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SpaceX Starship pop test opens the door for 60,000 foot hop [update]
SpaceX has successfully destroyed a Starship ‘test tank’ for the fourth time, opening the door for the first high-altitude prototype to roll to the launch pad as soon as tomorrow.
The culmination of three nights and more than 20 hours of concerted effort, SpaceX was finally able to fill Starship test tank SN7.1 with several hundred tons of liquid nitrogen before dawn on September 23rd. With just an hour left in the day’s test window, SpaceX closed the tank’s vents, allowing its cryogenic contents to boil into gas and expand with no outlet. At 4:57 am CDT, SN7.1 burst, bringing its lengthy test campaign to a decisive end.
A handful of hours later, new road closure notices revealed SpaceX’s plan to roll Starship SN8 – the first full-size prototype and first ship meant for high-altitude testing – from its Boca Chica factory to the launch site.
Update: All road closures planned for Starship SN8’s roll to the launch pad (Sept 24) and first test campaign (Sept 27-29) have been canceled. Stay tuned for updates on the high-altitude prototype’s test schedule.
Short of new information from SpaceX or CEO Elon Musk, little is known about the results of SN7.1’s lengthy test campaign, but the fact that it survived two nights of nondestructive testing – including the use of hydraulic rams to simulate Raptor thrust – effectively clears Starship SN8 for suborbital testing. Based on a speculative, amateur analysis of the aftermath of SN7.1’s burst test, it can also be tentatively concluded that the tank failed almost exactly where one would expect it to: the in-situ weld attaching the upper tank dome to SN7.1’s steel ring hull.
SN7.1’s forward dome appears to have cleanly sheared off around much of its circumferential weld joint – exactly what one would theoretically expect from a good, uniform weld. Assuming that SN7.1 reached pressures well above 8.5 bar (~125 psi) before it burst, the tank’s final test can likely be deemed a success.
The very same day SpaceX kicked off what would become Starship SN7.1’s last burst test attempt, teams worked to install functional flaps on a full-scale Starship prototype (SN8) for the first time ever. Effectively answering the question of whether SpaceX would fully outfit the ship with a nosecone and flaps before its first acceptance tests, SN7.1’s successful pop was followed by road closure notices for SN8’s transport to the launch pad around dawn on September 24th and cryptic “SN8 Testing” as early as September 27th.
As of September 23rd, SN8’s twin aft flaps – large aerodynamic control surfaces meant to stabilize free-falling Starships – have been fully installed alongside ‘aerocovers’ that will protect each flap’s control mechanisms. The only hardware Starship SN8 is missing is a ~20m (~60 ft) tall nosecone, two smaller forward flaps, and the plumbing needed to access a smaller liquid oxygen “header” tank located in the tip of said nose.
At the moment, SpaceX has installed one Starship nosecone prototype atop five unpressurized rings – creating a full nosecone stack. That particular prototype has no liquid oxygen header tank, however, meaning that SpaceX would likely need at least a day or two to weld one of the noses with a header tank atop one of several finished five-ring sections. In other words, to transport SN8 to the pad tomorrow, there’s almost no chance that SpaceX will have time to finish and install a proper nosecone on the prototype, meaning that the company has chosen to test the Starship before that milestone.
Doing so should reduce any inconvenience caused by vehicle failure in the event that Starship SN8’s acceptance test campaign doesn’t go as planned. In hindsight, the inclusion of Starship SN8’s aft flaps and aerocovers during the ship’s first major tests was likely a necessity, given that almost half of each flap and its support structure is installed directly to the skin of its liquid oxygen tank. Theoretically, when chilled to the temperature of liquid nitrogen or oxygen, the diameter of the stainless steel rings Starship SN8 is built out of could shrink by as much as 0.3% (~20 mm or ~0.8 in).
Only half of Starship SN8’s aft flaps will be directly subject to that tank contraction, resulting in a relatively complex environment for such a large, high-stress mechanical system. As such, testing flap actuation under cryogenic loads is likely a critical part of SN8’s cryogenic proof test, otherwise meant to demonstrate the structural integrity and functionality of Starship’s propellant tanks. If SN8 rolls to SpaceX’s launch facilities on schedule, the Starship’s first cryogenic proof test could begin as early as 9pm CDT (UTC-5) on Sunday, September 27th.
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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
