The Long March-12 rocket, launched by China last week, utilized a new fuel that enhanced its payload capacity by 10%, according to the developer. This advancement comes as China expands its role in space, which includes ambitious lunar missions and an increasing number of commercial satellite launches, driving the demand for larger payloads.
Rather than developing larger and more expensive rocket bodies, the Beijing Institute of Aerospace Testing Technology, a subsidiary of the China Aerospace Science and Technology Corporation (CASC), focused on maximizing the energy density of the fuel. Most modern rocket launches use engines powered by liquid oxygen and kerosene (kerolox), but the traditional fuel mixture based on refined oil has reached its operational limits.
Researchers instead developed a new ‘high-energy synthetic kerosene’ for the engines. CASC reported last week that this fuel increased the specific impulse of the engine—a measure of efficiency similar to fuel economy in cars—by approximately eight seconds. A higher specific impulse means the engine generates more thrust from the same amount of fuel, and even an additional eight seconds can increase the rocket’s payload capacity by hundreds of kilograms. This allows rockets to carry more commercial satellites or heavier scientific instruments for deep-space missions.
Development and testing of the new fuel
The launch last Wednesday from the southern island of Hainan marked the culmination of 13 years of effort, according to CASC. ‘The research group, formed in 2013, overcame complex engineering challenges, including high-efficiency synthesis, precise purification, and control of coking during heat transfer,’ the corporation added. The fuel also underwent ‘a series of ground tests’ using various engine variants with thrust capacities ranging from 18 to 120 tons.
The team scaled up production to transition the fuel from the laboratory to the launch pad. Currently, there is a production line capable of producing 400 tons per year, with plans for a facility that can produce 2,000 tons. The final challenge was addressing the heat and humidity of Hainan, as well as the impact of sea salt, which can corrode sensitive equipment and disrupt electronics. To mitigate this, the team developed an intelligent refueling system that controlled temperature and fuel flows.
Future implications and applications
The new fuel could have significant implications for future space launches, where kerolox remains the industry standard. Currently, China’s main launch vehicles rely on it. For instance, kerolox powers the boosters of the heavy Long March-5 rocket, the main stage of the lighter Long March-6, and the entire medium-heavy Long March-7 rocket. It is also used by companies like the American SpaceX, which employs a similar mixture to power its Falcon-9 and Falcon Heavy rockets. The first private Chinese rocket using liquid fuel to reach orbit, the Tianlong-2, also utilized an alternative fuel—kerosene synthesized directly from coal, developed by the 165th Institute, another subsidiary of CASC.
Source: South China Morning Post