Launch Window/Lift Off Time | July 29, 2021 – 04:00 UTC | 12:00 BJT |
|---|---|
Mission Name | Tianhui-1-04, the fourth Tianhui-1 Earth observation satellite |
Launch Provider | China Great Wall Industry Corporation (CGWIC) |
Customer | Chinese Ministry of Defense |
Rocket | Long March 2D |
Launch Location | Site 9401 (SLS-2), Jiuquan Satellite Launch Center, China |
Payload mass | Unknown, up to 1,300 kg (2,900 lb) to Sun-synchronous orbit |
Where is the satellite going? | 490 x 505 km Sun-synchronous orbit |
Will they be attempting to recover the first stage? | No, the boosters of the rocket are not recoverable |
Where will the first stage land? | It will crash back over land in North-West China |
Will they be attempting to recover the fairings? | No, the fairings are not recoverable |
Are these fairings new? | Yes |
How’s the weather looking? | No information available |
This will be the: | – 54th flight of a Long March 2D) – 24th Chinese launch in 2021 – 70th orbital launch attempt of 2021 |
Where to watch | Official livestream (if available) |
What’s all this mean?
The China Great Wall Industry Corporation will launch the Tianhui-1-04 satellite atop a Long March 2D. It is an Earth observation satellite that will be deployed into a 490 km by 505 km Sun-synchronous orbit.
Tianhui Satellites
The Tianhui (or “sky drawing”) constellation of satellites are Earth observation satellites built by Dong Feng Hong and operated by the People’s Liberation Army, which is a part of the Chinese ministry of defence. The Tianhui-1-04 satellite will monitor the ground in both the visible and infrared spectrum, with two cameras. With these cameras the satellite has a resolution of under 5 meters and a field of view of roughly 25°. The satellite will also survey human activities.
Due to the nature of the payload, very little is known about the actual satellite. However, it is known that the satellite is equipped with two solar arrays and the two aforementioned cameras.
What is the Long March 2D?
The Long March 2D (also known as the Chang Zheng 2D, CZ-2D and LM-2D), is a two-stage rocket, predominantly used for launching satellites to low-Earth orbit (LEO) and SSO. The Long March 2D is a two-stage version of the Long March 4, and is the smallest of all the active Long March rocket series.
The rocket’s maiden flight was on August 9, 1992, and it has since had a near perfect launch history, with the only incident being a partial failure on December 28, 2016.
First Stage
The first stage is 27.91 m in length, and uses four YF-21C engines. YF-21C is the name given to the engine when it is part of a module comprised of four YF-20C engines. The engines burn dinitrogen tetroxide (N2O4 ) and unsymmetrical dimethylhydrazine (UDMH) in a gas generator cycle. Each engine produces 731 kN of thrust at sea level, with a specific impulse (ISP) of 259 seconds. In vacuum this is 816 kN of thrust with an ISP of 289 seconds.
Second Stage
The second stage is 10.9 m in length, and uses one YF-24C engine, which similarly to the first stage engines, burns dinitrogen tetroxide (N2O4 ) and unsymmetrical dimethylhydrazine (UDMH) in a gas generator cycle. The name YF-24C means it is part of a module comprising a YF-22 engine and a YF-23 vernier.
