News
Ex-SpaceX engineer leads Stratolaunch to major rocket engine test milestone
Led by rocket propulsion expert Jeff Thornburg, Stratolaunch – famous for owning the largest fixed-wing aircraft ever built – has completed the first hot-fire test of a full-scale rocket engine component known as the preburner, a major milestone in the development of any launch vehicle or propulsion system.
Despite the significant size and power of the component, destined to support an engine that will generate 200,000 pounds (~900 kN) of thrust, Thornburg and his team of engineers and technicians have managed to go from designing the preburner to successfully hot-firing a full-scale test article, an extraordinary achievement by any measure.
The team made amazing progress this week! Check out the #PGAEngine preburner’s first hot-fire test at @NASAStennis. #NewUSEngine pic.twitter.com/kKTnf0bj1S
— Stratolaunch (@Stratolaunch) November 6, 2018
Aside from SpaceX, Blue Origin, and Aerojet-Rocketdyne, Stratolaunch is the only private entity developing – let alone testing full-scale parts for – a liquid-fueled rocket engine as large as PGA. Shorthand for the Stratolaunch’s late founder and bankroller Paul G. Allen, PGA is a fuel-rich staged combustion cycle engine that uses liquid hydrogen and oxygen (hydrolox) fuel and oxidizer, typically resulting in high efficiency. In terms of scale and thrust, PGA is very closely comparable to SpaceX’s Merlin 1D engine, which uses kerosene instead of hydrogen but produces roughly 190,000 lbf (850 kN) of thrust and stands 4 feet (1.2m) wide and ~10 feet (~3m) tall.
Another major difference between PGA and Merlin 1D is the fact Merlin 1D’s nozzle is largely optimized for sea level while PGA is being built for a rocket that will be “launched” from a massive plane flying around 35,000 feet (~10.5 km), ultimately resulting in a nozzle that is much wider and longer, featuring nearly the same proportions as fully vacuum-optimized engines like SpaceX’s MVac. By widening the nozzle relative to the rest of the engine, rocket engines are able to operate far more efficiently at higher altitudes, where Earth’s atmosphere thins and exerts less pressure on the escaping exhaust gases. This is visualized well by the visible expansion of rocket exhausts during launches, morphing from a straight cylinder to a massive teardrop-shaped plume. At lower altitudes (and thus higher atmospheric pressures), wider nozzles can produce extreme turbulence and will ultimately shake themselves to destruction, preventing their usage on ground-launched rocket boosters.
Judging from official renders of the engine, PGA’s in-atmosphere variant appears to utilize a form of regenerative nozzle cooling very similar to that used on M1D, where liquid propellant flows through thin capillaries sandwiched between two or more layers of metal to cool the nozzle much like cold water chills the skin of an uninsulated water bottle.
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- A to-scale comparison of Falcon 1, Pegasus XL, MLV, and Falcon 9. (Teslarati/Stratolaunch/Wikipedia)
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- A render of Stratolaunch’s impressive PGA engine. Note the giant nozzle relative to the throat. (Stratolaunch)
Testing rocket engine preburners
In the case of staged combustion cycle hydrolox rocket engines, a small portion of liquid oxygen and all of the liquid hydrogen (hence “fuel-rich”) are mixed and combusted to generate hot gas that then spools up the engine’s primary turbopump(s), ultimately drawing fuel and oxidizer into the combustion quickly enough to ignite the engine and generate sustained thrust. The components that get those main turbopumps started are known collectively as the preburner, which is what Stratolaunch successfully tested – at full-scale – for the first time ever last week. For any liquid rocket engine that cannot solely rely on propellant tank pressure to deliver fuel to the combustion chamber, full-scale tests of preburners or gas-generators effectively mark the moment that engines truly become real.
“This is the first step in proving the performance and highly efficient design of the PGA engine. The hot-fire test is an incredible milestone for both the propulsion team and Stratolaunch.” – Jeff Thornburg, VP of Propulsion, Stratolaunch
Stratolaunch’s propulsion team will continue to test the preburner for longer durations and at higher power levels over the next several months, likely optimizing operations and tweaking or upgrading the preburner’s hardware as real tests produce valuable lessons-learned. Built entirely with additive manufacturing (3D printing), the team should be able to rapidly iterate on the physical design of the engine, a rarity in a field where traditional fabrication methods can take weeks or months to produce complex turbomachinery components with mercilessly strict tolerances.
According to Thornburg, the ultimate goal is to continue that additive-manufacturing-only strategy throughout the development of this rocket engine, theoretically enabling unprecedented design flexibility while also slashing production time throughout. PGA will ultimately power the creatively-named Medium Launch Vehicle (MLV), a small-ish air-launched rocket designed to place a respectable 3400 kg into low Earth orbit (LEO) as early as 2022, as well as a Heavy version of MLV and, potentially, a reusable spaceplane somewhere down the line.
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- PGA’s first full-scale preburner seen during assembly. (Stratolaunch)
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- PGA’s first full-scale preburner seen during assembly. (Stratolaunch)
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- Jeff Thornburg stands in front of Stratolaunch’s NASA Stennis Space Center test stand. (Stratolaunch)
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- The PGA preburner seen after installation at Stennis. (Stratolaunch)
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- The control center. (Stratolaunch)
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- MLV is released from Stratolauncher. (Stratolaunch)
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- A concept video produced by Stratolaunch shows the Roc launching a Kraken rocket. (Stratolaunch, via Wired)
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Elon Musk
Elon Musk hints Tesla investors will be rewarded heavily
“Hold onto your Tesla stock. It’s going to be worth a lot, I think. That’s my bet,” Musk said.
Elon Musk recently hinted that he believes Tesla investors will be rewarded heavily if they continue to hold onto their shares, and he reiterated that in a new interview that the company released on its social accounts this week.
Musk is one of the most successful CEOs in the modern era and has mammothed competitors on the Forbes Net Worth List over the past year as his holdings in his various companies have continued to swell.
Tesla investors, especially those who have been holding shares for several years, have also felt substantial gains in their portfolios. Over the past five years, the stock is up over 78 percent. Since February 2019, nearly seven years ago to the day, the stock is up over 1,800 percent.
Musk said in the interview:
“Hold onto your Tesla stock. It’s going to be worth a lot, I think. That’s my bet.”
Elon Musk in new interview: “Hold on to your $TSLA stock. It’s going to be worth a lot, I think. That’s my bet.” pic.twitter.com/cucirBuhq0
— Sawyer Merritt (@SawyerMerritt) February 26, 2026
It’s no secret Musk has been extremely bullish on his own companies, but Tesla in particular, because it is publicly traded.
However, the company has so many amazing projects that have an opportunity to revolutionize their respective industries. There is certainly a path to major growth on Wall Street for Tesla through its various future projects, including Optimus, Cybercab, Semi, and Unsupervised FSD.
- Optimus (Tesla’s humanoid robot): Musk has discussed its potential for tasks like childcare, walking dogs, or assisting elderly parents, positioning it as a massive long-term driver of company value.
- Cybercab (Tesla’s robotaxi/autonomous ride-hailing vehicle): a fully autonomous vehicle geared specifically for Tesla’s ride-sharing ambitions.
- Semi (Tesla’s electric truck, with mentions of expansion, like in Europe): brings Tesla into the commercial logistics sector.
- Unsupervised FSD (Full Self-Driving software achieving full autonomy without human supervision): turns every Tesla owner’s vehicle into a fully-autonomous vehicle upon release
These projects specifically are some of the highest-growth pillars Tesla has ever attempted to develop, especially in Musk’s eyes, as he has said Optimus will be the best-selling product of all-time.
Many analysts agree, but the bullish ones, like Cathie Wood of ARK Invest, are perhaps the one who believes Tesla has incredible potential on Wall Street, predicting a $2,600 price target for 2030, but this is not even including Optimus.
She told Bloomberg last March that she believes that the project will present a potential additive if Tesla can scale faster than anticipated.
Cybertruck
Tesla drops latest hint that new Cybertruck trim is selling like hotcakes
According to Tesla’s Online Design Studio, the new All-Wheel-Drive Cybertruck will now be delivered in April 2027. Earlier orders are still slated for early this Summer, but orders from here on forward are now officially pushed into next year:
Tesla’s new Cybertruck offering has had its delivery date pushed back once again. This is now the second time, and deliveries for the newest orders are now pushed well into 2027.
According to Tesla’s Online Design Studio, the new All-Wheel-Drive Cybertruck will now be delivered in April 2027. Earlier orders are still slated for early this Summer, but orders from here on forward are now officially pushed into next year:
🚨 Tesla has updated the $59,990 Cybertruck Dual Motor AWD’s estimated delivery date to April 2027.
First deliveries are still slated for June, but if you order it now, you’ll be waiting over a year.
Demand appears to be off the charts for the new Cybertruck and consumers are… pic.twitter.com/raDCCeC0zP
— TESLARATI (@Teslarati) February 26, 2026
Just three days ago, the initial delivery date of June 2026 was pushed back to early Fall, and now, that date has officially moved to April 2027.
The fact that Tesla has had to push back deliveries once again proves one of two things: either Tesla has slow production plans for the new Cybertruck trim, or demand is off the charts.
Judging by how Tesla is already planning to raise the price based on demand in just a few days, it seems like the company knows it is giving a tremendous deal on this spec of Cybertruck, and units are moving quickly.
That points more toward demand and not necessarily to slower production plans, but it is not confirmed.
Tesla Cybertruck’s newest trim will undergo massive change in ten days, Musk says
Tesla is set to hike the price on March 1, so tomorrow will be the final day to grab the new Cybertruck trim for just $59,990.
It features:
- Dual Motor AWD w/ est. 325 mi of range
- Powered tonneau cover
- Bed outlets (2x 120V + 1x 240V) & Powershare capability
- Coil springs w/ adaptive damping
- Heated first-row seats w/ textile material that is easy to clean
- Steer-by-wire & Four Wheel Steering
- 6’ x 4’ composite bed
- Towing capacity of up to 7,500 lbs
- Powered frunk
Interestingly, the price offering is fairly close to what Tesla unveiled back in late 2019.
Elon Musk
Elon Musk outlines plan for first Starship tower catch attempt
Musk confirmed that Starship V3 Ship 1 (SN1) is headed for ground tests and expressed strong confidence in the updated vehicle design.
Elon Musk has clarified when SpaceX will first attempt to catch Starship’s upper stage with its launch tower. The CEO’s update provides the clearest teaser yet for the spacecraft’s recovery roadmap.
Musk shared the details in recent posts on X. In his initial post, Musk confirmed that Starship V3 Ship 1 (SN1) is headed for ground tests and expressed strong confidence in the updated vehicle design.
“Starship V3 SN1 headed for ground tests. I am highly confident that the V3 design will achieve full reusability,” Musk wrote.
In a follow-up post, Musk addressed when SpaceX would attempt to catch the upper stage using the launch tower’s robotic arms.
“Should note that SpaceX will only try to catch the ship with the tower after two perfect soft landings in the ocean. The risk of the ship breaking up over land needs to be very low,” Musk clarified.
His remarks suggest that SpaceX is deliberately reducing risk before attempting a tower catch of Starship’s upper stage. Such a milestone would mark a major step towards the full reuse of the Starship system.
SpaceX is currently targeting the first Starship V3 flight of 2026 this coming March. The spacecraft’s V3 iteration is widely viewed as a key milestone in SpaceX’s long-term strategy to make Starship fully reusable.
Starship V3 features a number of key upgrades over its previous iterations. The vehicle is equipped with SpaceX’s Raptor V3 engines, which are designed to deliver significantly higher thrust than earlier versions while reducing cost and weight.
The V3 design is also expected to be optimized for manufacturability, a critical step if SpaceX intends to scale the spacecraft’s production toward frequent launches for Starlink, lunar missions, and eventually Mars.
Elon Musk hints Tesla investors will be rewarded heavily
Tesla drops latest hint that new Cybertruck trim is selling like hotcakes
