China’s Thunder-RS rocket engine passes 100-second test

For 100 seconds, Deep Blue Aerospace’s Thunder-RS engine kept firing. The commercial space startup, based in Wuxi, China, said the liquid-oxygen kerosene engine reached 1,297.5 kilonewtons of thrust, or about 132.3 tonnes, in its latest test—the first time it had crossed that steady-state duration threshold after a run of shorter firings.

Thunder-RS is being developed for Nebula-2, Deep Blue Aerospace’s planned large reusable rocket. The company says the vehicle is designed to lift more than 25 tonnes into low Earth orbit. Its goal is repeated use: the company says reusability is central to Nebula-2’s design goals, and a rocket capable of flying multiple times can cut launch costs and increase launch frequency.

The engine uses liquid oxygen and kerosene, while a significant part of its main structure is made with 3D printing. Deep Blue Aerospace says that manufacturing approach can speed up production and maintenance. The company was founded in 2016 by Huo Liang and has spent years testing its smaller Nebula-1, including a 100-meter hop in 2021, a one-kilometer flight in 2022 and a 10-kilometer vertical takeoff and landing test in Inner Mongolia in September 2024.

So what changes, concretely? If the engine progresses from ground testing to a full-scale rocket, Nebula-2 is intended to carry heavier payloads than Nebula-1 while recovering and flying again. For now, the evidence is narrower: one 100-second engine test reported by the company, not an orbital flight or a demonstrated reuse cycle.

The test arrives during a broader Chinese push toward reusable launchers. LandSpace’s Zhuque-3 completed a land-based recovery of its first stage on Wednesday, while the Long March-10B’s first stage was recovered at sea on July 10. Those efforts place Deep Blue Aerospace’s engine work inside a national commercial-space race that has accelerated since China encouraged private companies to enter the sector in 2014.