Gaofen-12-02 | Long March 4C

Lift Off Time
March 30, 2021 – 22:45 UTC
March 31, 2021 – 06:45 BJT
Mission Name
Gaofen-12-02, a Chinese remote sensing satellite
Launch Provider
(What rocket company launched it?)
China Aerospace Science Corporation (CASC)
(Who paid for this?)
China National Space Administration as part of the China High-resolution Earth Observation System
Long March 4C
Launch Location
Site 9401, SLS-2, Jiuquan Satellite Launch Center, China
Payload mass
Likely around ~1,100 kg, but a maximum of 2,800 kg (6,100 lbs) based on orbital parameters
Where did the satellite go?
Unknown sun-synchronous orbit, likely ~400 km circular
Did they attempt to recover the first stage?
No, this is not a capability of the CASC
Where did the first stage land?
It will crash on land in North-West China
Did they attempt to recover the fairings?
No, this is not a capability of CASC
Were the fairings new?
This was the:
– 33rd launch of a Long March 4C
– 8th Chinese launch of 2021
– 27th orbital launch attempt of 2021 (26th successful launch)
Where to watch
In the unlikely event of a replay, it will be listed here

How did it go?

The China Aerospace Science Corporation successfully launched an Earth observation satellite on their Long March 4C rocket. The Gaofen-12-02 mission launched from the Jiuquan Satellite launch center, in China, to a Sun-synchronous low Earth orbit with an unknown altitude. This launch marked the 28th launch of a Gaofen satellite.

Gaofen Satellites

The Gaofen constellation is a series of Chinese civilian Earth observation satellites. The constellation now consists of 27 satellites, with the Gaofen 02C satellite failing to reach orbit in September of 2020. The Gaofen constellation will provide Chinese civilians with near real time observations for geographical mapping, resource surveying, environmental research, climate change monitoring, and several other observation activities.

While not much is known about the Gaofen 12 satellites, a lot can be learned from the Gaofen 1 satellites, which are similar. Each satellite has a mass of roughly 1,100 kg (2,400 lbs) and is based on the CAST-2000 extended spacecraft bus. The Gaofen-12-02 satellite has a lifespan of roughly 5 to 8 years and contains two sets of cameras. The first set of high resolution cameras has a swath of roughly 69 km (43 miles) and the second set of wide field of view cameras has a swath of 830 km (516 miles).

The Gaofen-12-02 satellite is also equipped with a 3-axis stabilization which ensures that the satellites are always pointed towards the Earth. Due to this, an individual satellite is able to revisit every part of the Earth in under 4 days.

A Gaofen-1 satellite

Long March 4C

The Long March 4C is a 3 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, 2,600 kg into a Sun-synchronous orbit, and up to 1,500 kg into geostationary transfer obit (GTO).

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

First Stage

The first stage has 4 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 propellent. The first stage is 27.91 m tall, and 3.35 m in diameter.

Second Stage

The second stage runs on a single YF-24C engine, which contains 1 main YF-22C engine for thrust, and 4 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 m tall, 3.35 m in diameter, and carries 52,700 kg of propellent.

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 m tall and 2.9 m wide.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: