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SpaceX Starship hop debut aborted at the last second by Raptor engine
SpaceX’s full-scale Starship hop debut was aborted at the last second after an otherwise successful lead-up to the milestone, forcing the company to try again tomorrow.
Following a minor delay from August 2nd to August 3rd, SpaceX kicked off Starship SN5’s hop debut preparations relatively late into the 12-hour window, closing the highway and clearing the pad around 5pm CDT (22:00 UTC). The Starship SN5 tank section prototype was pressurized with ambient-temperature gas around the same time, while cryogenic liquid methane and oxygen propellant loading appeared to begin at roughly 6:20pm CDT (23:20 UTC).
Soon after, SpaceX CEO Elon Musk revealed that Starship was just 33 minutes away from launch, marching towards the first hop of a full-scale prototype at 6:56pm CDT. Unfortunately, possibly much less than a second before ignition, Starship SN5’s Raptor engine had different plans.
Musk says that one of Raptor engine SN27’s “spin start valves” failed to open moments before ignition, causing Starship to automatically abort the attempt. With more than an hour left in the window, SpaceX had time to briefly troubleshoot the bug and potentially turn the rocket around for a second attempt, but Musk announced some 50 minutes later that the company would stand down and try again tomorrow.
Musk’s description of the hop test abort sounds suspiciously similar to his description of the last abort of Starship SN5’s Raptor engine static fire test, in which a “fuel spin valve didn’t open.” If the root cause of both aborts is the same, there’s a good chance that SpaceX may need more time to properly investigate and fix the problem. A recurring issue is immediately much more concerning compared to a one-off bug, so there’s also a chance that SpaceX will go as far as replacing the Raptor engine currently installed on Starship SN5.
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If things look more severe than SpaceX initially thought they were after the static fire abort and a replacement engine is necessary, Starship SN5 will have to complete another static fire test with the new Raptor before it can proceed to a second hop attempt.
Based on live views of the launch attempt from NASASpaceflight and LabPadre, Starship SN5 likely aborted a matter of milliseconds before Raptor SN27 ignition and perhaps just a second or two before liftoff. Just like SpaceX’s workhorse Falcon 9 and Heavy rockets, the vehicle’s flight computer is fully in control of the countdown a minute or two before liftoff and can automatically abort far faster than any human could possibly react. Held to the launch mount by hold-down clamps, Starship could have technically analyzed the engine’s performance after ignition and aborted the launch even later into the count.
Once hold-down clamp release is commanded, Starship SN5 will attempt to fly a roughly 150m-tall (500 ft) arc heading southeast of the launch mount. Perhaps 10 seconds prior to touchdown, Starship will attempt to deploy an array of six odd legs and gently land a few hundred feet from the pad. As of now, assuming Raptor’s finicky valve can be easily rectified, SpaceX will work towards a second Starship SN5 hop attempt sometime between 8am and 8pm CDT on Tuesday, August 4th.
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Tesla Semi factory looks almost complete during Thanksgiving weekend
Based on recent drone videos, the Tesla Semi factory looks practically ready to start operations.
It appears that the Tesla Semi factory near Giga Nevada is already hard at work preparing for the initial production of the Class 8 all-electric truck. This was, at least, hinted at in a recent drone flyover of the facility from a longtime watcher.
The Tesla Semi factory after Thanksgiving
Drone operator and Tesla Semi advocate @HinrichsZane recently shared some footage he captured of the upcoming facility during the Thanksgiving weekend. Based on his video, it appears that Tesla gave its employees in the area the weekend off. One thing is evident from the video, however, and that is the fact that the Tesla Semi factory looks practically ready to start operations.
The Tesla Semi watcher did point out that the electric vehicle maker is still busy bringing in production equipment into the facility itself. Once these are installed, it would not be surprising if initial production of the Tesla Semi begins.
A new Tesla Semi
The upcoming completion of the Tesla Semi factory near Gigafactory Nevada seems all but inevitable in the coming months. What would be especially interesting, however, would be the vehicles that would be produced on the site. During Elon Musk’s presentation at the 2025 Annual Shareholder Meeting, a glimpse of the production Tesla Semi was shown, and it looks quite a bit different than the Class 8 all-electric truck’s classic appearance.
As could be seen in the graphic from the CEO’s presentation, the updated Tesla Semi will feature slim lightbar headlights similar to the new Tesla Model Y, Cybertruck, and the Cybercab. Tesla also teased a number of aerodynamic improvements that increased the truck’s efficiency to 1.7 kWh per mile. Extended camera units, seemingly for FSD, could also be seen in the graphic.
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Tesla scores major hire as Apple scientist moves to Optimus team
Chen, who advanced from individual contributor to technical lead during his time at Apple, noted that he was blown away by Tesla’s efforts and synergy.
Former Apple research scientist Yilun Chen has left the tech giant to join Tesla’s Optimus AI team. Chen, who advanced from individual contributor to technical lead during his time at Apple, noted that he was blown away by Tesla’s efforts and synergy.
Apple veteran closes a major chapter
In a farewell note, Yilun Chen reflected on his tenure at Apple as a period defined by rapid growth and exposure to notable internal projects, some of which remain unreleased. His roles spanned engineering, research, early product incubation, and hands-on prototyping, allowing him to build expertise across both mature and emerging teams.
Chen credited mentors, colleagues, and cross-functional collaborators for shaping his trajectory, calling the experience unforgettable and emphasizing how each team taught him different lessons about scaling technology, guiding product vision, and navigating fast-moving research environments. “Each role has offered me invaluable unique lessons… My deepest gratitude goes to my colleagues, mentors and friends,” he wrote.
Tesla’s Optimus lab secured the hire
Chen said the move to Tesla was driven by the momentum surrounding Optimus, a humanoid robot powered by LLM-driven reasoning and Physical AI. After visiting Tesla’s Optimus lab, he admitted that he was “totally blown away by the scale and sophistication of the Optimus lab and deep dedication of people when I got to visit the office.”
His first week at Tesla, he noted, involved spontaneous deep-tech discussions, a flat team structure, rapid prototyping cycles, and what he called a “crazy ideas with super-fast iterations” culture. Chen emphasized that the team’s ambition, as well as its belief that humanoid robots are now within reach, creates an energy level that feels aimed at changing the world.
-->“You can feel the energy to change the world here,” he wrote in a post on social media.
Elon Musk
Elon Musk gives nod to SpaceX’s massive, previously impossible feat
It was the booster’s 30th flight, a scenario that seemed impossible before SpaceX became a dominant force in spaceflight.
Elon Musk gave a nod to one of SpaceX’s most underrated feats today. Following the successful launch of the Transporter-15 mission, SpaceX seamlessly landed another Falcon 9 booster on a droneship in the middle of the ocean.
It was the booster’s 30th flight, a scenario that seemed impossible before SpaceX became a dominant force in spaceflight.
Elon Musk celebrates a veteran Falcon 9 booster’s feat
SpaceX completed another major milestone for its Smallsat Rideshare program on Friday, successfully launching and deploying 140 spacecraft aboard a Falcon 9 from Vandenberg Space Force Base. The mission, known as Transporter-15, lifted off two days later than planned after a scrub attributed to a ground systems issue, according to SpaceFlight Now. SpaceX confirmed that all payloads designed to separate from the rocket were deployed as planned.
The Falcon 9 used for this flight was booster B1071, one of SpaceX’s most heavily flown rockets. With its 30th mission completed, it becomes the second booster in SpaceX’s fleet to reach that milestone. B1071’s manifest includes five National Reconnaissance Office missions, NASA’s SWOT satellite, and several previous rideshare deployments, among others. Elon Musk celebrated the milestone on X, writing “30 flights of the same rocket!” in his post.
Skeptics once dismissed reusability as unfeasible
While rocket landings are routine for SpaceX today, that was not always the case. Industry veterans previously questioned whether reusable rockets could ever achieve meaningful cost savings or operational reliability, often citing the Space Shuttle’s partial reusability as evidence of failure.
-->In 2016, Orbital ATK’s Ben Goldberg argued during a panel that even if rockets could be reusable, they do not make a lot of sense. He took issue with Elon Musk’s claims at the time, Ars Technica reported, particularly when the SpaceX founder stated that fuel costs account for just a fraction of launch costs.
Goldberg noted that at most, studies showed only a 30% cost reduction for low-Earth orbit missions by using a reusable rocket. “You’re not going to get 100-fold. These numbers aren’t going to change by an order of magnitude. They’re just not. That’s the state of where we are today,” he said.
Former NASA official Dan Dumbacher, who oversaw the Space Launch System, expressed similar doubts in 2014, implying that if NASA couldn’t make full reusability viable, private firms like SpaceX faced steep odds.
Tesla Semi factory looks almost complete during Thanksgiving weekend
Tesla scores major hire as Apple scientist moves to Optimus team
