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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.
Elon Musk
Elon Musk gives his most telling Tesla-SpaceX merger conversation yet
Elon Musk hinted a Tesla-SpaceX merger could be coming, and Wall Street is taking notice.
Elon Musk gave his clearest signal yet that Tesla and SpaceX could eventually combine, telling the All-In Summit in Los Angeles that the two companies’ deepening collaboration makes the question worth asking. Sawyer Merritt first surfaced the highlight on X Tuesday.
Asked directly why Tesla and SpaceX remain separate given how closely they already work together, Musk told hosts at the summit: “Great question there. With all this collaboration, on so many levels, who can imagine what action one might take when there’s so much close collaboration in so many areas.” SpaceX President Gwynne Shotwell, who joined Musk on stage, added that SpaceX personnel have already moved into xAI to fill leadership and engineering gaps, saying the businesses are integrating “faster than I thought,” though “not fully integrated yet,”
The comments landed on top of merger speculation that has been building on Wall Street for months. JPMorgan has called a tie-up “strategically coherent on paper,” pointing to overlapping ambitions in AI, robotics, energy, transportation and space. Jefferies went further, estimating Musk could retain roughly 55.3 percent voting control in a deal structured without a premium, a scenario that would still leave room for Tesla shareholders to come out ahead. On Kalshi, traders now put the odds of a merger before 2028 at 66 percent.
Tesla’s stake in SpaceX, still under one percent, traces back to its earlier investment in xAI, which converted to SpaceX equity after SpaceX absorbed the AI company. The two are also jointly building Terafab, a chip facility in Austin meant to serve both Tesla’s AI computing needs and SpaceX’s satellite ambitions. Wedbush analyst Dan Ives has stood by a 2027 merger timeline for months, and Cathie Wood’s ARK Invest recently floated a similar case, an idea Musk pushed back on directly at the time.
Another Tesla SpaceX merger prediction by ARK Invest has Elon Musk talking
The timing adds another layer. Tesla has scheduled an October 1 unveiling for its next generation Roadster at a venue near SpaceX’s McGregor, Texas test site, using the phrase “Go for launch” in its promotional material. Both stocks dipped roughly 2 percent Monday before recovering slightly in premarket trading Tuesday, with SpaceX shares up about 0.4 percent and Tesla essentially flat.
Musk stopped short of confirming anything is in motion. But unlike his past denials of a corporate restructuring, this response didn’t rule one out, and it came with Shotwell sitting next to him describing an integration that’s already underway.
The Tesla Roadster unveiling is getting hyped up by the company’s CEO Elon Musk, who has been a big reason the product has such high expectations due to delayed timelines and a constant need to make it even more insane than before.
Tesla announced on September 12 that it would officially unveil the Roadster in Waco, Texas, on October 1, ending years of patience for fans and reservation holders who have waited for the all-electric supercar to enter production since 2017.
Musk has said that this event will be well worth the wait on several occasions, and last year on the Joe Rogan Experience, he said that there should be a closing chapter to supercars- the end of cars that aren’t focused on safety.
He said:
“Whether it’s good or bad, it will be unforgettable. My friend Peter Thiel once reflected that the future was supposed to have flying cars, but we don’t have flying cars. I think if Peter wants a flying car, he should be able to buy one. I think it has a shot at being the most memorable product unveil ever. This is some crazy technology in this car. Let’s just put it this way: if you took all the James Bond cars and combined them, it’s crazier than that.”
Musk’s teases have continued, and now that the event is roughly two weeks away, it seems like Roadster is finally going to show up and blow some minds:
It’s out of this world
— Elon Musk (@elonmusk) September 13, 2026
Excitement guaranteed
— Elon Musk (@elonmusk) September 13, 2026
Tesla has definitely dragged out the development of the Roadster, but there is a good reason for it.
Tesla has been working on many other projects, most notably self-driving efforts to increase passenger safety, and those simply took priority over the Roadster, a low-volume, high-performance sports car that has a lightning-fast acceleration rate of 0-60 MPH in just 1.1 seconds, could potentially fly, and contributes very little to the company’s mission.
However, many people have the Roadster on pre-order through the referral program or with their own money, and it is time that Tesla delivers on that.
Elon Musk
Elon Musk’s Boring Company has big plans for Las Vegas by year’s end
Elon Musk’s Boring Company says Vegas Loop stations will double by year end once again.
The Boring Company says the Vegas Loop’s station count will double by the end of the year, tying the target to a hiring push for drivers and operations managers in Las Vegas. “Vegas Loop is getting bigger – the station count will double by end of year!” the company wrote in a post on X, attaching listings for a Loop driver and a senior Loop operations manager.
The number checks out against what’s already public, with the Vegas Loop currently running 14 operational stations, while the Boring Company’s own project page lists 28 as the target for the end of 2026.
Vegas Loop is getting bigger – the station count will double by end of year!
Urgently hiring exceptional and enthusiastic Drivers and Ops Managers.
Apply here!
Driverhttps://t.co/ZUPXBYTONb
Senior Loop Ops Managerhttps://t.co/mV6V22V8jH pic.twitter.com/IZ9FqIw8WY
— The Boring Company (@boringcompany) September 14, 2026
Much of that growth is tied to tunnels that are already built and waiting on an opening date. A roughly two-mile dual tunnel system under Paradise Road, connecting Westgate to a planned station at 4744 Paradise Road, is expected to open in stages over the coming weeks, Las Vegas Convention and Visitors Authority chief executive Steve Hill told the Review-Journal last week. New stations at 4744 Paradise, Virgin Hotels Las Vegas, and the former Gordon Biersch site would come online with it, several of them built to speed up rides to Harry Reid International Airport ahead of Formula 1’s Las Vegas Grand Prix.
Clark County entitled Vegas Loop for 123 stations after approving 19 more in August, as Teslarati reported at the time. Entitlement and construction move at different speeds on this project, so county approval alone does not guarantee a station opens on any particular schedule.
Clark County approved 18 additional stations back in 2023, part of a plan that pushed the system’s target to 69 stations across 65 miles, doubling the network on paper for the first time. The target kept climbing after that, to roughly 93 stations by the end of that year and 104 by last year, before August’s vote pushed it to 123. This week’s announcement is the first time that doubling language has been attached to stations actually running rather than stations merely approved on a county map.
Ridership gives some sense of what a denser network could carry. Boring Company executive Mike Baier said in July that the Vegas Loop already moves around 40,000 passengers on busy convention days, a total that tops most light rail systems in the country despite the system running on a fraction of its planned tunnel mileage. Company leadership has projected ridership could triple or quadruple once the airport connector tunnels fully open.
Boring Company did not say which stations beyond those already under construction would open by year end, or whether the hiring push points to a fleet expansion alongside the new stops.
Elon Musk gives his most telling Tesla-SpaceX merger conversation yet
Tesla Roadster unveiling is getting hyped up by Elon Musk
