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SpaceX Starship stacked with ballast for hop test debut
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.
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.
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).
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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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 launched the all-electric, steering wheel-less, and pedal-less Cybercab last night at a quiet and small event in downtown Austin, Texas.
The launch, which marked the beginning of unsupervised ride-hailing for Tesla’s Robotaxi platform with Cybercab, has already caught the attention of the National Highway Traffic Safety Administration (NHTSA) who has more questions.
NHTSA opened an Audit Query (AQ) into the Cybercab’s Federal Motor Vehicle Safety Standards (FMVSS) certification that Tesla gave the vehicle. Manufacturers self-certify vehicles much of the time to avoid excessive regulatory delays.
Tesla Cybercab interior, note the lack of steering wheel and pedals. (Credit: @niccruzpatane/X< /a>)
However, the agency needs more information; it said in a summary:
“On September 3, 2026, Tesla began commercial deployment with a small number of its Cybercab vehicles in Austin, Texas. Tesla notified the Agency that it certified those Cybercab vehicles as compliant with all applicable Federal Motor Vehicle Safety Standards (FMVSS). Tesla also notified the Agency that it plans to gradually expand commercial deployment of the Cybercab to include additional vehicles and locations.”
It also went on to state that the Cybercab lacks traditional automotive controls, which is a groundbreaking move. The process is entirely new to the NHTSA, which gives the agency some leverage to put Tesla’s launch under a microscope:
“The vehicles lack permanently attached, conventional manual controls, such as a brake pedal, gas pedal, steering wheel, and mirrors. NHTSA is opening this AQ to examine the process and technical data on which Tesla relied when certifying the Cybercab and related issues. Among other things, NHTSA will consider the extent to which Tesla’s certification depended on determinations that certain FMVSS are inapplicable to the Cybercab.”
Tesla has added 45 Cybercab units to its fleet of Robotaxi-enabled cars in Austin, according to public documents the company submitted to the State of Texas over the past week. Enabling this level of self-driving is something Tesla has worked toward for many years, and now that it is finally here, it seems more than reasonable that regulatory agencies will have some questions.
Many outlets might try to frame this as a negative, but it is truly an agency looking to gain more information about groundbreaking tech that Tesla has been developing for years.
In an effort to keep riders, pedestrians, and property safe, any and all data accumulated from these first days, weeks, and months of rides will likely be shared with the NHTSA to enable broader rollout strategies across the United States and more in the future.
Tesla Robotaxi will be a 24/7 service: here’s when
Tesla Full Self-Driving will now overtake manual driving to avoid disaster
