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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
Starlink achieves major milestones in 2025 progress report
Starlink wrapped up 2025 with impressive growth, adding more than 4.6 million new active customers and expanding service to 35 additional countries, territories, and markets.
Starlink wrapped up 2025 with impressive growth, adding more than 4.6 million new active customers and expanding service to 35 additional countries, territories, and markets. The company also completed deployment of its first-generation Direct to Cell constellation, launching over 650 satellites in just 18 months to enable cellular connectivity.
SpaceX highlighted Starlink’s impressive 2025 progress in an extensive report.
Key achievements from Starlink’s 2025 Progress
Starlink connected over 4.6 million new customers with high-speed internet while bringing service to 35 more regions worldwide in 2025. Starlink is now connecting 9.2 million people worldwide. The service achieved this just weeks after hitting its 8 million customer milestone.
Starlink is now available in 155 markets, including areas that are unreachable by traditional ISPs. As per SpaceX, Starlink has also provided over 21 million airline passengers and 20 million cruise passengers with reliable high-speed internet connectivity during their travels.
Starlink Direct to Cell
Starlink’s Direct to Cell constellation, more than 650 satellites strong, has already connected over 12 million people at least once, marking a breakthrough in global mobile coverage.
Starlink Direct to Cell is currently rolled out to 22 countries and 6 continents, with over 6 million monthly customers. Starlink Direct to Cell also has 27 MNO partners to date.
“This year, SpaceX completed deployment of the first generation of the Starlink Direct to Cell constellation, with more than 650 satellites launched to low-Earth orbit in just 18 months. Starlink Direct to Cell has connected more than 12 million people, and counting, at least once, providing life-saving connectivity when people need it most,” SpaceX wrote.
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Tesla Giga Nevada celebrates production of 6 millionth drive unit
To celebrate the milestone, the Giga Nevada team gathered for a celebratory group photo.
Tesla’s Giga Nevada has reached an impressive milestone, producing its 6 millionth drive unit as 2925 came to a close.
To celebrate the milestone, the Giga Nevada team gathered for a celebratory group photo.
6 million drive units
The achievement was shared by the official Tesla Manufacturing account on social media platform X. “Congratulations to the Giga Nevada team for producing their 6 millionth Drive Unit!” Tesla wrote.
The photo showed numerous factory workers assembled on the production floor, proudly holding golden balloons that spelled out “6000000″ in front of drive unit assembly stations. Elon Musk gave credit to the Giga Nevada team, writing, “Congrats on 6M drive units!” in a post on X.
Giga Nevada’s essential role
Giga Nevada produces drive units, battery packs, and energy products. The facility has been a cornerstone of Tesla’s scaling since opening, and it was the crucial facility that ultimately enabled Tesla to ramp the Model 3 and Model Y. Even today, it serves as Tesla’s core hub for battery and drivetrain components for vehicles that are produced in the United States.
Giga Nevada is expected to support Tesla’s ambitious 2026 targets, including the launch of vehicles like the Tesla Semi and the Cybercab. Tesla will have a very busy 2026, and based on Giga Nevada’s activities so far, it appears that the facility will be equally busy as well.
News
Tesla Supercharger network delivers record 6.7 TWh in 2025
The network now exceeds 75,000 stalls globally, and it supports even non-Tesla vehicles across several key markets.
Tesla’s Supercharger Network had its biggest year ever in 2025, delivering a record 6.7 TWh of electricity to vehicles worldwide.
To celebrate its busy year, the official @TeslaCharging account shared an infographic showing the Supercharger Network’s growth from near-zero in 2012 to this year’s impressive milestone.
Record 6.7 TWh delivered in 2025
The bar chart shows steady Supercharger energy delivery increases since 2012. Based on the graphic, the Supercharger Network started small in the mid-2010s and accelerated sharply after 2019, when the Model 3 was going mainstream.
Each year from 2020 onward showed significantly more energy delivery, with 2025’s four quarters combining for the highest total yet at 6.7 TWh.
This energy powered millions of charging sessions across Tesla’s growing fleet of vehicles worldwide. The network now exceeds 75,000 stalls globally, and it supports even non-Tesla vehicles across several key markets. This makes the Supercharger Network loved not just by Tesla owners but EV drivers as a whole.
Resilience after Supercharger team changes
2025’s record energy delivery comes despite earlier 2024 layoffs on the Supercharger team, which sparked concerns about the system’s expansion pace. Max de Zegher, Tesla Director of Charging North America, also highlighted that “Outside China, Superchargers delivered more energy than all other fast chargers combined.”
Longtime Tesla owner and FSD tester Whole Mars Catalog noted the achievement as proof of continued momentum post-layoffs. At the time of the Supercharger team’s layoffs in 2024, numerous critics were claiming that Elon Musk was halting the network’s expansion altogether, and that the team only remained because the adults in the room convinced the juvenile CEO to relent.
Such a scenario, at least based on the graphic posted by the Tesla Charging team on X, seems highly implausible.