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Ex-SpaceX engine expert to help design rockets built for launch on world’s largest jet
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.
Stratolaunch has confirmed what most people have long speculated: it’s developing its own launch vehicles for its air-launch system, including a reusable space plane that could eventually carry people. pic.twitter.com/nF9lKVe4xk
— Jeff Foust (@jeff_foust) August 20, 2018
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.
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
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- Stratolaunch’s Roc shown with a triplet of Orbital ATK Pegasus XL rockets. (Vulcan Space)
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- Back in 2012, SpaceX briefly entertained the idea of a Falcon 9 variant optimized for air-launch, potentially including crew rating the rocket down the road. (Stratolaunch/Dynetics)
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- The Roc is inconceivably vast. (Stratolaunch)
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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- A concept video produced by Stratolaunch shows the Roc launching a Kraken rocket. (Stratolaunch, via Wired)
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- A concept video produced by Stratolaunch shows the Roc launching a Kraken rocket. (Stratolaunch, via Wired)
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- A concept video produced by Stratolaunch shows the Roc launching a Kraken rocket. (Stratolaunch, via Wired)
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- SpaceX’s subscale Raptor engine has completed more than 1200 seconds of testing in less than two years. (SpaceX)
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- BFS (circa 2017) shows off its complement of SL and Vacuum Raptor engines. SpaceX is moving back to something similar to this. (SpaceX)
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!
Tesla Full Self-Driving (Supervised) has taken yet another significant step forward in Europe. On May 29, Estonia became the third European Union country to approve the advanced driver-assistance technology, following approvals in the Netherlands and Lithuania.
Tesla Europe announced the news on X, confirming the expansion has continued across the continent that, at one time, seemed to be taking its sweet old time giving any approval to the FSD suite.
FSD Supervised now approved in Estonia🇪🇪. Rollout will begin soon pic.twitter.com/y5a64qlp5m
— Tesla Europe, Middle East & Africa (@teslaeurope) May 29, 2026
Estonia’s Transport Administration (Transpordiamet) granted the approval by recognizing the type certification issued by the Dutch vehicle authority RDW. This mutual recognition mechanism, enabled by EU regulations, allows other member states to fast-track deployment without repeating extensive local testing.
The Estonian authority noted that Tesla’s FSD had undergone rigorous evaluation on European roads for approximately 18 months before the initial Dutch approval in April 2026.
FSD Supervised remains classified as a Level 2 advanced driver-assistance system (ADAS). Drivers must maintain full attention, keep their hands on the wheel, and stay ready to intervene at any moment.
The system assists with tasks such as automatic lane changes, navigation through city streets, and responding to traffic objects, but it does not constitute full autonomy. Estonian officials emphasized this distinction, underscoring that safety responsibility lies entirely with the driver.
The rapid progression across the Baltic region highlights Tesla’s strategic approach to European expansion. The Netherlands provided the foundational type approval in April, unlocking doors for neighboring countries.
Lithuania followed swiftly in mid-May, with rollout beginning shortly thereafter. Estonia’s decision, coming just days later, demonstrates how smaller, digitally progressive nations are accelerating adoption.
Tesla owners in Estonia can expect an over-the-air software update in the coming weeks, bringing the latest FSD capabilities to compatible vehicles
This expansion builds on Tesla’s global momentum. FSD Supervised is now available in 11 countries worldwide, including the United States, Canada, Australia, and South Korea. In Europe, the approvals signal growing regulatory confidence in Tesla’s vision-based AI approach, which relies on cameras and neural networks rather than lidar or radar-heavy alternatives used by some competitors.
For Tesla, these European milestones are more than symbolic. They validate years of data collection and software iteration while opening new revenue streams through FSD subscriptions and purchases.
As the company continues refining its AI models with real-world miles from diverse driving environments, including Estonia’s variable winter conditions, the dataset grows richer, potentially benefiting global users.
Elon Musk has firmly denied recent media reports suggesting that SpaceX has reduced its target valuation for an upcoming initial public offering.
The denial came directly from the SpaceX and Tesla frontman on his social media platform X, where he responded with a single word, “False,” to a post from ZeroHedge that cited Bloomberg sources.
This swift rebuttal underscores Musk’s ongoing effort to manage speculation surrounding one of the most anticipated market debuts in recent history.
False
— Elon Musk (@elonmusk) May 29, 2026
According to the disputed reports, SpaceX had lowered its IPO valuation goal to at least $1.8 trillion from previous ambitions exceeding $2 trillion.
The claims emerged amid growing anticipation for the company’s confidential S-1 filing, which positions it for a potential public listing as early as June.
Some had pointed to strong revenue growth, particularly from the Starlink satellite internet service, which contributed heavily to the firm’s 2025 figures of $18.7 billion. Yet challenges persist in other areas, including substantial investments and losses tied to ambitious projects like Starship development and artificial intelligence initiatives, which plan to make life multiplanetary eventually.
Musk’s response highlights a pattern in which he actively counters what he views as inaccurate portrayals of his companies’ trajectories.
SpaceX, already valued privately at extraordinary levels, stands as a cornerstone of Musk’s empire alongside Tesla and xAI. The entrepreneur has long emphasized the transformative potential of reusable rockets and global broadband access, factors that fuel investor enthusiasm despite operational hurdles.
By rejecting the valuation downgrade narrative, Musk signals confidence in SpaceX’s fundamentals and its readiness for public markets on terms favorable to its long-term vision. People have been waiting a very long time to invest in SpaceX, and the valuation, as well as the introductory share price, is not going to need adjusting.
They’ll have plenty of suitors.
This episode reflects broader dynamics in the technology sector, where rumors often swirl around high-profile entities. Musk’s direct engagement with media narratives serves to maintain transparency and control the narrative around his ventures.
As SpaceX prepares for greater scrutiny in public markets, the founder’s denial reinforces optimism about its prospects. Supporters argue that the company’s innovative edge positions it for enduring success, far beyond short-term valuation debates. With the denial now public, attention turns to forthcoming regulatory filings that could provide clearer insights into SpaceX’s strategy and financial health.
The coming weeks promise to reveal more about how SpaceX will transition into a publicly traded powerhouse.
Tesla’s dreams of operating a fully autonomous ride-hailing platform just took a massive step toward reality, as two separate events have indicated the company is perhaps closer than ever to achieving self-driving as a product.
On Thursday, Tesla was granted authorization by the State of Texas to operate driverless vehicles in a commercial manner. On May 28, Senate Bill 2807, passed by the 89th Texas Legislature, took effect after being passed back on September 1, 2025.
The bill establishes a statewide regulatory framework requiring authorization from the Texas Department of Motor Vehicles for companies to operate automated vehicles commercially on Texas roads.
This covers driverless, or SAE Level 4+, operations for passenger transport, meaning Robotaxi, or freight.
Tesla and other companies can self-certify their vehicles and tech as long as they:
- Operate in compliance with Texas traffic laws
- Maintain proper registration, title, and insurance
- Use compliant automated driving systems
- Record onboard activity and handle system failures and glitches safely.
The new authorization, which was first reported by James Stephenson on X, allows companies to utilize their own processes to determine if their vehicles are ready to operate without drivers.
🚨BREAKING:
Tesla has been authorized by the State of Texas to operate driverless vehicles commercially under the new law that took effect today, May 28th, 2026. Tesla has officially self-certified the software running on its robotaxis as Level 4. $TSLA pic.twitter.com/KSJdsvlaW5— James Stephenson (@ICannot_Enough) May 28, 2026
It is a rule that expedites the entire approval process, keeping agencies out of a usually long, lengthy, and frustrating task that is essential to technological advancements. It essentially means Tesla can launch commercial Robotaxi operations at this point.
On the very same day, Tesla continued the momentum as CEO Elon Musk shared a video of Cybercab units autonomously driving off the property at Gigafactory Texas. This is a major step in the story of the Cybercab.
Mass production of the Cybercab started at Giga Texas in April, and it is already heading out of the factory on its own.
Cybercab driving itself out of the GigaTexas factory pic.twitter.com/EwAMVVDjYy
— Elon Musk (@elonmusk) May 28, 2026
These two major events mark a drastic step forward in Tesla’s progress toward Cybercab and the permissions it needs to operate a self-driving ride-hailing service. Tesla is now able to operate autonomously under Texas law by self-certifying, and with the potentially imminent rollout of Cybercab, Tesla’s autonomous dreams are starting to take serious shape.
Tesla Full Self-Driving expansion in Europe continues with new addition
Elon Musk strikes down reports on SpaceX IPO rumors
