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SpaceX Starship stacked with ballast for hop test debut

Starship SN4 has been outfitted with a ballast weight to enable its inaugural flight test. (NASASpaceflight - bocachicagal)

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SpaceX has installed a custom-built ballast atop its fourth full-scale Starship prototype, a sign that the company is rapidly approaching the ship’s first Starhopper-style hop test.

Although CEO Elon Musk officially “redirected” SpaceX’s resources away from Starship’s first flight and towards Crew Dragon’s NASA astronaut launch debut, the company continues to work around the clock to ready Starship SN4 for the program’s biggest test yet. Designed with the goal of creating a fully-reusable, ultra-capable launch vehicle that is unprecedentedly affordable, SpaceX’s Starship spacecraft and Super Heavy booster have made impressive progress over the last 12 or so months.

In July and August 2019, Starhopper – a low-fidelity testbed and proof of concept – successfully performed two untethered hop tests, ultimately flying more than 150m (~500 ft) above ground before safely touching down. Three months later, the first full-scale Starship prototype was destroyed almost immediately after its first pressure test began, a failure that lead SpaceX to expedite factory upgrades. Just six months later, SpaceX has completed multiple successful tests, including pressure tests that pushed beyond the pressures needed for safe human spaceflight, several full wet dress rehearsals (WDRs) with live propellant, and three Raptor engine static fires. In fewer words, Starship is ready for its next big test: flight.

SpaceX technicians prepare to complete a jerryrigged ballast weight for Starship SN4. (NASASpaceflight – bocachicagal)

However, Starship SN4 currently has just one Raptor engine installed and will remain in that configuration for its inaugural hop, expected to reach a maximum altitude identical to Starhopper (150m/500ft). The odd configuration means that the rocket will be propelled by asymmetric thrust, as Starship’s ‘thrust puck’ engine section is designed to hold three Raptor engines in a triangular formation. Raptor is capable of producing up to 200 metric tons (~440,000 lbf) of thrust with an unclear level of throttle control (likely mediocre according to comments made by Elon Musk).

Impressively, although it might seem reasonable to assume that Starship SN4 is about as heavy as the ~120 ton Starhopper, the clear and present need to install substantial ballast suggests otherwise. Combined with comments made during SN4’s April 2020 transport from factory to launch site, it appears that even SpaceX’s early Starship engine sections weigh just 50-60 metric tons (110,000-125,000 lb) empty. That weight doesn’t account for the flaps, heat shield, nose section, or many other heavy components that orbital Starships will eventually need but is still impressive.

Starship SN4 was transported to the launch pad on April 23rd. (NASASpaceflight – bocachicagal)
On May 27th, SpaceX installed a massive ballast weight on top of the Starship prototype. (NASASpaceflight – bocachicagal)

That impressive weight reduction, Raptor’s inability to safely throttle low, and the FAA’s lack of interest in dozens (up to hundreds) of tons of explosive propellant flying above or around populated areas poses its own challenges for the first full-scale Starship flight. The addition of ballast helpfully solves (or at least alleviates) several of those issues. Notably, ballast can prevent SpaceX from having to fuel Starship SN4 with dozens of extra tons of explosive propellant to counteract the high thrust of its single engine and permit a safe launch and landing.

At the same time, if Starship SN4’s wet weight is reduced by carrying less propellant during its first flight, that actually exacerbates the problem of Raptor’s small throttle range, as a lighter ship would be much harder to manage as the engine rapidly burns propellant and thus loses mass. With ballast, Raptor won’t have to throttle as low as it would otherwise have to to ensure a gentle rate of deceleration. Built out of sheet steel and two spare rolls of the same steel used to form Starship rings, Starship SN4’s new ballast likely increases its dry mass by some 50% or more (25+ metric tons).

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(NASASpaceflight – bocachicagal)
Starship SN4’s solid steel ballast. (NASASpaceflight – bocachicagal)

Pending Crew Dragon’s inaugural astronaut launch, now scheduled no earlier than 3:22 pm EDT (19:22 UTC), May 30th after weather delayed the first May 27th launch attempt, Starship SN4 has no testing periods on the calendar at the moment. Speaking around May 23rd, Musk stated that the ship was likely at least a “few weeks” away from its flight debut, suggesting that the ship will perform another static fire test to prepare for its first hop as early as next week. Stay tuned for updates as SpaceX’s works towards two very exciting Crew Dragon and Starship milestones.

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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 Robotaxi’s biggest rival sends latest statement with big expansion

The new expanded geofence now covers a broader region of Austin and its metropolitan areas, extended south to Manchaca and north beyond US-183.

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Credit: @AdanGuajardo/X

Tesla Robotaxi’s biggest rival sent its latest statement earlier this month by making a big expansion to its geofence, pushing the limits up by over 50 percent and nearing Tesla’s size.

Waymo announced earlier this month that it was expanding its geofence in Austin by slightly over 50 percent, now servicing an area of 140 square miles, over the previous 90 square miles that it has been operating in since July 2025.

Tesla CEO Elon Musk shades Waymo: ‘Never really had a chance’

The new expanded geofence now covers a broader region of Austin and its metropolitan areas, extended south to Manchaca and north beyond US-183.

These rides are fully driverless, which sets them apart from Tesla slightly. Tesla operates its Robotaxi program in Austin with a Safety Monitor in the passenger’s seat on local roads and in the driver’s seat for highway routes.

It has also tested fully driverless Robotaxi services internally in recent weeks, hoping to remove Safety Monitors in the near future, after hoping to do so by the end of 2025.

Although Waymo’s geofence has expanded considerably, it still falls short of Tesla’s by roughly 31 square miles, as the company’s expansion back in late 2025 put it up to roughly 171 square miles.

There are several differences between the two operations apart from the size of the geofence and the fact that Waymo is able to operate autonomously.

Waymo emphasizes mature, fully autonomous operations in a denser but smaller area, while Tesla focuses on more extensive coverage and fleet scaling potential, especially with the potential release of Cybercab and a recently reached milestone of 200 Robotaxis in its fleet across Austin and the Bay Area.

However, the two companies are striving to achieve the same goal, which is expanding the availability of driverless ride-sharing options across the United States, starting with large cities like Austin and the San Francisco Bay Area. Waymo also operates in other cities, like Las Vegas, Los Angeles, Orlando, Phoenix, and Atlanta, among others.

Tesla is working to expand to more cities as well, and is hoping to launch in Miami, Houston, Phoenix, Las Vegas, and Dallas.

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Tesla automotive will be forgotten, but not in a bad way: investor

It’s no secret that Tesla’s automotive division has been its shining star for some time. For years, analysts and investors have focused on the next big project or vehicle release, quarterly delivery frames, and progress in self-driving cars. These have been the big categories of focus, but that will all change soon.

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(Credit: Tesla)

Entrepreneur and Angel investor Jason Calacanis believes that Tesla will one day be only a shade of how it is recognized now, as its automotive side will essentially be forgotten, but not in a bad way.

It’s no secret that Tesla’s automotive division has been its shining star for some time. For years, analysts and investors have focused on the next big project or vehicle release, quarterly delivery frames, and progress in self-driving cars. These have been the big categories of focus, but that will all change soon.

I subscribed to Tesla Full Self-Driving after four free months: here’s why

Eventually, and even now, the focus has been on real-world AI and Robotics, both through the Full Self-Driving and autonomy projects that Tesla has been working on, as well as the Optimus program, which is what Calacanis believes will be the big disruptor of the company’s automotive division.

On the All-In podcast, Calcanis revealed he had visited Tesla’s Optimus lab earlier this month, where he was able to review the Optimus Gen 3 prototype and watch teams of engineers chip away at developing what CEO Elon Musk has said will be the big product that will drive the company even further into the next few decades.

Calacanis said:

“Nobody will remember that Tesla ever made a car. They will only remember the Optimus.”

He added that Musk “is going to make a billion of those.”

Musk has stated this point himself, too. He at one point said that he predicted that “Optimus will be the biggest product of all-time by far. Nothing will even be close. I think it’ll be 10 times bigger than the next biggest product ever made.”

He has also indicated that he believes 80 percent of Tesla’s value will be Optimus.

Optimus aims to totally revolutionize the way people live, and Musk has said that working will be optional due to its presence. Tesla’s hopes for Optimus truly show a crystal clear image of the future and what could be possible with humanoid robots and AI.

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Tesla Robotaxi fleet reaches new milestone that should expel common complaint

There have been many complaints in the eight months that the Robotaxi program has been active about ride availability, with many stating that they have been confronted with excessive wait times for a ride, as the fleet was very small at the beginning of its operation.

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Credit: Tesla

Tesla Robotaxi is active in both the Bay Area of California and Austin, Texas, and the fleet has reached a new milestone that should expel a common complaint: lack of availability.

It has now been confirmed by Robotaxi Tracker that the fleet of Tesla’s ride-sharing vehicles has reached 200, with 158 of those being available in the Bay Area and 42 more in Austin. Despite the program first launching in Texas, the company has more vehicles available in California.

The California area of operation is much larger than it is in Texas, and the vehicle fleet is larger because Tesla operates it differently; Safety Monitors sit in the driver’s seat in California while FSD navigates. In Texas, Safety Monitors sit in the passenger’s seat, but will switch seats when routing takes them on the highway.

Tesla has also started testing rides without any Safety Monitors internally.

Tesla Robotaxi goes driverless as Musk confirms Safety Monitor removal testing

This new milestone confronts a common complaint of Robotaxi riders in Austin and the Bay, which is vehicle availability.

There have been many complaints in the eight months that the Robotaxi program has been active about ride availability, with many stating that they have been confronted with excessive wait times for a ride, as the fleet was very small at the beginning of its operation.

With that being said, there have been some who have said wait times have improved significantly, especially in the Bay, where the fleet is much larger.

Tesla’s approach to the Robotaxi fleet has been to prioritize safety while also gathering its footing as a ride-hailing platform.

Of course, there have been and still will be growing pains, but overall, things have gone smoothly, as there have been no major incidents that would derail the company’s ability to continue developing an effective mode of transportation for people in various cities in the U.S.

Tesla plans to expand Robotaxi to more cities this year, including Miami, Las Vegas, and Houston, among several others.

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