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SpaceX Starship fires up three Raptor engines in prelude to high-altitude flight
Update: At 1:21am CDT (6:21 UTC) on October 20th, Starship SN8 ignited all three of its Raptors’ preburners, producing a spectacular fireball noticeably larger than the one produced during the rocket’s first October 19th preburner test. A mere two hours later, with no break in between, the steel rocket prototype fully ignited all three Raptor engines for the first time ever, likely producing thrust equivalent to ~90% of a nine engine Falcon 9 booster for a brief moment.
Crucially, aside from physically demonstrating Raptor’s multi-engine capabilities, Starship SN8 – already a first-of-a-kind prototype – completed and survived a static fire seemingly unscathed on its first attempt. If the data SpaceX gathers from the milestone is as good as the test appeared to be, the company could be just a few days away from installing Starship SN8’s recently-stacked nosecone, followed by a second triple-Raptor static fire test. If that second static fire goes well, SN8’s next task will be the first high-altitude Starship flight test.
Minutes after an adjacent highway was scheduled to reopen, SpaceX’s first high-altitude Starship prototype – serial number 8 – attempted what was likely the first multi-engine Raptor test ever.
At 6:01 am, October 19th, Starship SN8’s trio of Raptor engines were barely unleashed, producing a large fireball indicative of a ‘preburner’ ignition test. One of the most complex rocket engines ever developed, Raptor relies on a maximally efficient but temperamental “full-flow staged combustion” cycle (FFSC), a concise name for the many, many steps required to turn liquid propellant into thrust.
Adding additional difficulty, Raptor’s full-flow staged combustion necessitates ignition of gaseous oxygen and methane in the combustion chamber. Given that the Raptor-powered Starship spacecraft and Super Heavy booster exclusively use cryogenic liquid methane and oxygen, a major challenge posed by FFSC is the need to efficiently turn that ultra-cold propellant into hot gas almost instantaneously. This is where gas generators (or preburners) come in.
In a full-flow staged combustion engine, both oxidizer and fuel require their own separate turbopumps, which then require their own preburners to create the pressures needed to power those turbopumps and the gas the combustion chamber ignites to produce thrust. A step further, to enable high combustion chamber pressure like Raptor’s 300+ bar (~4400+ psi), those preburners need to produce gas at far higher pressures to account for energy losses as those gases wind their way through the engine’s plumbing.
As a result, preburners are possibly the single most stressed system in an engine like Raptor. Unsurprisingly, this has often lead SpaceX to separately test each engine’s preburners as a sort of partial static fire before the actual engine ignition test. This is the test Starship SN8 attempted in the early morning on October 19th, representing Raptor’s very first multi-engine ignition event.
Curiously, moments before preburner ignition, one of the three Raptor engines appeared to command an aggressive jet-like vent of liquid oxygen identical to a vent seen just a few hours prior during the first aborted preburner test. There’s thus a chance that only two of SN8’s three Raptor engines successfully started their preburners
Raptor is the first FFSC engine in the world to fly and – as far as the duration of lifetime testing and volume production goes – is almost certainly the most advanced of the three FFSC programs to graduate to static fire tests. In other words, given that SN8’s test campaign is the first time SpaceX has ever attempted to operate multiple adjacent Raptor engines at the same time, it’s not a huge surprise that progress towards the first three-engine static fire has been cautious and halting. Mirroring its Sunday/Monday testing, SpaceX will put Starship SN8 through another preburner and/or static fire attempt between 9pm and 6am CDT (UTC-5) on October 19/20. Even more 9-6 test windows are scheduled on October 21st and 22nd.
Meanwhile, not long after Starship SN8’s first preburner test was completed, SpaceX teams rolled a section of five steel rings inside a small windbreak and stacked the first truly functional nosecone – already outfitted with forward flaps – atop it. If Starship SN8 survives its first full triple-Raptor preburner and static fire tests, that new nosecone will likely be rolled to the launch pad for in-situ installation, topping off the rocket ahead of a spectacular 15 km (~50,000 ft) flight test.
Tesla (NASDAQ: TSLA) is set to hold its Earnings Call for the first quarter of 2026 on Wednesday, and there are a lot of interesting things that are swirling around in terms of speculation from investors.
With the company’s executives, including CEO Elon Musk, answering a handful of questions that investors submit through the Say platform, fans want to know a lot of things about a lot of things.
These five questions come from Retail Investors, who are normal, everyday shareholders:
- When will we have the Optimus v3 reveal? When will Optimus production start, since we ended the Model S and Model X production earlier than mid-year? What’s the expected Optimus production rate exiting this year? What are the initial targeted skills?
- What milestones are you targeting for unsupervised FSD and Robotaxi expansion beyond Austin this year, and how will that drive recurring revenue?
- How will Hardware 3 cars reach Unsupervised Full Self-Driving?
- When do you expect Unsupervised Full Self-Driving to reach customer cars?
- When will Robotaxi expand past its current limited rollout?
Additionally, these are currently the three questions that are slated to be answered by Institutional Firms, which also answer a handful of questions during the call:
- Now that FSD has been approved in the Netherlands and is expected to launch across Europe this summer, can you discuss your Robotaxi strategy for the region?
- What enabled you to finish the AI5 tapeout early and were there any changes to the original vision? Last week, Elon said AI5 will go into Optimus and the Supercomputer, but one month ago said it would go into the Robotaxi. Has AI5 been dropped from the vehicle roadmap?
- Given the recent NHTSA incident filings, can you update us on the Robotaxi safety data? If safety validation remains the primary bottleneck, why not deploy thousands of vehicles to accelerate the removal of the safety driver?
The questions range through every current Tesla project, including FSD expansion and Optimus. However, many of the answers we will get will likely be repetitive answers we’ve heard in the past.
This is especially pertinent when the questions about when Unsupervised FSD will reach customer cars: we know Musk will say that it will happen this year. Is Tesla capable of that? Maybe. But a more transparent answer that is more revealing of a true timeline would be appreciated.
Hardware 3 owners are anxiously awaiting the arrival of FSD v14 Lite, which was promised to them last year for a release sometime this year.
The Earnings Call is set to take place on Wednesday at market close.
Elon Musk
Elon Musk reveals shocking Tesla Optimus patent detail
What looked promising on paper and in simulations failed to deliver the reliability required for a robot expected to handle delicate tasks like folding laundry, assembling electronics, or assisting in factories and homes.
Elon Musk revealed a shocking detail on the Tesla Optimus patent that was revealed last week. Despite it being made public for the first time, Musk said the company has already moved on from the design, an incredible truth about the development of new technology: things move fast.
Musk dropped a bombshell about the Tesla Optimus humanoid robot hand patent that was released last week. Musk, candidly replying to a post late at night on X, revealed that what is a new technology to many fans and insiders is actually old news to those developing the tech directly.
“We already changed the design,” Musk said. “This one didn’t actually work.”
We already changed the design. This one didn’t actually work.
— Elon Musk (@elonmusk) April 19, 2026
Patents, after all, are often viewed as blueprints for future products. Yet Musk revealed that the rolling contact mechanism—intended to provide smooth, low-friction articulation in the fingers—had already been scrapped after real-world testing exposed its shortcomings.
What looked promising on paper and in simulations failed to deliver the reliability required for a robot expected to handle delicate tasks like folding laundry, assembling electronics, or assisting in factories and homes.
The hand has been one of the biggest challenges for Tesla engineers since Optimus development started years ago. Musk has said that there is not enough recognition for how incredible and useful the human hand is, and designing one for a humanoid robot has been the biggest challenge of all.
Tesla is stumped on how to engineer this Optimus part, but they’re close
This moment underscores the persistent engineering hurdles in achieving reliable humanoid hand dexterity. Human fingers are marvels of evolution: 27 bones, intricate tendons, ligaments, and a network of sensors working in perfect harmony. Replicating that in metal and silicon is extraordinarily difficult.
Rolling contacts promised reduced wear and precise motion, but testing likely revealed issues with durability under repeated stress, grip stability on varied surfaces, or the micro-precision needed for fine motor skills.
These aren’t minor tweaks, but instead they represent fundamental challenges that have plagued robotics teams for decades. Even advanced competitors struggle here—hands remain the Achilles’ heel of most humanoids because the margin for error is razor-thin.
A fraction of a millimeter off, and a robot drops a glass or fails to button a shirt.
What makes Musk’s reply remarkable is how it signals Tesla’s direct communication style on prototype limitations. While many companies guard failures behind glossy marketing and vague timelines, Tesla openly shares setbacks.
Musk was forthcoming about the failure of this recent design. This transparency builds trust with investors, engineers, and fans. It shows Tesla treats Optimus development like true science: rapid iteration, rigorous testing, and zero tolerance for hype that doesn’t match reality.
The disclosure from Musk also highlights Tesla’s blistering pace of development. By the time the patents are published, which is often over a year after the initial filing, the technology has already evolved.
Optimus is far from a static product, and it’s a living project advancing weekly.
In the high-stakes race for general-purpose robots, Tesla’s approach stands out. Admitting a finger-joint design “didn’t actually work” isn’t a weakness—it’s confidence.
True innovation demands confronting failure head-on, and Musk just reminded the world that Optimus is being engineered that way. The next version of those hands is already in testing, and it will be better because Tesla isn’t afraid to say what didn’t work.
Elon Musk
Tesla is sending its humanoid Optimus robot to the Boston Marathon
Tesla’s Optimus robot is heading to the Boston Marathon finish line
Tesla’s Optimus humanoid robot will be stationed at the Tesla showroom at 888 Boylston Street in Boston, right along the final stretch of the Boston Marathon today, ready to cheer on runners and pose for photos with spectators.
According to a Tesla email shared by content creator Sawyer Merritt on X, Optimus will be at the Boston Boylston Street showroom on April 20, coinciding with Marathon Monday weekend. The Boston Marathon finishes on Boylston Street, and the surrounding area draws hundreds of thousands of spectators along with international broadcast coverage. Placing Optimus there puts it in front of a massive public audience at zero advertising cost.
Just got this email. @Tesla’s Optimus robot is coming to Boston.
“Join us from April 19 to 20, 2026, at Tesla Boston Boylston Street showroom to meet Optimus, our humanoid robot, for Marathon Monday. Optimus will be cheering with you on the sidelines and posing for photos.” pic.twitter.com/chxoooO2xV
— Sawyer Merritt (@SawyerMerritt) April 18, 2026
The Tesla showroom is at 888 Boylston Street, between Gloucester Street and Fairfield Street. The final mile of the marathon runs directly along Boylston Street, with runners passing the big stores before reaching the finish line at Copley Square.
Optimus was first announced at Tesla’s AI Day event on August 19, 2021, when Elon Musk presented a vision for a general-purpose robot designed to take on dangerous, repetitive, and unwanted tasks. In March 2026, Optimus appeared at the Appliance and Electronics World Expo in Shanghai, where on-site staff stated that mass production of the robot could begin by the end of 2026. Before that, it showed up at the Tesla Hollywood Diner opening in July 2025 and at a Miami showroom event in December 2025.
Tesla’s well-calculated display of Optimus gives the public a low-pressure first encounter with a robot that Tesla is preparing to soon deploy at scale. The company has previously indicated plans to manufacture Optimus robots at its Fremont facility at up to 1 million units annually, with an Optimus production line at Gigafactory Texas targeting 10 million units per year.
Tesla showcases Optimus humanoid robot at AWE 2026 in Shanghai
Musk has said that Optimus “has the potential to be more significant than the vehicle business over time,” and separately that roughly 80 percent of Tesla’s future value will come from the robot program. Whether that holds depends on production execution. For now, Boston gets a preview of what that future looks like, standing at the finish line on Boylston Street while 32,000 runners pass by.
Tesla Q1 Earnings: What Elon Musk and Co. will answer during the call
Elon Musk reveals shocking Tesla Optimus patent detail
