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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.
News
Lucid unveils Lunar Robotaxi in bid to challenge Tesla’s Cybercab in the autonomous ride hailing race
Lucid’s Lunar robotaxi is gunning for Tesla’s Cybercab in the autonomous ride hailing race
![Lucid Lunar robotaxi concept [Credit: Rendering by TESLARATI]](https://www.teslarati.com/wp-content/uploads/2026/03/lucid-lunar-robotaxi-concept-teslarati-rendering.jpg)
Lucid Group pulled back the curtain on its purpose-built autonomous robotaxi platform dubbed the Lunar Concept. Announced at its New York investor day event, Lunar is arguably the company’s most ambitious concept yet, and a direct line of sight toward the autonomous ride haling market that Tesla looks to control.
At Lucid Investor Day 2026, the company introduced Lunar, a purpose-built robotaxi concept based on the Midsize platform.
A comparison to Tesla’s Cybercab is unavoidable. The concept of a Tesla robotaxi was first introduced by Elon Musk back in April 2019 during an event dubbed “Autonomy Day,” where he envisioned a network of self-driving Tesla vehicles transporting passengers while not in use by their owners. That vision took another major step in October 2024 when, Musk unveiled the Cybercab at the Tesla “We, Robot” event held at Warner Bros. Studios in Burbank, California, where 20 concept Cybercabs autonomously drove around the studio lot giving rides to attendees.
Fast forward to today, and Tesla’s ambitions are finally materializing, but not without friction. As we recently reported, the Cybercab is being spotted with increasing frequency on public roads and across the grounds of Gigafactory Texas, suggesting that the company’s road testing and validation program is ramping meaningfully ahead of mass production. Tesla already operates a small scale robotaxi service in Austin using supervised Model Ys, but the Cybercab is designed from the ground up for high-volume, low-cost production, with Musk stating an eventual goal of producing one vehicle every 10 seconds.
At Lucid Investor Day 2026, the company introduced Lunar, a purpose-built robotaxi concept based on the Midsize platform.
Into this landscape steps Lucid’s Lunar. Built on the company’s all-new Midsize EV platform, which will also underpin consumer SUVs starting below $50,000. The Lunar mirrors the Cybercab’s core philosophy of having two seats, no driver controls, and a focus on fleet economics. The platform introduces Lucid’s redesigned Atlas electric drive unit, engineered to be smaller, lighter, and cheaper to manufacture at scale.
Unlike Tesla’s strategy of building its own ride hailing network from scratch, Lucid is partnering with Uber. The companies are said to be in advanced discussions to deploy Midsize platform vehicles at large scale, with Uber CEO Dara Khosrowshahi publicly backing Lucid’s engineering credentials and autonomous-ready architecture.
In the investor day event, Lucid also outlined a recurring software revenue model, with an in-vehicle AI assistant and monthly autonomous driving subscriptions priced between $69 and $199. This can be seen as a nod to the software revenue stream that Tesla has long championed with its Full Self-Driving subscription.
Tesla’s Cybercab is targeting a price point below $30k and with operating costs as low as 20 cents per mile. But with regulatory hurdles still ahead, the window for competition is open. Lucid’s Lunar may not have a launch date yet, but it arrives at a pivotal moment, and when the robotaxi race is no longer viewed as hypothetical. Rather, every serious EV player needs to come to bat on the same plate that Tesla has had countless practice swings on over the last seven years.
Elon Musk
Brazil Supreme Court orders Elon Musk and X investigation closed
The decision was issued by Supreme Court Justice Alexandre de Moraes following a recommendation from Brazil’s Prosecutor-General Paulo Gonet.
Brazil’s Supreme Federal Court has ordered the closure of an investigation involving Elon Musk and social media platform X. The inquiry had been pending for about two years and examined whether the platform was used to coordinate attacks against members of the judiciary.
The decision was issued by Supreme Court Justice Alexandre de Moraes following a recommendation from Brazil’s Prosecutor-General Paulo Gonet.
According to a report from Agencia Brasil, the investigation conducted by the Federal Police did not find evidence that X deliberately attempted to attack the judiciary or circumvent court orders.
Prosecutor-General Paulo Gonet concluded that the irregularities identified during the probe did not indicate fraudulent intent.
Justice Moraes accepted the prosecutor’s recommendation and ruled that the investigation should be closed. Under the ruling, the case will remain closed unless new evidence emerges.
The inquiry stemmed from concerns that content on X may have enabled online attacks against Supreme Court justices or violated rulings requiring the suspension of certain accounts under investigation.
Justice Moraes had previously taken several enforcement actions related to the platform during the broader dispute involving social media regulation in Brazil.
These included ordering a nationwide block of the platform, freezing Starlink accounts, and imposing fines on X totaling about $5.2 million. Authorities also froze financial assets linked to X and SpaceX through Starlink to collect unpaid penalties and seized roughly $3.3 million from the companies’ accounts.
Moraes also imposed daily fines of up to R$5 million, about $920,000, for alleged evasion of the X ban and established penalties of R$50,000 per day for VPN users who attempted to bypass the restriction.
Brazil remains an important market for X, with roughly 17 million users, making it one of the platform’s larger user bases globally.
The country is also a major market for Starlink, SpaceX’s satellite internet service, which has surpassed one million subscribers in Brazil.
Elon Musk
FCC chair criticizes Amazon over opposition to SpaceX satellite plan
Carr made the remarks in a post on social media platform X.
U.S. Federal Communications Commission (FCC) Chairman Brendan Carr criticized Amazon after the company opposed SpaceX’s proposal to launch a large satellite constellation that could function as an orbital data center network.
Carr made the remarks in a post on social media platform X.
Amazon recently urged the FCC to reject SpaceX’s application to deploy a constellation of up to 1 million low Earth orbit satellites that could serve as artificial intelligence data centers in space.
The company described the proposal as a “lofty ambition rather than a real plan,” arguing that SpaceX had not provided sufficient details about how the system would operate.
Carr responded by pointing to Amazon’s own satellite deployment progress.
“Amazon should focus on the fact that it will fall roughly 1,000 satellites short of meeting its upcoming deployment milestone, rather than spending their time and resources filing petitions against companies that are putting thousands of satellites in orbit,” Carr wrote on X.
Amazon has declined to comment on the statement.
Amazon has been working to deploy its Project Kuiper satellite network, which is intended to compete with SpaceX’s Starlink service. The company has invested more than $10 billion in the program and has launched more than 200 satellites since April of last year.
Amazon has also asked the FCC for a 24-month extension, until July 2028, to meet a requirement to deploy roughly 1,600 satellites by July 2026, as noted in a CNBC report.
SpaceX’s Starlink network currently has nearly 10,000 satellites in orbit and serves roughly 10 million customers. The FCC has also authorized SpaceX to deploy 7,500 additional satellites as the company continues expanding its global satellite internet network.
![Lucid Lunar robotaxi concept [Credit: Rendering by TESLARATI]](https://www.teslarati.com/wp-content/uploads/2026/03/lucid-lunar-robotaxi-concept-teslarati-rendering-80x80.jpg)
Lucid unveils Lunar Robotaxi in bid to challenge Tesla’s Cybercab in the autonomous ride hailing race
Brazil Supreme Court orders Elon Musk and X investigation closed
