There's A New SpaceX Engine To Replace Raptor 3!

Never stop improving. SpaceX is pushing rocket engine technology forward with Raptor 3, designed to deliver more performance with less complexity. But Musk has already revealed what's next. Raptor 4, targeting 300 metric tons of sea level thrust at roughly the same weight as Raptor 3. If achieved, that would mark another major step in Starship's engine development. So what makes Raptor 4 different and why does Starship need even more power? We are now in 2026, the year of Starship V3. Before that came V1 in 2023 and 2024, followed by V2 in 2025. Each generation brought new improvements, addressing the shortcomings of its predecessor and moving Starship closer to SpaceX's ultimate goal, a fully reusable launch system. And one of the biggest changes with V3 was the introduction of Raptor 3. Since then, SpaceX has made considerable progress. Starship has demonstrated controlled landings, S40 survived its flight and landing sequence, and S41 reached orbit and deployed its first operational payload. Step by step, the program is moving forward. And here at GreatSpaceX, we're always working to improve as well. Recently though, our subscriber growth has started to slow down. So if you enjoy our coverage and haven't subscribed yet, consider clicking that button. Your support helps us grow and continue bringing you the latest updates on Starship. Thank you so much. Now, let's get back to V3. Despite all this progress, some major challenges remain. And one of the most important is the very technology that powers the entire system. The Raptor engine. SpaceX has always pursued continuous improvement, using test results and flight data to identify problems and refine its designs. Now, Musk has revealed the next step in that process. Raptor 4. But before we look at what this new engine could deliver, we need to understand why SpaceX is already Looking Beyond Raptor 3 Let's start with Starship's recent flights. During flights 12 and 14, engine shutdowns were reported during the Super Heavy Booster's flight, reducing the number of engines available at certain points in the mission. Starship's upper stage has also encountered engine-related issues, including problems involving its Raptor vacuum engines. Musk has previously attributed some engine anomalies to software issues. These incidents highlight an important point. An engine's performance isn't measured by thrust alone. It must ignite reliably, respond correctly to commands, operate consistently under demanding conditions, and withstand repeated flight cycles. And when a rocket relies on dozens of engines working together, consistency becomes especially important. That brings us to a revealing statement from Musk himself. In a post on X, he wrote, We can only reliably get to around 230 tons of force with Raptor 3. That figure deserves a closer look. Raptor 3 was rated at approximately 230 metric tons of force at sea level. When SpaceX introduced Raptor 3, however, it highlighted a target of around 280 tons of force at sea level. So why would Musk now describe 230 tons of force as the level Raptor 3 can reliably achieve? The key distinction is between a published performance target and the thrust level Musk says SpaceX can currently achieve reliably. His statement suggests there's still a gap between Raptor 3's stated design performance and the level the company can consistently count on. It doesn't mean every engine produces exactly 230 tons of force during every flight, nor does it establish a single cause for the difference. But it does raise an important question. How much more performance can SpaceX reliably extract from its current engine? Consider the potential impact across an entire booster. Super Heavy uses 33 Raptor engines. If each produced 230 tons of force simultaneously, their combined nominal sea level thrust would be approximately 7,590 tons of force. At 280 tons per engine, the theoretical total would rise to around 9,240 tons. These are simplified calculations, assuming all 33 engines operate at the stated thrust Actual vehicle performance depends on operating conditions and the engine configuration. Still, the difference is substantial, and it helps explain why SpaceX is looking for ways to increase not just peak performance, but the thrust it can reliably achieve. So what might be holding Raptor 3 back? Part of the answer lies in the engine's design philosophy. Compared with Raptor 2, Raptor 3 was designed to reduce mass and simplify construction by integrating components and eliminating external hardware, including separate engine heat shields. The goal was to reduce complexity. Make manufacturing more efficient and improve performance. But simplifying an engine doesn't automatically eliminate the challenges of operating it. Rocket engines must function under extreme temperatures, pressures, vibration, and mechanical loads, and the conditions experienced by an engine installed on a flying rocket can differ significantly from those encountered during an individual test. When dozens of engines operate together, their exhaust flows. Thermal loads, control systems, and surrounding vehicle structures all become part of a much larger engineering problem. A design that performs well on a test stand must still prove itself as part of the complete launch system. Maintainability is another consideration. Integrating components can reduce weight and simplify assembly, but engineers must still be able to inspect, diagnose, and repair the engines efficiently when something goes wrong. However, we shouldn't assume these design trade-offs are necessarily responsible for the thrust limitation Musk described. The precise technical reasons haven't been fully explained. What we do know is that SpaceX wants more reliable performance. And that's where Raptor 4 enters the picture. In another post on X, Musk revealed the target for the next generation engine. Raptor 4 will be 300 tons of thrust at sea level and hopefully about the same mass. There it is. 300 tons of force at sea level, at roughly the same mass as Raptor 3. If SpaceX can achieve that, it would represent another significant step in the evolution of its propulsion system. But the comparison needs some context. Against the 230 tons that Musk says Raptor 3 can reliably achieve, a 300 ton target represents An increase of about 30%. Compared with Raptor 3's earlier 280-ton design target, the increase is closer to 7%. Both figures tell part of the story. The first highlights the potential improvement over the reliable performance Musk describes today. Either way, the objective is clear, more thrust without a significant increase in engine mass. And that could have major implications for Starship, using 33 engines at 300 tons each Super Heavy could theoretically produce approximately 9,900 tons of combined sea-level thrust. That's remarkably close to the 10,000-ton milestone SpaceX has been pursuing. But the benefits of Raptor 3 wouldn't depend on thrust alone. Reliability could prove just as important. Every engine must start when commanded, respond predictably, and perform through the critical phases of flight. Unexpected shutdowns can reduce available thrust and complicate the vehicle's flight profile. For a fully reusable rocket, the engine must also support repeated operations without requiring excessive maintenance between flights. That means Raptor 4 has to do more than hit a high number on a specific specification sheet. It needs to deliver dependable performance across the conditions Starship will encounter. And Musk's goal of keeping its mass roughly unchanged makes that challenge even more demanding. If Raptor 4 can produce more thrust without becoming heavier, it could improve the engine's thrust-to-weight ratio. That gives vehicle designers more flexibility when optimizing the complete rocket. But achieving that balance while maintaining durability, reliability, and efficient manufacturing is no small feat. SpaceX has already made significant challenges, Changes to simplify Raptor 3. Now the challenge is to build on that foundation and push performance further. So what could Raptor 4 mean for the next generation of Starship? SpaceX's future Starship designs are expected to push the vehicle size, payload capacity, and operational capabilities further. The proposed V-4 specifications discussed here include a vehicle standing more than 140 meters tall with the booster carrying approximately 4,050 tons of propellant and the ship holding around 2,300 tons. These figures remain projections rather than confirmed final specifications, but they illustrate the scale of the system SpaceX is aiming to develop. The proposed engine configuration is equally ambitious. Super Heavy would use a cluster of 33 engines, while the ship would feature 9, 3 optimized for operation near sea level, and 6 designed for greater efficiency in the vacuum of space. That would bring the complete vehicle to 42 engines. For a launch system of this size, improvements in engine performance can have consequences across the entire design. Higher thrust could help lift a heavier vehicle and provide more performance margin during ascent. Lower engine mass could also help improve the overall vehicle's mass efficiency. SpaceX has discussed ambitious payload targets for future Starship configurations, including more than 200 metric tons to orbit in a fully reusable system. But reaching that goal would depend on far more than engine thrust. Vehicle mass, propellant capacity, structural design, trajectory, and the demands of reusability would all play a role. Raptor 3 represented a major step towards simplifying the engine and reducing its mass. Raptor 4's challenge will be to build on these improvements while delivering greater thrust and dependable operation. If SpaceX succeeds, the new engine could help unlock more of Starship's performance potential, Particularly as the company works toward orbital refueling. Lunar missions and eventually crewed journeys to Mars. But before Raptor 4 can deliver on its promise, SpaceX must overcome several engineering challenges. First, ignition and restart reliability. With dozens of engines operating together, every startup must be carefully controlled. SpaceX needs to ensure Raptor can ignite consistently and respond reliably during ascent, boostback, and landing. Then there's thermal management. Raptor operates under extreme temperatures and pressures, making effective cooling, durable materials, and reliable seals essential for repeated use. Manufacturing and maintenance present another challenge. SpaceX must produce engines consistently while ensuring they remain practical to inspect, repair, and replace. Ultimately, Raptor 4 must balance thrust, weight, reliability, durability, and manufacturability. Its success won't depend on raw power alone. But on whether it can deliver that power consistently, will Raptor 4 give Starship the performance and reliability it needs to reach the next level? We'll have to wait and see. How many launches will SpaceX need to refuel Starship in orbit? Fewer launches mean a simpler, faster path to making orbital refueling a reality. But Elon Musk has just thrown a surprise. So what did he say and how close is SpaceX to making this ambitious technology work? After years of development, Starship finally reached orbit on its 14th flight. But reaching orbit is only the beginning. The ultimate destination is the Moon, Mars, and beyond. And if you want to follow every step of that journey, subscribe to GreatSpaceX so you don't miss the next major breakthrough. Now, let's get back to the story. Starship has reached orbit, but there's a major problem. Much of its propellant is already gone by the time it gets there, leaving it without enough fuel to continue all the way to the moon or Mars. So, how can SpaceX send Starship farther without loading all that propellant before launch? The answer is orbital refueling. Instead of carrying everything it needs from the ground, Starship would receive additional propellant once it's already in space. To make that possible, SpaceX plans to use specialized Starship tankers. These vehicles are designed to carry propellant into orbit, rendezvous with another Starship or an orbital depot, and transfer their fuel. Once the receiving spacecraft has enough propellant, it can begin the next leg of its journey. Simple in concept, extremely challenging in practice. And one question could determine just how practical this entire system will be. How many tanker launches will SpaceX need to fuel a single lunar landing mission? Recently, journalist Eric Berger brought that question back into the spotlight on X. According to Berger, during a recent aerospace safety advisory panel call, panel member Charlie Prichard suggested that refueling a Starship for a lunar landing mission could require about 22 flights. Berger also covered the estimate in an article for Ars Technica, where he serves as a senior space editor, and 22 launches is a staggering number. Previous estimates I've seen were closer to a dozen. Now the latest reported figure has climbed to nearly twice that amount. To put that into perspective, SpaceX has launched Starship just 14 times so far. That means, fueling a single lunar mission could require more tanker flights than the than the number of Starship flights conducted across the entire program to date. Of course, SpaceX expects its launch cadence and production capabilities to improve as Starship matures. But launching more frequently won't solve every problem. Each tanker must deliver enough usable propellant and the entire refueling sequence has to work reliably before the lunar lander can depart. So, is 22 launches really the number SpaceX should expect? Musk doesn't think so. Look no further than the replies beneath Eric Burr. In Berger's post, Musk responded with a prediction that would dramatically change the conversation. In a post on X, he wrote, That's way too high. Actual number will be more like 6 to 8. 6 to 8 launches instead of 22. If Musk is right, that could make Starship's orbital refueling campaign far more manageable. The biggest benefits would be lower costs, shorter timelines, and fewer complex operations. Even with reusable rockets, every tanker launch requires preparation, ground support, and coordination. This schedule is especially important for Mars missions, where launch opportunities come roughly every 26 months. Missing one could mean waiting for more than two years for the next one. Fewer launches could also reduce operational complexity, but reliability remains a major challenge. SpaceX must coordinate multiple vehicles, dock in orbit, and transfer cryogenic propellant without losing too much to boil off. Liquid methane and oxygen must remain extremely cold so the longer propellant stays in orbit, the more important thermal management becomes. Ultimately, Musk's estimate remains a prediction, not a demonstrated capability. SpaceX still needs to prove that its tankers can deliver enough usable propellant and refuel another Starship reliably. If the requirement really is 6-8 launches, lunar missions could become considerably easier to manage. If it remains closer to 22, the logistical challenge will be much greater. The real milestone isn't the number of launches, it's proving that Starship can refuel in orbit and make the entire process work reliably. Until SpaceX demonstrates that capability, the difference between 6 and 22 remains an open question. So, what will SpaceX have to do to turn Elon Musk's prediction into reality? The answer came from Musk himself earlier this year, before Starship V3 even made its debut. In a post on X, he explained, the Starship V4 tanker version will deliver over 200 tons of propellant per flight, so more like 5 or 6 tanker flights to refill the Lunar Transit Starship in orbit. It shouldn't be too much of a problem if we're doing more than 10,000 flights per year. That's right, Musk was already suggesting an even lower number than his more recent estimate, just 5 or 6 tanker flights, and his strategy rests on two major goals, deliver more propellant with every launch and dramatically increase Starship's launch cadence. Let's start with the vehicle itself. SpaceX plans to develop Starship V4, a future version designed to push the system's performance even further. According to the projections discussed here, the V4 booster could reach 81 meters in length up from 72.3 meters for the V3. The ship could grow to 61 meters compared with 52.1. Its engine configuration is also expected to evolve with six vacuum-optimized engines bringing the ship's total to nine. Meanwhile, projected thrust figures could reach around 10. 10,000 tons for the booster and 2,700 tons for the ship. These changes are intended to increase Starship's overall performance and propellant capacity. The booster could carry more than 4,000 tons of propellant, while the ship could hold around 2,300 tons. But there is an important distinction to make here. Carrying more propellant isn't the same as transferring more propellant to another spacecraft in orbit. For orbital refueling, the critical figure is how much usable fuel the tanker can actually deliver to the receiving Starship. And that's where the specialized V-4 tanker comes in. Rather than prioritizing crew accommodations or conventional cargo, this version would be optimized specifically for transporting propellant. Musk has suggested that each V-4 tanker could deliver more than 200 tons per flight. If SpaceX achieves that target, each launch could supply a substantial amount of fuel to the receiving spacecraft, reducing the number of tanker flights needed to prepare for a lunar mission. Consider a simplified example, if the receiving starship needed 1200 tons of additional propellant and each tanker transferred 200 tons, SpaceX would need 6 flights. A mission requiring more propellant would need additional flights, while one requiring less could need fewer. The actual number would depend on the mission's fuel requirements, the amount transferred per tank, and how much propellant remains usable throughout the process. Still, the principle is straightforward. The more fuel each tanker delivers, the fewer launches SpaceX needs. But Musk's vision doesn't stop at increasing the amounts of propellant carried per flight. His second goal could change the way SpaceX operates altogether. He wants Starship to fly at an extraordinary rate In that same February statement, Musk pointed to a long-term ambition of more than 10,000 Starship flights per year. That's an enormous target. It would average more than 27 flights per day, requiring a level of production, launch infrastructure, vehicle reuse, and operational efficiency far beyond what Starship has demonstrated so far. Achieving that cadence would be a monumental challenge in its own right, but if SpaceX could eventually approach it, the implications for orbital refueling would be significant. Whether a lunar mission required 5 tanker flights, 8, or even 20, those launches would represent a much smaller share of the company's overall annual flight capacity. Frequent launches could also give SpaceX greater flexibility when scheduling tanker missions and replenishing propellant supplies. In other words, the goal is not just to make each tanker more capable, it's to make delivering propellant to orbit a routine operation. Of course, launch cadence alone won't solve every problem. SpaceX needs to demonstrate reliable orbital docking, large-scale propellant transfer, long-duration cryogenic storage, and the ability to coordinate multiple launches safely. A higher flight rate won't automatically guarantee that these operations are inexpensive or reliable. But combining higher capacity tankers with frequent launches could fundamentally change the economics and logistics of Starship's refueling system. And the consequences could extend far beyond the moon. Reliable orbital refueling could help make lunar landings more practical, support more ambitious missions to Mars, and eventually contribute to the transportation infrastructure needed for sustained human activity beyond Earth. That's the bigger picture. The challenge isn't simply getting Starship into orbit. It's building a system that can repeatedly deliver enough propellant to send spacecraft wherever they need to go. And if SpaceX can turn Musk's projections into demonstrated capabilities, deep space exploration could become far more achievable. But there's still one major question. Can SpaceX prove that its V-4 tanker can actually deliver more than 200 tons of propellant per flight and scale up its launch operations enough to make orbital refueling routine? Because until the company demonstrates both, Five or six tanker launches remain a target, not a proven result. And if SpaceX gets this right, it won't just change how Starship reaches the moon, it could determine whether a future mission to Mars requires a handful of refueling flights or an orbital operation on a scale humanity has never attempted before. Despite Musk's ambitious estimates, SpaceX still faces major challenges, and NASA's own Artemis architecture shows just how complicated orbital refueling could become. NASA has outlined a concept involving a dedicated propellant depot in Earth orbit. SpaceX would launch the depot, send multiple Starship tankers to fill it, and then launch Starship HLS to dock with the depot and collect the fuel needed for its lunar mission. This approach would let SpaceX accumulate propellant over time, but it introduces another challenge, keeping enormous quantities of cryogenic propellant cold enough to remain usable in orbit. Liquid methane and oxygen gradually warm as heat enters their tanks, potentially causing boil-off and reducing the fuel available for the mission. So, orbital refueling isn't just about transferring fuel, it's about delivering, storing, and managing enough propellant to make a lunar landing possible. The first major step should come as early as 2027. SpaceX President Gwynne Shotwell has pointed toward an orbital refueling demonstration in early 2027. The initial test is expected to involve two Starships, one acting as the tanker and the other receiving the propellant. Both vehicles would need to reach orbit, rendezvous, establish a connection, and demonstrate that propellant can move between them. But proving ship-to-ship transfer won't mean the entire lunar... A depot-based campaign would require additional tanker launches, long-term storage, and another transfer operation before the lander could depart for the moon. SpaceX must also improve Starship's recovery and reuse capabilities. Recovering both the Super Heavy booster and ship, then returning them to flight with minimal Minimal refurbishment would help support their frequent launches. It's tanker strategy. The company has discussed ambitions of reaching roughly one launch per week in the first half of 2027, potentially increasing to two per week in the second half. Those remain targets, however, and achieving them will require faster production, more launch infrastructure, and shorter turnaround times. Meanwhile, engineers must demonstrate reliable docking, control cryogenic fluid transfer, manage tank pressure and temperature, and measure how much usable propellant reaches the receiving vehicle. NASA will also play a critical role, ensuring that Starship HLS and its supporting refueling architecture meet the requirements of the Artemis program. If the initial demonstration succeeds, SpaceX could gather real-world data needed to refine its system and determine how many tanker launches a lunar mission will actually require. Musk believes that number could eventually fall to just six to eight launches, but SpaceX SpaceX must prove the technology before that estimate can be treated as achievable. The real milestone isn't transferring fuel once, it's making orbital refueling reliable, repeatable, and practical enough to support missions to the moon and eventually Mars. Stay tuned to GreatSpaceX as SpaceX approaches one of the most important technical challenges in Starship's development. I'm Kevin and I'll see you in the next video. Until then, keep looking up!