A new Chinese rocket startup based in Xi’an has successfully completed a long-duration hot fire test of its Chi closed-cycle kerosene-liquid oxygen rocket engine.

The company, Mega Engine Technology, announced on May 25 that a single “Chi” engine accumulated 1,000 seconds of successful operation during the test campaign. With the latest test, the program’s total accumulated test time has now reached 2,000 seconds.

Mega Engine’s Chi test

According to Mega Engine, Chi, its high-pressure oxygen-rich staged combustion engine demonstrated rapid startup and stable combustion during the test. Following an inspection, the hardware was fully intact, the company noted in a social media post.

Chi—which translates as “blazing” in English—is designed for throttleable thrust ranging from 35 to 75 tons at sea level. The engine has a vacuum thrust of 87 tons. It delivers a sea-level specific impulse of 302 seconds and 350 seconds in vacuum.

The engine supports variable thrust, multiple restarts, and reuse, making it ideal for high-altitude propulsion on medium and large rockets or as first-stage power for smaller vehicles.

Founded as recently as 2024, Mega Engine has moved extremely quickly. By April 2025, the company had completed development and initial testing of its first staged-combustion engine. Now, it has reached the latest impressive testing milestone early in its existence.

The core team consists of specialists in advanced liquid rocket engines. Co-founder Zhang Chenxing, for example, holds a PhD from MIT, according to a report from Spacenews. The firm’s rapid progress in oxygen-rich staged combustion technology also suggests it has experienced personnel from China’s state-owned propulsion programs.

China’s growing launch sector

With the new test, Mega Engine has introduced itself as a new domestic supplier of high-performance engines for commercial launch providers, particularly for second and upper stages.

China’s state-owned Academy of Aerospace Propulsion Technology has led the development of similar engines, such as the YF-100 series. The Chi engine’s closed-cycle design is expected to provide a specific impulse advantage over open-cycle alternatives like the YF-102 already in commercial use.

Mega Engine has also announced plans for an even larger engine. The company aims to unveil the 200-ton-class Yan closed-cycle kerolox engine later this year. The company describes high-pressure closed-cycle engines as the “deep water zone” of commercial liquid propulsion. Most private firms have opted for simpler methane or open-cycle systems.

Together, the Chi and Yan engines are intended to create a reusable LOX/kerosene family serving a wide range of vehicle sizes.

The new Chi test highlights the role of new commercial operators in China’s growing launch sector. In recent years, the country has been expanding its launch capacity to compete with the US and SpaceX. The country is in the process of launching major satellite megaconstellations, including Guowang and Qianfan. It is also gearing up for future crewed moon missions by training astronauts aboard its Tiangong space station.

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