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SpaceX’s orbital Starship prototype gets frosty during first successful ‘cryoproof’
For the first time, SpaceX has put the first orbital-class Starship – a prototype known as Ship 20 (S20) – through a routine cryogenic proof test, filling the rocket with several hundred tons of liquid nitrogen to simulate its explosive propellant.
While it’s impossible to jump to conclusions before members of the public can return to the pad to take photos or CEO Elon Musk takes to Twitter to discuss the results, Ship 20’s first ‘cryoproof’ appears to have been largely successful [Edit: Musk has confirmed that the test went well]. Relative to the almost three-dozen cryoproofs SpaceX has completed with more than a dozen other Starship, booster, and test tank prototypes over the last two years, though, Ship 20’s first major test still has some oddities.
Historically, every cryoproof of a full Starship prototype has been visually unique and virtually impossible to predict. Without any direct insight from SpaceX or Elon on the objectives, plan, or timeline of tests, the process of watching tests (via unofficial webcams, of course) and attempting to interpret why certain things look the way they do or what’s going on at any given moment is a bit trying to interpret eroded hieroglyphics.
At the most basic level, cryogenic tanking tests – whether with Starship, Super Heavy, or test tanks and liquid oxygen (LOx)/methane (LCH4) propellant or neutral liquid nitrogen (LN2) – are fairly simple. The vehicle is attached to pad systems, powered on, and partially or fully loaded with cryogenic fluids. Once the desired test objectives are achieved or attempted, the vehicle is then detanked (drained of propellant or LN2).
Thanks to the fact that they’re incredibly cold (-160 to -200C; -260 to -330F), the LOx/LCH4 or LN2 Starships are filled with quickly chill the thin steel tanks containing them. With no insulation to speak of, that supercooled steel then freezes water vapor out of the humid South Texas air, creating a layer of frost/ice that generally follows the level of the cryogenic liquids in Starship’s tanks. Throughout that process, those cryogenic liquids inevitably come into contact with ambient-temperature Starship tanks and plumbing (white-hot in comparison) and warm up, boiling off into gas as a result.
A gaseous chemical is far less dense than its liquid form, meaning that the pressure inside Starship’s fixed tanks can rapidly become unmanageable after even a small amount of boiloff. To maintain the correct tank pressures, Starship – like all other rockets – occasionally vents off the gas that forms. And thus, the two main methods of interpreting the hieroglyphics that are cryoproof tests: frost levels and venting.
Compared to earlier prototypes, Starship S20’s first cryoproof has been… unusual. Most notably, SpaceX began loading the rocket with liquid nitrogen around 8pm CDT. Its LOx (bottom) and CH4 (top) tanks were then slowly filled to around 30-50% of their full volume over the next hour. However, rather than detanking, SpaceX then partially drained the methane tank but filled the LOx tank further before leaving the LOx tank more or less fully filled for more than two hours, occasionally topping it off with fresh liquid nitrogen.
Then, almost four hours after LN2 loading began, Starship performed several massive vents. Ordinarily, given the hours of testing prior, those vents would have assuredly been detank vents – effectively depressurizing Starship’s tanks as they’re drained of fluid. However, those vents instead coincided with the rapid loading of one or several hundred more tons of LN2, seemingly topping off Starship S20 in the process. Around that point, it’s possible that SpaceX began the pressure testing portion of Ship 20’s cryoproof, (mostly) closing the rocket’s vents and allowing the pressure to gradually increase to flight levels (and maybe even higher).
Many, many months ago, when SpaceX was deep into cryoproofing the first full-size Starship prototypes, Musk revealed an operating pressure goal of 6 bar (~90 psi). Ships were eventually successfully tested above 8 bar (~115 psi), giving Starship a healthy ~30% safety margin. As the first orbital-class Starship prototype, Ship 20 likely needs to hit those tank pressures more so than any ship before it to have a shot at surviving its orbital launch debut and orbital-velocity reentry attempt.
Beyond the basics of cryoproofing, Starship S20 also marked a crucial step forward on September 29th/30th, becoming the first ship to complete a cryoproof test with a full heat shield installed. While it’s impossible to judge exactly how well S20’s ~15,000-tile heat shield performed, views from public webcams showed no obvious signs of tiles shattering and falling off as Starship repeatedly cooled and warmed – contracting and expanding as a result. Additionally, still in contact with the air, the steel tank skin under a majority of Ship 20’s tiles would have likely covered itself in a layer of frost and ice, but the heat shield appeared to handle that invisible change without issue.
It’s possible that dozens or hundreds of tiles bumped together and chipped or cracked in a manner too subtle to be visible on LabPadre or NASASpaceflight webcasts, but that can only be confirmed or denied when the road reopens and local photographers can capture higher-resolution views of Starship. For now, it appears that Ship 20’s first cryoproof was highly successful, hopefully opening the door for Raptor installation and static fire testing in the near future. Stay tuned for more!
Update: As is almost tradition by now, SpaceX CEO Elon Musk didn’t take long to tweet about the results of Starship S20’s first cryoproof, confirming that the “proof was good!”
Tesla has reached a notable benchmark in its autonomous driving program after its Robotaxi fleet surpassed one million miles of unsupervised operation. The company made the announcement during its Cybercab event in Austin on September 3.
Tesla Vice President of AI Ashok Elluswamy told attendees he was happy to report the fleet had achieved one million miles of unsupervised Robotaxi operation as a testament to safety.
The new total marked a sharp increase from the 380,000 unsupervised miles Tesla disclosed during its second-quarter 2026 earnings update in late July.
In roughly six weeks, the company added about 620,000 miles. That acceleration followed Tesla’s decision to remove in-vehicle safety monitors from most of its operations outside the San Francisco Bay Area.
Credit: Tesla
Tesla first launched Robotaxi service in Austin in June 2025 with safety drivers present. It later began fully unsupervised rides and expanded into Dallas, Houston, Miami, Orlando, and Tampa. The San Francisco Bay Area remains the exception, where a safety monitor still rides in the vehicle under California permitting rules.
The company has not released a city-by-city breakdown of the one million unsupervised miles.
The milestone arrived as Tesla began offering public Cybercab rides in Austin. The purpose-built vehicle has no steering wheel or pedals and is designed only for autonomous ride-hailing. Production versions joined the existing fleet of modified Tesla vehicles already operating in the service.
Tesla’s unsupervised mileage is growing at a double-digit weekly rate according to earlier company comments, yet its fleet size remains modest compared with established competitors. Waymo has accumulated more than 200 million fully autonomous rider-only miles. Tesla has described its own unsupervised operations as having recorded zero notable incidents in the period leading up to the July update.
The one-million-mile figure reflects Tesla’s shift from supervised testing to broader driverless service in multiple states. It also highlights the company’s strategy of using both existing Model Y vehicles and the new Cybercab to scale its network.
Credit: Tesla
Whether the rapid recent growth continues will depend on further city expansions, regulatory approvals, and the performance of the purpose-built Cybercab in everyday paid rides. Tesla has not specified how many of the latest miles involved the new vehicle versus the rest of the fleet.
The announcement underscores Tesla’s progress toward a larger robotaxi network while illustrating the remaining gap in total autonomous experience relative to longer-operating rivals.
Tesla AI lead Ashok Elluswamy said this week that 24-hour Robotaxi service is close. Replying on X to a rider who wanted Cybercab trips all night, he wrote that the capability would arrive “next month or so” once “the next tech to merge on the v15 plan” is ready.
The comment landed on September 4, one day after Tesla opened public Cybercab rides in Austin. It is the clearest near-term timeline yet for overnight unsupervised operation. Tesla’s paid Robotaxi network currently runs from 6 a.m. to 10 p.m. seven days a week across Austin, Dallas, Houston, Miami, Orlando, and Tampa.
next month or so. the next tech to merge on the v15 plan will enable it.
— Ashok Elluswamy (@aelluswamy) September 4, 2026
That 16-hour window is shorter than the 6 a.m. to 2 a.m. schedule the company used for much of the prior year.
Elluswamy did not name the specific feature or say whether the change would apply first to purpose-built Cybercabs, the existing Model Y fleet, or both. He also offered no city-by-city rollout list. The link to Full Self-Driving v15 is nevertheless significant.
Tesla has described v15 as a step-change architecture with seven parallel improvement tracks and roughly ten times more parameters than earlier builds. Early versions of that software already operate on the Robotaxi fleet and contain about 40 percent of the planned gains.
By July 2026, the unsupervised fleet had logged more than 380,000 miles across six cities in two states with what the company called an impeccable safety record and no notable incidents caused by the vehicles themselves. Tesla has repeatedly argued that camera-based end-to-end neural networks, rather than extra sensors, are the core of the solution.
Overnight service would test that claim in lower-light conditions and would also raise vehicle utilization, a key variable for Robotaxi unit economics. The company has already begun using public Superchargers at night and is building dedicated Robotaxi charging sites.
Riders have asked why software must change if the cars already drive in the dark. The practical answer appears to be reliability and scale: Tesla has held back mass expansion until more of the v15 stack is merged, citing the need for higher confidence before putting thousands of unoccupied vehicles on streets around the clock.
If the next module arrives on the timetable Elluswamy sketched, 24-hour service could begin in October 2026 in at least some markets.
That would mark a shift from a daytime-bounded pilot to a service that can run whenever demand exists, including the late-night hours that have so far remained out of reach.
Tesla is beginning to roll out Full Self-Driving Supervised v14.3.9 with a new active safety layer that can take control even when the driver is operating the car manually.
Tesla AI said the software can activate FSD on the driver’s behalf when an imminent collision is detected and Automatic Emergency Braking may not be enough. It may also engage if the system detects heavy distraction or an accidental FSD disengagement.
FSD Supervised v14.3.9 starting to roll out shortly
This release includes a new active safety feature set: FSD Supervised can now activate on your behalf when an imminent collision is detected and Automatic Emergency Braking (AEB) may not be enough.
It may also engage if we…
— Tesla AI (@Tesla_AI) September 4, 2026
The capability is essentially Automatic Collision Evasion. However, unlike conventional AEB, which mainly applies the brakes in a straight line, this feature can use steering, braking, and acceleration together if the car calculates that stopping alone will not prevent impact and a safer path exists. The system may change lanes or move toward a shoulder when conditions allow, then continue driving after the immediate threat is handled rather than simply coming to a stop.
The intervention is meant as a last-resort safety net, not a replacement for attentive driving.
Tesla Full Self-Driving v14.3.7 early review: FSD saved me from an accident
Tesla’s own description still frames FSD as supervised assistance. Secondary reports on internal release notes say the feature can fire while the car is being driven manually if cabin-camera monitoring suggests the driver is not sufficiently attentive, such as reaching toward the back seat, or if FSD appears to have been turned off unintentionally.
After the emergency maneuver, the car is expected to alert the driver and request a return to manual control.
The safety case is straightforward. Many collisions happen in the last second because a driver is looking away, fumbles a control, or faces an obstacle that braking cannot fully solve. A system that can both recognize that AEB is insufficient and execute a coordinated evasive path can reduce those remaining high-severity events.
Re-engaging after accidental disengagement also addresses a practical failure mode: a small steering nudge that drops FSD at the worst moment. The advantage is a background safety net that uses the same vision stack already running in v14, instead of leaving the car solely to emergency braking once the driver is no longer in command.
The feature still depends on FSD being enabled and, according to reports, an active FSD purchase or subscription. It does not make the vehicle unsupervised. Drivers remain responsible, and Tesla has not published how often the system is expected to intervene or how it will handle false positives.
If the rollout is conservative and the false-alarm rate stays low, the update is a meaningful step: FSD is no longer only a feature the driver turns on. In the rare moments when disaster is already forming, it can step in.
Tesla crosses major Unsupervised Self-Driving milestone
Tesla Robotaxi will be a 24/7 service: here’s when
