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SpaceX preparing for third Starship ‘full stack’
SpaceX appears to be preparing Starship 20 and Super Heavy Booster 4 for their third ‘full stack’ demonstration after two seemingly successful tests in August 2021 and February 2022.
The first, completed in early August 2021, was mostly for show and saw SpaceX stack the unfinished prototypes with a giant crane – fighting the coastal winds throughout. After just a few hours stacked, Ship 20 was removed and returned to Starbase, where workers spent several more weeks (mostly) finishing the prototype. Booster 4 followed suit several weeks later and ultimately took another three months of work to reach some level of test readiness.
After Ship 20 and Booster 4 completed a series of tests in the last few months of 2021 and early 2022, the two were re-stacked in mid-February – once again for show. This time, the stacked Starship served as a backdrop for SpaceX CEO Elon Musk’s first official Starship presentation in more than two years. However, despite the fact that neither prototype was actually tested during the second stack, SpaceX did use the opportunity to partially debut Starbase’s ‘orbital launch integration tower’ and used that towers trio of giant arms to lift, stack, and stabilize Starship S20 on top of Super Heavy B4.
Ship 20 was ‘destacked’ with the tower’s arms just a few days after Musk’s event – an undeniably rapid and impressive achievement for the first real use of the ‘chopstick’ arms but still far from demonstrating that Ship 20, Booster 4, or the orbital launch site (OLS) are ready for orbital test flights. Since then, however, Starbase’s launch facilities have admittedly been almost as busy as they’ve ever been with Starship and Super Heavy cryoproof tests.
Ship 20 completed its first basic OLS cryogenic proof test or ‘cryoproof’ just two days after it was destacked. Additional Starship S20 cryoproofs followed on February 17th (the day after), February 22nd, and March 3rd. Super Heavy B4 completed its own cryoproofs on February 18th and March 1st, the latter of which may have actually been the fullest a Starship booster has ever been filled. All told, SpaceX completed no less than six major B4/S20 cryoproof tests in 15 days.
Crucially, all six cryoproofs were performed with Starbase’s nascent orbital tank farm, thoroughly testing its storage and distribution capabilities. Additionally, because SpaceX began liquid methane deliveries on February 13th, some of those tests – particularly with Ship 20 – may have even been proper wet dress rehearsals, meaning that SpaceX may have filled the rocket(s) with liquid methane (LCH4) and liquid oxygen (LOx) propellant to replicate preparations for a real launch.
At a minimum, Super Heavy Booster 4’s oxidizer tank was fully filled with liquid oxygen – and possibly pressurized with hot gaseous oxygen – during its March 1st cryoproof, while its fuel tank was filled about two-thirds of the way either with liquid nitrogen (LN2) or methane. Prior to its February and March tests, Booster 4 had already completed three cryoproofs – some also using LOx – in December 2021. Ship 20 had completed a cryoproof and four static fire tests.
All told, short of finally performing a full Super Heavy wet dress rehearsal and static fire at the orbital launch site, it’s not all that clear what more SpaceX can derive from additional individual cryoproof testing of Ship 20 or Booster 4. Several things do still need to be demonstrated, however. First, the OLS launch tower has yet to use its arms to remotely install a Super Heavy on the orbital launch mount. More importantly, SpaceX has yet to use the launch tower and its swinging ship umbilical arm to cryoproof or fuel a Starship while stacked on top of a Super Heavy. Finally, SpaceX has also yet to simultaneously perform a cryoproof or wet dress rehearsal test of a stacked Starship and Super Heavy, which will be necessary for orbital test flights.
One or several of those to-be-completed tests may be why SpaceX appears to have begun preparing to install Ship 20 on top of Booster 4 for the third time. On March 14th, Starship S20 was moved towards the launch tower and on March 15th, the ship was slotted between its ‘chopstick’ arms. Based on stack #2, the ship could be lifted at any point – day or night – and installed on top of Super Heavy in a matter of hours.
News
Nvidia CEO Jensen Huang explains difference between Tesla FSD and Alpamayo
“Tesla’s FSD stack is completely world-class,” the Nvidia CEO said.
NVIDIA CEO Jensen Huang has offered high praise for Tesla’s Full Self-Driving (FSD) system during a Q&A at CES 2026, calling it “world-class” and “state-of-the-art” in design, training, and performance.
More importantly, he also shared some insights about the key differences between FSD and Nvidia’s recently announced Alpamayo system.
Jensen Huang’s praise for Tesla FSD
Nvidia made headlines at CES following its announcement of Alpamayo, which uses artificial intelligence to accelerate the development of autonomous driving solutions. Due to its focus on AI, many started speculating that Alpamayo would be a direct rival to FSD. This was somewhat addressed by Elon Musk, who predicted that “they will find that it’s easy to get to 99% and then super hard to solve the long tail of the distribution.”
During his Q&A, Nvidia CEO Jensen Huang was asked about the difference between FSD and Alpamayo. His response was extensive:
“Tesla’s FSD stack is completely world-class. They’ve been working on it for quite some time. It’s world-class not only in the number of miles it’s accumulated, but in the way it’s designed, the way they do training, data collection, curation, synthetic data generation, and all of their simulation technologies.
“Of course, the latest generation is end-to-end Full Self-Driving—meaning it’s one large model trained end to end. And so… Elon’s AD system is, in every way, 100% state-of-the-art. I’m really quite impressed by the technology. I have it, and I drive it in our house, and it works incredibly well,” the Nvidia CEO said.
Nvidia’s platform approach vs Tesla’s integration
Huang also stated that Nvidia’s Alpamayo system was built around a fundamentally different philosophy from Tesla’s. Rather than developing self-driving cars itself, Nvidia supplies the full autonomous technology stack for other companies to use.
“Nvidia doesn’t build self-driving cars. We build the full stack so others can,” Huang said, explaining that Nvidia provides separate systems for training, simulation, and in-vehicle computing, all supported by shared software.
He added that customers can adopt as much or as little of the platform as they need, noting that Nvidia works across the industry, including with Tesla on training systems and companies like Waymo, XPeng, and Nuro on vehicle computing.
“So our system is really quite pervasive because we’re a technology platform provider. That’s the primary difference. There’s no question in our mind that, of the billion cars on the road today, in another 10 years’ time, hundreds of millions of them will have great autonomous capability. This is likely one of the largest, fastest-growing technology industries over the next decade.”
He also emphasized Nvidia’s open approach, saying the company open-sources its models and helps partners train their own systems. “We’re not a self-driving car company. We’re enabling the autonomous industry,” Huang said.
Elon Musk
Elon Musk confirms xAI’s purchase of five 380 MW natural gas turbines
The deal, which was confirmed by Musk on X, highlights xAI’s effort to aggressively scale its operations.
xAI, Elon Musk’s artificial intelligence startup, has purchased five additional 380 MW natural gas turbines from South Korea’s Doosan Enerbility to power its growing supercomputer clusters.
The deal, which was confirmed by Musk on X, highlights xAI’s effort to aggressively scale its operations.
xAI’s turbine deal details
News of xAI’s new turbines was shared on social media platform X, with user @SemiAnalysis_ stating that the turbines were produced by South Korea’s Doosan Enerbility. As noted in an Asian Business Daily report, Doosan Enerbility announced last October that it signed a contract to supply two 380 MW gas turbines for a major U.S. tech company. Doosan later noted in December that it secured an order for three more 380 MW gas turbines.
As per the X user, the gas turbines would power an additional 600,000+ GB200 NVL72 equivalent size cluster. This should make xAI’s facilities among the largest in the world. In a reply, Elon Musk confirmed that xAI did purchase the turbines. “True,” Musk wrote in a post on X.
xAI’s ambitions
Recent reports have indicated that xAI closed an upsized $20 billion Series E funding round, exceeding the initial $15 billion target to fuel rapid infrastructure scaling and AI product development. The funding, as per the AI startup, “will accelerate our world-leading infrastructure buildout, enable the rapid development and deployment of transformative AI products.”
The company also teased the rollout of its upcoming frontier AI model. “Looking ahead, Grok 5 is currently in training, and we are focused on launching innovative new consumer and enterprise products that harness the power of Grok, Colossus, and 𝕏 to transform how we live, work, and play,” xAI wrote in a post on its website.
Elon Musk
Elon Musk’s xAI closes upsized $20B Series E funding round
xAI announced the investment round in a post on its official website.
xAI has closed an upsized $20 billion Series E funding round, exceeding the initial $15 billion target to fuel rapid infrastructure scaling and AI product development.
xAI announced the investment round in a post on its official website.
A $20 billion Series E round
As noted by the artificial intelligence startup in its post, the Series E funding round attracted a diverse group of investors, including Valor Equity Partners, Stepstone Group, Fidelity Management & Research Company, Qatar Investment Authority, MGX, and Baron Capital Group, among others.
Strategic partners NVIDIA and Cisco Investments also continued support for building the world’s largest GPU clusters.
As xAI stated, “This financing will accelerate our world-leading infrastructure buildout, enable the rapid development and deployment of transformative AI products reaching billions of users, and fuel groundbreaking research advancing xAI’s core mission: Understanding the Universe.”
xAI’s core mission
Th Series E funding builds on xAI’s previous rounds, powering Grok advancements and massive compute expansions like the Memphis supercluster. The upsized demand reflects growing recognition of xAI’s potential in frontier AI.
xAI also highlighted several of its breakthroughs in 2025, from the buildout of Colossus I and II, which ended with over 1 million H100 GPU equivalents, and the rollout of the Grok 4 Series, Grok Voice, and Grok Imagine, among others. The company also confirmed that work is already underway to train the flagship large language model’s next iteration, Grok 5.
“Looking ahead, Grok 5 is currently in training, and we are focused on launching innovative new consumer and enterprise products that harness the power of Grok, Colossus, and 𝕏 to transform how we live, work, and play,” xAI wrote.
Nvidia CEO Jensen Huang explains difference between Tesla FSD and Alpamayo
Elon Musk confirms xAI’s purchase of five 380 MW natural gas turbines
