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NASA’s SLS Moon rocket almost aces vital prelaunch test on 7th try
Following several incomplete attempts in April, June, August, and September, NASA’s first Space Launch System (SLS) Moon rocket has almost aced a vital prelaunch test on the seventh try.
NASA says that “all objectives were met” during the ten-hour test, which wrapped up around 4:30 pm EDT (20:30 UTC) on Wednesday, September 21st. Despite the rocket running into multiple additional issues, some old and others new, the agency was confident enough in the preliminary results of the wet dress rehearsal (WDR) – deemed a “cryogenic demonstration test” – to reaffirm that it’s still working towards a third launch attempt as early as September 27th.
That launch date is not set in stone, but NASA also hasn’t ruled out the window after the latest round of SLS testing. The agency will host a press conference on Friday, September 23rd, to provide its final decision and offer more details about the seventh wet dress rehearsal.
Despite NASA’s apparent confidence after the test, which was admittedly smoother than most previous SLS tests at the launch pad, it was far from smooth. The immediate story of the “cryogenic demonstration test” dates back to the SLS Artemis I rocket’s second so-called “launch attempt” on September 3rd. During that attempt, the launch was aborted well before SLS was ready when NASA detected a major hydrogen fuel leak around one of the quick-disconnect umbilical panels that fuels and drains the rocket. Remote troubleshooting was unable to solve the problem, forcing NASA to stand down.
Over the last few weeks, teams inspected, tested, and repaired the faulty Tail Service Mast Umbilical (TSMU), preparing for a cryogenic proof test meant to verify that the issue was fixed. During that September 21st test, the TSMU still leaked significantly for the whole duration, but it did so more predictably and – unlike prior leaks – never violated the limits that would trigger a launch abort.
But near the end, a different umbilical panel developed a significant hydrogen leak that did violate those launch constraints, meaning that NASA would have likely had to stand down yet again if it had attempted to launch before completing additional testing. The test was completed successfully, but its goals and constraints were not the same as those facing a launch.
A NASA-developed rocket leaking hydrogen is unfortunately a tale as old as time. That the agency that struggled with hydrogen leaks throughout the 30-year career of the Space Shuttle appears to be just as flabbergasted by nearly identical problems on a new rocket – SLS – that has Shuttle ‘heritage’ on almost every square inch is not surprising, even if it is somewhat embarassing.
Liquid hydrogen fuel always has been and likely always will be a massive pain to manage in any rocket, but especially in a large rocket. As the smallest element in the universe, it is fundamentally leak-prone. Combined with the fact that it only remains liquid below the extraordinarily low temperature of -253°C (-423°F), generates ultra-flammable hydrogen gas as it continually attempts to warm to a more stable temperature, and naturally embrittles most metals, it’s an engineering nightmare by almost every measure.
For all that pain, hydrogen does provide rocket engineers exceptional efficiency when properly exploited, but even that positive aspect is often diminished by hydrogen’s ultra-low density. For rocket stages that have already reached orbit, hydrogen-oxygen propellant offers unbeatable efficiency. But for a rocket stage that will never be used in orbit, like the SLS core stage, hydrogen fuel is rarely worth the tradeoffs – a reality that SLS is unfortunately providing a strong reminder of.
Demonstrating the Groundhog Day-esque nature of NASA rockets and hydrogen leaks, the same leaky TSMU panel that aborted SLS’ September 3rd launch attempt (sixth WDR) and had to be fixed and retested on September 21st also caused a hydrogen leak that partially aborted the rocket’s third wet dress rehearsal attempt in April 2022. NASA then rolled the rocket back to the Vehicle Assembly Building (VAB), where workers spent almost two months inspecting and reworking the fuel TSMU and fixing other issues. During its first test (WDR #4) after rolling back to the pad in June, the same fuel TSMU leaked and NASA had to return the rocket to the VAB again to fix the problem.
The fuel TSMU then leaked on the SLS rocket’s first launch attempt (really WDR #5), but the problem was resolved and was not what caused NASA to stand down. It was, however, a primary reason behind NASA’s second aborted launch attempt (WDR #6). With any luck, the eighth time will be the charm.
Tesla confirmed this morning that it has sent the first production units, manufactured with no steering wheel or pedals, to on-road testing in Austin, sharing video of the first rides with no human controls.
The lack of steering wheels and pedals in the Cybercab aligns with Tesla’s self-certification of Robotaxi as Level 4 SAE, a platform it plans to make widespread through internal vehicles and customer-owned cars that will operate and generate revenue for individuals.
The start of these engineering tests is a major signal for Tesla, which plans to bring driverless, wheel-less, and pedal-less Cybercabs to market in the coming months. With production already well underway at Gigafactory Texas, where the Cybercab is built, there is some inclination to believe the first public rides could happen sooner rather than later.
Engineering tests of the first production Cybercab have begun in Austin pic.twitter.com/fk3KQvcE8a
— Tesla (@Tesla) June 30, 2026
Tesla’s engineering tests will put the Cybercab in real-world scenarios, testing not only the hardware, but more importantly, the software that drives the car around Austin with nobody supervising it within the car.
This is perhaps the biggest part of the internal testing process, especially prior to allowing regular, everyday people to hail the Cybercab for an autonomous ride. These early rides serve as a true benchmark for Tesla: How many rides can it achieve safely? How many miles did it travel consecutively without needing an intervention? What scenarios challenge the Full Self-Driving suite the most?
The proper precautions have already been put into place as well, as Tesla released the First Responders Guide to Cybercab over the weekend, ensuring that emergency services have 24/7 access to Robotaxi Assistance, as well as other boundaries, such as Geofencing features that can be used to redirect autonomous vehicle traffic due to accidents, road closures, construction, or maintenance.
Cybercab seems genuinely close to being added to the Robotaxi fleet in Austin, but Tesla has prioritized safety throughout this entire process. Therefore, we think it could be months before it truly starts giving rides to the public. People have been frustrated with this, but Robotaxi in Austin has a tremendous safety record so far, so the slow rollout has kept people safe and accidents to a minimum.
The most important thing is that Tesla continues to show consistent progress in the Cybercab’s ramp-up toward fleet addition. A few weeks back, we saw the EPA reward the Cybercab a Certificate of Conformity, allowing it to enter the stream of commerce. Then, we saw Tesla add decals, signaling that it was likely about to start testing it publicly. That has now happened.
The next big move will be the announcement of the first rides, so this Summer should be filled with anticipation.
For years, there have been images and videos across social media platforms that have reminded me of when I was a 15-year-old kid teased by “Xbox 720” videos on YouTube. These videos are of the supposed “Tesla Phone” that Elon Musk was secretly developing in between leading Tesla with its electric cars and SpaceX with its reusable rockets.
Would you buy a Tesla phone ? pic.twitter.com/aaTwvvIJit
— Tesla Owners Silicon Valley (@teslaownersSV) October 6, 2023
Although Musk has put those rumors to bed several times, it was never completely out of the realm that he could get involved in cell phones in some capacity. Think outside the box and more macro-level, though. Instead of reinventing the computer, Musk reinvented connectivity by developing Starlink with SpaceX.
It could be something similar, TD Cowen analyst Gregory Williams said in a note last week, where he hinted SpaceX could be gathering some steam to acquire T-Mobile.
Williams said it would be the “clear choice” for SpaceX if it decided to go through with a network acquisition. He also suggested AT&T.
The move would be possible through selling more of its own stock, which would help SpaceX raise the money to purchase T-Mobile, which would cost roughly $300 billion. It could be one of the moves SpaceX makes post-IPO in terms of an acquisition: it already acquired Cursor AI for $60 billion.
Other analysts, like Dan Ives of Wedbush, believe SpaceX and Tesla will eventually merge into one anyway, and that conglomeration could come as soon as this year, some have said.
The implications of SpaceX purchasing T-Mobile are massive. A combined entity would create a truly ubiquitous network: T-Mobile’s terrestrial 5G towers and Starlink’s growing constellation of Direct-to-Cell satellites. This would essentially eliminate dead zones across the U.S. and potentially globally.
SpaceX would instantly become a full-scale facilities-based carrier with satellite differentiation; a huge advantage. This would pressure AT&T and Verizon heavily.
There are also concerns like a potential reduction in long-term competition, and of course, a deal of that size would face intense scrutiny from government agencies.
The strategic fit is compelling due to the existing Starlink–T-Mobile partnership and complementary technologies (space + terrestrial). It could create a dominant integrated communications player. However, the regulatory, financial, and execution hurdles are enormous — this remains highly speculative with no indication SpaceX is actively pursuing it right now.
Tesla revealed a major new Cybercab detail in a guide it released for First Responders, showing new territory in its beliefs and intentions for the ride-hailing-focused vehicle that entered production in April.
The First Responders Guide is released to give fire departments, paramedics, and other emergency personnel the proper guidance on what to do in the event of an accident, entrapment, or other situation that would require immediate attention.
On one of the pages of the First Responders Guide, Tesla revealed a stark detail about the Cybercab, which could help personnel enter the vehicle more easily in case of an emergency.
Tesla Cybercab has one important piece that AI4 cars might need for FSD
It shows Tesla has no intention of releasing any Cybercab units that were initially proposed for ride-hailing services for the general public with any manual controls, meaning a steering wheel or pedals:
“A Cybercab equipped with steering wheel, brake pedal, and an acceleration pedal is typically an engineering or test vehicle, and operates at SAE Level 2 autonomy. Cybercab is not typically equipped with a steering wheel or acceleration and brake pedals.”
New official Cybercab documentation from Tesla:
“A Cybercab equipped with steering wheel, brake pedal, and an acceleration pedal is typically an engineering or test vehicle, and operates at SAE Level 2 autonomy. Cybercab is not typically equipped with a steering wheel or… https://t.co/P6ut1mZyzr pic.twitter.com/yq6skl9s2J
— Sawyer Merritt (@SawyerMerritt) June 27, 2026
This is a major development for those who continue to believe Tesla planned to release the Cybercab with any sort of manual controls so that passengers could take over if needed. However, when Tesla started manufacturing production versions of the Cybercab in Giga Texas earlier this year, they were spotted without a steering wheel or pedals.
It essentially confirms the company has no intentions of bringing manual controls to the car’s production versions. Some have argued that the likelihood of Tesla having something
There still are some Cybercab units out there with a steering wheel and pedals, and as Tesla said, these cars are engineering or test vehicles, which have Safety Monitors on board to help the car out of a precarious situation or emergency.
Tesla sends production Cybercab with no steering wheel, pedals to on-road testing
Tesla Phone? Not quite, but close: analyst
