Long March 6 lofts five Ningxia-1 satellites

by Rui C. Barbosa

The second Chinese orbital launch in less than three hours took place on Wednesday with a Long March-6 launch vehicle orbiting five remote sensing satellites from the Taiyuan Satellite Launch Center, Shanxi Province. Launch of the five Ningxia-1 satellites took place at 06:35 UTC from the LC16 Launch Complex.

The new satellites – also designated Zhongzi, were developed by the DFH Satellite Co., Ltd. and the Shanghai Academy of Spaceflight Technology (SAST) – are part of a commercial satellite project financed by the Ningxia Jingui Information Technology Co., Ltd. and will be mainly used for remote sensing detection.

This mission was the first low-inclination orbital launch for the Long March-6 launch vehicles, in response to the mission needs. The rocket was submitted to a series of technical upgrades, including take-off roll, horizontal guidance, new composite material double-walled mount barrel and others.

The CZ-6 Chang Zheng-6 is a liquid-propellant, small-load space launch vehicle developed by SAST.

The launch vehicle is based on the 3.35m-diameter boosters, which have been developed as a strap-on booster for the CZ-5 family of SLV.

The core stage consists of a single 120t-thrust YF-100 engine that burns oxygen and kerosene (LOX/Kerosene) propellant, which causes less pollution compared to the UDMH/N2O4 (nitrogen tetroxide) propellant currently in use.

The Long March-6 is designed for small-load launch missions, with a sun-synchronous orbit (700km SSO) capability of 1,080 kg.

In September 2009, the Chang Zheng-6 launch vehicle development program was officially approved by the Chinese Government and the first flight was expected to take place in 2013. SAST was tasked with the development of the new launch vehicle in July 2008.
The overall length is 29.237 m with a total mass at liftoff of 103,217 kg. The dry mass of the three stages combined is 9,020 kg. Fairing diameter is 2.25 m / 2.6 m, and the vehicle is capable of launching a payload of 1,080 kg to a 700 km SSO orbit (500 kg if only Chinese tracking stations are used).

The first stage has a 3.35 meter diameter and is equipped with a single YF-100 engine, consuming 76,000 kg of kerosene RP-1/LOX. The YF-100 engine is capable of a ground thrust of 1,177 kN and a ground specific impulse of 2.9 km/s. Burn time is 155 seconds. The first stage uses four 1000 N thrusters for roll control.

The second stage has 2.25 meter diameter and consumes 15,150 kg of kerosene RP-1/LOX. It is equipped with a YF-115 developing 147.1 kN (sea level) or 176.5 kN (vacuum), with a vacuum specific impulse of 3.35 km/s. The second stage uses four 25 N thrusters for roll control.

The third stage is equipped with four engines with 4 kN (each), along with eight 100 N thrusters for attitude control. The engines are powered by a mixture of kerosene and hydrogen peroxide.

Situated in the 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 launch area for the new Long March-6 rocket, a technical area for rocket and spacecraft preparations, a communications center, mission command and control center, and a space tracking center.

The stages of the rocket were 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).

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