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NASA scrubs first SLS Moon rocket launch attempt
NASA has scrubbed the first attempted launch of its Space Launch System (SLS) Moon rocket after running into multiple issues, one of which could not be solved in time.
The delay is bad news for the tens to hundreds of thousands of tourists who traveled to Cape Canaveral, Florida to witness the launch in person. Worse, by NASA’s own implicit admission, there’s a good chance the main problem SLS encountered could have already been dealt with and rectified in advance of the launch attempt if the space agency had finished testing the rocket earlier this summer.
Ultimately, that omission turned the first SLS launch attempt into more of a continuation of the rocket’s first four wet dress rehearsal (WDR) attempts, none of which ended as expected. NASA engineers will now have to decide how to proceed and whether the SLS rocket can be made ready in time for another launch attempt on September 2nd or 5th. If not, the next opportunity could be weeks away.
As far as SLS test operations go, the August 28/29th launch attempt was fairly ordinary, with the rocket running into multiple issues – a few minor, a few significant, and one identical to a previous problem. The first problem – a hydrogen leak near the SLS rocket’s base – came after a risk of lightning delayed the start of propellant loading by more than an hour. A very similar, if not identical, hydrogen fuel leak had already occurred during official wet dress rehearsal testing in April and July.
That leak was fixed on the fly by properly chilling all related systems, and propellant loading was eventually completed – albeit a few hours late thanks to inclement weather. Shortly after, there were reports of a crack that needed careful analysis. Only later did NASA specify that the suspected crack was in the rocket’s foam insulation rather than its structures, the latter of which could have been a catastrophic problem.
Around the same time, the true showstopper of the day occurred when NASA attempted to chill the SLS Core Stage’s four RS-25 engines, all of which flew several times aboard reusable Space Shuttle orbiters. Three engines performed (mostly) as expected, flowing a bit of liquid hydrogen fuel to cool themselves down, but one – engine #3 – was never able to make progress toward the optimal temperature needed for ignition (~5°C/~41°F). After hours of remote troubleshooting attempts, no progress had been made, and NASA ultimately decided to scrub the launch attempt at T-40 minutes to liftoff.
Over the course of four separate wet dress rehearsal attempts in April and June 2022, NASA was never able to test the core stage’s engine chill capabilities. In a post-scrub press conference, Jim Free – NASA’s Associate Administrator of the Exploration Systems Development Division – revealed that all four engines were warmer than intended, further confirming that skipping a fully nominal wet dress rehearsal was likely a mistake. Clear and present evidence aside, Free stated that he and other executives still believed skipping that test was the right decision, claiming that ending explicit WDR testing reduced the number of times the rocket needed to be moved on its transporter.
Making the situation even harder to explain, Artemis I Mission Manager Mike Sarafin revealed in the conference Q&A that Boeing had changed the design of parts of the SLS engine chill (bleed) system after the Core Stage finally conducted a nominal static fire test at Mississippi’s Stennis Space Center. Completed in March 2021, the SLS rocket then sat inside NASA’s Kennedy Space Center, Florida Vehicle Assembly Building (VAB) for a full year before attempting its first wet dress rehearsal tests at the launch pad.
The first round of three WDRs were not as smooth as NASA expected and instead uncovered three relatively small issues: a hydrogen leak, a single faulty upper stage valve, and problems with a ground supply of nitrogen gas. Those small issues led NASA to roll SLS back to the VAB for repairs, incurring a minimum multi-week delay that stretched into two months. SLS also failed to complete a fourth WDR attempt in July 2022, but NASA decided to overlook the rocket parts and phases of preflight operations that were never actually tested as planned, one of which was the engine chill system.
If NASA cannot fix the RS-25 chill system within the next few days, it will be forced to roll the entire rocket and mobile launch platform back to the VAB to – at a minimum – replace its flight termination system (FTS). The US Eastern Range requires that all rocket FTS systems be tested no more than 15 days before launch, and NASA was able to secure special permission for a gap of up to 25 days. However, because Boeing’s Core Stage design places the FTS system in a location that is reportedly inaccessible at the pad, the entire SLS rocket will need to roll back to the VAB to have its FTS systems “retested” after that period.
As a result, NASA’s SLS launch debut will be delayed by several weeks (at best) if it can’t recycle for another attempt on September 2nd or 5th. The next window runs from September 20th to October 4th, but the SLS rocket took 10 days to go from its latest rollout to first launch attempt – a figure that doesn’t include the time required to remove the rocket from the pad, roll it back to the VAB, and conduct any necessary repairs or tests while back in the bay. If NASA can’t fix the engine problem at the pad by September 3rd or 4th, the true delay could be more like 4-6 weeks.
With any luck, that won’t happen, but it’s clear that a lot of stress and discomfort could have been avoided if NASA had gone into its first launch attempt knowing that its SLS rocket was truly ready.
Investor's Corner
Tesla Robotaxi gets a massive upgrade in Nevada
Nevada regulators just approved a massive expansion of Tesla’s robotaxi fleet across the entire county.
Tesla’s robotaxi footprint in Nevada just grew by roughly 500 times in a single regulatory vote.
The Nevada Transportation Authority approved Tesla’s full Autonomous Vehicle Network Company permit on Thursday, clearing the way for the company to deploy up to 5,000 driverless vehicles across Clark County over the next 12 months. The decision came during a four hour general session meeting that Tesla investor Sawyer Merritt watched live and reported on X, noting the vote replaces the interim order that had limited Tesla to just 10 robotaxis on a narrow stretch of the Las Vegas Strip.
EXCLUSIVE: Tesla has just officially received approval for its full Autonomous Vehicle Network Company permit in Nevada, clearing the way for Tesla to launch a paid public Robotaxi service in Las Vegas.
This officially allows @Tesla to deploy up to 5,000 robotaxis over the next… pic.twitter.com/DPs5UtUlrE
— Sawyer Merritt (@SawyerMerritt) August 20, 2026
That earlier cap, covered here after it surfaced on August 13, came with restrictions that looked stricter than what Tesla runs in Austin: a 45 mph speed ceiling, no airport pickups, and a geofence confined to the Strip corridor. The new approval extends Tesla’s operating authority to all of Clark County, with room to request an even wider geofence across the state.
Tesla representatives at the meeting said they have no intention of putting 5,000 cars on the road right away. Commercial rides are expected to start within 30 days, pending vehicle inspections, insurance filings, and fare approval, the standard steps every robotaxi operator in Nevada has had to clear.
Tesla’s own Robotaxi account replied to the news with a short line, The golden future is upon us.
The timing lines up with Tesla’s broader robotaxi push this month. The company is preparing to open Cybercab rides to the public in Austin as soon as this month, and it opened a sweepstakes for riders to win a seat at the launch event. Tesla filed its original application for a 5,000 vehicle Nevada fleet back in June, a request regulators trimmed to 10 vehicles when they issued the interim order in July. Thursday’s vote effectively grants the number Tesla asked for from the start.
Zoox, the Amazon owned robotaxi operator, has run in Nevada since 2025 and was capped at 100 vehicles before Thursday’s decision. Tesla’s new ceiling puts it well ahead of that comparison on paper, though the company has said its actual fleet size will depend on how quickly FSD v15 rolls out, the software update executives have called the gateway to scaling unsupervised robotaxi operations nationwide.
Tesla welcomed JPMorgan analysts to one of its factories earlier this month, with the Wall Street firm highlighting its findings in a new note to investors. One of the more pertinent pieces of information is that Tesla admitted to slowly integrating Model Y vehicles into its Robotaxi fleet, but it has a good reason.
JPMorgan analysts recently toured Tesla’s Fremont Factory and met with the company’s investor relations team, emerging with a clearer picture of the automaker’s Robotaxi strategy. According to the bank’s note, Tesla is intentionally limiting the addition of Model Y vehicles to its existing Robotaxi fleet.
The firm’s analysts said:
“Tesla indicated it is intentionally holding back on adding Model Y units to the robotaxi fleet, expressing confidence in its ability to scale Cybercab in the near-term. On FSD V15, Tesla views this release as a step-change in performance, comparable to the leap from V13 to V14. The V15 upgrade encompasses seven core technologies, with ~40% of those currently being tested in the robotaxi fleet, where initial feedback has been encouraging.”
JPMorgan after meeting with Tesla recently in Fremont:
“Tesla indicated it is intentionally holding back on adding Model Y units to the robotaxi fleet, expressing confidence in its ability to scale Cybercab in the near-term. On FSD V15, Tesla views this release as a step-change… pic.twitter.com/W9yGCWRT3C
— Sawyer Merritt (@SawyerMerritt) August 20, 2026
Far from signaling delays or doubts about autonomy, the move reflects strong management confidence in the near-term scalability of the purpose-built Cybercab.
Tesla has operated its Robotaxi service primarily with modified Model Ys since launching in Austin and expanding to other markets. Yet the company is now deliberately holding back further Model Y conversions. The rationale is straightforward: leadership believes the Cybercab, a two-seat, steering-wheel- and pedal-free vehicle optimized for high utilization, can ramp production and deployment more efficiently in the coming months.
This dedicated form factor promises better unit economics for the majority of rides, which typically involve one or two passengers, while freeing consumer Model Y inventory for retail sales.
Supporting this pivot is Full Self-Driving (FSD) software version 15, which Tesla describes as a genuine step-change in performance, comparable to the leap from V13 to V14. The update incorporates seven core technologies; roughly 40 percent are already undergoing real-world testing in the current Robotaxi fleet, with early feedback described as encouraging.
Tesla is carefully managing software development to minimize regressions in core driving functions as new capabilities are added. Management positions V15 as the primary gateway to scaling unsupervised FSD. Importantly, the existing AI and Hardware 4 stack is already capable of running V15 and supporting unsupervised operation.
Cybercab itself is only the first vehicle on the platform. Tesla reiterated that additional form factors will follow, pointing to concepts such as the earlier “Robovan” demonstration as examples of how the architecture can evolve.
Tesla’s mysterious Robovan makes a sneak peek with Optimus in Terafab video
Parallel progress continues on the Optimus humanoid robot, which remains on track for start of production in the coming months, with commercial sales possible as early as the second half of 2027. Generation 3 details will be revealed closer to production to preserve competitive advantages, while Generation 4 scope will draw on real-world Gen 3 experience.
JPMorgan left the meeting with a deeper appreciation for Tesla’s manufacturing automation and maintained its $475 price target. The decision to slow Model Y Robotaxi integration is therefore not a setback but a calculated prioritization of a more efficient, purpose-built solution that management believes is ready to scale.
SpaceX CEO Elon Musk announced today that the company will likely attempt to catch the Starship upper stage with its launch tower arms “in a few months.”
In a post on X, Musk wrote, “Looks like we will probably catch the ship with the tower in a few months. If there had been a tower out to sea where we practiced landing the ship, it would have been caught.” He added that the first reflight of a Starship vehicle is expected by the end of 2026 or early 2027, describing it as “a fork in the road of history for consciousness reaching the stars.”
Looks like we will probably catch the ship with the tower in a few months. If there had been a tower out to sea where we practiced landing the ship, it would have been caught.
First reflight of the ship will be either end of this year or early next. That will be a fork in the… https://t.co/O5g9pqrzyo
— Elon Musk (@elonmusk) August 20, 2026
Musk’s prediction comes amid ongoing progress toward full reusability of the Starship system, a two-stage rocket designed for rapid turnaround and dramatically lower launch costs. Catching the upper stage, known simply as “ship,” with the Mechazilla tower’s mechanical arms would mark a major milestone. It would allow both stages to return directly to the launch site for quick refurbishment and reuse, eliminating the need for ocean recovery.
Musk has previously signaled plans for a ship catch. In July, shortly after SpaceX’s wildly successful Starship 13 mission, he stated that the company would attempt to catch the ship with the tower on the next flight unless problems emerged in the mission data review. Earlier comments also outline conditions such as successful soft ocean landings before attempting a land recovery to minimize risk.
SpaceX has solved Starship’s biggest challenge, Elon Musk says
The latest update from Musk adjusts this timeline to a few months, reflecting the iterative nature of the test campaign.
SpaceX has already demonstrated the tower catch technique successfully with the Super Heavy booster on a couple of occasions. The first successful booster catch occurred during Flight 5 in October 2024, when the massive first stage returned to the Starbase pad in Texas and was plucked from the air by the tower arms.
Additional catches followed on later flights, including Flight 7, proving the concept for the booster and building confidence in the system as a whole.
Achieving a similar catch for the upper stage would represent a significant step forward. The ship returns from much higher speeds and greater heat loads after orbital or near-orbital flight. Success would advance SpaceX’s goal of full and rapid reusability, potentially reducing the cost of access to orbit by a factor of 100 or more and supporting ambitions for frequent satellite deployments, lunar missions, and eventual Mars flights.
Musk has long emphasized that true reusability, refueling rather than discarding hardware, is essential for making humanity a multi-planetary species.
As SpaceX continues refining Starship through successive test flights, the coming months will test whether the ambitious catch timeline can be met. The combination of prior booster successes and improving ship landing precision suggests the company is steadily closing in on this historic capability.
Tesla Robotaxi gets a massive upgrade in Nevada
Tesla admits to slow Model Y Robotaxi integration, but for a good reason
