Long March 3B/E launching APStar-9

ChinaSat 6D | Long March 3B/E

Lift Off Time
April 15, 2022 – 12:00 UTC | 20:00 BJT
Mission Name
ChinaSat 6D, a Chinese communication satellite
Launch Provider
(What rocket company launched it?)
China Academy of Launch Vehicle Technology
(Who paid for this?)
China Satcom
Long March 3B/E
Launch Location
LC-2, Xichang Satellite Launch Center, China
Payload mass
Unknown, up to 5,500 kg (12,100 lb) to GTO
Where did the satellite go?
Geostationary Earth Orbit (initial orbit: Geostationary Transfer Orbit)
Did they attempt to recover the first stage?
No, the Long March 3B/E is not capable of booster recovery
Where did the first stage land?
It crashed over land in North-West China
Did they attempt to recover the fairings?
No, the Long March 3B/E is not capable of fairing recovery
Were these fairings new?
This was the:
– 142nd flight of a Long March 3 (any variant)
– 39th orbital launch attempt of 2021 (38th successful)
Where to watch
Unofficial Replay

What’s This All Mean?

The China Academy of Launch Vehicle Technology successfully launched the ChinaSat 6D satellite into a Geostationary Transfer Orbit (GTO). The Long March 3B/E launched from Launch Complex-2, at the Xichang Satellite Launch Center, in China.

ChinaSat 6D Satellite

The ChinaSat 6D satellite is a replacement for the ChinaSat 6A satellite, which was launched in September of 2010. ChinaSat 6A was initially meant to remain in service until 2025, but a leak in the Helium Pressurization System caused its replacement to be launched early. The ChinaSat (also called Zhongxing) constellation is a series of commercial Communication Satellites that provide high bandwidth uplink and downlink radio and TV coverage to China.

The satellite is equipped with 25 C-band transponders, two solar panels, batteries, and an on-board propulsion system; the satellite will spend the upcoming months raising its orbit into a 125º Geostationary Orbit (GEO)–where it is expected to have an on-orbit lifespan of 15 years.

ChinaSat 6D–along with the other satellites in the constellation–was built by the Chinese state-owned company China Academy of Spaceflight Technology. The satellite constellation is operated by the also state-owned company China Satcom.

What Is The Long March 3B?

Despite the Chinese rockets having different heritages, most of China’s orbital launch vehicles use the “Long March” (Chang Zheng) naming scheme. The Long March 3B is a three stage rocket, with an optional fourth stage. The rocket has four liquid-fueled side boosters, and first launched in 1996.

The Long March 3B/E, the enhanced version of the Long March 3B, was first launched in 2007 and has greater Geostationary Transfer Orbit (GTO) payload capacity. The enhanced 3B/E’s have a larger first stage and larger side boosters, compared to the original Long March 3B. As a result, its payload capacity to GTO was increased from 5,100 kg to 5,500 kg.

The Long March 3B series features the following sections or stages:

  • Side boosters
  • First (center) stage (ignited at launch)
  • Second stage
  • Third stage
  • Optional fourth stage

Side Boosters

There are 4 side boosters that each use one YF-25 engine, which is powered by Unsymmetrical Di-Methyl Hydrazine (UDMH) and Nitrogen Tetroxide (N2O4).

The regular Long March 3B’s side boosters are 15.33 m (50.3 ft) long, but on the enhanced version they are 16.1 m (52.3 ft) long, producing 740 kN of thrust. The YF-25 engine has a specific impulse (ISP) of 260 seconds, and burns for 140 seconds on the 3B/E variant.

First (Center) Stage

The first stage has 4 YF-21C engines, which also use UDMH / N2O4 for propellant. The first stage has an ISP of 260 seconds and produces 2,960 kN of thrust. The LM-3B first stage is 23.27 m (76.35 ft) tall, but the 3B/E is 24.76 m (81.23 ft) tall.

Long March 3B/E, launch, APStar-9
Long March 3B/E launch with APStar-9 (Credit: ChinaNews.com)

Second Stage

The second stage is powered by a single YF-22E engine. However, attitude control is provided by a single YF-23 Vernier engine, and combined, these engines are known as a YF-24 module. The engine runs on UDMH and N2O4 and produces 742 kN of thrust. The second stage is 12.9 m (42.3 ft) tall and burns for 185 seconds.

Long March 3, rocket family
The Long March 3 family of rockets (Credit: CGWIC)

Third Stage

The third stage is 12.4 m (40.7 ft) long and is powered by 2 YF-75 engines. Unlike the other stages, this stage is powered by liquid hydrogen (LH2) and liquid oxygen (LOX).

The third stage will burn after the second stage is jettisoned, in order to continue to raise the orbital apogee (maximum altitude). Once the target apogee has been achieved, it shuts down. The vehicle will then coast to apogee, where the stage relights and burns to raise the perigee (lowest altitude) of the orbit.

Optional Fourth Stage

The fourth stage runs on UDMH / N2O4, and has a singular YF-50D engine.

Rocket section adapted from Andy Law

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