Long March 3B/E launching Beidou-3G2Q

Tianlian 2-02 | Long March 3B/E

Lift Off Time
December 13, 2021 – 16:09 UTC
December 14, 2021 00:09 BJT
Mission Name
Tianlian 2-02, flight Y82
Launch Provider
(What rocket company launched it?)
China Academy of Launch Vehicle Technology (CALT)
(Who paid for this?)
China National Space Administration (CNSA)
Long March 3B/E
Launch Location
Xichang Satellite Launch Center, Sichuan Province, China
Payload mass
600 kg
Where is the satellite going (eventually)?
Geostationary Earth Orbit (GEO)
Did they attempt to recover the first stage?
Where did the first stage land?
It crashed back over land
Did they attempt to recover the fairings?
Were these fairings new?
This was the:
– 61st launch of a Long March 3B/E
– 51st orbital launch from China in 2021
– 131st orbital launch attempt in 2021 (124th successful)
Where to watch
Launch Replay

How Did It Go?

China launched the second of its Tianlian 2 satellites into Earth orbit on December 14, 2021, local time. The launch was reported to be a success according to CNSA. When in its final orbit, it will also offer data relay services for low- and mid-orbiting satellites and will be used to track and monitor spacecraft launches, according to CNSA.

What Is Tianlian 2-02?

Tianlian 2 is a series of tracking and data relay satellites, similar to the USA TDRS satellites. They are used to support other satellites in Low Earth Orbit (LEO) and Medium Earth Orbit (MEO). The system is also used to communicate between the Chinese Space Station and Beijing.

Tianlian 1 satellites used S-band radio with 2 GHz frequency. Tianlian 2 however uses K-band radio with a frequency in excess of 20 GHz.

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 rockets 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 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.

The Long March 3 family of rockets
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.

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