News
SpaceX Starbase construction takes priority as next orbital Starship, Super Heavy pair come together
As SpaceX teams slowly prepare the first orbital-class Starship and Super Heavy booster for the next-generation rocket’s first full-stack launch, the company has simultaneously begun assembling a second ship/booster pair. However, it’s clear that orbital pad construction remains a priority.
Known as Ship 20 and Booster 4, the two stages of the first orbital-class Starship first arrived at the launch site in early August. Only eight weeks later has Starship S20 finally become the first of the pair to attempt and complete one of two crucial proof tests, opening the door for one or several Raptor static fires in the coming week or two. Meanwhile, Booster 4 has had all 29 of its Raptor engines installed, uninstalled, and reinstalled and twice been placed on and removed from Starbase’s orbital launch mount in the same time frame but has yet to attempt any proof testing.
Despite the apparent delays and challenges slowing Ship 20 and Booster 4’s test debuts and two plodding FAA reviews that appear all but guaranteed to preclude an orbital launch attempt in 2021, though, SpaceX has recently begun assembling a second two-stage Starship.
Save for Starhopper back in 2019, no Starship or Super Heavy prototype has spent nearly as long at the launch site without a single test as Ship 20 and Booster 4 have. To an extent, there have likely been some technical delays while assembling, outfitting, and working with two first-of-their-kind prototypes. Still, the difference between past vehicles like Starship SN15 and Super Heavy Booster 3 are so stark that some portion of the testing delays almost has to be a conscious decision made by SpaceX.
To be able to fully proof and static fire test Super Heavy B4, SpaceX first needs to plumb, wire, and outfit Starbase’s orbital launch mount and complete a majority of the orbital pad’s massive tank farm. However, the orbital pad and its many unfinished systems are situated just a thousand (~300m) east of the suborbital launch site and Starship test facilities, which are complete and ready for testing. To test a Starship at those facilities, SpaceX has to entirely clear the pad of personnel – now several hundred people at the peak of construction – for 6-12+ hours.
The implication is that SpaceX management effectively chose to rip off the bandage now rather than later, sacrificing timely testing of Starship S20 to allow a near-total focus on orbital pad construction and activation over the last ~8 weeks. It’s hard to say if that’s paid off but the fact that SpaceX has chosen this particular moment to begin assembling the next orbital-class Starship and Super Heavy suggests that a clearer plan is starting to come together.
B4/S20, meet B5/S21
Parts of Starship S21 and Super Heavy B5 have been floating around Starbase’s build site for weeks. There was a multi-week period, for example, where the site’s massive high bay was effectively unused – clearly a conscious choice given SpaceX’s history of Starship prototype production earlier this year and late last. Parts of Super Heavy B5 were likely ready for assembly (i.e. stacking) by mid to late August. The ‘mid bay’ used for Starship tank section assembly has been similarly underutilized for even longer – only recently accepting its first Starship S21 section after supporting assembly of the orbital pad’s final storage tank.
Instead, Booster 5 stacking began around September 15th. At the current rate of assembly, which has slowed down considerably in the last week, SpaceX’s second flightworthy Super Heavy could reach its full 69m (~225 ft) height as early as mid-October. Starship S20 likely won’t be far behind. Further, thanks to SpaceX’s preferred style of continuous improvement, Booster 5 and Ship 21 production already appear well on track to outpace Booster 4 and Ship 20. With B5, rather than installing a range of external equipment (avionics, wiring, plumbing) after assembly is finished, SpaceX appears to be completing some of those subsystems during stacking, potentially speeding up final assembly by 1-2+ weeks. With S21, SpaceX has begun outfitting the Starship’s nose cone with heat shield tiles far earlier in the assembly process than it did with S20.
Given that it has taken SpaceX the better part of a month to finish and spot-fix Starship S20’s heat shield since the prototype’s second trip to the test site, taking those lessons learned to heart and getting Starship S21’s heat shield installation right on the first try could cut weeks from final assembly.
In the meantime, after completing Ship 20’s first cryoproof test on September 29th, SpaceX will hopefully be able to kick off the first six-engine Raptor static fire test campaign within the next week or so. With any luck, the start of B5/S21 assembly also means that the orbital launch pad is nearly ready to support Super Heavy B4’s first proof tests, even if static fires with anything close to a full set of 29 Raptors appear to be weeks away. Regardless, it looks like it won’t be long before SpaceX will be juggling two pairs of orbital-class Starships and Super Heavy boosters.
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
