By 
December 1st, 2024
Image credit: GLOBALink/Inside Outer Space screengrab
China on Saturday scored a successful maiden launch of its Long March-12. Also, the booster lifted off from the Hainan commercial spacecraft launch site in the southern island province of Hainan. It marked the inaugural mission from the country’s first commercial launch facility.
The Long March-12 departed the site’s No. 2 launch pad, hurling two experimental satellites into their planned orbits.
The November 30th flight also tested a key model of rocket engine known as YF-100K that powered Long March 12’s first stage.
Image credit: CCTV/Inside Outer Space screengrab
Importantly, YF-100K engines will also be used to power Long March-10, the booster now under development to send Chinese astronauts to the Moon before 2030.
Liquid oxygen/kerosene engines
The Long March-12 was developed by the Shanghai Academy of Spaceflight Technology under the China Aerospace Science and Technology Corporation (CASC). That rocket is currently the country’s largest single-core carrier rocket in payload capacity, featuring a two-stage configuration propelled by six liquid oxygen/kerosene engines.
The first stage is powered by four liquid oxygen/kerosene engines, each with a thrust of 1,250 kilonewtons.
Image credit: GLOBALink/Inside Outer Space screengrab
The second stage uses two liquid oxygen/kerosene engines with a thrust of 180 kilonewtons each, China Central Television (CCTV) reported.
The booster sports a carrying capacity of no less than 12 tons in low Earth orbit and no less than six tons in 700-km sun-synchronous orbit.
Dual launch pads
The Hainan commercial spacecraft launch site currently features two launch pads for liquid-propellant rockets. The Number 1 pad is designed for the Long March-8, China’s new-generation medium-lift carrier rocket.
Image credit: GLOBALink/Inside Outer Space screengrab
The Number 2 pad can accommodate multiple rocket types with varying diameters from commercial rocket companies.
Each pad has an annual launch capacity of 16 launches, reports CCTV.
Pump-backswing
Li Bin, vice president, Sixth Academy of the China Aerospace Science and Technology Corporation (CASC) is chief engineer of the liquid oxygen kerosene engine.
“The pump-backswing engine operates like a person swinging only their legs while keeping the upper body still. In other words, the engine’s nozzle is the only part that moves. This limited movement reduces the engine’s profile and the area it sweeps, allowing the rocket to be designed more compact,” Li told CCTV.
Image credit: CCTV/Inside Outer Space screengrab
Li confirmed that more engines can be installed in a diameter of 3 meters or 8 meters.
“This engine is an improved version based on our original 120-ton engine. It features a pump-backswing design with a supplementary combustion cycle. Compared to the previous 120-ton engine, we have reduced the weight by 20 percent, increased the thrust by five percent, and enhanced the overall performance,” said Li.
Batch production
“The success of the new service tower, the new rocket, as well as our new team and new mechanism, could be viewed as a milestone in the history of China’s commercial space sector,” said Liu Hongjian, president of the Hainan International Commercial Aerospace Launch (HICAL), which built and operates the launch site.
Image credit: CCTV/Inside Outer Space screengrab
Wu Jialin of the Shanghai Academy of Spaceflight Technology under the CASC, added that design engineers took into account the rocket’s batch production and industrialization.
“The diameter of the Type I rocket decides its carrying capacity. Both of its first stage and second stage have a diameter of 3.8 meters. Its first stage has four 130-tonne liquid oxygen kerosene engines and the second stage has two 18-tonne liquid oxygen kerosene engine. Its takeoff thrust is at 5,000 kilonewtons, which makes it a medium-sized rocket,” said Zhao Zhijie, a staff member of CASC.
Image credit: CCTV/Inside Outer Space screengrab
The carrying capacity of the rocket can be enhanced by a larger diameter, Zhao said, which allows it to fly with more fuel, but diameter enlargement should take into consideration factors like transportation and manufacturing.
Assembly, test, transportation
“A larger diameter has a higher demand for manufacturing techniques and transportation, because the rocket needs to be transported to the launch pad once it completes manufacturing. The third consideration is the carrying capacity of the rocket,” Zhao added.
To make the rocket a medium to large-sized one, “we have to make it a cluster carrier rocket, which means it has higher complexity,” continued Zhao. “If we take into the simplicity of configuration into consideration, the diameter should not be too large or too short. Besides, diameter of the rocket’s body should also match its engines. The diameter of 3.8 meters of Long March-12 carrier rocket can meet all the demands I [have] mentioned,” said Zhao.
Image credit: GLOBALink/Inside Outer Space screengrab
Targeting the country’s commercial flight sector, the carrier rocket has a different model for assembly, test, and transportation, allowing it to lie flat while completing the procedures, notes CCTV.
“Our technical area no longer needs a high assembly building, which is typically seen when the rocket stands vertically. Since its assembly and tests can be completed while the rocket now lies flat, it does not need a high factory,” said Zhao.
Go to these CCTV/GLOBALink videos that focus on the Long March-12 at:
https://www.facebook.com/share/v/18KEjxVY2x/
Posted in Space News
