Spaceflight Insider

First piece of new Chinese weather satellite constellation launches

Long March 2D launches Yunhai-1

China’s Long March 2D launches with the Yunhai-1 satellite. Photo Credit: Xinhua

China conducted a second rocket launch in as many days sending into orbit Yunhai-1, the first satellite of a new constellation of meteorological Earth-orbiting satellites.

Riding atop a Long March 2D rocket at 7:14 a.m. China Standard Time Nov. 12 (19:14 p.m. EST / 23:14 GMT Nov. 11) from the Jiuquan Satellite Launch Center’s Launch Complex 43/603, the Yunhai-1 weather satellite was placed into a polar orbit of some 470 miles (760 kilometers) in altitude.

Little is known about this satellite aside from where it was built: the Shanghai Academy of Spaceflight Technology (SAST). Per Chinese state media, the spacecraft will be primarily used for atmospheric, marine and space environment exploration; disaster prevention and mitigation, and scientific experiments.

Yunhai is Chinese for cloud-sea. This is likely because the satellite will use radio occultation measurements for measuring clouds in the atmosphere.

According to Spaceflight101, it is likely the Yunhai-1 part of the new constellation will be used primarily for data collection for the civilian sectors while other satellites may be used to collect data for the Chinese military.

The Long March 2D was developed by SAST. It is a two stage launcher that can send 7,700 pounds (3,500 kilograms) to low-Earth orbit or 2,800 pounds (1,300 kilograms) to a Sun-synchronous orbit. It stands 135 feet (41 meters) tall with a diameter of 11 feet (3.35 meters). Fully fueled, it weighs more than 230 metric tons.

The 92-foot-tall (28-meter-tall) first stage YF-21C engine burns for the first 170 seconds of the launch. Burning toxic Unsymmetrcial Dimethylhydrazine (UDMH) and Nitrogen Tetroxide (NTO) propellants, the engine provides 665,884 pounds (2,962 kilonewtons) of thrust.

Once the first stage burns out and separates, the second stage takes control. It is nearly 36 feet (11 meters) in length and sports a YF-24C main engine along with a vernier engine that also consumes UDMH and NTO. The main engine produces 166,808 pounds (742 kilonewtons) of thrust while the vernier produces 10,500 pounds (47 kilonewtons).

This launch was the 240th flight of a Long March rocket and China’s 18th of 2016 with more planned before the end of the year. As of right now, the next flight is expected to occur Nov. 20. It will be a Long March 3C with the Tianlian-1 data relay satellite perched atop. However, as has been seen in the past, the country often launches satellites unannounced.




Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.

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