SpaceX
SpaceX’s Starship hopper spotted with trio of dual-bell Raptor engines
Following a brief ‘hop’ (via crane) off of a concrete build stand, the aft section of SpaceX’s first full-scale Starship hopper (Starhopper?) revealed that SpaceX technicians have already installed what appear to be three real Raptor engines, presumably the first time the propulsion system has ever been mounted to something that might eventually fly.
For a number of reasons, there is a strong chance that these Raptors are actually just boilerplate placeholders standing in as structural guides for the real deal some months down the line. On the other hand, there are also a number of reasons to assume that these apparent engines are indeed real Raptors.
Star ship hopper might be a bit bigger than we thought and with the crane placements over the nose end of the vehicle. This could suggest, @SpaceX are planning to move the segment elsewhere perhaps to the welding stand? We will have to wait and see. (Austin Barnard📸) #2019🚀 pic.twitter.com/kn8hhUPWCU
— Austin Barnard🚀 (@austinbarnard45) January 1, 2019
Despite an already shocking series of rapid-fire developments in the South Texas Starhopper saga, the abrupt appearance of what appears to be three Raptor engines – mirroring CEO Elon Musk’s recent statement that the test vehicle would sport three Raptors – is by far the most unexpected moment yet for the prototype Starship. Purportedly a full-scale prototype of BFR’s upper stage/spaceship (now known as Starship), Musk indicated over the last two weeks that the hopper has been designed to perform a number of hop tests in which the craft’s three Raptors would power it to a range of (relatively low) altitudes above Boca Chica, Texas.
According to a recent FCC filing related to this test program, SpaceX is currently seeking a license for Starship hop tests that will not exceed 5 km (3.1 mi) in altitude and/or 6 minutes in duration. There is admittedly nothing mentioned about the maximum allowed velocity during those tests, but – much like Blue Origin performs supersonic tests of New Shepard in Cape Horn, Texas – SpaceX will likely seek and be granted permission to break the sound barrier during those hypothetical tests. Nevertheless, a 5km ceiling is a fairly significant cap on the range of performance Starhopper will be able to test – accelerating vertically at 2Gs, Starhopper could travel from sea level to 5km in less than 30 seconds while reaching speeds no higher than Mach 1-1.5.
- SpaceX technicians and engineers are continuing to work at a breakneck pace on Starhopper. (NASASpaceflight – bocachicagal)
- At this rate, the hopper will likely wind up around 40m (130 feet) tall. (NASASpaceflight – bocachicagal)
- A close examination of these three engine-like protrusions suggests a level of fit and finish far exceeding a boilerplate stand-in. (NASASpaceflight – bocachicagal)
Combined with the apparent fact that this Starhopper’s fins seem unlikely to ever actuate (i.e. no aerodynamic control surfaces), it’s probable that this ad hoc prototype is only meant to perform a very limited range of hop tests, perhaps as basic as ironing out the kinks of operating a trio of gimballed Raptors and ensuring that they can safely and reliably launch, hover, and land a very large Starship-shaped mass simulator. Falcon 9’s Grasshopper and F9R reusability testbeds performed a very similar task some five years ago, offering SpaceX engineers the opportunity to optimize software and hardware needed to reliably recover real orbital-class rockets after launch. Although Falcon 9 has nine gimballed Merlin 1D engines, SpaceX has long sided with the sole center Merlin as the dedicated landing engine and has only briefly experimented with triple-Merlin landing burns.
Dual-expansion whaaaaat?
According to Musk, Raptor – an advanced liquid methane and oxygen engine with a uniquely efficient propulsion cycle – was expected to produce an impressive ~2000 kN (200 ton, 450K lbf) of thrust in its finished form as of September 2018. However, Musk also mentioned in a late-2017 Reddit AMA that SpaceX engineers were modifying the ship’s design to ensure engine-out reliability during all regimes of flight, landing in particular. To accomplish this feat with an engine as powerful as Raptor, two or three Raptors – capable of producing as much as 600 tons of thrust total – would need to reliably throttle as low as 25%, assuming a landing mass of around 150t. To allow a nearly empty ship (~100t) to still reliably land with three Raptors ignited, the engines would need to be able to throttle to 20% or less.

Known as deep throttling in rocketry, ensuring stable combustion and thrust at 20% (let alone 40%) throttle is an extraordinarily challenging feat, often subjecting engines to forces that can literally tear non-optimized hardware apart. To achieve such a deep throttle capability without excessively disrupting the engine’s design, SpaceX appears to have potentially sided with less efficient but extremely simple alternative, known as a dual-bell (or dual-expansion) rocket nozzle. A 1999 Rocketdyne paper concisely explained the primary draws of such a nozzle:
“The [altitude-compensating] dual-bell nozzle offers a unique combination of performance, simplicity, low weight, and ease of cooling” – Horn & Fisher, 1999
Exactly
— Elon Musk (@elonmusk) December 27, 2018
Given that SpaceX has decided to delay the introduction and certification of a vacuum-optimized Raptor engine, choosing to instead use the same Raptor on both BFR stages, something like a dual-bell nozzle would be one of the best possible ways for the company to retain some of the efficiency benefits of a vacuum engine while also drastically improving design simplicity, ease of manufacturing, and cutting development time. Aside from offering efficiency gains by way of altitude compensation, a dual-bell nozzle also happens to enable a given engine to operate a much wider throttle range by mitigating problems with flow separation and instability.
- A gif of Raptor throttling over the course of a 90+ second static-fire test in McGregor, Texas. (SpaceX)
- Note that Merlin 1D and prior Raptor prototypes both feature traditional single nozzles. (Pauline Acalin)
- An overview of dual-bell and deflection nozzles. Raptor appears to have now graduated to the former style. (Johan Steelant, 2011)
- Starhopper’s Raptors feature a very distinct seam and second curve, indicative of a dual-bell nozzle. (NASASpaceflight /u/bocachicagal)
For Starhopper and Starship, both aspects are an undeniable net-gain and it’s entirely possible that these dual-bell nozzles – if successfully demonstrated – could find their way onto Falcon 9 and Falcon Heavy to further boost their booster performance and efficiency.
For prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket recovery fleet check out our brand new LaunchPad and LandingZone newsletters!
News
SpaceX’s Starfall just went from secret to storefront
SpaceX now pitches Starfall missions with 1,000 kg payloads, weeks of microgravity, and Starlink connectivity.
SpaceX has put up a dedicated commercial page for Starfall, its disk shaped reentry capsule, laying out for the first time what customers actually get when they book a flight. The page, live at spacex.com/starfall, pitches “affordable, routine access to microgravity” and invites companies to get in touch about flying manufacturing, research or testing payloads.
The specs are short and specific. Each Starfall mission carries up to 1,000 kg of payload, supplies 1 kW of power and connects through an Ethernet interface. Mission length is tailored to the customer, and the payload stays online the entire time through Starlink, which means researchers can pull data from an experiment while it is still in orbit instead of waiting for splashdown.
SpaceX is launching a secret spacecraft that could change how things are made in space
SpaceX is aiming the service at three markets. Biomedical customers are told they can grow stem cell organoids, replacement tissue and layered biomaterials. Pharmaceutical companies are pitched on protein and small molecule drug crystals, which form smaller and more uniform shapes without gravity driven convection. Materials science rounds out the list, with semiconductors and other next generation materials grown in vacuum and microgravity.
The page also makes clear which rocket SpaceX is counting on. “By launching on Starship, Starfall brings a reliable and scalable cadence previously unavailable to the market,” the company wrote, contrasting weeks of continuous microgravity with the seconds offered by drop towers and parabolic flights. No price or first operational flight date is listed.
The commercial push is a sharp turn from how Starfall started. SpaceX said almost nothing about the capsule ahead of its first flight in June, and nearly everything known came from FAA and FCC filings describing a disk about 10.2 feet wide and 2.5 feet tall that can return 2,200 pounds of cargo. By its second flight on the Bandwagon-5 rideshare in October, Starfall was listed by name on the mission page, though SpaceX still did not say what it carried.
Customers appear to be lining up. SpaceX said in its third quarter results that it signed three commercial Starfall missions during the quarter. On the earnings call, President Gwynne Shotwell described the capsule as providing “routine relatively low cost access to microgravity environments for scientific research, including improving our understanding of diseases like cancer and diabetes,” and said the three new missions would fly on Starship.
The branding effort extends past the website. SpaceX added a Starfall T-shirt to its online store on Monday as part of a batch of new merchandise, giving the program a place next to Starship, Starlink and Starshield in the company’s lineup.
The move also puts SpaceX in more direct competition with companies it launches. Varda Space Industries, which has built much of the in-space manufacturing market so far, flew its W-Series 7 capsule on the same Bandwagon-5 mission as Starfall in October. Varda’s capsules are roughly three times smaller than Starfall, and SpaceX controls the ride to orbit for both.
Starfall’s near term cadence depends on Starship. SpaceX is preparing for Flight 15 after completing static fires of Ship 42 and its Super Heavy booster in late October, and is aiming to catch both stages with the launch tower on that flight.
Elon Musk
Grok Bot users hit with weekly limits early, Elon Musk explains what happened
Elon Musk said weeks ago during SpaceX’s third-quarter earnings call that the company’s Grok Bot, its autonomous AI Agent platform, was showing “the fastest growth of a product” that he’d ever seen in his life.
Now, SpaceXSI is scaling back Grok Bot users’ weekly limits, much to the surprise of those who have relied on it to take away monotonous tasks in their lives.
Elon Musk’s terse November 1 reply on X captured a sharp tension in the early days of agentic AI. Responding to a user who asked for a Grok Bot usage reset after hitting 100 percent with four days still left on the weekly cycle, Musk wrote: “The cost of serving Grok Bot was unsustainably high relative to revenue.”
@DogecoinNorway The cost of serving Grok Bot was unsustainably high relative to revenue
— Elon Musk (@elonmusk) November 1, 2026
The post arrived amid a wave of similar complaints from paying subscribers whose meters had jumped unexpectedly toward or to the limit, sometimes overnight and with little corresponding activity. It also stood in clear contrast to statements Musk had made only days and weeks earlier.
On the SpaceX third-quarter earnings call in mid-to-late October, Musk had described Grok Bot in almost the opposite terms. He called it “the fastest growth of a product that I’ve ever seen in my life” and said he had “never seen anything grow this fast.”
Company figures put paid weekly users at roughly 800,000 earlier in the month, more than doubling over the prior period. Daily active users had climbed from under 100,000 in early September to over 600,000 by late October.
Musk emphasized that the product has no free tier and that users appear to be getting real value beyond what they pay. In other remarks, he noted that usage per user was rising rather than declining, the opposite of the usual decay pattern for new software.
Grok Bot, launched around August, functions as an always-available agent with its own persistent cloud computer; it can schedule, research, shop, browse, and execute multi-step workflows even after the user steps away. Access is bundled into X subscription tiers (roughly $30, $100, and $200 per month) and certain Cursor plans, drawing from shared weekly usage pools whose exact sizes have not been publicly detailed.
The economics of that model are what Musk’s November 1 post put in the spotlight. Agentic systems burn far more compute than ordinary chatbot exchanges. Each task can trigger repeated model calls, tool use, web actions, and sustained background work.
When growth is as rapid as Musk celebrated, the absolute compute bill scales quickly even if average revenue per user stays fixed under flat monthly subscriptions. Industry observers noted the opportunity cost as well: the same GPUs can be rented to other AI labs at higher rates.
A simple back-of-the-envelope comparison circulating after the post illustrated the gap: if every reported daily user paid the top tier, annualized subscription revenue would still be modest relative to the scale of compute infrastructure SpaceX is building and leasing to companies like Anthropic.
Some users also reported possible dashboard anomalies around the same period, though Musk’s framing treated the underlying cost-revenue imbalance as the core issue rather than a pure metering glitch.
The juxtaposition is the core of this exchange. Within roughly two weeks of publicly framing Grok Bot as an unprecedented success with strong unit economics and no free tier, Musk acknowledged that serving the same product had become unsustainable relative to the revenue it generates.
For the broader industry, the episode underscores a structural challenge of the agent era: demand is real and growing faster than many expected, yet the cost of fulfilling that demand through always-on, multi-step agents can outrun subscription pricing before companies can adjust limits, introduce metered billing, or raise prices.
Musk’s reply did not promise an immediate reset or higher allowances; it simply stated the constraint. In doing so, it supplied a rare, explicit public data point on the unit economics of a high-profile AI agent just as adoption numbers were still being celebrated as the fastest in Musk’s experience.
The tension between rapid, paid growth and the compute required to deliver it is now on the record.
Elon Musk
Elon Musk calls Earth’s data centers “peanuts” next to what SpaceX is planning in orbit
Elon Musk says SpaceX capex efficiency is underestimated as orbital data centers loom by 2028.
Elon Musk is pushing back on one of the biggest worries hanging over SpaceX stock. In a reply on X on Sunday, Musk said the company’s capital expenditure efficiency is severely underestimated. He was responding to a Milk Road Stocks post citing analyst Kyle Reidhead, who estimates SpaceX will need to spend roughly $470 billion over the next five quarters.
Reidhead built that figure around the target SpaceX set on its third quarter earnings call: 13 gigawatts or more of compute by the end of 2027. In his breakdown, Nvidia captures 83 to 89 percent of the spending. SpaceX ended the quarter with 1.7 GW of nameplate compute and guided to $35 billion to $40 billion in fourth quarter capex, as Teslarati reported.
Musk did not attach a number to his claim, but the earnings call shows the argument. CFO Bret Johnsen said new compute currently pays for itself in under a year at today’s pricing, and Musk said that window could shrink to six months next year. Using that pace, Reidhead argues about $230 billion of the $470 billion could come from operating cash flow and about $60 billion from SpaceX’s roughly $90 billion cash pile, leaving around $180 billion to borrow. Musk confirmed last week that SpaceX had already closed a new $40 billion debt raise to buy GPUs.
The ground buildout is not the end goal. It is what is meant to pay for the move to orbit. Replying on Friday to charts built from Sequoia partner Shaun Maguire’s SpaceX model, Musk wrote that “Terrestrial compute will be peanuts compared to orbital compute,” adding that orbital compute deployed per month “probably exceeds terrestrial around the end of 2028 and then far exceeds it in 2029.”
Maguire’s model shows how steep that path is. It has capex climbing from $88 billion this year to $290 billion in 2027 and $369 billion in 2028, with SpaceX burning $77.8 billion in cash this year and $122.6 billion next year before turning $114.9 billion cash positive in 2028. Musk’s response to the model was, “I think we can do better.”
The orbital half runs through Starmind. SpaceX plans to operate up to 1 million AI satellites flying in clusters of about 10, linked by roughly 10 terabits of bandwidth, with deployment of thousands of units starting as soon as late 2027 out of its Gigasat factory in Bastrop, Texas, according to SpaceX’s space safety page. Musk has said each Starmind spacecraft will carry more than 250 kW of solar power.
Getting there depends on launch volume. Maguire’s model assumes 250 Starship flights in 2028, up from two this year and 38 next year. The nearer test is financial: SpaceX guided to $33 billion to $37 billion in first quarter 2027 revenue, more than double the $14.58 billion it booked in Q3, and Musk reposted that guidance again on Sunday morning.






