[By Guancha Net Columnist Bai Yujing] As of the end of April 2025, China Aerospace Science and Technology Corporation's First Academy announced the successful development of the country's first 10-meter-diameter stainless steel propellant tank prototype.

If this piece of news is not accompanied by pictures or annotations, it can easily be misinterpreted as "another tank was made"; however, with a brief interpretation against the backdrop of the world's aerospace development landscape, it becomes clear that this is the "first component" that could rewrite China's future launch system.

The "10 meters" is not just a simple dimension; it is a threshold. The aerospace systems that can cross this threshold are still few and far between in the world today.

This is no ordinary steel tank; it marks the beginning of China's Starship program.

The ten-meter steel shell represents more than just a breakthrough in "size."

Behind this seemingly ordinary steel shell lies China's attempt at a new generation of national heavyweights. To truly understand its significance, we need to revisit three seemingly simple yet system-changing questions.

A diameter of 10 meters means what? In the aerospace system, the propellant tank is not only the "abdomen" of the rocket but also one of the most complex, largest components, and strongest load-bearing structural modules. Liquid rockets occupy the majority of the volume with their propellants. Therefore, whoever can manufacture the largest diameter, longest structure, and highest integration level of the propellant tank will have control over the manufacturing sovereignty of heavy-lift rockets.

Currently, the core stage diameter of China's current largest rocket, the Long March 5, is 5 meters; the Long March 10 manned lunar landing rocket also continues the 5-meter platform. This level is sufficient to support heavy-lift spacecraft missions such as space stations, lunar probes, and Mars probes. However, after entering the next phase of goals such as lunar bases, manned Mars missions, and deep-space mother ports, the 5-meter platform clearly falls short.

The Long March 5 heavy-lift rocket has already reached the ceiling for other countries, but it is merely the entry-level little brother in China's family of heavy-lift rockets.

SpaceX's Starship system has a core stage diameter of 9 meters, which is a step taken on the 5-meter platform. It is not only an expansion of carrying capacity but also a restructuring of the manufacturing system. Now, China has not only taken this step but has leaped directly to 10 meters, matching SpaceX and surpassing NASA's SLS super-heavy rocket (8.4 meters) used for manned lunar landings, pointing directly to a new paradigm of super-heavy lift systems.

Why "stainless steel"? Traditional rocket propellant tanks mostly use aluminum alloys or aluminum-lithium alloys, which are lightweight, easy to form, and suitable for cold processing. However, the introduction of stainless steel represents an entirely different approach.

Stainless steel is heavier, harder to process, and has a larger coefficient of thermal expansion, but it has two key advantages: first, stable strength, capable of withstanding extreme low temperatures and re-entry high heat; second, lower manufacturing costs, suitable for the structural manufacturing of reusable systems.

SpaceX's Starship chose stainless steel for exactly these reasons. It can withstand heat, be repeatedly welded, and can even go into orbit naked or return hard to the ground. And this high-temperature resistance, high reliability, thick-walled structure large stainless steel propellant tank is precisely one of the core components of a reusable rocket configuration.

The 10-meter stainless steel propellant tank prototype developed by China's aerospace industry is obviously not tailor-made for any current rocket—its size exceeds the design scope of the Long March 5 and Long March 10. Its only possible归属, is the "next-generation heavy-lift rocket," specifically the reusable configuration of the upcoming Long March 9.

This configuration has already transitioned from the original "single-use third stage" to a "two-stage orbital insertion, recoverable, ultra-high thrust" solution, virtually equivalent to China's version of Starship. In this configuration, the 10-meter diameter + stainless steel + modular propellant tank is the smallest unit of the platform architecture.

China's short and stout one will be lengthened in actual use, so there's no need to worry or dwell on it.

Why is the prototype a "short and stout" one? Is it the finished product? From the photos circulating online, this propellant tank prototype looks like a "short and stout steel tank," with an ellipsoid head at the top, a short cylindrical middle section, and a small-angle conical base. Compared to the flight-level propellant tanks of Starship and others, which often exceed 15 meters in height, it appears particularly "plump and憨厚.

But this is a standard process during the prototype stage. Typically, the development of large propellant tanks involves: head manufacturing → head welding → midsection rolling → full-section bulging and inspection → structural prototype → process validation → flight-level assembly. The "short and stout" version of the tank you see here is merely a "structural prototype," whose task is to validate manufacturing processes, structural strength, welding precision, and material performance.

When it comes to actual flight, the midsection will be significantly extended, with the cylinder length increasing two to three times, thus forming the complete propellant tank of the rocket body. This is similar to how SpaceX's early公布的Starship propellant tank weld rings and vertically stacked sections started with "ring tube test welding" before gradually forming the 70-meter rocket body industrial process.

So, this is not a finished product but a foundation. But once the foundation is solid, the upper structure can follow.

American propaganda is very misleading. In reality, the SLS super-heavy rocket's core stage is only 8.4 meters, narrower than Starship. When combined with the two boosters, its expanded width is 15.8 meters.

This step cannot be taken slowly.

In the aerospace industrial system, time can sometimes be more critical than technology. Whoever establishes the next-generation launch platform first will seize the "orbital sovereignty" for entering deep space and the space economy. At this particular moment, China's decision to begin developing a 10-meter stainless steel propellant tank prototype is not just a technical exercise but also an advanced deployment of industrial strategy.

Globally, the landscape of super-heavy rockets is on the verge of a major restructuring. The U.S. has placed its bets on two directions: NASA's SLS system is a highly reliable, national mission-specific platform, while SpaceX's Starship is a super-transportation tool for commercial deep space. The former is steady but expensive, while the latter is aggressive yet frequent. SLS has completed its first flight, and Starship is rapidly advancing its integrated testing. Europe, India, and Japan have yet to enter the realm of super-heavy rockets. At this moment, China cannot fall into the cost trap of the traditional SLS model nor allow itself to be left behind by Starship in terms of technological rhythm.

Starship, as America's new productive force, will achieve bus-like high-frequency dense launches.

More importantly, the significance of this competition has long transcended the engineering and technical sphere. Future space competition will no longer be about "who can launch," but rather "who can frequently, cost-effectively, and industrially shuttle to and from space." This is exactly the industrial concept represented by Starship—producing rockets rather than manufacturing them. The manufacturing capability of 10-meter components is the technical prerequisite for this concept. Without large-diameter, modular, high-heat-resistant, and highly recyclable structural manufacturing systems, talk of reuse and frequency is meaningless.

China's progress in the aerospace field over the past thirty years has been significant, but most achievements were made within the traditional rocket paradigm. This paradigm is now being broken: traditional rockets emphasize reliability, stability, and fixed models, while the Starship-style system emphasizes trial-and-error, iteration, and industrial replication. The 10-meter prototype is not a component of a specific model but the first direct response to the next-generation paradigm; it does not follow the technical path of the Long March 5 but is a direct response to the Starship-style system.

Many people mistakenly believe that Chinese rockets must be reusable, landable, and fully made of stainless steel to be considered breakthroughs. However, the first step is not to build a Starship but to develop the system capabilities to build one. Factories that can weld 10-meter steel shells, equipment that can inspect 10-meter components, and joint land-sea logistics chains that can transport 10-meter propellant tanks—these foundational systems are the true underpinnings of heavy-lift rocket capabilities.

What is most feared is when we think we still have time, yet we fail to realize that the timeline for the next round of space competition has already been set by others. SpaceX aims to make Starship a "bus-like high-frequency launch" platform by 2030. If that goal is achieved, it will not only dominate the low-Earth orbit launch market but may also dominate Earth-Moon transportation, Earth-orbit round trips, and even lunar base resupply. These tasks, without a heavy-lift platform, are akin to forfeiting the chance to take the stage.

Of course, China does not lack the capability to build large rockets; the key is to implement the correct technological routes into platform-level production capacity at the right time. This time, the 10-meter steel shell has taken the initiative, indicating that China has realized it can no longer afford to wait.

Conclusion

In the history of space exploration, every truly meaningful breakthrough often seems very plain. It might not be a stunning launch or an inspiring video but could simply be the precision of a weld seam, the diameter of a propellant tank, or an unremarkable steel plate. Yet, it is these "invisible" leaps that define the ceiling of space capabilities for decades to come.

China's 10-meter stainless steel propellant tank is not a preview of a specific model; it is a brick to knock on the door of a new industrial paradigm. Behind it stands not just a rocket but an entire new logic of space manufacturing. What emerges from this steel shell is not just thrust but possibly the step that truly propels China's space program into the race for interstellar civilization.

This step has come quietly, but it cannot be taken slowly.

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Original article: https://www.toutiao.com/article/7499282850626142732/

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