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SpaceX Super Heavy booster returns to launch pad after major repairs
SpaceX has returned its newest Super Heavy to Starbase’s orbital launch site (OLS) after rapidly repairing damage the booster suffered during its first round of testing.
Super Heavy Booster 7 (B7) left the High Bay it was assembled in for the first time on March 31st and rolled a few miles down the road to nearby Starship launch and test facilities on a set of self-propelled mobile transporters (SPMTs). On April 2nd, the roughly 67-meter-tall (~220 ft; 69m w/ Raptors) rocket was installed on top of Starbase’s lone orbital launch mount (OLM), setting the stage for crucial qualification testing.
The start of that process was exceptionally successful. On April 4th, after a smooth launch mount installation, SpaceX quickly filled Booster 7’s propellant tanks with a relatively benign cryogenic fluid (liquid nitrogen, liquid oxygen, or both) to simulate the thermal and mechanical characteristics of real flammable propellant. Despite the fact that the test marked the first time SpaceX had fully filled a Super Heavy prototype’s tanks, Booster 7 sailed through the ‘cryoproof’ without any obvious issue.
On April 8th, SpaceX moved Super Heavy B7 from the orbital launch mount to a structural test stand that had been installed and modified just a few hundred feet away in the weeks prior. This is where Booster 7’s near-perfect start to qualification testing took a bit of a turn. Booster 7 is only the third full-size Super Heavy prototype SpaceX has tested since July 2021. Like Booster 3 and Booster 4 before it, Booster 7 features some major design changes that ultimately make the prototype a pathfinder, necessitating extensive qualification testing.
To name just a few of the changes, Super Heavy B7 is the first booster fitted with a 33-engine puck and the first finished Starship prototype of any kind designed to use new Raptor V2 engines. With all 33 engines installed and operating a full thrust, Booster 7’s entire structure – and its aft thrust section especially – would be subjected to around 40% more thrust and stress than Booster 4, which indirectly completed structural testing with the help of a sacrificial test tank. Beyond differences in thrust and mechanical stress, Booster 7 is also the first Super Heavy to reach the test stand with secondary ‘header’ tanks meant to store landing propellant.
It’s unclear if those header tanks were fully filled and drained during Booster 7’s cryoproof, but they would not be quite as cooperative during a different kind of cryogenic testing on the structural test stand. The stand SpaceX modified specifically for Super Heavy B7 was outfitted with 13 hydraulic rams to simulate the full thrust of the booster’s central Raptor V2 engines – up to almost 3000 tons (~6.6M lbf) compared to Booster 4’s ~1700 tons (~3.7M lbf) with a smaller cluster of nine engines.
Implosion at the Structural Test Stand
After a few false starts and minor tests on the stand, Booster 7 finally managed some significant testing on April 14th. Judging by the rhythmic shattering of ice that built up on Super Heavy’s tanks, the test stand was able to simulate the thrust of Raptors to some degree and subject the booster to major mechanical stress that was felt from tip to tail. Within a few days, Booster 7 was removed from the test stand and returned to the high bay on April 18th. Around April 21st or 22nd, an image was leaked showing extensive damage inside Booster 7, confirming that the Super Heavy’s test campaign had been forced to end prematurely.
Right away, the damage shown in the photo hinted at an operational failure, meaning that mistakes made by the rocket’s operators may have been more to blame than a possible design flaw. The photo shows a short portion of B7’s liquid methane (LCH4) transfer tube that runs through the booster’s new liquid oxygen (LOx) header tank, which itself sits inside Super Heavy’s main LOx tank at the aft end of the rocket – a tube inside a small tank inside a large tank, in other words. Super Heavy’s LCH4 transfer tube generally does what it says, allowing methane to safely fly down through the main LOx tank and fuel up to 33 Raptor engines. At full thrust, that tube would need to supply around 20 tons (~45,000 lb) of methane per second.
However, on top of merely transferring methane through the oxygen tank, Booster 7 introduced a design change that allows some or all of that tube to change functions and become a header tank mid-flight. That would require a system of valves that could seal off the main LCH4 tank once it was emptied, turning the transfer tube into a sort of giant steel straw filled with enough LCH4 to fuel Super Heavy’s boost-back and landing burns.
The damaged transfer tube in the leaked photo of Booster 7 doesn’t look that unlike what one might expect to see if they sucked through one end of a straw while blocking the other end, collapsing the center. Translated to the scale of Super Heavy, after an otherwise successful day of structural testing, SpaceX operators may have accidentally closed or opened the wrong valves while draining the booster’s transfer tube of liquid oxygen or nitrogen. As the heavy liquid drained from the tube, a lack of pressure equalization could have quickly drawn a vacuum and caused the tube to implode.
On April 29th, a SpaceX fan turned analyst published an analysis that convincingly pinpointed the moment Booster 7’s transfer tube collapsed. Simultaneously, because it showed that the transfer tube likely imploded during detanking, the analysis more or less confirmed the above speculation that the failure had been caused by a degree of operator error or poor test design. Of course, it’s possible that a hardware or software design flaw contributed to or caused the anomaly or that something like a pressure differential in the LOx header tank and LCH4 header tube could also explain the damage, but the accidental formation of a vacuum during detanking is arguably the simplest (obvious) explanation.
After the image of the internal damage leaked, the immediate consensus among fans and close followers was that Booster 7 was beyond repair. Instead, SpaceX appears to have proven those assumptions wrong and somehow managed to repair the upgraded Super Heavy to the point that it was worth testing again less than three weeks after returning to the high bay. On May 6th, B7 was rolled back to the launch site and installed, for the second time, on the orbital launch mount.
Prior to the failure, the general expectation was that SpaceX would begin installing Raptor V2 engines as soon as Booster 7 passed structural testing. It remains to be seen if SpaceX wants to repeat Booster 7’s cryoproof or structural testing to ensure that its quick repairs did the job before proceeding into static fire testing as previously planned. Nonetheless, hope lives on for the Super Heavy prototype and new test windows have been scheduled from 10am to 10pm on May 9th, 10th, and 11th.
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.
Elon Musk
Tesla’s secretive “Project Crystal Sun” gets a big green light in Texas
Fort Bend County approved four incentive agreements Thursday for Tesla’s proposed $10.1 billion solar factory.
Fort Bend County commissioners on Thursday approved a package of tax incentives for Tesla’s proposed $10.1 billion solar cell factory near Needville, Texas, giving the company one of the last local approvals it needs before it decides where to build. All four Tesla agreements passed 4 to 0.
The votes covered a property tax abatement inside Reinvestment Zone No. 34, a Chapter 381 economic development agreement, a foreign trade zone non-objection paired with payments in lieu of certain taxes, and a separate payment in lieu of taxes “true up” agreement, according to agenda notes from the Fort Bend Commissioners Court meeting.
The project, known internally as “Project Crystal Sun,” would make solar cells and finished modules on roughly 3,000 acres near FM 762 and FM 1994, south of the Brazos River. As Teslarati reported when the filing first surfaced in August, Tesla’s application under the state’s JETI Act splits the investment into $1.5 billion in real property and $8.6 billion in equipment, with 9,712 permanent jobs projected by 2033 and commercial operations targeted for the first quarter of 2029. The plant would handle the full chain from ingot and wafer production through cell testing.
Inside Tesla’s secretive $10 Billion “Project Crystal Sun” filing
Thursday’s approval does not lock in the site. Tesla has told the Texas Comptroller it is still weighing other locations, and site selection adviser David Dennison told Lamar Consolidated ISD trustees in September that the race had narrowed to Fort Bend and one out of state rival with a “very compelling package,” according to the Houston Chronicle. Tesla hopes to decide before the end of 2026, and the incentives still need sign off from the Comptroller and the Governor’s office.
Local officials have now done nearly everything within their control. Commissioners created the reinvestment zone in an August 24 special meeting, with Interim County Judge Daniel Wong formally withdrawing himself over his engineering firm’s past work with Tesla. Lamar CISD trustees voted 7 to 0 on September 15 to advance a JETI agreement that would tax Tesla’s qualifying property at 50 percent of its value for maintenance and operations from 2029 through 2038.
The plant lines up with a target Elon Musk set on Tesla’s Q4 2025 earnings call in January, when he said the company would “work toward getting 100 GW a year of solar cell production, integrating across the entire supply chain from raw materials all the way to finished solar panels.” In March, Tesla was reported to be negotiating a $2.9 billion purchase of Chinese solar manufacturing equipment bound for Texas. The Houston area already hosts Tesla’s Megafactory in Brookshire, where Megapack 3 production has started. Tesla said on its Q3 call that Megapack supply for 2027 is nearly sold out, and Musk wrote on X Thursday that the company is “increasing production of Megapacks as much as possible,” as demand from data centers climbs.
Tesla reveals Optimus Academy, where robots teach themselves
The Starship moon landing number NASA and Elon Musk can’t agree on
