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.
- A to-scale comparison of Falcon 1, Pegasus XL, MLV, and Falcon 9. (Teslarati/Stratolaunch/Wikipedia)
- 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.
- PGA’s first full-scale preburner seen during assembly. (Stratolaunch)
- PGA’s first full-scale preburner seen during assembly. (Stratolaunch)
- Jeff Thornburg stands in front of Stratolaunch’s NASA Stennis Space Center test stand. (Stratolaunch)
- The PGA preburner seen after installation at Stennis. (Stratolaunch)
- The control center. (Stratolaunch)
- MLV is released from Stratolauncher. (Stratolaunch)
- A concept video produced by Stratolaunch shows the Roc launching a Kraken rocket. (Stratolaunch, via Wired)
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Investor's Corner
Tesla Optimus is already benefiting investors, top Wall Street firm says
Piper Sandler has updated its detailed valuation model for Tesla (NASDAQ: TSLA), concluding that at recent share prices around $400–$420, investors are essentially acquiring the company’s ambitious Optimus humanoid robot project at no extra cost.
Tesla Optimus is already benefiting investors from a fiscal standpoint, at least that is what Alexander Potter at Piper Sandler, a top Wall Street firm covering the company, says.
Piper Sandler has updated its detailed valuation model for Tesla (NASDAQ: TSLA), concluding that at recent share prices around $400–$420, investors are essentially acquiring the company’s ambitious Optimus humanoid robot project at no extra cost.
Analyst Alexander Potter, in the firm’s latest “Definitive Guide to Investing in Tesla,” built a comprehensive framework covering 17 separate product lines.
This granular approach values Tesla’s core businesses—including electric vehicles, energy storage, Full Self-Driving (FSD) software, in-house insurance, Supercharging network, and a standalone robotaxi operation—at approximately $400 per share, without assigning any value to Optimus or related inference-as-a-service opportunities.
“At $400/share, we think investors can buy Optimus for ‘free,’” Potter stated in the note. Piper Sandler maintained its Overweight rating on Tesla shares and a $500 price target, which implicitly attributes roughly $100 per share to the robot-related businesses— a figure the analyst views as potentially conservative.
The updated model incorporates elements often overlooked by other sell-side analysts, such as detailed forecasts for Tesla’s insurance operations, Supercharger revenue, and a distinct valuation for the robotaxi business separate from FSD software licensing. It also accounts for Tesla’s 2025 CEO compensation plan for the first time.
Potter acknowledged that his estimates for 2026 and 2027 fall below Wall Street consensus, citing factors like declining deliveries from certain discontinued models and reduced regulatory credit income.
However, he expressed limited concern, noting that traditional vehicle delivery metrics are expected to matter less over time as FSD subscriber growth and robotaxi deployment metrics gain prominence. On Optimus specifically, Potter suggested the humanoid robot program, combined with inference services, “arguably will be worth more than Tesla’s other businesses combined,” though the firm has not yet produced formal long-term forecasts for these segments.
Tesla shares have traded near the $400 range in recent sessions, reflecting ongoing investor focus on the company’s autonomous driving progress and expansion into robotics and AI. The Optimus project remains in early development stages, with Tesla aiming to deploy the robots initially for internal factory tasks before broader commercial applications.
This Piper Sandler analysis highlights the growing emphasis among some investors and analysts on Tesla’s long-term technology platform potential beyond its current automotive and energy businesses.
As with any forward-looking valuation, outcomes will depend on execution timelines, technological breakthroughs, regulatory approvals for autonomous systems, and market adoption of humanoid robotics—areas that carry significant uncertainty and execution risk.
The note underscores a common theme in Tesla coverage: differing views on how to quantify emerging high-growth opportunities like robotics within the company’s overall enterprise value. Investors are advised to consider their own risk tolerance and conduct thorough due diligence regarding these speculative elements.
News
Tesla Giga Texas buzzing as new Cybertruck appears to enter production
Additionally, the Cybercab manufacturing ramp-up is continuing amidst Tesla’s busy May, which includes a handful of things from an automotive perspective.
Tesla Giga Texas is buzzing with a lot of action, as it appears the new Cybertruck trim that was offered a few months back has entered production. Additionally, the Cybercab manufacturing ramp-up is continuing amidst Tesla’s busy May, which includes a handful of things from an automotive perspective.
Drone operator Joe Tegtmeyer captured striking footage over Giga Texas on the morning of May 11, 2026, revealing fresh batches of Cybertrucks that may mark the start of series production for the long-awaited $59,990 Dual Motor AWD variant.
Tesla launches new Cybertruck trim with more features than ever for a low price
The vehicles lined up in staging areas, and we got a great look at three of the units parked on the property:
Hard to say for sure, but production of the $59K AWD @Cybertruck may be just getting started here on this early and soggy morning at Giga Texas … this version is much harder to visually distinguish from the premium AWD versions, so I’ll come back on Wednesday and we’ll see if… pic.twitter.com/UX7yCQpgeC
— Joe Tegtmeyer 🚀 🤠🛸😎 (@JoeTegtmeyer) May 11, 2026
Tegtmeyer notes the difficulty in visually distinguishing this base AWD model from higher-trim versions, unlike the earlier Long-Range RWD that lacked a motorized tonneau cover.
Tesla launched the $59,990 Dual Motor AWD Cybertruck in late February 2026 with a brief introductory pricing window that closed by month’s end.
Initial U.S. delivery estimates of June 2026 quickly slipped to September–October and, for newer orders, as far as April 2027.
The move underscores robust consumer interest in a more accessible all-wheel-drive Cybertruck priced under $60,000 before incentives—positioning it as a volume play for Tesla’s electric pickup lineup while premium AWD and Cyberbeast variants continue to be sold as usual.
Meanwhile, Cybercab production at the same Austin facility shows steady, if deliberate, progress. Tegtmeyer’s latest flyover documented dozens of glossy production-spec Cybercabs parked in the outbound lot—consistent with Tesla’s early statements that initial output would remain modest before scaling later in 2026.
The purpose-built robotaxi, unveiled in 2024 and lacking a steering wheel or pedals, rolled its first unit off the line in February. Volume manufacturing began in April, with early examples already undergoing autonomous testing around the factory grounds.
Elon Musk has repeatedly emphasized that Cybercab and Semi production will start slowly before ramping “exponentially” toward year-end. The presence of multiple finished units signals Tesla’s Unboxed manufacturing process is maturing, even as the company balances Cybertruck output with autonomy milestones.
Recent drone imagery also shows ongoing construction for Optimus and test-track expansions, highlighting Giga Texas’s evolving role as Tesla’s hub for next-generation vehicles.
For Cybertruck buyers, the potential ramp of the $59K AWD offers hope of shorter waits and broader market access. For autonomy enthusiasts, the growing fleet of Cybercabs hints at robotaxi service trials on the horizon.
While official confirmation from Tesla remains pending, Tegtmeyer’s footage provides the clearest public signal yet that both programs are advancing in parallel at Giga Texas.
News
Tesla Full Self-Driving gains momentum in Europe with new country mulling approval
Tesla is advancing FSD’s technology across Europe with fresh talks underway in Ireland, signaling broader regulatory progress. On May 10, Ireland’s Department of Transport confirmed that Tesla is actively engaging with national authorities, including the National Standards Authority of Ireland (NSAI) to secure approval for FSD Supervised.
Tesla Full Self Driving (FSD) technology is gaining momentum in Europe, with yet another new country mulling a potential approval for operation on its roads.
Tesla is advancing FSD’s technology across Europe with fresh talks underway in Ireland, signaling broader regulatory progress. On May 10, Ireland’s Department of Transport confirmed that Tesla is actively engaging with national authorities, including the National Standards Authority of Ireland (NSAI) to secure approval for FSD Supervised.
While the department noted that full rollout in Ireland would ultimately depend on EU-level clearance, the engagement marks a notable step forward in Tesla’s European expansion strategy, Irish media outlet RTE said.
The news comes on the heels of a landmark breakthrough in the Netherlands. In April, Dutch vehicle authority RDW granted the first-ever EU type approval for FSD Supervised after 18 months of rigorous testing on public roads and tracks. The provisional approval allows the system on all Dutch roads, with Tesla already rolling it out to select owners following mandatory safety training.
The Netherlands has since notified the European Commission and is advocating for wider recognition, positioning the Dutch decision as a potential template for the bloc.
Europe has long lagged behind the United States, China, and other markets where FSD is more widely available. Strict EU regulations on automated driving systems have required extensive validation, but momentum is building.
Tesla now lists the Netherlands alongside established markets such as the U.S., Canada, Australia, and South Korea on its regional FSD page. Other countries, including Belgium, are reportedly fast-tracking their own review processes in response to the Dutch precedent.
Analysts see Ireland’s involvement as strategic. As a smaller EU member with unique road challenges—narrow rural lanes, hedgerows, and variable weather—successful validation there could demonstrate FSD’s adaptability and strengthen the case for harmonized EU approval.
Tesla has indicated it aims for broader EU deployment as early as summer 2026, though the timeline remains fluid. Discussions at the EU’s Technical Committee on Motor Vehicles continue, with a possible vote later in the year. Some member states, particularly in Scandinavia, have expressed reservations over edge cases like speeding protocols and long-term safety data.
For Tesla, European expansion is more than a software update; it unlocks significant growth. The continent’s dense population and high vehicle ownership could accelerate data collection, refine the AI models powering FSD, and pave the way for unsupervised autonomy and robotaxi services.
Owners stand to benefit from enhanced safety features and reduced driver fatigue, while regulators weigh innovation against proven risk reduction. Early Dutch results already cite safety improvements:
Tesla Full Self-Driving shows stunning maneuver in Europe to silence skeptics
But the work is far from done, and challenges are still present. FSD Supervised still requires driver attention and a readiness to intervene. EU rules emphasize that the technology is not fully autonomous, placing legal responsibility on the human operator. Tesla must also navigate varying national road conditions and public perception.
Nevertheless, the Ireland talks underscore a clear trajectory: one national approval at a time, Europe is inching closer to widespread FSD access. If the Dutch model gains traction, Summer 2026 could mark the beginning of a transformative chapter for autonomous driving on European roads.
Tesla’s persistent engagement with regulators is starting to pay off, and it suggests the company is still heavily committed to the expansion efforts across Europe, despite the red tape it has had to persist through.








