China is progressing with its program to develop full-flow staged-combustion-cycle methane engines. These engines, poised to generate 200 tons of thrust each, are designed to power the reusable Long March 9 super heavy-lift launcher. Authors from the Xi’an Aerospace Propulsion Institute, under the China Aerospace Science and Technology Corp. (CASC), have recently detailed these advancements. Testing efforts have included firing prototype and scaled components, signaling important progress in the overall design and component development.
The move towards methane engines marks a strategic shift in China’s space exploration endeavors, particularly for large-scale deep space missions. This shift is underscored by the plan to utilize clusters of 26 reusable engines for the first stage of the Long March 9, aiming for a maiden test flight by 2033. This development not only signifies a leap in engine reliability and reusability but also aligns with China’s broader space exploration goals, including potential Mars missions.
Research in this domain began in China as early as the 1980s, culminating in the creation of 10-ton and 80-ton-thrust methane-liquid oxygen (methalox) engines, with the latter having undergone successful hot fire tests. The paper from the Xi’an institute draws a comparison between China’s full-flow staged-combustion-cycle methalox engine and SpaceX’s Raptor engine, highlighting its comparative advantages over other domestic and international methane engines, including Blue Origin’s BE-4.
However, the authors acknowledge the challenges that lie ahead. The complexity of the full-flow staged-combustion-cycle engines, encompassing issues such as system configuration, integrated layout, final assembly, and ignition control, poses significant technological hurdles. Moreover, they note that China’s foundational capabilities in fully developing these engines are still relatively nascent, necessitating bolstered efforts in related technologies to complete this intricate and technically demanding project.
Despite these challenges, the aspiration for low-cost, highly reliable, and rapidly reusable engines is seen as crucial to achieving national space objectives. Such a development would not only enhance China’s space sector but also serve as a hallmark of technological advancement.
Parallel progress in methane engines is also observed among Chinese commercial entities. Noteworthy developments include the Mingfeng-1 engine by CASIC, Landspace’s Tianque engines for the Zhuque-2 rocket, and the JD-1/Focus-1 engine for iSpace’s Hyperbola rocket series. Landspace’s Zhuque-2, the first methalox rocket to reach orbit, and its upcoming stainless steel Zhuque-3 rocket, exemplify the commercial sector’s growing capabilities in this arena. Meanwhile, iSpace’s recent hop test for its Hyperbola rockets and plans for further testing reinforce the momentum in China’s commercial space sector.
This focus on methane engines aligns with a global shift in space transportation strategies. Initially, the Long March 9 was planned to be powered by kerosene-liquid oxygen engines, a design based on an expendable launch system. However, influenced by global trends and internal advancements, newer designs now feature methalox engines without boosters, with some variants resembling SpaceX’s Super Heavy/Starship stack.
Beyond the Long March 9, China is also developing a heavy-lift rocket aimed at lunar missions by 2030. This rocket, an upgrade to the Long March 5, will feature kerolox engines with potential recovery and reusability for its first stages.
In summary, China’s progress in developing full-flow staged-combustion-cycle methane engines for the Long March 9 is an important milestone in its space exploration journey. While challenges remain, these developments represent a strategic shift in China’s approach to space technology, with potential implications for future deep space missions and the global space industry at large.