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SpaceX’s thin-skinned Starship ‘test tank’ passes first trial
CEO Elon Musk says that a new thin-skinned Starship ‘test tank’ just passed its first trial, taking advantage of delays to Starship SN9’s planned high-altitude launch debut.
Delayed by a lack of FAA approval for unknown reasons, Starship SN9’s 12.5-kilometer (7.8 mi) launch debut (virtually identical to SN8’s 12.5 km launch last month) is in limbo pending an “FAA review” according to Musk. SpaceX thus found itself with at least 24 hours of guaranteed inactivity for Starship SN9, time the company rapidly chose to fill with crane transportation and, more importantly, the first Starship ‘test tank’ stress test in months.
Known as Starship SN7.2, SpaceX’s latest ‘test tank’ is the third to carry the SN7 moniker and appears to have been built primarily to test refinements to the rocket’s structural design. Following test tanks SN7.0 and SN7.1, both used to qualify the use of a new steel alloy on an otherwise unchanged design, SN7.2 – likely built out of the same alloy – is instead focused on determining if SpaceX can begin trimming the margins of an increasingly mature technology.
Curiously, SN7.2 is a sort of fusion of its predecessors: combining the stout stature of SN7.0 with SN7.1’s use of an aft thrust dome, but without SN7.1’s Starship-style skirt (the three rings at its bottom). Welded directly to its black test stand, it’s unclear why SpaceX chose to give SN7.2 a thrust dome, given that the thrust of Raptor engines can only be simulated with hydraulic rams if the tank is installed on one of two Starship launch mounts.
Regardless, whether SpaceX actually tests that aspect of SN7.2, the tank’s most important task is determining if future Starships (and perhaps Super Heavy boosters) can be built out of thinner, lighter steel rings. Its domes appear to be identical to past ships but writing on the exterior of the tank strongly implied that its three rings were built out of 3mm steel rather than the 4mm sheets that have made up every Starship built in the last 12 months.
SpaceX began loading the thin-skinned tank with liquid nitrogen (used to simulate cryogenic propellant without the risk of an explosion) around 9am CST and spent around three hours performing an “initial pressure test.” It’s unclear what that test entailed but it most likely involved raising the tank’s internal pressure to levels achieved by SN7.0 and SN7.1 Musk has previously said that that 6 bar was the bare minimum necessary for orbital flight, translating to 7.5-8.5 bar to achieve an industry-standard safety margin of 25-40%.
That SN7.2 survived that initial pressure test bodes well for the significant mass reductions SpaceX will need to optimize Starships for efficient orbital flight, potentially shaving 5-10 metric tons off the dry mass of future ships. For orbital rocket stages, every single kilogram of mass reduction translates to an extra kilogram of cargo capacity, whereas boost stages (i.e. Super Heavy) offer far more lenient ratios on the order to 10:1, meaning that adding 5-10 kilograms of rocket hardware reduces maximum payload capacity by just ~1 kg.
Depending on when SpaceX is allowed to launch Starship SN9, the company’s next test could involve pressurizing SN7.2 until it bursts, determining if the tank’s thinner skin substantially impacts its performance as a pressure vessel.
Tesla has officially launched public Robotaxi rides in Austin, Texas, without a Safety Monitor in the vehicle, marking the first time the company has removed anyone from the vehicle other than the rider.
The Safety Monitor has been present in Tesla Robotaxis in Austin since its launch last June, maintaining safety for passengers and other vehicles, and was placed in the passenger’s seat.
Tesla planned to remove the Safety Monitor at the end of 2025, but it was not quite ready to do so. Now, in January, riders are officially reporting that they are able to hail a ride from a Model Y Robotaxi without anyone in the vehicle:
I am in a robotaxi without safety monitor pic.twitter.com/fzHu385oIb
— TSLA99T (@Tsla99T) January 22, 2026
Tesla started testing this internally late last year and had several employees show that they were riding in the vehicle without anyone else there to intervene in case of an emergency.
Tesla has now expanded that program to the public. It is not active in the entire fleet, but there are a “few unsupervised vehicles mixed in with the broader robotaxi fleet with safety monitors,” Ashok Elluswamy said:
Robotaxi rides without any safety monitors are now publicly available in Austin.
Starting with a few unsupervised vehicles mixed in with the broader robotaxi fleet with safety monitors, and the ratio will increase over time. https://t.co/ShMpZjefwB
— Ashok Elluswamy (@aelluswamy) January 22, 2026
Tesla Robotaxi goes driverless as Musk confirms Safety Monitor removal testing
The Robotaxi program also operates in the California Bay Area, where the fleet is much larger, but Safety Monitors are placed in the driver’s seat and utilize Full Self-Driving, so it is essentially the same as an Uber driver using a Tesla with FSD.
In Austin, the removal of Safety Monitors marks a substantial achievement for Tesla moving forward. Now that it has enough confidence to remove Safety Monitors from Robotaxis altogether, there are nearly unlimited options for the company in terms of expansion.
While it is hoping to launch the ride-hailing service in more cities across the U.S. this year, this is a much larger development than expansion, at least for now, as it is the first time it is performing driverless rides in Robotaxi anywhere in the world for the public to enjoy.
Tesla has scheduled its Earnings Call for Q4 and Full Year 2025 for next Wednesday, January 28, at 5:30 p.m. EST, and investors are already preparing to get some answers from executives regarding a wide variety of topics.
The company accepts several questions from retail investors through the platform Say, which then allows shareholders to vote on the best questions.
Tesla does not answer anything regarding future product releases, but they are willing to shed light on current timelines, progress of certain projects, and other plans.
There are five questions that range over a variety of topics, including SpaceX, Full Self-Driving, Robotaxi, and Optimus, which are currently in the lead to be asked and potentially answered by Elon Musk and other Tesla executives:
- You once said: Loyalty deserves loyalty. Will long-term Tesla shareholders still be prioritized if SpaceX does an IPO?
- Our Take – With a lot of speculation regarding an incoming SpaceX IPO, Tesla investors, especially long-term ones, should be able to benefit from an early opportunity to purchase shares. This has been discussed endlessly over the past year, and we must be getting close to it.
- When is FSD going to be 100% unsupervised?
- Our Take – Musk said today that this is essentially a solved problem, and it could be available in the U.S. by the end of this year.
- What is the current bottleneck to increase Robotaxi deployment & personal use unsupervised FSD? The safety/performance of the most recent models or people to monitor robots, robotaxis, in-car, or remotely? Or something else?
- Our Take – The bottleneck seems to be based on data, which Musk said Tesla needs 10 billion miles of data to achieve unsupervised FSD. Once that happens, regulatory issues will be what hold things up from moving forward.
- Regarding Optimus, could you share the current number of units deployed in Tesla factories and actively performing production tasks? What specific roles or operations are they handling, and how has their integration impacted factory efficiency or output?
- Our Take – Optimus is going to have a larger role in factories moving forward, and later this year, they will have larger responsibilities.
- Can you please tie purchased FSD to our owner accounts vs. locked to the car? This will help us enjoy it in any Tesla we drive/buy and reward us for hanging in so long, some of us since 2017.
- Our Take – This is a good one and should get us some additional information on the FSD transfer plans and Subscription-only model that Tesla will adopt soon.
Tesla will have its Earnings Call on Wednesday, January 28.
Elon Musk shared an incredible detail about Tesla Cybercab’s potential efficiency, as the company has hinted in the past that it could be one of the most affordable vehicles to operate from a per-mile basis.
ARK Invest released a report recently that shed some light on the potential incremental cost per mile of various Robotaxis that will be available on the market in the coming years.
The Cybercab, which is detailed for the year 2030, has an exceptionally low cost of operation, which is something Tesla revealed when it unveiled the vehicle a year and a half ago at the “We, Robot” event in Los Angeles.
Musk said on numerous occasions that Tesla plans to hit the $0.20 cents per mile mark with the Cybercab, describing a “clear path” to achieving that figure and emphasizing it is the “full considered” cost, which would include energy, maintenance, cleaning, depreciation, and insurance.
Probably true
— Elon Musk (@elonmusk) January 22, 2026
ARK’s report showed that the Cybercab would be roughly half the cost of the Waymo 6th Gen Robotaxi in 2030, as that would come in at around $0.40 per mile all in. Cybercab, at scale, would be at $0.20.
Credit: ARK Invest
This would be a dramatic decrease in the cost of operation for Tesla, and the savings would then be passed on to customers who choose to utilize the ride-sharing service for their own transportation needs.
The U.S. average cost of new vehicle ownership is about $0.77 per mile, according to AAA. Meanwhile, Uber and Lyft rideshares often cost between $1 and $4 per mile, while Waymo can cost between $0.60 and $1 or more per mile, according to some estimates.
Tesla’s engineering has been the true driver of these cost efficiencies, and its focus on creating a vehicle that is as cost-effective to operate as possible is truly going to pay off as the vehicle begins to scale. Tesla wants to get the Cybercab to about 5.5-6 miles per kWh, which has been discussed with prototypes.
Additionally, fewer parts due to the umboxed manufacturing process, a lower initial cost, and eliminating the need to pay humans for their labor would also contribute to a cheaper operational cost overall. While aspirational, all of the ingredients for this to be a real goal are there.
It may take some time as Tesla needs to hammer the manufacturing processes, and Musk has said there will be growing pains early. This week, he said regarding the early production efforts:
“…initial production is always very slow and follows an S-curve. The speed of production ramp is inversely proportionate to how many new parts and steps there are. For Cybercab and Optimus, almost everything is new, so the early production rate will be agonizingly slow, but eventually end up being insanely fast.”
BREAKING: Tesla launches public Robotaxi rides in Austin with no Safety Monitor
Tesla Earnings Call: Top 5 questions investors are asking
