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Ex-SpaceX engine expert to help design rockets built for launch on world’s largest jet

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8 years ago

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Stratolaunch, an aerospace company funded by Microsoft-made billionaire Paul Allen to build the world’s largest flightworthy aircraft, has announced a decision to build its own liquid-fueled rockets, to be air-launched from the aforementioned mega-plane.

Targeting an inaugural launch of the first version of the rocket – currently nicknamed “Kraken” – as early as 2022, Stratolaunch has chosen Jeff Thornburg, formerly SpaceX’s Vice President of Propulsion Engineering and the father of the company’s Mars-focused Raptor engine, to lead its foray into in-house rocket propulsion development and manufacturing.

But first: building the world’s largest aircraft

Stratolaunch’s first task at hand, however, is to begin flight-testing the largest (hopefully) operational aircraft in history, a prerequisite for the company’s longer-term orbital rocket and spaceplane aspirations. Nicknamed “Roc” after a mythical (and fictional) bird so large it could carry an elephant, the plane certainly lives up to its namesake. Featuring a full six of the same engines that power Boeing’s once-record-breaking 747 airliner and a wingspan that could easily fit three smaller 737 airliners with room to spare, it is genuinely difficult (if not impossible) to successfully convey the sheer scale of Roc outside of witnessing it in person.

Stationed in California’s Mojave Desert, the aircraft’s one and only copy is, for the most part, completed and has spent the brunt of 2018 conducting runway taxi tests, hopefully culminating in an inaugural flight test later this year or early next year. Designed to lift orbital-class rockets weighing as much as 250 metric tons (550,000 lb) to an altitude of at least 9100 meters (30,000 feet), the primary benefit of using aircraft as launch platforms derives from the simple fact that the atmospheric density at 30,000 feet is more than three times less than that at sea level. Similar to aircraft, rocket performance dramatically improves as atmospheric density decreases: less atmosphere means lower drag and pressure.

Rockets that launch from sea-level have to grapple with the difficulties of Earth’s relatively thick atmosphere at that height, with major launch events like “Max-Q” being big concerns almost solely because the dense air exerts major forces on launch vehicles and demands extreme measures like throttling down booster engines (very inefficient) and optimizing structures for aerodynamic efficiency despite the fact that rockets spend very little time operating in a significant atmosphere.

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A launch pad without a rocket (sort of)

However, the simple fact of the matter is that billionaire Paul Allen’s colossal aircraft essentially does not have a single air-launched rocket in the world that can properly take advantage of its capabilities. Originally sized and designed with an air-launched version of SpaceX’s Falcon 9 in mind, that relationship folded amicably after roughly a year (2012), at which point SpaceX realized it would need to almost completely redesign a unique variant of Falcon 9. Your author will readily admit that they have admired the insanity of such a massive plane while still severely doubting its practical utility.

Thankfully, it appears that Allen is adamantly opposed to the idea that Stratolaunch is some silly whim to build the world’s largest plane. Rather, he is exceptionally reserved and pragmatic when discussing the aerial launch platform, according to a recent and extensive interview by Wired Magazine’s Steven Levy.

“Allen isn’t one to show exuberance, and when he speaks about the plane he focuses on its future utility. ‘When you see that giant plane, it’s a little nutty,’ he says. ‘And you don’t build it unless you’re very serious, not only about wanting to see the plane fly but to see it fulfill its purpose. Which is getting vehicles in orbit.’ – Paul Allen, 2018

 

Currently, Orbital ATK’s (now Northrop Grumman Innovation Systems) air-launched Pegasus XL rocket is the only “customer” in the world that can realistically use Stratolaunch as a launch platform, not exactly an impressive or sustainable launch vehicle with a maximum performance of less than 450 kg (~1000 lbs) to low Earth orbit for an incredible ~$40 million per (expendable) flight.

To answer that call and ensure Stratolaunch’s utility, the company reportedly began seriously considering its own in-house expendable and reusable rockets and propulsion systems sometime in 2016, plans that have since grown concrete and been publicly embedded into Stratolaunch’s overarching mission. Nicknamed “Kraken” after the mythical sea monster, the company hopes to develop an initially expendable rocket system capable of launching 3400 – 6000 kg (~7500 – 13250 lbs) into low Earth orbit with single booster and triple booster variants. Further down the line, Stratolaunch is eyeing the design and production of a fully and rapidly reusable orbital spaceplane, potentially including a version that would carry astronauts into space.

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Normally, one might simply roll their eyes at yet another startup touting small(ish) expendable rockets with first launches no earlier than the early 2020s – the market is getting to be absurdly and impossibly overcrowded at this point. However, Stratolaunch differs for one fundamental and reason: they have placed ex-SpaceX propulsion executive and expert Jeff Thornburg at the helm of the company’s freshly public rocket propulsion wing. While at SpaceX, Mr. Thornburg spent all but one of his five years with the company (2011-2015) single-mindedly focused on the development and engineering of all aspects of the Raptor rocket engine, a next-generation propulsion system designed to enable SpaceX’s sustainable colonization of Mars.

Raptor is an exceptional rocket engine thanks in no small part to Thornburg’s brilliance as a propulsion engineer, and that same brilliance and half-decade of experience at the most successful rocket startup in existence could ultimately prove a massive boon for Stratolaunch’s otherwise interesting but unexceptional expendable rocket concepts.

Put simply, under Jeff Thornburg’s direction and with access to founder Paul Allen’s considerable wealth, Stratolaunch is undoubtedly worth keeping a close eye in the future, both far and near.

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!

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Investor's Corner

SpaceX reports beat in first earnings while minimizing losses

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56 minutes ago

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August 4, 2026

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Credit: SpaceX | X

SpaceX (NASDAQ: SPCX) reported a beat in revenues and EBITDA in its first earnings call report while also minimizing losses as its business continues to gain momentum.

After its IPO in July, SpaceX saw some tough losses on Wall Street due to a major selloff after a delay in its 13th Starship test flight. The ship launched later that week and completed what was arguably the most successful IFT operation in the Starship program’s history.

Nevertheless, the company is continuing on and reported some encouraging financials while also promoting what appears to be a robust outlook moving forward in its Space, AI, and Connectivity divisions.

SpaceX to report first-ever earnings today: here’s what to expect

Earnings Results

  • Revenues: $7.8 billion reported vs. $6.7 billion expected
  • Adjusted EBITDA: $3.5 billion vs. $2 billion expected
  • Net loss of $541 million, an improvement of $467 million from net loss of $1.0 billion

Additionally, CFO Bret Johnsen had these comments:

“2026 has been a momentous year so far, and the second quarter demonstrated the true power of SpaceX. Revenue growth accelerated across all our business segments and we delivered strong operating leverage, with significant margin expansion led by our new AI compute agreements. Our unparalleled leadership in launch, Starlink subscriber growth, new enterprise and government partnerships, and best-in-class AI infrastructure underscore our ability to drive meaningful scale and deliver attractive returns. As a newly public company, we are delighted to welcome our broad base of shareholders and bondholders. We ended the second quarter with $100 billion of cash, cash equivalents, and marketable securities, and $47.5 billion in backlog. This financial strength gives us substantial capacity to invest in Starship, Starlink Broadband and Mobile satellites, and our AI platform, while maintaining a disciplined long-term capital allocation framework.”

Space Business Highlights

SpaceX shared some of its biggest Space Business Highlights for Q2:

  • Space revenues grew 55% sequentially and 29% year-over-year to $962 million, driven by a higher number of large customer launches and a favorable customer shift compared to the prior year
  • Total costs and expenses for the Space segment were up by $389 million year-over-year, as we continued to accelerate R&D investments in our Starship program, which we believe will reduce the cost to orbit by 99% or more relative to the historical average, and unlock significant revenue potential across all business segments
  • Leading launch provider for the world with 78 launches and 1,041 metric tons of mass to orbit deployed over the six months ended June 30, 2026, primarily allocated to Connectivity for the deployment of our Starlink constellation
  • Starship V3 development continued to advance towards full and rapid reusability:
    • Completed Starship V3’s first suborbital mission in May, Flight 12, which achieved a successful lift off from our new Starbase pad, a precision landing of Starship’s upper stage, and deployment of modified V2 Starlink satellites
    • Subsequent to the second quarter, completed Starship Flight 13 in July, which achieved all flight objectives including deploying 20 production V3 satellites, demonstrating in-space relight of a Raptor engine, and executing the softest ever splashdown of Starship, providing critical views of an intact heatshield

SpaceX will report its earnings today at 4:30 P.M. EDT.

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Elon Musk

Elon Musk sends second warning to SpaceX shorts ahead of first earnings

Published

2 hours ago

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August 4, 2026

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Credit: Grok Imagine

Elon Musk issued a second pointed warning to SpaceX short sellers on Tuesday, just hours before the company was set to release its first quarterly earnings as a publicly traded firm. Responding to a report highlighting elevated short interest, Musk wrote on X: “I try to warn them, but they just double down …”

The comment came as data from S3 Partners showed roughly 95 percent of available SPCX shares to borrow were on loan, translating to about 34 percent short interest as a percentage of the float. The stock has traded under pressure since its record-breaking IPO in June 2026, declining significantly from early peaks.

This marks the second such message from Musk in under three weeks.

On July 17, amid post-IPO volatility, he stated: “The survival probability of firms who maintain a significant short position in SpaceX over time is very low.” At that time, SPCX had fallen roughly 30 percent from its peak above a $2.6 trillion valuation, with short sellers reportedly realizing gains of about $8.7 billion.

Elon Musk sends first warning to SpaceX short sellers

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Musk’s warning aligned with optimistic analyses projecting that Starship-driven cost reductions could enable a multi-trillion-dollar space economy through applications such as orbital solar power, asteroid mining, data centers, and Mars-related projects, positioning SpaceX as critical infrastructure.

SpaceX is scheduled to report second-quarter results after the market close later today, followed by a webcast. Analysts anticipate revenue near $6.9 billion, reflecting growth in Starlink, launch services, and AI-related segments. The earnings release precedes a major lockup expiration on August 6 that could free hundreds of millions of insider shares.

Musk has a long track record of confronting short sellers, particularly regarding Tesla, where he has argued that persistent bearish positions underestimate transformative technologies. Critics view his optimism as overly ambitious given near-term stock fluctuations, while supporters see temporary dips as opportunities in a longer-term expansion of the space economy.

As SpaceX opens its books to public scrutiny for the first time, the high short interest and Musk’s repeated cautions set the stage for heightened market attention on the results and management’s commentary.

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Tesla’s AI lead doubles down on FSD’s speed strategy, and owners are confused

Published

5 hours ago

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August 4, 2026

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Credit: Tesla

Tesla’s AI lead Ashok Elluswamy doubled down on the company’s strategy regarding Full Self-Driving’s speed settings, and owners are definitely confused.

Earlier versions of Full Self-Driving allowed owners to set a max speed that the vehicle could travel while operating under the semi-autonomous driver assistance platform. This allowed more customization for the driver, giving them the ability to experience FSD’s robust performance with their own personal preferences.

Speed is massively important for obvious reasons — it’s not only a question of keeping the vehicle occupants comfortable by traveling at a safe speed, but it’s also something that could contribute to a ticket or infraction from law enforcement.

With the release of FSD v14 last year, Tesla removed the ability to set a max speed and instead opted for five Speed Profiles, ranging from “Sloth,” the most conservative, to “Mad Max,” the most aggressive and spirited. These profiles not only control speed, but also how frequently the vehicle will execute passes, perform lane changes, and other contributing factors.

The removal of the Max Speed setting was a major complaint amongst the Tesla community because it left owners scrambling for a way to experience suitable behaviors while traveling at an appropriate speed. Most felt the driving profiles would be a good indicator of the behaviors, while speed would still be left up to the discretion of the driver.

Instead, Tesla’s Speed Profiles determine both, and the constant tinkering of how they behave has been a major bottleneck and point of confusion for both owners and the company. From update to update, the Speed Profiles will change, sometimes more drastically than others. Some owners have complained that the “Standard” profile is too fast, while others have experienced “Mad Max” traveling below the speed limit:

These things change with each update, but the big complaint is that owners are on the hook for any tickets that come from FSD’s infractions; that’s the caveat of the suite being named FSD (Supervised). It ultimately means the driver is responsible, and the automaker has no liability when it comes to speeding tickets or general traffic infractions.

It is the driver’s responsibility to take over or adjust based on this.

Elluswamy essentially confirmed that there are no plans to bring back Max Speed control, because it is what he referred to as “an anti pattern.” He then echoed something that CEO Elon Musk has started to really push with FSD, and that’s the idea that Tesla is really honing in on the preferences of the driver.

Owners were confused by Tesla’s decision, stating that there must be a better way, especially considering disengagements for incorrect speeds are common:

From personal experience and using FSD for over 72 percent of my driving miles since v14 was released late last year, I make Speed Profile adjustments constantly. If FSD is traveling a tad too quickly, I will scale it back, and if it’s too conservative, I’ll make it more aggressive.

I don’t complain about making the Speed Profile changes too frequently, but it would certainly be nice to have it happen less frequently. There are far too many times I am concerned about getting a ticket, even in Standard mode.

The biggest issue for me, personally, which seems to be echoed throughout the community, is the fact that Tesla’s goal is to minimize disengagements. Many drivers are stating that speed is a major reason for disengagements.

However, Tesla is not willing to bring back this one level of input because it would technically be a regression.

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Whether it’s right or wrong in your opinion, it is what Tesla is going with, and it seems like it has pivoted quite a bit from its other strategies for minimizing interventions by pushing its AI to behave in a way that would fit the occupant’s personal preferences.

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