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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!
Elon Musk
Elon Musk calls out $2 trillion SpaceX IPO valuation as ‘BS’
In a swift rebuke on X, Elon Musk dismissed reports claiming SpaceX had confidentially filed for an initial public offering targeting a valuation above $2 trillion, labeling the information as unreliable.
Elon Musk is quick to call out any false information regarding him or his companies on his social media platform, known as X.
A recent report that claimed SpaceX was aiming to go public with an IPO in the coming weeks at a massive valuation of $2 trillion was called out by Musk, who referred to it as “BS.”
In a swift rebuke on X, Elon Musk dismissed reports claiming SpaceX had confidentially filed for an initial public offering targeting a valuation above $2 trillion, labeling the information as unreliable.
The exchange highlights ongoing media speculation about the rocket company’s future and Musk’s frustration with what he views as inaccurate financial reporting. The report came from Bloomberg.
Don’t believe everything you read.
Bloomberg publishes bs.
— Elon Musk (@elonmusk) April 3, 2026
The controversy erupted on April 2, 2026, when influencer Mario Nawfal amplified claims from Bloomberg.
The outlet posted that SpaceX had boosted its IPO target valuation above $2 trillion, describing it as potentially one of the largest public offerings in history. Musk challenged the story.
It echoes past instances where Musk has corrected valuation rumors about his companies, emphasizing that speculation often outpaces reality.
Background context adds nuance.
Earlier reports indicated SpaceX had filed confidential IPO paperwork with the U.S. Securities and Exchange Commission, potentially positioning it for a record-breaking debut that could eclipse Saudi Aramco’s 2019 listing.
Initial estimates pegged a possible valuation north of $1.75 trillion, building on a post-merger figure around $1.25 trillion after SpaceX absorbed xAI. A subsequent Bloomberg update claimed advisers were floating figures above $2 trillion to investors, with the offering potentially raising up to $75 billion.
SpaceX remains a private powerhouse. Its achievements include thousands of Starlink satellites providing global broadband, routine Falcon 9 rocket reusability, and a mission to slash launch costs, along with ambitions for Starship to enable Mars colonization.
The company also benefits from government contracts with NASA and the Department of Defense. A public listing could democratize access for retail investors while subjecting SpaceX to greater scrutiny and quarterly reporting pressures.
Critics of the reports point to the confidential nature of filings, which limits verifiable details. Musk has previously downplayed inflated valuations, once calling an $800 billion figure for SpaceX “too high.”
Supporters argue that hype around mega-IPOs, especially amid the ongoing AI fervor, fuels premature narratives that distract from core technical milestones, such as full Starship reusability and Starlink constellation expansion.
The incident reflects broader tensions in tech finance. Anonymous sourcing in valuation stories can drive market chatter and betting activity, yet it risks misinformation.
Bloomberg defended its reporting through multiple articles citing “people familiar with the matter,” but Musk’s blunt dismissal resonated widely on X, with users piling on to question media reliability.
Whether SpaceX ultimately goes public remains uncertain. Musk has teased an IPO tied to Starlink maturity, but priorities center on engineering breakthroughs over Wall Street timelines. For now, the $2 trillion figure joins a list of rumored milestones that Musk insists should be taken with skepticism.
Elon Musk
Elon Musk reveals date of SpaceX Starship v3’s maiden voyage
The announcement arrives after Flight 11 on October 13 of last year, which concluded a busy 2025 testing campaign. Since then, SpaceX has focused on ground testing, including cryoproofing of Ship 39 and preparations for Booster 19, the first V3 Super Heavy.
SpaceX CEO Elon Musk has revealed the timeline for the next Starship launch. It will be the first launch using SpaceX’s revamped design for Starship, as its v3 rocket will take its maiden voyage sooner than many might expect.
Musk announced on April 3 on X that the next Starship flight test, and the first flight of the upgraded v3 ship and booster, is 4 to 6 weeks away. The update signals the end of a nearly six-month hiatus since the program’s last launch.
Elon says the first V3 Starship launch will occur in 4-6 weeks
It will be the first Starship launch since Flight 11 on October 13, 2025 https://t.co/QnnYPTdbUu
— TESLARATI (@Teslarati) April 3, 2026
The upcoming mission, designated as Starship’s 12 integrated flight test (IFT-12), marks a significant milestone. It will be the debut of the v3 configuration, featuring a taller Super Heavy Booster and Starship upper stage. The changes SpaceX has made with the v3 rocket and booster are an increased propellant capacity and the more powerful Raptor 3 engines.
Earlier predictions from Musk in March had pointed to an April timeframe, but the latest timeline now targets a launch window in early to mid-May 2026.
The V3 iteration represents a substantial evolution from previous Starship prototypes. Engineers have optimized the design for improved manufacturability, higher thrust, and greater efficiency. Raptor 3 engines deliver significantly more power while reducing weight and production costs compared to earlier variants.
With these enhancements, SpaceX aims to boost payload capacity toward 200 metric tons to low Earth orbit in a fully reusable configuration — a dramatic leap from the roughly 35-ton target of prior versions. Such capabilities are critical for ambitious goals, including NASA’s Artemis lunar missions and eventual crewed flights to Mars.
The announcement arrives after Flight 11 on October 13 of last year, which concluded a busy 2025 testing campaign. Since then, SpaceX has focused on ground testing, including cryoproofing of Ship 39 and preparations for Booster 19, the first V3 Super Heavy.
Recent activities have involved static fires, activation of the new Pad 2 at Starbase in Boca Chica, Texas, and integration of Raptor 3 engines.
A prior incident with an early V3 booster on the test stand in late 2025 contributed to the delay, necessitating additional assembly and qualification work.
Musk’s timeline updates have become a hallmark of the Starship program, often described with characteristic optimism.
SpaceX’s Starship V3 is almost ready and it will change space travel forever
While past targets have occasionally shifted by weeks, the rapid iteration pace remains impressive. However, don’t be surprised if this timeline shifts again, as Musk has been overly optimistic in the past with not only launches, but products under his other companies, too.
SpaceX continues to refine launch infrastructure, including new propellant loading systems and tower mechanisms designed to support higher cadence operations. A successful V3 flight could pave the way for more frequent tests, tower catches of both booster and ship, and progression toward operational reusability.
The v3 debut is viewed as a transition point for Starship, moving beyond experimental flights toward a system capable of supporting large-scale deployment of Starlink satellites, lunar landers, and interplanetary transport.
Success on IFT-12 would demonstrate not only the new hardware’s performance but also SpaceX’s ability to recover from setbacks and maintain momentum.
As the 4-to-6-week countdown begins, anticipation builds at Starbase. Teams are finalizing vehicle stacking, conducting final pre-flight checks, and preparing for regulatory approvals. The world will be watching to see if Starship V3 can deliver on its promise of transforming humanity’s access to space.
Elon Musk
SpaceX to launch military missile tracking satellites through new Space Force contract
SpaceX wins a $178.5M Space Force contract to launch missile tracking satellites starting in 2027.
The U.S. Space Force awarded SpaceX a $178.5 million task order on April 1, 2026 to launch missile tracking satellites for the Space Development Agency. The contract, designated SDA-4, covers two Falcon 9 launches beginning in Q3 2027, one from Cape Canaveral Space Force Station in Florida and one from Vandenberg Space Force Base in California. The satellites, built by Sierra Space, are designed to bolster the nation’s ability to detect and track missile threats from orbit.
The award falls under the National Security Space Launch Phase 3 Lane 1 program, which Space Force uses to move payloads to orbit on faster timelines and at more competitive prices. “Our Lane 1 contract affords us the flexibility to deliver satellites for our customers, like SDA, more easily and faster than ever before to all the orbits our satellites need to reach,” said Col. Matt Flahive, SSC’s system program director for Launch Acquisition, in the official press release.
SpaceX is quietly becoming the U.S. Military’s only reliable rocket
The SDA-4 contract is the latest in a long string of national security wins for SpaceX. As Teslarati reported last month, the Space Force recently shifted a GPS III satellite launch from ULA’s Vulcan rocket to SpaceX’s Falcon 9 after a significant Vulcan booster anomaly grounded ULA’s military missions indefinitely. That move made it four consecutive GPS III satellites transferred to SpaceX after contracts were originally awarded to its competitor.
This didn’t come without a fight and dates back years. SpaceX originally had to sue the Air Force in 2014 for the right to compete for national security launches, at a time when United Launch Alliance held a near monopoly on the market. Since then, the company has steadily displaced ULA as the dominant provider, and last year the Space Force confirmed SpaceX would handle approximately 60 percent of all Phase 3 launches through 2032, worth close to $6 billion.
With missile defense satellites now part of its launch manifest alongside GPS, communications, and reconnaissance payloads, SpaceX is giving hungry investors something to chew on before its imminent IPO.
Elon Musk calls out $2 trillion SpaceX IPO valuation as ‘BS’
Elon Musk reveals date of SpaceX Starship v3’s maiden voyage
