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SpaceX begins installing Raptor engines on first Super Heavy booster
SpaceX has installed a Raptor engine on a Super Heavy booster prototype for the first time, defying expectations and setting the rocket up for two major tests as early as this week.
On Thursday, July 8th, SpaceX briefly filled Super Heavy Booster 3’s (B3) propellant tanks with benign nitrogen gas. The vehicle seemingly came to life for the first time that morning when it was spotted using its tank vents – a generally incontrovertible sign that the complex mechanical system that is a rocket is functional. Later that day, the public highway and beach adjacent to SpaceX’s launch site were briefly closed for what was expected to be an ambient pressure and/or cryogenic proof test.
Booster 3 never got to the cryogenic proof test – easily confirmed thanks to the frost that forms on most rockets’ exteriors as main tanks are filled with extremely cold liquid nitrogen. No such frost formed, no major venting occurred, and the road was only closed for the first two hours of a six-hour test window.
According to Next Spaceflight’s Michael Baylor, SpaceX did complete a “brief ambient proof” during that relatively short closure, though very little activity was visible during the test. Friday’s 14-hour test window was canceled the next morning, leaving SpaceX the rest of the weekend to prepare the first functional Super Heavy booster for its first truly challenging test – cryo proof.
Instead, late on Saturday, July 10th, SpaceX rolled Raptor 57 (R57) from build site to launch pad and began installing the engine on Booster 3 just a few hours later. Prior to Raptor 57’s installation, most prominent (albeit unofficial) voices in the SpaceX fan community anticipated no more than cryogenic proof testing for Booster 3 – no static fires, in other words.
However, it was fairly apparent that Super Heavy Booster 3 and the modified suborbital launch mount it was installed on were both outfitted for testing more complex than a cryo proof alone. Notably, B3 rolled to the pad with multiple labeled methane pressure vessels (COPVs), extensive plumbing, and autogenous pressurization control panels installed – all of which continued to be actively worked on after the booster was installed at the launch site.
While it’s technically not impossible to build a ground testing Starship prototype that’s capable of a wide variety of tests but never actually used to its full extent, doing so would be well out of character for SpaceX and make little sense in general. As such, it’s not a major surprise that SpaceX has now begun to install Raptor engines on Super Heavy Booster 3. What is surprising is that SpaceX is installing Raptor engines on a first-of-its-kind Super Heavy prototype before any fully integrated booster has completed cryogenic testing.
Based on Starship’s ~18-month test history, there is a real possibility Super Heavy B3 will fail during cryogenic proof testing. Even accepting that SpaceX’s testing processes and expertise have matured dramatically after dozens of Starship tests on the ground and in flight, the chance remains. In other words, SpaceX’s decision to begin installing Raptors on Super Heavy before ensuring structural and mechanical integrity implies some combination of unusual confidence in a prototype as unproven as Booster 3 and a distinct lack of concern at the prospect of losing at least two Raptor engines in a hypothetical test failure.
Knowing SpaceX and CEO Elon Musk’s goals for Raptor, the latter implication isn’t much of a surprise but it’s always interesting to have direct visual evidence that Raptor is, in fact, so cheap to build and easy to install that the minor effort and few days of possible delays required to reduce the risk of losing multiple engines just aren’t worth it.
As such, it’s now clear that Super Heavy Booster 3 will have at least one or two Raptor engines installed during its very first cryogenic proof test – currently no earlier than 12pm to 8pm CDT (UTC-5) on Monday, July 12th. Assuming SpaceX’s confidence is well-placed and Booster 3 passes its first cryogenic tests without issue, the real question now is how many Raptors will be installed and ignited during Super Heavy’s first static fire test?
Tesla is set to inaugurate its dedicated Semi factory in Sparks, Nevada, this evening, but drone footage has already started to show who is expected on the handover stage.
Zanegler, a drone operator who regularly documents Tesla Semi operations in Nevada, filmed a row of new-generation Semi units parked outside of the plant with customer branding applied. The liveries visible in the video include companies like PepsiCo, U.S. Foods, Einride, DHL, WattEV, and others that have committed to utilizing Tesla’s Class 8 electric truck in their fleets.
Tesla Semi Pre-Reveal Revealed!
Excited to share this segment of the drone flight one day prior to the Tesla Semi Reveal event.
They have added branding to several Tesla new generation semis.
Including:
Pepsico
US Foods
Einride
LTS
Nevoya
OK Produce
ABF Freight
DHL
WattEV… pic.twitter.com/KoFOg2FouR— Zanegler (@HinrichsZane) September 24, 2026
Several of those company names already sit within Tesla’s public ordering book, including PepsiCo, which has been the program’s primary anchor customer since the first Semi deliveries in December 2022. PepsiCo now runs dozens of Tesla Semi units in daily service, with drivers completing regional routes.
Einride placed a 500-unit order in August, which was, at the time, the largest single Semi commitment. First deployments of their Semi units are planned for this month and will eventually span across California, Texas, New Jersey, Illinois, and Georgia. Meanwhile, IMC Logistics announced a 50-truck California order this week.
Tesla Semi lands the biggest electric truck deal in U.S. history
Other names, like LTS, OK Produce, and HMD, have not been widely confirmed as firm buyers, but their presence on the lot is perhaps the clearest signal that Tesla intends to expand on that list this evening at the event.
Tesla first unveiled the Semi back in 2017 with a 2019 production target.
Limited pilot builds reached PepsiCo in late 2022, and high-volume production began at the new 1.7-million-square-foot plant that sits logically positioned next to Tesla’s Gigafactory Nevada. Tesla Semi program director Dan Priestley has said that Tesla expects to build “many thousands” of Semi units this year, but as with every Tesla release, there have been set expectations of an S-curve ramp.
Outside estimates still put 2026 deliveries in the 5,000-to-15,000 range, but it will ultimately depend on Tesla’s readiness to put those units out, as well as how smoothly production is moving internally.
Tesla’s Semi Rollout event is set to start tonight at the Sparks factory, and it will be livestreamed on X starting at 6 p.m. PDT / 9 p.m. ET.
The Tesla App is now giving owners a better indication of what to expect when visiting a Supercharger site, as it is now sharing Site Maps in the app itself, making the feature no longer exclusively available in the car.
Tesla owners can now preview a Supercharger’s layout and live stall status from their phone thanks to the App’s new software version, v4.61.0. Zooming into a supported Supercharger on the charging map now switches the familiar street view into a site-specific map that shows stall positions, occupied bays, out-of-service posts, and a live count of open Superchargers.
It will even show you which specific Tesla model is charging at each occupied stall.
You can now see Live Site Maps in the latest Tesla app (4.61.0.) pic.twitter.com/JIL8QzR8hu
— Zack (@BLKMDL3) September 18, 2026
This is the same view drivers first saw inside the car with the 2025 Holiday Update, which started as a pilot for Tesla in California and Texas. Those early maps showed layout, nearby amenities, and the status of each operational stall. The feature has spread to most Superchargers in the U.S., but now Tesla wants the feature available through the Smartphone App, which is now rolling out to owners.
The in-vehicle screen maps remain a richer 3D canvas and originally required AMD Ryzen infotainment hardware, which left many Intel-based Model 3 and Model Y owners without the view. The app version removes that hardware barrier, so any owner can now get a preview of their upcoming Supercharger stop on their phone.
Anyone with the updated version of the app can open a Site Map on their phone. The feature has provided some additional peace of mind to anxious travelers and those who might be looking for a place that is less congested for faster charging speeds. It is a meaningful addition to many owners, especially for trips to unfamiliar locations.
You can now pick a Supercharger location that might be more aligned with what you are looking for or need: you can pick a site based on what stalls are open, where ADA stalls sit, how you will pull in, and more, instead of circling a crowded lot after arriving. Owners of older cars now have access to the feature without having to purchase a new vehicle altogether.
Site Mpas will not reserve a stall, nor will it change how Fast Charging works. Tesla does something simpler and more useful by giving owners a dedicated preview of the Supercharger they’re about to charge, turning an unknown parking lot into a place that may seem more familiar thanks to the preview.
Interested in ordering a Tesla? Use my referral code for three free months of Full Self-Driving (Supervised) here.
Investor's Corner
Tesla Optimus Gen 3 shows off a cleaner, factory-ready design in new app discovery
Renders hidden inside Tesla’s Android app show Optimus Gen 3’s design before any official reveal.
![Tesla Optimus Gen 3 [Credit: Tesla]](https://www.teslarati.com/wp-content/uploads/2026/03/tesla-optimus-gen3-diner.jpg)
Tesla may have accidentally given a first look at its newest Optimus Gen 3 humanoid robot when photos were found in the Tesla smartphone app.
Design files tucked inside a recent Android version of the Tesla app appear to show the third generation humanoid robot next to the older Gen 2.5 prototype. The assets were extracted from the app package by Tesla community member @wholemars, who posted the renders on X late Tuesday night before deleting them. The Tesla Newswire reshared the side by side comparison on Wednesday, and the images have circulated widely since.
Tesla Optimus Gen 2.5 vs Gen 3 comparison via @WholeMars on X
The files are labeled “gen3” and were built as models for Tesla app’s own interface, as validated directly by Grok to be official.
The comparison shows a robot that looks built for a factory line rather than a lab bench. Gen 2.5’s exposed mechanical linkages and gold plating on the knees and shins are gone. In their place, Gen 3 uses matte black fairings on the lower legs, paired with a more contoured champagne gold body. Flexible covers now seal the joint where the torso meets the upper thighs, keeping bearings and moving parts sealed from debris and unnecessary contact.
The body panels fit more tightly, and the hands, which Tesla has said carry 22 degrees of freedom, look far more refined than those on earlier units.
This most recent leak fills a gap Tesla has left open for most of the year. Elon Musk said on March 31 that Optimus 3 was walking around but needed “some finishing touches” before it could be shown, a delay Teslarati covered when Tesla missed its first quarter reveal target. Musk later said Tesla would hold the design back until closer to production, partly to keep competitors from copying it. No reveal date has been announced.
The app itself has been preparing for Optimus for months. In July, code in the Tesla app pointed to a dedicated robot phone key, a consent screen for collecting video and spatial data while Optimus works inside a home, and an alert system for low battery and mechanical faults. Finished 3D models of Gen 3 suggest the interface owners will eventually use is moving past placeholder code toward something Tesla intends to ship.
Manufacturing is moving in parallel. Tesla tore out the original Model S and Model X lines at Fremont this summer to make room for Optimus production, with a planned capacity of one million robots a year. At Giga Texas, the steel frame of a dedicated Optimus factory is nearing completion ahead of a targeted 2027 start, with Musk pointing to an eventual output of 10 million units annually.
Tesla drops big hints ahead of Semi handover event
Tesla App now shows you what your Supercharger will look like upon arrival
![Tesla Optimus Gen 3 [Credit: Tesla]](https://www.teslarati.com/wp-content/uploads/2026/03/tesla-optimus-gen3-diner-80x80.jpg)
