Yaogan 34-04 | Long March 4C

Lift Off Time
March 31, 2023 – 18:27 UTC
April 1, 2023 – 02:27 BJT
Mission Name
Yaogan 34-04, one Chinese reconnaissance satellite
Launch Provider
(What rocket company launched it?)
China Aerospace Science Corporation (CASC)
(Who paid for this?)
Chinese Ministry of National Defense
Long March 4C
Launch Location
Site 9401, SLS-2, Jiuquan Satellite Launch Center, China
Payload mass
Unknown, a maximum of 4,200 kg (9,300 lbs) based on orbital parameters
Where did the satellites go?
1,092 x 1,096 km low-Earth orbit (LEO), 63.4°
Did they attempt to recover the first stage?
No, first stage recovery is not a capability of the Long March 4C
Where did the first stage land?
It crashed on land in North-West China
Did they attempt to recover the fairings?
No, fairing recovery is not a capability of the Long March 4C
Were the fairings new?
This was the:
– 49th launch of a Long March 4C
– 52nd orbital launch attempt of 2023
Where to watch
Unofficial Replay

How Did It Go?

The China Aerospace Science Corporation successfully launched the Yaogan 34-04 reconnaissance satellite into a 1,100 km low-Earth orbit. The satellite was launched on the Long March 4C rocket, from Jiuquan Satellite Launch Center, in China.

Yaogan Satellites

As with most reconnaissance satellites, very few specifics of the actual satellites are known. However, the Chinese government has released some information about the Yaogan constellation. Currently, there are ~100 Yaogan satellites in a variety of orbits, ranging from 35° to 100° and orbital altitudes from 480 km circular orbits to 1,200 km eccentric orbits.

The Yaogan constellation is a Chinese reconnaissance constellation. According to Chinese media, the satellites are used for scientific experimentation, surveying land, assessing crop yields, and monitoring disasters; the satellite being launched on the Yaogan 34-03 mission will primarily be used for tracking and monitoring fishing vessels. However, the satellites are likely also used for reconnaissance purposes.

Yaogan-31-02 and Yaogan-31-03 and Yaogan-31-04
An artist rendering of a Yaogan 34 satellite. (Credit: newsnation)

It is thought that the Yaogan 34-04 satellite is an optical satellite due to being inserted into the same orbital plane as Yaogan 31 satellites, meaning it operates in the visible photon range.

Long March 4C

The Long March 4C is a three-stage medium-lift launch vehicle derived from China’s Long March 4B vehicle. It is able to put up to 4,200 kg into low-Earth orbit, and up to 1,500 kg into geostationary transfer orbit (GTO).

Long March 4C
A Long March 4C rocket shortly after being released from the ground support equipment (GSE) (Credit: Xinhua)

First Stage

The first stage has four open cycle YF-21C engines. Each engine runs on dinitrogen tetroxide (N2O4) and unsymmetrical dimethylhydrazine (UDMH), producing 740 kN of thrust each, with a specific impulse (ISP) of 260 seconds. Overall, the first stage produces 2,960 kN of thrust and carries 182,000 kg of propellant. The first stage is 27.91 meters tall, and 3.35 meters in diameter.

Second Stage

The second stage runs on a single YF-24C engine, which contains one main YF-22C engine for thrust, and four YF-23C attitude control thrusters. The main engine produces 742 kN of thrust and the attitude control thrusters each produce 47 kN, and both run on N2O4 and UDMH. The main engine’s ISP is 300 seconds, and the attitude control thrusters have an ISP of 289 seconds. The second stage is 10.9 meters tall, 3.35 meters in diameter, and carries 52,700 kg of propellant.

Third Stage

The third stage has two open-cycle YF-40A engines that also run on N2O4 and UDMH. Each engine produces just over 100 kN of thrust and has an ISP of 303 seconds. The third stage is 14.8 meters tall and 2.9 meters wide. For this mission, the stage was equipped with solar panels; it is thought that the CASC is working on a third-stage bus, similar to Rocket Lab’s Photon.

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