China launched an experimental satellite from the Taiyuan Satellite Launch Center on Friday morning using the Long March-4B – Chang Zheng-4B – (Y49) rocket. The launch took place at 23:01 UTC (Thursday) from Launch Complex LC9.
Onboard was the third Shiyan-6 satellite that the Chinese press refers to for space environment surveys and experiments on related technologies.
The new satellite, developed by the DFH Satellite Co. Ltd of the Chinese Academy of Spaceflight Technology, is the first series to be launched from Taiyuan. The two previous launches took place from the Jiuquan Satellite Launch Center.
The change in orbital site and launch vehicle permitted the Shiyan-6 (03) to be orbited on a Sun-synchronous orbit at an altitude of 1,000 km with an orbital inclination of 99.5 deg.
Various Shiyan satellite series was used to test technologies to be applied to future satellites.
The first Shiyan satellite was launched on April 18, 2004, by a Long March-2C rocket from the Xichang Satellite Launch Center.
This was China’s first experimental digital imaging system capable of stereo Earth-terrain mapping, also testing the digital imaging capability for the then-new generation of Chinese military reconnaissance spacecraft in development.
Similar to Shiyan-1, Shiyan-2 was launched on November 18, 2004, also from Xichang and using a Long March-2C launch vehicle. Shiyan-3 and Shiyan-4 were both launched from Jiuquan. Both satellites were experimental vehicles with digital imaging systems capable of stereo Earth-terrain mapping. Shiyan-3 was launched on November 5, 2008, and Shiyan-4 was launched on November 20, 2011, and Shiyan-5 was launched on November 24, 2013.
The first Shiyan-6 was launched on November 19, 2018, with Shiyan-6 (02) being launched on July 4, 2020. Both launches used Long March-2D launch vehicles out of Jiuquan.
The feasibility study of the CZ-4 Chang Zheng-4 began in 1982 based on the FB-1 Feng Bao-1 launch vehicle. Engineering development was initiated in the following year. Initially, the Chang Zheng-4 served as a backup launch vehicle for Chang Zheng-3 to launch China’s communications satellites.
After the successful launch of China’s first DFH-2 communications satellites by Chang Zheng-3, the primary mission of the Chang Zheng-4 was shifted to launch sun-synchronous orbit meteorological satellites. On the other hand, the Chang Zheng-4B launch vehicle was first introduced in May 1999 and developed by the Shanghai Academy of Space Flight Technology (SAST), based on the Chang Zheng-4.
The rocket can launch a 2,800 kg satellite into low Earth orbit, developing 2,971 kN at launch. With a mass of 248,470 kg, the CZ-4B is 45.58 meters long and has a diameter of 3.35 meters.
SAST began to develop the Chang Zheng-4B in February 1989. Initially, it was scheduled to be commissioned in 1997, but the first launch didn’t occur until late 1999. The modifications introduced on the Chang Zheng-4B included a larger satellite fairing and replacing the original mechanical-electrical control on the Chang Zheng-4 with electronic control.
Other modifications were improved telemetry, tracking, control, and self-destruction systems with smaller size and lighter weight, a revised nozzle design in the second stage for better high-altitude performance. Other improvements included a propellant management system for the second stage to reduce the spare propellant amount, thus increasing the vehicle’s payload capability and a propellant jettison system on the third stage.
The first stage has a 24.65-meter length with a 3.35-meter diameter, consuming 183,340 kg of N2O4/UDMH (gross mass of the first stage is 193.330 kg).
¡Video del Lanzamiento!
La Corporación de Ciencia y Tecnología Aeroespacial de China lanzo este 8 de abril a las 23:01 UTC el Long March 4B donde llevo a órbita el satélite Shiyan-6 03, la misión fue confirmada como exitosa por la misma corporación china. pic.twitter.com/K6AZ7f93Cz
— Conexión Espacial (@conexionspacial) April 9, 2021
The vehicle is equipped with a YF-21B engine capable of a ground thrust of 2,971 kN and a ground-specific impulse of 2,550 Ns/kg. The second stage has a 10.40-meter length with a 3.35-meter diameter and 38,326 kg, consuming 35,374 kg of N2O4/UDMH.
The vehicle is equipped with a YF-22B main engine capable of a vacuum thrust of 742 kN and four YF-23B vernier engines with a vacuum thrust of 47.1 kN (specific impulses of 2,922 Ns/kg and 2,834 Ns/kg, respectively).
The third stage has a 4.93-meter length with a 2.9-meter diameter, consuming 12,814 kg of N2O4/UDMH. With a gross mass of 14,560 kg, it is equipped with a YF-40 engine capable of a vacuum thrust of 100.8 kN and a specific impulse in a 2,971 Ns/kg vacuum.
Situated in Kelan County in the northwest part of the Shanxi Province, the Taiyuan Satellite Launch Center (TSLC) is also known by the Wuzhai designation. It is used mainly for polar launches (meteorological, Earth resources, and scientific satellites).
The launch center has two single-pad launch complexes, a technical area for rocket and spacecraft preparations, a communications center, a mission command and control center, and a space tracking center.
The rocket stages are transported to the launch center by railway and offloaded at a transit station south of the launch complex. They were then transported by road to the technical area for checkout procedures.
The launch vehicles were assembled on the launch pad by using a crane at the top of the umbilical tower to hoist each stage of the vehicle in place. Satellites were airlifted to the Taiyuan Wusu Airport about 300km away and then transported to the center by road.
The TT&C Centre, also known as Lüliang Command Post, is headquartered in the city of Taiyuan. It has four subordinate radar tracking stations in Yangqu (Shanxi), Lishi (Shanxi), Yulin (Shaanxi), and Hancheng (Shaanxi).
Next in line for China:
In a decisive month for the future of the Chinese space manned presence, the major launch in the last year for China will be the orbiting of the Tianhe-1 core module of its future modular space station.
Currently being in the final stages of preparation at Wenchang, the launch of Tianhe-1 is expected on April 29 using a Long March-5B rocket.
On April 27, the first two Qilu remote sensing satellites (Qilu-1 and Qilu-4) should be launched from Taiyuan using the Long March-6 (Y5) rocket.
It is also expected the Long March-11 (Y10) rocket will launch from the Xichang Satellite Launch Center with an undisclosed cargo.