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Ex-SpaceX engineer leads Stratolaunch to major rocket engine test milestone

Stratolaunch has successfully completed the first full-scale test of its 200,000-lbf thrust PGA rocket engine. (Stratolaunch)

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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.

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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.

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.

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“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.

 


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!

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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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I figured out how to charge my Tesla at my rented townhouse – Here’s how

I hope that this article is able to help the prospective EV buyer or the current Tesla owner who is living in a rental and does not have a straightforward solution to home charging. My situation will be presented in this article, and I will tell you why I went with the solution I went with, and alternatives, because there is more than one way to do this.

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When I bought my Tesla Model Y Premium All-Wheel-Drive last year, I knew I would have to try to figure out a way not become totally reliant on Superchargers. After about six months of ownership, it came time to resolve that problem once and for good, and being a tenant in a rented townhouse community definitely added to my challenge.

Before I even bought my Tesla, I emailed my leasing office to see if the community had any plans to bring EV charging to the neighborhood. I had made myself available to them as I am familiar with a lot of the solutions out there and how much of an advantage this could be for the community, and attracting new tenants. After months of trying, I bought my Tesla in August anyway, and figured I’d be able to find an answer — whether positive or negative — and go from there.

I hope that this article is able to help the prospective EV buyer or the current Tesla owner who is living in a rental and does not have a straightforward solution to home charging. My situation will be presented in this article, and I will tell you why I went with the solution I went with, and alternatives, because there is more than one way to do this.

My Challenge with Home Charging

In a rental community, apartment complex, or even townhouse row, parking spots are a little complicated. I have assigned parking at my house, and unfortunately, my parking spot is not right in front of my front door. Instead, it is staggered, so my car is parked in front of my neighbor’s front door.

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Initially, I had spoken to my neighbor whose spot is right in front of my front door and had gotten permission to park in their spot during the day while it is vacant. However, I was not going to be able to upgrade my outlet from a 110v-120v to the typical and suggested 220v-240v alternative.

I knew that this would mean I would need to be in my permanent spot because charging sufficiently, especially in preparation for trips or errands, would require overnight charging.

The Tesla Mobile Connector is 20 feet long, which is sufficient for most applications. Mine, however, required about 30 feet, maybe even a little more, to charge.

My Options

I had a few options: Use the Mobile Connector and park in my neighbor’s spot and charge when I could, buy an 8 or 10-gauge extension cord that could handle moving power from the Mobile Connector to my car, or buy an NACS to NACS extension cord.

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I didn’t really want to do the first option, considering I knew that spot would only be available when my neighbor was not there. It didn’t seem like a viable option, and I figured it would be better to figure out something from my personal, permanent parking spot anyway.

The 10-gauge extension cord option was what I first considered: it was less expensive than buying an NACS extension, it was more readily available, and it was the first thing my friends who are electricians recommended.

However, running this option would have put the Mobile Connector in the grass or on the ground, and I was not interested in doing that. Running the risk of having that $300 connector that came with the car in the grass and exposing it to dew, dogs, and various other things just did not seem like the best idea.

I looked around for some NACS to NACS connectors, and there are a lot of options. Given that this was something that was going to plug into a $50,000 car, I chose to spend the additional money on one that was not from Amazon, and I went with this one from A2Z, which was recommended by other owners, and their reputation seemed more than positive. I was leaning toward this option anyway because it would keep the Mobile Connector off the ground, and it gave me an additional 16 feet of length to work with.

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This was the solution.

Putting It Into Action

It was a relatively simple process: Plug the Mobile Connector into my house, plug the NACS to NACS extension into the Mobile Connector, plug the NACS extension into the car. It all worked immediately, but there are some things you should know if you are also planning to do this.

The first is that you should be very aware that these cables are going to be a target of thieves. I don’t have too much of an issue with this in my area, but if you’re in a place where copper wiring is heavily sought after, be sure to keep these in a place where they won’t be stolen. I put mine away when they’re not charging, and at night, they’re visible from my Ring camera, so I’m not overly concerned. Definitely be aware of it, though.

Additionally, if you’re going to run it across the sidewalk like I am, you’re going to want to pick up some sort of cable cover from a local hardware store. I picked up this one from Amazon because it was a little more heavy-duty, and it was big enough to cover the thicker gauge of the NACS to NACS extension:

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I’ve considered picking up a second one for the visible cable, but I am undecided.

So far, I’ve been able to add some range to my car three times using this strategy, and while it is very slow, it is definitely worth it. It’s better than it sitting there stagnant.

Speed of Charging

Tesla says the Mobile Connector will provide you with between 3 and 5 miles of range per hour when plugged into a typical wall outlet. That is about what I’ve gotten with it. From 30 percent to 80 percent, be aware that it will take well over 24 hours to charge your car.

I plan to cover some additional details on this as time goes on, including any troubleshooting I might have to do, how much my electric bill goes up, and whether or not I run into any issues with my neighbors or my leasing office.

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If you’re looking for some help on an at-home charging solution or have any questions about my setup, please email me at joey@teslarati.com.

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Starlink V2 to bring satellite-to-phone service to Deutsche Telekom in Europe

Starlink stated that the system is designed to deliver 5G speeds directly to compatible smartphones in remote areas.

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Credit: Deutsche Telekom/X

Starlink is partnering with Deutsche Telekom to roll out satellite-to-mobile connectivity across Europe, extending coverage to more than 140 million subscribers across 10 countries.

The service, planned for launch in 2028 in several Telekom markets, including Germany, will use Starlink’s next-generation V2 satellites and Mobile Satellite Service (MSS) spectrum to enable direct-to-device connectivity.

In a post on X, the official Starlink account stated that the agreement will be the first in Europe to deploy its V2 next-generation satellite-to-mobile technology using new MSS spectrum. The company added that the system is designed to deliver 5G speeds directly to compatible smartphones in remote areas.

Abdu Mudesir, Board Member for Product and Technology at Deutsche Telekom, shared his excitement for the partnership in a press release. “We provide our customers with the best mobile network. And we continue to invest heavily in expanding our infrastructure. At the same time, there are regions where expansion is especially complex due to topographical conditions or official constraints,” he said.

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“We want to ensure reliable connectivity for our customers in those areas as well. That is why we are strategically complementing our network with satellite-to-mobile connectivity. For us, it is clear: connectivity creates security and trust. And we deliver. Everywhere.”

Under the partnership, compatible smartphones will automatically switch to Starlink’s satellite network when terrestrial coverage is unavailable, enabling access to data, voice, video, and messaging services.

Telekom reports 5G geographic coverage approaching 90% in Germany, with LTE exceeding 92% and voice coverage reaching up to 99%. Starlink’s satellite layer is intended to extend connectivity beyond those terrestrial limits, particularly in topographically challenging or infrastructure-constrained areas.

Stephanie Bednarek, VP of Starlink Sales, also shared her thoughts on the partnership. “We’re so pleased to bring reliable satellite-to-mobile connectivity to millions of people across 10 countries in partnership with Deutsche Telekom. This agreement will be the first-of-its-kind in Europe to launch Starlink’s V2 next-generation technology that will expand on data, voice and messaging by providing broadband directly to mobile phones,” she said. 

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Starlink’s V2 constellation is designed to expand bandwidth and capacity compared to its predecessor. If implemented as outlined, the 2028 launch would mark one of the first large-scale European deployments of integrated satellite-to-phone connectivity by a major telecom operator.

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Tesla back on top as Norway’s EV market surges to 98% share in February

Tesla became Norway’s top-selling brand with 1,210 registrations, representing a 16.6% share.

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Credit: Grok Imagine

Tesla reclaimed the top spot in Norway’s auto market in February as electric vehicles captured more than 98% of all new car registrations.

The rebound follows a sharp January slump triggered by VAT rule changes, which prompted numerous car buyers to advance their purchases into late 2025.

As per data from the Norwegian Road Traffic Information Council (OFV), 7,127 new electric vehicles were registered in February, representing a 98.01% market share. Fossil-fuel vehicles and hybrids accounted for just 2% of total new registrations.

Total new car registrations reached 7,272 units in February, hinting at a rapid recovery after January sales fell nearly 75% year-over-year following VAT adjustments.

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OFV Director Geir Inge Stokke noted that similar patterns were observed after previous VAT changes in 2022, with demand temporarily weakening before normalizing, as noted in an Allt Om Elbil report. 

“We are now seeing signs that the market is returning to a more normal level of activity, which we also experienced after the VAT change in 2022. At that time, changes in demand led to a weak start to 2023. We have seen the same pattern this year,” he said. 

Amidst this trend, the Tesla Model Y made a strong comeback in the domestic market. After an unusually weak January that saw the Tesla Model Y drop to seventh place, the model returned to the top of Norway’s sales chart in February.

The Model Y recorded 1,073 registrations, giving it a 14.8% market share for the month. Tesla also became Norway’s top-selling brand with 1,210 registrations, representing a 16.6% share. Toyota followed with 941 registrations, while Volkswagen, Volvo, and Skoda rounded out the top five brands.

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The February data suggests that Tesla’s January dip was tied more to timing effects around VAT adjustments than to structural demand shifts. It would then be interesting to see how the rest of the year unfolds for Tesla, particularly as the company pushes for the release of its Full Self-Driving (Supervised) system to Europe this year. 

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