th’s static fire, SpaceX CEO Elon Musk and COO/President Gwynne Shotwell agreed that Starship’s orbital launch debut could happen as early as March 2023. After today’s test, a March 2023 launch may be within reach.
Rewatch Super Heavy Booster 7’s historic static fire below.
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.
Tesla shows what Roadster drivers will see on screen before thruster activation
Tesla reveals Optimus Academy, where robots teach themselves
