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SpaceX’s Starship Raptor Vacuum engine plans laid out by CEO Elon Musk

A 2016 render of Raptor Vacuum. Much has changed about the engine's design in the three years since, but SpaceX is still pursuing a vacuum variant. (SpaceX)

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Elon Musk says that SpaceX Starship engine upgrades are on track to begin static fire tests of a Raptor Vacuum variant as few as a “couple months” from now.

Designed to enable more efficient performance in thin atmosphere or vacuum, Musk admitted that the first version(s) of Raptor Vacuum (RVac) will likely be a compromise between efficiency and speed of development. Nevertheless, the faster SpaceX can prepare Raptor Vacuum for flight, the easier it will be for Starship to begin serious (sub)orbital flight tests.

As it turns out, SpaceX’s first and only official render of Raptor – published in September 2016 – showed the engine’s vacuum-optimized variant. In the years since, CEO Elon Musk has vacillated between keeping the vacuum engines as a central Starship feature and simply replacing them with regular sea level Raptors to expedite the spacecraft’s debut. The 2016 and 2017 vehicles featured a mixture of vacuum and sea-level engines, whereas Musk revealed a vehicle with sea-level engines only in 2018.

Known as the Interplanetary Transport System in 2016, the ship featured six vacuum Raptors and 3 SL engines. (SpaceX)
In 2017, Big Falcon Spaceship shrunk and changed to 4 x RVac and 3x x Raptor SL engines. (SpaceX)
In 2018, Musk decided to sidestep vacuum engines entirely, moving to 7 SL Raptors. (SpaceX)

Perhaps less than a month after Musk’s September 2018 presentation, the SpaceX CEO made the decision to radically redesign the vehicle – newly christened Starship and Super Heavy – by moving from a carbon composite aerostructure to stainless steel. At first, the seven SL Raptors remained a part of the design, but Musk took to Twitter in 2019 to indicate that SpaceX had changed gears again and had reprioritized Raptor Vacuum development.

This came as a bit of surprise and it should go without saying that there’s a significant chance that Musk/SpaceX will oscillate in the opposite direction once again before Raptor Vacuum is actually ready for flight. This time, though, Musk has sketched out a development schedule and strategy that suggests SpaceX is much more serious this time.

Most notably, Musk claims that the first Raptor Vacuum prototype could be ready for static fire testing just a “couple months” from now, an immensely ambitious schedule for any large liquid rocket engine development program. Nevertheless, Musk did indicate that the “V1.0” Raptor Vacuum design would be significantly compromised and “suboptimal”, an intentional decision to prioritize the engine’s “speed of development”.

Even then, Musk believes that the first variant – featuring a shortened bell nozzle – could still be up to 12% more efficient than sea level Raptors and thus already 70-80% of the way to the physical limit of methane-oxygen rocket efficiency.

A sea-level Raptor engine is static-fired at SpaceX’s McGregor, TX test facilities. (SpaceX)

On a positive note, shrinking V1.0 Raptor Vacuum’s nozzle a bit from its nominal length will likely mean that SpaceX can static fire fully-integrated engines at its McGregor, TX test facilities, critical for speedy development. If not, the company has experience with alternatives through Merlin Vacuum, which can only be tested on the ground with its lengthy nozzle detached. This method just makes it dramatically harder to optimize a vacuum nozzle design, as full-scale, flight-like testing is nearly impossible if a given vacuum engine can’t be tested on the ground with said nozzle installed.

Vacuum engines need such large and unwieldy nozzles in order to make them as efficient as possible. In a very simplistic sense, a rocket engine nozzle directs the flow of superheated, ultrafast gases in order to squeeze as much momentum transfer as possible out of available propellant. The lower the pressure of the surrounding atmosphere is, the more those gases will expand immediately after leaving the nozzle – giant vacuum nozzles simply try to harness the additional momentum available from that extra expansion. This is why rocket exhausts appear to spread and thin out as launch vehicles reach higher and higher altitudes.

A Falcon 9 upper stage’s vacuum nozzle glows white hot during an orbital MVac burn. (SpaceX)

In this sense, the perfect theoretical vacuum nozzle is quite literally infinitely long. The job of vacuum rocket engineers is to find the perfect balance between that impractical theoretical perfection and the limits of real-world materials and dynamics. In theory, SpaceX’s sea-level Raptor engines have already been designed to operate in vacuum conditions, while the engine’s closed-cycle design and regeneratively (i.e. propellant) cooled nozzle should apply well to a vacuum design.

If SpaceX is lucky, there will be few roadblocks in the way of simply lengthening a SL Raptor-style nozzle and calling it a day, in which case it would be impressive but not all that surprising if SpaceX is actually able to begin RVac testing before the end of 2019. Once a rough V1.0 engine is in place, the process of optimizing efficiency can be done slowly and methodically, all while exploiting an unprecedented wealth of data from flight and orbit-tested Raptor Vacuum engines.

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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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Tesla launches V2L Outlet Adapter for Premium Model Y in the U.S.

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Credit: Tesla

Tesla has launched a new Vehicle-to-Load (V2L) Outlet Adapter for Premium Model Y vehicles in the United States, meaning you can now power devices like laptops or light strings with your vehicle’s battery.

It appears the capability will be available for any Model Y Premium trim, including those that were purchased prior to the Adapter being launched. It will also only impact Juniper Model Y vehicles, so the first-gen owners will unfortunately not have access to this capability.

If your Model Y was purchased before Tesla renamed the trim levels to “Premium” and “Standard,” it does not seem to be compatible. My Model Y is technically a Premium build, as it is the Long Range All-Wheel-Drive. However, Tesla says it is not compatible with my vehicle.

For $80, you can now utilize your car as a portable charger for small appliances or devices. This is perfect for things like tailgates, concerts, or camping, as you can now plug in devices that you might use. Those string lights for camping? That laptop for the other games that are on at the tailgate?

They’ll both utilize energy from your Tesla’s battery to be powered. This is the first time Tesla has expanded the capability to vehicles outside of the Model Y Performance and Cybertruck. However, this feature has been highly requested by owners for an extended period of time.

Tesla launched the Outlet Adapter in China last year:

Tesla China rolls out Model Y L V2L adapter, and it’s free for early owners

You will need the Mobile Connector to operate the Outlet Adapter: the Outlet Adapter will plug into the main housing of the Mobile Connector, where the appropriate adapter to charge your vehicle will plug in.

It is rated for 120 volts and 20 amps, and has a max power rating of 2.4kW.

You can buy it here from Tesla for $80.

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Tesla Roadster unveiling nears, and it will fly: The Information

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(Credit: Dami Kolz/Twitter)

Tesla is nearing its long-awaited unveiling of the all-electric Tesla Roadster, a new report from The Information claims, as the company has said several times this year that the event would take place “soon.”

Now, it appears there is movement on Tesla’s end regarding when it will happen.

The report says that Tesla will unveil the Roadster as soon as this month with a SpaceX version that will utilize cold-gas thrusters to help the vehicle float for a short period of time. This is something CEO Elon Musk has talked about with the Roadster for years.

Additionally, due to the delays, Tesla explored “a variety of designs” for the Roadster, potentially planning to abandon the design it showed off for the first time in 2017 and adopting an entirely new aesthetic.

According to The Information, Tesla considered utilizing a repurposed Model S Plaid and even wanted to upgrade the look to something like a Lamborghini Countach.

Elon Musk teases Tesla Roadster unveiling once again

We’ve heard all of these things before, including teases about the date and how “soon” the Roadster will finally be ready to be shown off to the world (for the second time). Musk said that the event would occur in April, then May, then Chief Designer Franz von Holzhausen continued to say it would be coming “soon.”

We do expect to see the Roadster by the end of the year, and now with this new report swirling, it appears it could be sooner rather than later.

The wait has been incredibly long, but there is likely a good reason for it. Tesla’s desire to make the Roadster the craziest vehicle on the road was non-negotiable, and it likely took a lot of time and resources to develop and perfect into something that was safe and suitable for a vehicle like this.

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Tesla finally got its Nevada Robotaxi Permit but with a few catches hard to miss

Nevada granted Tesla’s robotaxi permit, but capped the fleet at just ten vehicles for now.

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Concept art of a Tesla Cybercab in Las Vegas Strip as rendered via Grok

Tesla has received its robotaxi permit in Nevada, more than two months after regulators closed the public comment period on the company’s application. News of the approval surfaced Wednesday night when Tesla investor and longtime company watcher Sawyer Merritt posted a copy of the interim order, and the Nevada Transportation Authority’s own carrier registry now lists the permit, AVNC Permit 002 under Docket 26-05015, as active for Tesla Robotaxi, LLC.

Tesla asked Nevada in June for authority to run up to 5,000 vehicles in Clark County within a year, however the permit the NTA issued is initially capping Tesla at ten fully autonomous vehicles and confines them to a defined geofence along the Las Vegas Strip corridor. Any expansion of that operating area, or any increase to the fleet size, requires the NTA’s approval first.

The order also sets rules that look more restrictive than what Tesla runs in Austin. Rides are barred on roads with posted speed limits above 45 miles per hour, pickups are off limits within a quarter mile of Harry Reid International Airport without separate authorization, and every vehicle has to carry visible “Robotaxi” markings while notifying riders before each trip that no one is driving. The order also requires “appropriate human supervision”, language that suggests Nevada isn’t ready to let Tesla offer the rides without a safety monitor that it has run in parts of Austin since January. As with standard protocol with robotaxi services, Tesla must report any accident, system failure, or vehicle that becomes stranded on a Nevada road within five business days.

Tesla is entering a market Nevada already knows well. Zoox, the Amazon owned robotaxi company, has run its own autonomous vehicle permit in the state since last year, building up to roughly 100 vehicles and 350,000 rides along the Strip. That history likely explains why the NTA started Tesla at ten cars rather than the fleet size the company asked for. The agency has a template for scaling a permit up once a company proves out its safety record.

Tesla’s Nevada application first surfaced in June, when the company filed for the permit alongside plans for a maintenance hub in southwest Las Vegas. The company has said it won’t meaningfully scale its robotaxi fleet anywhere until FSD v15 ships, expected in late 2026 or early 2027, which makes the ten vehicle cap less of a constraint today than it might look on paper. For now, Tesla has the legal right to start Nevada rides. Whether it starts before FSD v15 arrives is a separate question the permit doesn’t answer.

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