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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.

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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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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.

 

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.

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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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FAA kicks off review of SpaceX’s bid to fly Starship nearly every day

FAA is reviewing SpaceX’s plan for 456 Starship launches a year, up from 25 today.

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1 hour ago

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October 14, 2026

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Rendering of Elon Musk overlooking a Starship fleet (Credit: Grok)

The FAA said Tuesday that it will prepare an environmental impact statement on SpaceX’s proposal to run as many as 456 Starship launches and 912 landings a year from Starbase, Texas. SpaceX is currently authorized for 25 launches and 50 landings annually, which makes the request roughly 18 times the existing ceiling. The notice of intent is set to publish in the Federal Register on Wednesday.

The plan comes in two phases. Phase 1 would allow up to 100 launches and 200 landings a year, on any day and at any hour. Phase 2, which the FAA says could arrive within several years, would raise the limit to the full 456 launches, still at any hour but only on weekdays. The agency noted that 912 landings is the upper limit for the Texas facility no matter where a given mission begins, and that Starship and Super Heavy could come down at the launch site or in the Gulf and open ocean.

A draft statement will be released for public comment at a later date, and the FAA has not said when. According to the Federal Registar, written comments are due November 30 on regulations.gov under docket FAA-2026-12808, with in person scoping meetings on November 17 in Brownsville and November 19 in Port Isabel, plus a virtual session on November 18. The review will weigh air quality, wildlife, coastal resources, water, noise, and aviation, and the FAA said any increase beyond this proposal would need its own separate review.

The numbers look large next to what Starbase has actually done. Starship has flown three times from Texas this year, including Flight 14 on September 28, the first orbital flight, which deployed 26 Starlink V3 satellites. Bloomberg reported that Starbase has never launched more than five times in a calendar year. The current cap of 25 comes from an FAA approval in May 2025. In February, the agency also approved up to 44 Starship launches a year from Launch Complex 39A in Florida, so Phase 1 in Texas alone would more than double that allowance.

Musk has said Starship could eventually fly more than once per hour within less than a decade, per Bloomberg. The nearer term target is Flight 15. Musk said on October 10 that it is hopefully four to six weeks away and will try to catch the ship with the tower, as Teslarati covered. That flight still runs under the existing 25 launch limit, and so would every Starbase launch for as long as the new review takes.

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As of mid morning Pacific time on Tuesday, SpaceX had not posted about the filing on its own account.

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Tesla Roadster livestream: everything Tesla has revealed before Thursday night

Tesla will stream the Roadster event Thursday at 7:55 p.m. Central. Here is what’s known.

Published

10 hours ago

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October 13, 2026

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Concept rendering of a Tesla Roadster with SpaceX Package via Grok

Tesla will stream its next generation Roadster event live this Thursday, October 15, at 7:55 p.m. Central, according to a post from the official Tesla account shared late Monday. Texas is on daylight time, and outlets have read the post as local Central time, which puts the Tesla Roadster livestream at 8:55 p.m. Eastern and 5:55 p.m. Pacific. The stream is expected on Tesla’s X account, where the announcement went up.

This is the second date for the event. Tesla posted a “Go for launch” image on September 12 that set the unveil for October 1, and invitations sent to reservation holders placed it in Waco, Texas, at 8:30 p.m. Eastern, for guests 21 and older with tickets that could not be transferred. Until this week, Tesla had not said the event would be broadcast at all.

On September 28, Tesla moved the event to October 15, citing severe weather and the fact that the demo can only be held outdoors. Elon Musk then said the cause was high winds, a comment that pushed speculation that the car will leave the ground on stage.

The event will be held in Waco, which sits close to SpaceX’s McGregor rocket test site, where the FAA closed airspace up to 10,000 feet from September 18 through October 2 for the original date. Another restriction covering Wednesday, October 14, has been reported near the site, which could mean a rehearsal, though that is unconfirmed.

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What Tesla will actually show comes from speculative reports that the vehicle will be unmanned, and spectators will be kept several hundred yards back for safety. A SpaceX package is reportedly code named A71, and linked to what Musk has hinted at in the past – thrusters that could bring 0 to 60 mph down to about one second, compared with the 1.9 seconds quoted for the base car in 2017. Tesla also closed its Semi event with a Roadster teaser suggesting a design that looks different from the original prototype, and has said the event will include pricing, specifications, and production targets.

The 2017 figures remain the only official ones: 620 miles of range, a top speed above 250 mph, and prices of $200,000 for the base car and $250,000 for the Founders Series. Tesla reopened reservations last month with a $5,000 card payment followed by a $45,000 wire within ten days, and the deposit is refundable. Production is expected at Giga Texas in 2027 or 2028.

Tesla reports third quarter earnings on October 21, six days after the stream, so whatever price or timeline appears Thursday night will land just ahead of that call.

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Elon Musk

SpaceX just combined Grok, Cursor, and X into one mega plan

SpaceXSI merges Grok, Cursor, and X Premium into one plan, raising questions for Tesla owners.

Published

20 hours ago

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October 13, 2026

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SpaceX Super Intelligence has rolled out The X Subscription, a single plan that combines Grok, Grok Bot, Cursor, and X Premium.

There are five levels, including a free plan that includes daily Grok access and a starter allowance for Cursor’s coding agents. Plus is $8 per month, Premium is $30, Super is $100, and Ultra is $200. Usage scales as you move up, with Premium offering four times the Plus allowance, Super 15 times, and Ultra 50 times. Annual billing brings the prices down a bit further, with Premium at $300 per year.

The $30 Premium tier is where SpaceXSI says it packs the benefits of SuperGrok, Cursor Pro, and X Premium+, which previously added up to $90 per month. Grok Bot, the agent that handles tasks like ordering food or managing a calendar, is included from Premium upward but not on Plus. Paid plans share one weekly usage pool across Grok and Cursor, and each plan includes at least twice the coding usage of the comparable Cursor plan. Third party models in Cursor remain available on Premium and above, but they are billed separately at API list prices.

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That last detail matters because of what has happened around Cursor this year. SpaceX exercised its option to buy the company for $60 billion in June, and the deal closed in August. Weeks later, OpenAI said it will cut Cursor’s access to its models on November 12. Bundling Cursor with Grok usage gives SpaceXSI a reason to steer developers toward its own models.

Tesla integrates Grok Bot into its vehicles for the ultimate personal assistant

For Tesla owners, the connection is Grok Bot. Tesla brought it into its vehicles last month, and at that point access inside the car was limited to SuperGrok Heavy subscribers. Grok Bot is now enabled across every Cybercab and the rest of the Model Y Robotaxi fleet. Neither SpaceXSI nor Tesla has said how the new plans change inside the car access for owners, or whether a $30 Premium subscription now covers Grok Bot in a personal Tesla. That is the question owners will want answered first.

The company is also changing its name along the way. The rollout follows the rebrand Musk announced on October 4, when he said SpaceXAI would become SpaceXSI, and the plan page now carries that branding.

The X Subscription is available to new customers starting now, and SpaceXSI says it will reach everyone globally over the next few days. Existing SuperGrok, Cursor, and X Premium subscribers do not have to switch. The option to move will appear gradually in billing settings, with a prorated refund for the unused time on the old plan. Switching is permanent once the accounts are unified, and old plans are closed to new sign ups.

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