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SpaceX fires Falcon Heavy’s 27 booster engines ahead of “most difficult launch ever”
For the third time ever, SpaceX has successfully performed a critical static-fire test of an integrated Falcon Heavy, briefly igniting all 27 of its Merlin 1D engines to verify the health and readiness of the rocket.
Per SpaceX’s official confirmation, a “quick-look” inspection of static fire telemetry has indicated that the company’s Falcon Heavy rocket is ready for its second launch in less than three months, a milestone that could also allow both flight-proven side boosters to tie SpaceX’s own record for booster turnaround. Falcon Heavy Flight 3 is now scheduled to launch the US Air Force’s Space Test Program 2 (STP-2) mission no earlier than 11:30 pm ET (03:30 UTC), June 24th. According to SpaceX CEO Elon Musk, the mission will unequivocally be the company’s “most difficult launch ever”.
Coincidentally, on top of being Falcon Heavy’s first scheduled night launch, STP-2 has now also marked the massive rocket’s first nighttime static fire. During this critical test, Falcon Heavy briefly ignites all 27 of its three boosters’ Merlin 1Ds and throttles the engines up to full thrust, much like airliners sometimes set their brakes and throttle up before attempting to take off. The difference between Falcon Heavy and passenger aircraft is nevertheless rather significant, given that Falcon Heavy produces ~15x the thrust of an A380 – the world’s most powerful mass-produced passenger aircraft – at liftoff: 22,820 kN (5.1M lbf) to the massive jet’s meager 1,440 kN (0.3M lbf).
Despite all of that thrust, Falcon Heavy is held down during static fire by eight accurately-named hold-down clamps, themselves a part of a massive transport/erector, which is itself anchored directly to Pad 39A’s concrete foundation. In short, Falcon Heavy (and especially Falcon 9) is not going anywhere until those hold-down clamps are explicitly released. Thanks to SpaceX’s avoidance of the solid rocket boosters used by almost every other modern launch vehicle, Falcon 9 and Heavy rockets can abort at any point prior to clamp release, offering a uniquely broad abort capability.
As such, not only does SpaceX’s dedicated pre-launch static fire fully test the rocket’s health, but the same procedure is essentially repeated in the seconds before clamp release during an actual orbital launch attempt. If at any point Falcon 9’s autonomous onboard computer decides that it doesn’t like any of the thousands of channels of telemetry it’s constantly analyzing, it can command an engine shutdown and total launch abort even if all first stage engines have already ignited and reached full thrust. If routine McGregor, TX acceptance testing – also involving a full static fire – is accounted for, every single Falcon 9 booster technically completes three fully-integrated static fires before its inaugural liftoff. Falcon Heavy is slightly different, as each booster is independent test-fired in Texas but the integrated rocket can only perform static fires at Pad 39A.
After those three critical tests, flight-proven Falcon boosters are subjected to the less stringent few-second static fires SpaceX performs at the launch pad 3-7 days before a given launch. With Falcon Heavy Flight 3, the rocket’s center core, upper stage, and payload fairing are all brand new, fresh from either SpaceX’s Hawthorne factory or McGregor acceptance testing. However, both side cores – Block 5 boosters B1052 and B1053 – are flight-proven, having successfully completed their first launches and landings on April 11th, less than 70 days ago.
Set by regular old Falcon 9 boosters, SpaceX’s current record for booster turnaround time (time between two launches) is 71 days (set in June 2018), while the Block 5 upgrade’s record stands at 74 days (set in October 2018). If Falcon Heavy’s STP-2 launch holds strong on June 24th, B1052 and B1053 will simultaneously tie SpaceX’s Block 5 turnaround record. This would be accomplished despite the added pressure from the US Air Force’s decision to use STP-2 as a sort of dress rehearsal for certifying all flight-proven commercial rockets, an honor (and burden) that likely added extra work, oversight, and scrutiny to the process of refurbishing and relaunching B1052 and B1053.
“[T]he US Air Force has decided that STP-2 presents an excellent opportunity to begin the process of certifying flight-proven SpaceX rockets for military launches. The STP-2-related work is more of a preliminary effort for the USAF to actually figure out how to certify flight-proven commercial rockets, but it will still be the first time a dedicated US military mission has flown on a flight-proven launch vehicle. Down the road, the processes set in place thanks – in part – to STP-2 and Falcon Heavy may also apply to aspirational rockets like Blue Origin’s New Glenn and ULA’s “SMART” proposal for Vulcan reuse.”
— Teslarati.com, 06/16/2019
In a last-second surprise, SpaceX updated Falcon Heavy center core B1057’s planned drone ship landing site from a brief 40 km (25 mi) to more than 1240 km (770 mi) off the coast of Florida. SpaceX set its current record for recovery distance less than three months ago during Falcon Heavy’s commercial launch debut, in which Block 5 center core B1055 landed nearly 970 km (600 mi) offshore on drone ship Of Course I Still Love You (OCISLY). If all goes well, B1057 – the second finished Block 5 center core – will absolutely crush its predecessor’s record, implying that the booster will likely be subjected to SpaceX’s most difficult reentry and recovery yet.
For more on what CEO Elon Musk describes as “[SpaceX’s] most difficult launch ever”, check out these previous articles on an unexpected ultra-fast booster reentry and the extraordinary challenge facing Falcon upper stage.
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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
