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SpaceX delays Starhopper’s first flight a few days despite Raptor preburner test success
SpaceX has (partially) ignited Starhopper’s freshly-installed Raptor engine, successfully verifying that the engine is ready for its next major test: a full ignition and static firing. Although successful, SpaceX still has some work to do before the vehicle is ready for its first untethered flight(s).
July 15th’s progress is just the latest in a several day-series of preflight tests designed to reduce the likelihood that Starhopper is destroyed over the coming days and (hopefully) weeks. If all goes planned during the awkward Starship prototype’s first foray into hover tests, SpaceX CEO Elon Musk has stated that he will provide an official presentation updating the public on the status of the company’s ever-changing next-generation rocket.
The past week or so of Starhopper preflight testing began with Raptor serial number 6 (SN06) completing the last of a series of acceptance test fires in McGregor, Texas on June 10th. Even on its own, this was a major milestone for the new SpaceX engine: Raptor SN06 was the first of the new, full-scale engines to pass the acceptance test program with flying colors. According to Musk, for the engine to complete those tests so successfully, SpaceX had to solve a challenging bug in which some sort of mechanical resonance (i.e. vibration) damaged or destroyed Raptors SN01-05.
Hours later, the engine began a short ~450 mi (720 km) journey south to Starhopper, located in Boca Chica, Texas. The engine arrived on July 11th and was fully installed on Starhopper by the following evening (July 12th), at which point SpaceX put Starhopper and Raptor through some mild but valuable thrust vector controller (TVC) tests, wiggling the car-sized engine to ensure it can accurately steer the prototype rocket.
Around two days after the above ‘wiggle’ test was successfully completed, SpaceX moved into the next stage, partially fueling Starhopper with liquid methane and oxygen propellant and helium pressurant in what is known in rocketry as a wet dress rehearsal (WDR). The (implicitly) successful WDR was capped off with a duo of what can now safely be concluded were some sort of Raptor test preceding even pre-ignition operations. Whatever the tests were, they appear to have been completed successfully.
That appears to be the case because less than 24 hours after their completion, on July 15th, SpaceX once again began loading Starhopper with propellant and pressurant for a second round of wet testing. This time around, SpaceX got right into more critical Raptor tests once enough propellant was loaded, igniting the engine’s interwoven oxygen and methane preburners.
Previously discussed 24 hours ago in a Teslarati article focused on Raptor wiggles and other miscellaneous tests, Raptor is an extremely advanced rocket engine based on a cycle (i.e. how propellant is turned into thrust) known as full-flow staged combustion.
“In a staged-combustion engine like Raptor, getting from the supercool liquid oxygen and methane propellant to 200+ tons of thrust is quite literally staged, meaning that the ignition doesn’t happen all at once. Rather, the preburners – essentially their own, unique combustion chambers – ignite an oxygen- or methane-rich mixture, the burning of which produces the gas and pressure that powers the turbines that bring fuel into the main combustion chamber. That fuel then ignites, producing thrust as they exit the engine’s bell-shaped nozzle.
Unintuitively, conditions inside the preburner – hidden away from view – are actually far more intense than the iconic blue, purple, and pink flame that visibly exists Raptor’s nozzle. Much like hot water will cool while traveling through pipes, the superheated gaseous propellant that Raptor ignites to produce thrust will also cool (and thus lose pressure) as it travels from Raptor’s preburner to its main combustion chamber. If the pressure produced in the preburners is too low, Raptor’s thrust will be (roughly speaking) proportionally limited at best. At worst, low pressure in the preburners can trigger a “hard start” or shutdown that could destroy the engine. According to Elon Musk, Raptor’s oxygen preburner thus has the worst of it, operating at pressures as high or higher than 800 bar (11,600 psi, 80 megapascals).”
In full-flow staged combustion (FFSC), even more complexity is added as all propellant that touches the engine must necessarily end up traveling through the main combustion chamber to eke every last ounce of thrust out of the finite propellant a rocket lifts off with. As such, FFSC engines can be about as efficient as the laws of physics allow any given chemical rocket engine to be, at the cost of exceptional complexity and brutally difficult development.
Additionally, FFSC physically requires two separate preburners and then makes things even harder by making each separate preburner (methane and oxygen) depend on each other’s operation for the engine to fully ignite. This means that no individual preburner can be used to kickstart Raptor – instead, SpaceX must somehow spin the turbopumps that feed propellant into each preburner with some separate system. This is all just to emphasize the fact that Raptor’s ignition sequence is a spectacularly complex orchestra of valves, spark plugs, sensors, and magic. This is why it’s valuable for Raptor to test its preburner system independently of an actual ignition test, at least as long as the engine is still in the development stages.
According to NASASpaceflight.com managing editor Chris Bergin, what this practically translates to is a minor Starhopper hover test delay of 1-2 days, while the static fire has also been pushed roughly 24 hours from July 15th to July 16th. If that full static fire produces lots of happy data, Starhopper could be cleared for a hover test debut attempt as early as Wednesday or Thursday (July 17/18).
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Investor's Corner
Tesla (TSLA) Q4 and FY 2025 earnings call: The most important points
Executives, including CEO Elon Musk, discussed how the company is positioning itself for growth across vehicles, energy, AI, and robotics despite near-term pressures from tariffs, pricing, and macro conditions.
Tesla’s (NASDAQ:TSLA) Q4 and FY 2025 earnings call highlighted improving margins, record energy performance, expanding autonomy efforts, and a sharp acceleration in AI and robotics investments.
Executives, including CEO Elon Musk, discussed how the company is positioning itself for growth across vehicles, energy, AI, and robotics despite near-term pressures from tariffs, pricing, and macro conditions.
Key takeaways
Tesla reported sequential improvement in automotive gross margins excluding regulatory credits, rising from 15.4% to 17.9%, supported by favorable regional mix effects despite a 16% decline in deliveries. Total gross margin exceeded 20.1%, the highest level in more than two years, even with lower fixed-cost absorption and tariff impacts.
The energy business delivered standout results, with revenue reaching nearly $12.8 billion, up 26.6% year over year. Energy gross profit hit a new quarterly record, driven by strong global demand and high deployments of MegaPack and Powerwall across all regions, as noted in a report from The Motley Fool.
Tesla also stated that paid Full Self-Driving customers have climbed to nearly 1.1 million worldwide, with about 70% having purchased FSD outright. The company has now fully transitioned FSD to a subscription-based sales model, which should create a short-term margin headwind for automotive results.
Free cash flow totaled $1.4 billion for the quarter. Operating expenses rose by $500 million sequentially as well.
Production shifts, robotics, and AI investment
Musk further confirmed that Model S and Model X production is expected to wind down next quarter, and plans are underway to convert Fremont’s S/X line into an Optimus robot factory with a capacity of one million units.
Tesla’s Robotaxi fleet has surpassed 500 vehicles, operating across the Bay Area and Austin, with Musk noting a rapid monthly expansion pace. He also reiterated that CyberCab production is expected to begin in April, following a slow initial S-curve ramp before scaling beyond other vehicle programs.
Looking ahead, Tesla expects its capital expenditures to exceed $20 billion next year, thanks to the company’s operations across its six factories, the expansion of its fleet expansion, and the ramp of its AI compute. Additional investments in AI chips, compute infrastructure, and future in-house semiconductor manufacturing were discussed but are not included in the company’s current CapEx guidance.
More importantly, Tesla ended the year with a larger backlog than in recent years. This is supported by record deliveries in smaller international markets and stronger demand across APAC and EMEA. Energy backlog remains strong globally as well, though Tesla cautioned that margin pressure could emerge from competition, policy uncertainty, and tariffs.
Tesla is bringing closure to its flagship Model S and Model X vehicles, which CEO Elon Musk said several years ago were only produced for “sentimental reasons.”
The Model S and Model X have been light contributors to Tesla’s delivery growth over the past few years, commonly contributing only a few percentage points toward the over 1.7 million cars the company has handed over to customers annually since 2022.
However, the Model S and Model X have remained in production because of their high-end performance and flagship status; they are truly two vehicles that are premium offerings and do not hold major weight toward Tesla’s future goals.
On Wednesday, during the Q4 2025 Earnings Call, Musk confirmed that Tesla would bring closure to the two models, ending their production and making way for the manufacturing efforts of the Optimus robot:
“It is time to bring the Model S and Model X programs to an end with an honorable discharge. It is time to bring the S/X programs to an end. It’s part of our overall shift to an autonomous future.”
Musk said the production lines that Tesla has for the Model S and Model X at the Fremont Factory in Northern California will be transitioned to Optimus production lines that will produce one million units per year.
Tesla Fremont Factory celebrates 15 years of electric vehicle production
Tesla will continue to service Model S and Model X vehicles, but it will officially stop deliveries of the cars in Q2, as inventory will be liquidated. When they’re gone, they’re gone.
BREAKING: Tesla will wind down Model S and Model X production next quarter, Elon Musk confirms.
“It is time to bring the Model S and Model X programs to an end with an honorable discharge.” pic.twitter.com/Czn7aQjJE1
— TESLARATI (@Teslarati) January 28, 2026
Tesla has been making moves to sunset the two vehicles for the better part of one year. Last July, it stopped taking any custom orders for vehicles in Europe, essentially pushing the idea that the program was coming to a close soon.
Musk said back in 2019:
“I mean, they’re very expensive, made in low volume. To be totally frank, we’re continuing to make them more for sentimental reasons than anything else. They’re really of minor importance to the future.”
That point is more relevant than ever as Tesla is ending the production of the cars to make way for Optimus, which will likely be Tesla’s biggest product in the coming years.
Musk added during the Earnings Call on Wednesday that he believes Optimus will be a major needle-mover of the United States’ GDP, as it will increase productivity and enable universal high income for humans.
Investor's Corner
LIVE BLOG: Tesla (TSLA) Q4 and FY 2025 earnings call
Tesla’s (NASDAQ:TSLA) earnings call follows the release of the company’s Q4 and full-year 2025 update letter.
Tesla’s (NASDAQ:TSLA) earnings call follows the release of the company’s Q4 and full-year 2025 update letter, which was published on Tesla’s Investor Relations website after markets closed on January 28, 2025.
The results cap a quarter in which Tesla produced more than 434,000 vehicles, delivered over 418,000 vehicles, and deployed 14.2 GWh of energy storage products. For the full year, Tesla produced 1.65 million vehicles and delivered 1.63 million, while total energy storage deployments reached 46.7 GWh.
Tesla’s Q4 and FY 2025 Results
According to Tesla’s Q4 and FY 2025 Update Letter, the company posted GAAP earnings per share of $0.24 and non-GAAP EPS of $0.50 in the fourth quarter. Total revenue for Q4 came in at $24.901 billion, while GAAP net income was reported at $840 million.
For full-year 2025, Tesla reported GAAP EPS of $1.08 and non-GAAP EPS of $1.66 per share. Total revenue reached $94.83 billion, including $69.53 billion from automotive operations and $12.78 billion from the company’s energy generation and storage business. GAAP net income for the year totaled $3.79 billion.
Earnings call updates
The following are live updates from Tesla’s Q4 and FY 2025 earnings call. I will be updating this article in real time, so please keep refreshing the page to view the latest updates on this story.
16:25 CT – Good day to everyone, and welcome to another Tesla earnings call live blog. There’s a lot to unpack from Tesla’s Q4 and FY 2025 update letter, so I’m pretty sure this earnings call will be quite interesting.
16:30 CT – The Q4 and FY 2025 earnings call officially starts. IR exec Travis Axelrod opens the call. Elon and other executives are present.
16:30 CT – Elon makes his opening statement and explains why Tesla changed its mission to “Amazing Abundance.” “With the continued growth of AI and robotics, I think we’re headed towards a future of universal high income,” Musk said, adding that along the way, Tesla will still be improving its products while keeping the environment safe and healthy.
16:34 CT – Elon noted that the first steps for this future are happening this year, thanks to Tesla’s autonomy and robotics programs, which will be launching and ramping this year. He also highlighted that Tesla will be making major investments this year, though the company will be very strategic when it comes to its funding. “I think it makes a ton of strategic sense,” Musk said.
16:36 CT – Elon also announces the end of the Model S and Model X programs “with an honorable discharge.” If you’re interested in buying a Model S or X, it’s best to do it now, Musk said. The Model S and Model X factory in Fremont will be replaced by an Optimus line. “It’s slightly sad, but it is time to bring the S and X program to an end. It’s part of our overall shift to an autonomous future,” Musk said.
16:38 CT – Elon discusses how Unsupervised FSD is now starting for the Robotaxi service. He noted that these Unsupervised Robotaxis don’t have any chase cars as of yesterday. He reiterated Tesla’s plans for owners to be able to add their own vehicles to the Robotaxi fleet. Autonomy target for the end of the year is about a quarter or half of the United States, Musk said.
16:41 CT – Elon noted that the Tesla Energy team is absolutely killing it. He also stated that Tesla expects its Energy business to continue growing, and that the “solar opportunity is underrated.”
16:43 CT –Elon also added that Tesla Optimus 3 will be unveiled in about three months, probably. The Model S and Model X line in Fremont will be a million-unit Optimus production line. Looks like Optimus is really coming out of the gate with large, meaningful volumes. “The normal S curve for manufacturing ramps is longer for Optimus,” Musk stated. “Long term, I think Optimus will have a significant impact on the US GDP.”
16:44 CT – Elon closes his opening statements with a sincere thanks to the Tesla team. He also noted that he feels fortunate to be able to work alongside such a talented workforce.
Elon ends his opening remarks with an optimistic prediction about the future.“The future is more exciting than you can imagine,” he concluded.
16:47 CT – Tesla CFO Vaibhav Taneja makes his opening remarks. He discusses several aspects of Tesla’s Q4 milestones. He noted that Tesla Energy achieved yet another gross profit record during the fourth quarter. There’s insane demand for the Megapack and Powerwall. Backlogs for these products are healthy this 2026. He also noted that Tesla ended 2025 with a bigger vehicle order backlog compared to recent years.
16:53 CT – Investor questions from Say begin. The first question is about Tesla’s expectations for the Robotaxi Network. Lars Moravy noted that it has the advantage of manufacturing and scale, and Tesla believes that the Robotaxi Network will significantly grow year over year. Elon highlighted that the Cybercab will be produced with no steering wheel or pedals. No fallback. Elon also noted that Tesla expects to produce more Cybercabs than all its other vehicles combined in the future.
16:51 CT – The next question is if Tesla still expects to launch new models, such as affordable cars. Lars Moravy noted that Tesla did release affordable variants last year, and Tesla is still pushing hard to lower its costs. That being said, Tesla is really pushing the Cybercab as its total addressable market is larger than consumer-owned cars. Lars also mentioned that Tesla will produce different vehicles for its Robotaxi services.
16:56 CT – Elon noted that eventually, Tesla will produce mostly autonomous cars. The exception would be the next-generation Roadster, which will be a true driver’s car.
17:03 CT – A question about Elon’s past comments about a potential next pickup truck was asked. Lars noted that the Cybertruck is still performing well in the electric pickup truck segment, though Tesla is known for flexibility. Elon added that Tesla will be transitioning the Cybertruck line to a fully autonomous vehicle line. He also stated that the Cybertruck is a useful vehicle. “An autonomous Cybertruck will be useful for that.”
17:10 CT – A question was asked about when FSD will be 100% Unsupervised. Elon noted that 100% Unsupervised FSD is already being used today, though only in the Austin Robotaxi program. Tesla is still being extremely careful with its rollout.
When asked about Tesla’s chip program, Elon noted that he feels pretty good about Tesla’s chip strategy. But in terms of selling Tesla’s chips outside Tesla, the company has to make sure it has enough chips for Optimus robots, data centers, and other programs first.
17:18 CT – Analyst questions begin. First up is Wolf Research. He asks about Tesla’s increasing Capex, specifically where the majority of it is going. The Tesla CFO noted that programs in six factories are going live this year, so that consumes Capex. The Optimus program also consumes a lot of resources. The growth of Tesla’s current capacity is also consuming a lot of resources. As for how these programs will be funded, the CFO pointed to Tesla’s massive war chest, as well as initiatives such as the Robotaxi Network.
17:21 CT – Morgan Stanley asks about Tesla’s xAI investment. The analyst asked about more information about how Tesla and xAI will work together. The CFO noted that this investment is part of Master Plan Part IV. Elon also mentioned some advantages for xAI’s technology for Tesla’s products, like Grok being used to manage a Robotaxi fleet or a group of Optimus robots.
17:24 CT – Barclays asks Elon about the constraints on memory. Does Tesla have any near term constraints for Tesla vehicles’ memory? Elon responded that the Tesla AI computer is already very compute and memory-efficient. The intelligence per gigabyte is important. Musk noted that Tesla is ahead of the industry by an order of magnitude or more.
17:29 CT – Cannacord asks about startups from China entering the humanoid market. What competitive advantage does Optimus have compared to these rivals? Elon stated that he believes China will be a key competitor in the humanoid robot market. China will be the toughest competitor for Tesla. That being said, Elon noted that Tesla believes Optimus will be ahead in real-world intelligence, electromechanical dexterity, and hand design.
Tesla (TSLA) Q4 and FY 2025 earnings call: The most important points
Tesla brings closure to flagship ‘sentimental’ models, Musk confirms
