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SpaceX’s Elon Musk talks Starship heatshield, rocket landings on Joe Rogan podcast
In a multi-hour February 2021 interview with Elon Musk himself, Joe Rogan inexplicably told the famous engineer and CEO that he had never seen a SpaceX rocket landing.
Of course, the 200+ minute conversation did produce a few minor tidbits of interesting information about SpaceX (and much more about Tesla projects), but Rogan’s statement that he’d never seen a SpaceX rocket landing before stole the limelight by a long shot.
SpaceX landed its first Falcon 9 booster – to an extraordinary amount of fanfare – in December 2015. In the five years since that breakthrough, SpaceX has successfully landed Falcon boosters 73 more times. A full 26 of those landings occurred in just the last 12 months. Falcon Heavy – responsible for spectacular, crowd-favorite performances – completed three dual-booster landings and one triple-booster landing between February 2018 and June 2019.
It’s not unimaginable that almost every single human on Earth with some level of access to the internet or social media is at least vaguely aware of or has watched videos of SpaceX landing rockets. To be clear, it is an unequivocal fact – including past comments on landings from Rogan himself – that Rogan has watched SpaceX land Falcon boosters at least once, if not several times. The only real takeaway, fellow readers, is that heavy, long-term drug use is inadvisable.
Cringeworthy moments aside, the interview did produce a select few minor details that weren’t explicitly known before. Most notably, Musk briefly discussed the challenge of developing a heat shield capable of safely returning orbital Starships back to Earth and revealed the main issue that SpaceX is currently working on.
Over the last six or so months, SpaceX has been gradually expanding small installations of heat shield tiles on Starship prototypes, ranging from vehicles that never left the ground to high-altitude Starships SN8 and SN9. Those tile installations have grown from a handful (4-8 on Starhopper in 2019) to literal hundreds on the most recent Starship completed by SpaceX.
During earlier ground testing and more recent hop tests with Starships SN5 and SN6, some of those ceramic composite tiles actually fell off or shattered, perhaps due to vibrations from Raptor engines or mechanical stress caused by Starship shrinking and contracting from thermal expansion. According to Musk, what SpaceX is trying to determine with those coupon-style tests is how to install a heat shield with tiles that are neither too close together or too far apart.
According to Musk, ceramic heat shield tiles placed too close together will ultimately shatter, break, or fall off when subjected to the stresses of Starship operations. Those stresses include the violent vibrations created by rocket propulsion supersonic to hypersonic travel, as well as airframe expansion and contraction that occurs when Starship’s steel hull is cyclically heated and cooled by Raptor burns and cryogenic propellant. In other words, assuming fragile, ceramic tiles are a necessity, they need to be placed far enough apart to avoid all of those possible pitfalls.
On the opposite hand, though, the entire point of Starship’s heat shield is to insulate it from extreme thermal stress during atmospheric reentry. If individual tiles are situated too far apart, superheated gas (plasma) produced during reentry will find its way between those tiles, heating up the structure they’re meant to keep cool. In the case of Starship, its steel hull is more than twice as resilient to reentry heating than comparable vehicles (like the Space Shuttle) with common aluminum frames, but a few millimeters of steel is still not enough to prevent weakening, damage, or outright burn-through in the face of orbital reentry.
In essence, SpaceX has to “get the gaps just right” – not too far apart to protect the airframe from plasma intrusion but not so close together that tiles impact or damage their neighbors as Starship cools and warms.
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
