Long March 2C launches Shijian-9 tech demonstrator satellite duo

by Rui C. Barbosa

The Chinese have launched their much delayed Shijian-9 mission on Sunday, involving a pair of technology demonstrator satellites.  The launch took place at 03:25UTC from the Taiyuan Satellite Launch Center using a Long March 2C (Chang Zheng-2C/SMA) launch vehicle.

Chinese Launch:

The two satellites were developed by the Shanghai Academy of Spaceflight Technology (SAST) for the Chinese Commission of Science, and the Technology and Industry for National Defence (COSTIND).

The mission will conduct on-orbit experiments for electric propulsion, testing the XIPS-20 xenon gas ion thruster system. It will also test high precision and high stability control systems, high efficient power supply and advanced thermal control technology. The satellites features also instruments for Earth observation.

“Shijian” means “Practice” and this series of satellites have previously been used with a variety of configurations and missions for scientific research and technological experiments.

This was the 169th successful Chinese orbital launch, the 169th launch of a Chang Zheng launch vehicle, the 40th successful orbital launch from Taiyuan, the 14th successful orbital Chinese launch in 2012 and the fourth from Taiyuan this year.

The Chang Zheng-2C launch vehicle:

The Chang Zheng-2C a low Earth orbit launch vehicle derived from DF-5 ICBM. The rocket is a two stage hypergolic launch vehicle with a total length of 35.17 meters, a diameter of 3.35 meters and a total mass of 192,000 kg. The CZ-2C is most frequently used version of Long March Launch Vehicles which had 14 consecutive successful flights till October of 1994. In order to meet the user’s need,

China Academy of Launch Vehicle (CALT) developed a new smart dispenser upper stage, the CZ-2C/SD has been used commercially in the late 1990s and conducted seven consecutive successful launches for Iridium program.

The CZ-2C launch vehicle now comes in two versions, with a basic version comprising of a two-stage CZ-2C for LEO with typical launch capability of 3,366 kg, and a three-stage version known as the CZ-2C/CTS with a typical launch capability of 1,456 kg. The CTS upper stage for CZ-2C is a three-axis stabilized stage capable of delivering one or more satellites.

This launcher provides a flexible mechanical and electrical interfaces and length-adjustable fairing for various satellites.

The first stage is equipped with a cluster of four YF-20A engines (YF-21), with a length of 23.72 meters, a gross mass of 151,000 kg (empty mass of 8,600 kg) and a burn time of 130 seconds.

The second stage is equipped with a cluster of one YF-22A engine with fixed nozzles and a swivelling venire motor consisting of four YF-23 chambers motors (the YF-24), with a length of 8.71 meters, a gross mass of 38,200 kg (empty mass of 3,200 kg) with a burn time of 112 seconds (main engine) and 287 second (vernier).

For this launch the CZ-2C used an SMA upper stage – possibly using the SpaB-140C solid motor – increasing the SSO payload capability to 1,900 kg.

Following the opening 120 seconds of the Chang Zheng-2C/SMA ascent, separation occurs at T+122 seconds with the second stage igniting while still attached to the first stage. Fairing jettisoning is usually set for T+3 minutes and 52 seconds.

The shutdown of the second stage takes place in two phases. First, at T+5 minutes and 1 seconds main engine shutdown takes place while the vernier engines keep firing for an additional 10 minutes, with vernier shutdown taking place at T+10 minutes 13 seconds. Separation of the third stage takes place three seconds after vernier engines shutdown.

Depending on the mission, the vehicle the enters a coast phase until T+48 minutes and 8 seconds when solid rocket motor ignition takes place for a final burn. Spacecraft separation usually occurs at T+50 minutes and 13 seconds..

The Taiyuan Satellite Launch Center:

Situated in the Kelan County on 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 center is at a height of 1400-1900m above sea level, and is surrounded by mountains to the east, south and north, with the Yellow River to its west.

The annual average temperature is 4-10 degrees C, with maximum of 28 degrees C in summer and minimum of -39 degrees C in winter.

TSLC is suitable for launching a range of satellites, especially for low earth and sun-synchronous orbit missions.

The center has state-of-the-art facilities for launch vehicle and spacecraft testing, preparation, launch and in-flight tracking and safety control, as well as for orbit predictions.

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