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NASA’s SLS Moon rocket almost aces vital prelaunch test on 7th try

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4 years ago

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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.

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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.

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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.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Investor's Corner

Lucid denies rumors of bankruptcy after over 40% stock drop

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4 hours ago

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July 14, 2026

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Credit: Lucid

Electric vehicle maker Lucid Group has denied rumors of an imminent bankruptcy after a report from this morning sent the stock on a dramatic drop on Wall Street, seeing losses of more than 40 percent during trading hours.

Lucid’s Director of Communications, Nick Twork, responded to the report from Eletric-Vehicles.com, which stated the company’s restructuring advisor, AlixPartners, was asked to review two decisions: taking Lucid shares private or filing for Chapter 11 bankruptcy protection.

The report also claims AlixPartners told the Lucid board to “concentrate on Gravity production while improving its quality, and to temporarily hold back the Lucid Air, the sedan that has defined the company since its launch.”

Twork said:

Shares rebounded after the response to the report, halving its losses as the trading day neared 3 p.m. Eastern.

Lucid has struggled to get its sales off the ground and into more respectable numbers, but the company is in its early years, when things are hard to begin with. It is also backed by several notable investors, including the Saudi Public Investment Fund (PIF), which has nearly limitless money and likely would not ditch an investment of this size so soon.

Lucid shares were down just 14 percent at the time of publication, a far cry from the 55 percent its losses topped out at during the day.

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Tesla owner attempts resale of Model S Signature Edition for over $260k

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7 hours ago

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July 14, 2026

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Credit: Tesla

A Tesla owner who purchased a Model S Signature Edition, one of the final 250 units of the all-electric flagship vehicle that the company discontinued earlier this year, is attempting to sell the car despite a no-resale clause that prohibits reselling for the first year.

The car is being sold by J&S Autohaus in Ewing, New Jersey, and is priced at $260,490, well above the $159,420 that Tesla sold it for earlier this year.

To those who do not know, the Model S Signature was a highly exclusive, limited-run farewell variant of the Model S Plaid that was produced this year to mark the end of production of both the Model S and Model X, Tesla’s two flagship vehicles.

Limited to just 250 units with invite-only sales, it serves as a collector’s item celebrating the legacy of the Model S, which helped pioneer Tesla’s electric vehicle success since its 2012 launch.

It bundles top-tier performance with bespoke cosmetic and luxury upgrades, plus Tesla’s Luxe Package. Here’s what the Model S Signature has over the typical Model S Plaid:

  • Exclusive Exterior – Unique Garnet Red Paint, matching door handles, gold Tesla “T” badges upfront, gold Plaid and Signature badging at the rear.
  • Premium Interior – White Alcantara upholstery with gold piping/accents, gold Plaid seat badges, Signature-marked door sills, individually numbered dashboard plaque, gold puddle lights, special interior lighting sequence, and a custom Signature key fob.
  • Performance Upgrades – Carbon-ceramic brakes with gold calipers
  • Bundled Luxe Package – Full Self-Driving (Supervised), four years of Premium Connectivity, free lifetime Supercharging
  • Performance Metrics – ~1,020 horsepower, sub-2-second 0-60 MPH, ~390-mile range

Tesla quickly introduced a No Resale Agreement for the Signature Editions of the Model S and Model X, which would penalize the seller for “the amount of $50,000 or the value received as consideration for the sale or transfer, whichever is greater.”

The company continues:

“If you sell or otherwise transfer the ownership of your Model S or Model X, the remainder of the Recommended Maintenance, Wheel and Tire Protection Plan, and Windshield Protection Plan will transfer automatically to the buyer. The Full Self-Driving (Supervised), Free Supercharging and Premium Connectivity will not transfer with the vehicle and will terminate once the ownership of the Model S or Model X is transferred.”

Tesla will likely come after the seller, especially as it has been about two months since Tesla launched deliveries.

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Tesla Full Self-Driving v14.3.5 Early Impressions: new features and early performance

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10 hours ago

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July 14, 2026

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Credit: TESLARATI

Tesla rolled out Full Self-Driving (Supervised) v14.3.5 yesterday, and about fifty miles of driving on the new version has given me enough time to highlight what seems to be strong about the release and what is not.

Additionally, Tesla has added a few new features with this specific update, which we’ll highlight as well.

Tesla Full Self-Driving v14.3.5 Performance

The new update is business as usual. Things seem to be running completely normal and necessary, but there are a few things that we’ve seemed to pick up on based on our own experience with v14.3.5, as well as what other users are seeing.

Initially, it seems to be more aware of its surroundings, making moves that are incredibly courteous to other drives and operating just a tad more reserved than what the suite might have done previously.

We had two instances where it showed this, the first being FSD needing to pass a Flagger Force vehicle that was placing down signage for the day. Their work truck was right at the front corner of a right-hand turn; typically where most cars travel when they take that turn.

FSD v14.3.5 recognized this, slowed down, and took the turn wide with no issues:

Additionally, v14.3.5 backed up for a semi truck that was making a wide turn onto a road my car was on. This is not new, but it seemed to be backing up for courtesy; it didn’t seem completely necessary, but it might have put some peace of mind in the truck driver’s head:

X user Mike P, also a Pennsylvania native like myself, shared three clips of his Tesla running v14.3.5 performing similar maneuvers. He said:

“FSD turns right into a small alley that only fits one car at a time, sees oncoming car, reverses out of alley to make space, realizes oncoming car is actually parking, re-enters alley.”
Check it out here:

It seems like Speed Profiles are still in need of some tweaking; I am adjusting what Speed Profile I’m in frequently, constantly changing it to get it to travel at the correct speed. This was an issue for me on v14.3.4. It seems like they’re just a little inconsistent.

Terrible Parking

Parking attempts on v14.3.5 were not good. There are quite a few people who have said this:

David Moss, the Tesla owner who has taken multiple coast-to-coast drives without any interventions, also has had some issues with parking early on with v14.3.5:

New Features

Tesla has added the ability to open Camera Preview at any time. Previously, it was only available in Park. Here’s what that feature looks like in action:

Check back later this week for a longer review of what we’ve noticed on Full Self-Driving v14.3.5.

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