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SpaceX preparing Super Heavy, Starbase for booster’s next steps
Amid a flurry of deliveries and work on several new Starship boosters, SpaceX is preparing the first truly finished Super Heavy for its next steps.
Partially completed by early September, Super Heavy Booster 4 (B4) supported SpaceX’s iconic ‘full stack’ fit test back on August 6th before returning to the build site but has mostly just floated around Starbase’s launch and test facilities in the seven weeks since its second trip to the pad. On September 10th, CEO Elon Musk himself suggested that SpaceX had plans to static fire the booster as early as mid-September – more than six weeks ago. Obviously, nothing even approximating Super Heavy testing transpired. Instead, at least relative to rapid-fire Starbase operations in the two years prior, SpaceX has almost absentmindedly worked on the booster, mostly completing partially-finished wire runs that run its full 69m (~225 ft) length.
In the last few weeks, though, the type of work being done on Super Heavy B4 has changed.
On September 26th, to give the Starbase construction crew more room to install giant arms on the orbital pad’s ‘launch tower,’ SpaceX removed Super Heavy B4 from the launch mount for the second time, temporarily relocating it to an unused patch of the pad’s old landing zone. Booster 4 hasn’t been moved since. However, while probably a bit slower than SpaceX would have liked, large-scale work on the Starship launch tower was effectively completed last week with the installation of two giant rocket-catching ‘Mechazilla’ arms.
A great deal of work has also been done on Starbase’s orbital tank farm over the last two months, including the installation of the last few storage tanks, the ‘sleeving’ of those tanks, a great deal of plumbing, and the start of real propellant deliveries. Save for a few days spent testing Starship S20 in late September and mid-October, the pad construction crews that have to evacuate the pad for 6-12 hours for every test have had three full months to work without interruption. Perhaps the most optimistic explanation for the unusually long gap between Booster 4 and Ship 20 rollout and testing is that SpaceX consciously chose to put off vehicle tests to avoid disrupting orbital launch site construction and retasked nearly all Starbase workers for that construction.
Regardless, with the launch tower and orbital tank farm now more or less structurally complete and work already underway to prepare the tank farm to support its first booster tests, most of the work that may have been drawing focus and resources away from ship and booster preparations appears to be wrapping up. That may be why, for the third time, SpaceX technicians began removing a number of Raptor engines from Super Heavy B4 around the start of October.
Aside from removing around a third to half of Super Heavy’s 29 Raptors, SpaceX also began slowly but surely installing parts of a steel heatshield designed to protect those engines during ground testing, ascent, and reentry. Newer Raptors have also been trickling from Starbase’s build site to the launch pad for installation on the booster and more engines will likely be (re)installed as heatshield installation progresses.
Perhaps the most unusual part of recent Super Heavy B4 work is the apparent application of some kind of foam around several racks of pressure vessels (COPVs), hydraulic manifolds, and umbilical connections installed around the booster’s base. Those racks will eventually be enclosed inside steel ‘aerocovers’ already staged beside Super Heavy. A number of Twitter users believe that the foam being selectively applied is for acoustic deadening – meant to protect sensitive electronics, valves, and computers from the brutal environment Super Heavy itself will produce at liftoff and during ground testing.
Ultimately, with Booster 4 work ramping back up and the zenith of orbital pad construction activity now likely behind SpaceX, preparations for major Super Heavy testing will hopefully resume. SpaceX has yet to perform a full Super Heavy wet dress rehearsal (WDR; fully filling a rocket’s tanks and performing a launch countdown) or fire up more than three Raptors on a booster or ship prototype. With any luck, that will finally change in the final months of 2021.
Although the two vehicles are built for completely different use cases, Tesla utilized engineering expertise while developing both the Cybercab and Semi to build a thermal architecture that would fit both vehicles. Of course, with some slight revisions.
The development was noted by Lars Moravy and Dan Priestley last week at Tesla’s Semi Handover event in Sparks, Nevada, where the company showed off its dedicated production facility for the Class 8 truck.
🚨 Tesla designed the integrated thermal systems for Cybercab and Semi at the same time as the vehicles were both in development
Tesla wanted to build one thermal system that worked with both vehicles, apart from small modifications.
Semi and Cybercab share parts 🤯 pic.twitter.com/KmzSsUbrcg
— TESLARATI (@Teslarati) September 25, 2026
Tesla’s decision to develop one thermal architecture for both the Cybercab and Semi is one of the more revealing engineering choices in the company’s 2026 lineup:
“We designed it at the same time we designed the Cybercab and we said okay we’re going to take our most efficient vehicle and our biggest vehicle and we’re going to take one thermal system and make it work for both.”
Core parts, meaning the compressor, pumps, and heat exchangers, are shared, with only modest changes to cooling-loop sizing and a larger radiator on the truck. The result, they said, is a compressor and thermal stack already proven across millions of miles, delivering “reliability from day one.”
Priestley also highlighted a practical payoff of the indirect design:
“There’s no AC lines, there’s no refrigerant lines…It comes from the factory fully charged, sealed with refrigerant, and it just exchanges coolant. It doesn’t actually run refrigerant up to the front of the vehicle.”
This eliminates potentially leak-prone plumbing that would otherwise require hands-on service, reducing overall uptime and potentially cutting into business margins. The megamanifold runs cabin HVAC and every powertrain heating and cooling loop at once, recapturing waste heat from motors and the battery instead of dumping it the way a diesel engine does.
The approach is just the latest chapter in a continuing story of stretching thermal solutions across wildly different vehicles. Model Y’s Octovalve evolved into the Super Manifold used on Cybertruck, and later Model S/X refreshes. Cybercab then introduced Supermanifold V3, which Tesla says is 80 percent automated to build and 38 percent more efficient than typical automotive thermal systems.
This thermal system is also shared with Cybercab – one thermal system for both our most efficient vehicle & our biggest vehicle
— Tesla Semi (@tesla_semi) September 25, 2026
Tesla has done the same with the 4680 cells, both being utilized in the Cybertruck and Semi, and with heat-pump compressors that Priestley noted were already common across the passenger-car fleet.
Concurrent development of crucial vehicle elements buys scale and reliability that a truck-only thermal system could not match. High-volume passenger car parts are cheaper and more accessible, which can give fleets a sealed, low-maintenance loop of operation from their first day of operation.
For owners and operators, that translates into less energy spent on cabin heat in the colder months, fewer refrigerant-related repairs, and a thermal architecture already stress-tested at passenger-car volumes before the first high-volume Semi left the lines in Nevada.
Tesla CEO Elon Musk certainly tipped off some details of the Tesla Roadster event with a broadening of information regarding the company’s decision to delay the unveiling for two weeks.
For years, people have speculated about what the Roadster will be capable of. While there have been plenty of things said about what it *could* do, we have not seen or been told by Tesla what it will actually be capable of.
However, over the past few days, Tesla’s weather updates have truly pushed the speculation into Plaid Mode, basically all but confirming the car will have some sort of aerial capability — whether that would be hovering or fully flying remains to be seen — but it definitely seems that it will be able to leave the ground intentionally.
“Because this event can only be held outdoors…”
Tesla posted on Monday that it would delay the Roadster event until October 15, and it indicated that it had to do this because the event “can only be held outdoors.”
With the potential SpaceX collaboration to develop cold-gas thrusters that will help the vehicle go airborne, doing this indoors is probably not a safe, or even plausible, possibility.
Roadster event update
We’ve been tracking the weather closely with local meteorologists, but given the severe conditions predicted & because this event can only be held outdoors, we’ve made the difficult decision to reschedule.
New date is October 15. Additional details to…
— Tesla (@Tesla) September 28, 2026
FAA Airspace Restriction
The FAA gave Tesla a Temporary Flight Restriction (TFR) for 10,000 feet above ground level, much higher than the typical 2,000-foot restrictions that are usually placed at SpaceX’s McGregor, Texas site.
Tesla Roadster event requires restricted airspace, and the FAA obliges
Some have said that this massive increase is due to Tesla’s need to restrict unauthorized drone use for spying on the event.
Elon Admits High Winds
“Due to high winds, the new Roadster demo is postponed by 2 weeks,” Musk said in a post on X yesterday.
Due to high winds, the new Roadster demo is postponed by 2 weeks https://t.co/dV3ojDh1iT
— Elon Musk (@elonmusk) September 30, 2026
A reply reading, “What’s strong wind got to do with a car demo with four grounded wheels?” was directly below Musk’s post, satirically and sarcastically probing for more details.
All signs are pointing toward an aerial demonstration for the Roadster.
Tesla has secured $30 billion in fresh credit lines from Citibank and Wells Fargo in an effort to scale its biggest current projects.
Tesla agreed to a $20 billion three-year delayed-draw term loan facility from Citibank, it announced on Tuesday. Additionally, it signed a five-year, $8 billion revolving credit facility and a $2 billion, 364-day term credit facility with Wells Fargo.
In a filing with the Securities and Exchange Commission (SEC), that it “may draw” from the $20 billion delayed-draw term “from time to time” and “no more than ten times during the 18 months following the closing date.” This loan matures on September 29, 2029.
The five-year revolving facility from Wells Fargo will also be accessed by Tesla “from time to time,” and will become due and payable on September 29, 2031. Tesla can request two separate one-year extensions.
On the $2 billion, 364-day revolving loan, it becomes due and payable on September 28, 2027. Tesla can also increase its additional commitments to an additional $4 billion across the Revolving Facilities. This would increase the total facilities to $14 billion. Tesla said it does not plan to utilize any of these loans in 2026.
Tesla plans to utilize the money to help prop up its ambitions to scale its biggest products, each of which is either in early launch phases or still in development. Of course, we’re talking about Cybercab and Semi, which have launched, and Optimus, which is still under heavy development and working toward initial release.
All three Tesla products have one thing in common: they’ve all required Tesla to build new manufacturing lines for them.
For the Semi, Tesla built a brand new factory in Sparks, Nevada, adjacent to the Tesla Gigafactory. For Optimus, Tesla sunset Model S and X production at the Fremont Factory, which brought an end to the two flagship models, thus creating manufacturing space for the humanoid robot. Finally, Cybercab is being built at Gigafactory Texas and officially entered production earlier this year.
The cash will help Tesla bolster its finances for the continuing development of these products. Tesla said that it forecasts its CapEx to be over $25 billion, up from just over $8.5 billion last year. These loans surely help with that spending.
Tesla Cybercab and Semi have more in common than you might think
Elon Musk weather update tips Tesla Roadster speculation into Plaid Mode
