At 15:49 on July 30, 2025, the Long March 8A Y3 carrier rocket successfully launched Satellite Internet Low Orbit Group 06 satellites (9 satellites) into space at the No. 1 station of the Haishang Commercial Space Launch Site. At 18:21 on August 4, 2025, the Long March 12 Y2 carrier rocket successfully launched Satellite Internet Low Orbit Group 07 satellites (9 satellites) into space at the second station of the Hainan Commercial Space Launch Site. As the main rockets for the construction of my country’s satellite Internet constellation, the Long March 8A and Long March 12 rockets will surely play a very important role in my country’s subsequent high-density constellation networking missions. A simple comparative analysis of these two rockets will facilitate a better understanding of these two rockets.
1. Comparison of core parameters
Long March No. 8A
Long March 12
configuration
Two and a half levels
two levels
diameter
3.35 meters
3.8 meters
high
50.539 meters
about 62 meters
quality
About 371 tons
About 430 tons
low earth orbit payload
9.8 tons
≮12 tons (200 km)
≮10 tons (300 km)
sun synchronous orbit payload
7 tons (700 km)
6.8 tons (900 km)
≮6 tons (700 km)
2. Comparison of rocket composition
(1) One sub-level
The first stage of the Long March 8A carrier rocket has a diameter of 3.35 meters and is equipped with two YF-100 engines with a thrust of 120 tons; the diameter of the Long March 12 carrier rocket is 3.8 meters and is equipped with four pump-back liquid oxygen/kerosene engines YF-100J with a thrust of 1,250 kN.
One-stage engine comparison:
YF-100J is a one-way swing behind the pump. Compared with YF-100, it has the advantages of small mass eccentricity, small swing envelope, and easy layout of swing components.
Long March No. 8A
Long March 12
engine
YF-100
YF-100J
oxidizing agent
liquid oxygen
liquid oxygen
incendiary agent
kerosene
kerosene
sea level thrust
1223.5 kN
1250 kN
sea level specific impulse
2942 m/s
2958 m/s
vacuum thrust
1339.48 kN
1397 kN
Vacuum specific impulse
3286 m/s
338.2 s
(2) Second level
The second stage of the Long March 8A launch vehicle has a diameter of 3.35m and is equipped with two YF-75H hydrogen and oxygen engines with a vacuum thrust of 10 tons; the second stage of the Long March 12 launch vehicle has a diameter of 3.8 m and is equipped with two YF-115B liquid oxygen/kerosene engines with a thrust of 180kN.
Second-stage engine comparison:
Long March No. 8A
Long March 12
engine
YF-75H
YF-115B
cycle mode
closed expansion cycle
High-pressure supplementary combustion oxygen-rich staged combustion cycle
oxidizing agent
liquid oxygen
liquid oxygen
incendiary agent
liquid hydrogen
kerosene
vacuum thrust
10 t
180 kN
(3) Boosting
The Long March 8A launch vehicle is bundled with two 2.25m diameter liquid boosters, each equipped with a YF-100 engine with a thrust of 120 tons. The Long March 12 launch vehicle does not have a booster.
3. Rocket evaluation
The Long March 8A launch vehicle was developed by the First Academy of Aerospace Science and Technology. Compared with the Long March 8, the Long March 8A launch vehicle is equipped with a universal hydrogen-oxygen final stage and a larger-diameter fairing, which makes up for my country’s urgent need for low-orbit giant constellation network launches in the future. As a launch vehicle with higher carrying capacity and a larger-sized fairing, the Long March 8A not only further enhances my country’s low-orbit payload launch capabilities, but also can be launched not only from Station 201 of the Wenchang Space Launch Site, but also from Station 1 of Hainan Shangfa, which will greatly improve the construction progress of my country’s low-orbit satellite Internet constellation.
Long March 12 was developed by the Eighth Academy of Aerospace Science and Technology and is my country’s first 3.8-meter-diameter single-core liquid launch vehicle. The Long March 12 was originally the Eighth Academy’s failed bid for the Long March 10. In 2020, the Eighth Academy made the plan public under the tentative name XLV20 and changed the rocket configuration to a polished rod configuration. The initial research on Long March 12 is based on the research previously undertaken by the Eighth Institute. In January 2024, XLV20 was officially named Long March 12. Compared with the promising foundation of Long March 8A, the road to project establishment of Long March 12 is more tortuous. A very important feature of the Long March 12 launch vehicle is the first use of coal-based aerospace kerosene to fly into space. Our country is a country “rich in coal and poor in oil”. Coal-based aerospace kerosene is more in line with our country’s national conditions and can better ensure the security of our country’s aerospace energy strategy. In addition, the Long March 12 uses a 4-meter-diameter rocket body. Before the Long March 12, my country’s liquid launch vehicles, except for the Long March 5, were basically 3.35-meter-diameter rockets. The Long March 12 broke through this rocket body diameter limit, increased the propellant loading by 30%, and improved the rocket thrust performance by about 108%.
