Long March 2D lofts Yaogan Weixing-24 for China

by Rui C. Barbosa

The Chinese have launched yet another spy satellite, this time via a Long March 2D rocket. The launch of Yaogan Weixing-24 “remote sensing” satellite comes just six days after they orbited the Yaogan-23 spacecraft. This latest launch occurred at 0712UTC on Thursday, lifting off from the 603 Launch Pad of the LC43 Launch Complex at the Jiuquan Satellite Launch Center.

Chinese Launch:

Once again Chinese media is referring to the new satellite as ‘a new remote sensing bird that will be used for scientific experiments, land survey, crop yield assessment, and disaster monitoring.’

As was the case in the last launches of the Yaogan Weixing series, western analysts believe this class of satellites is used for military purposes.

Yaogan-24 is probably an electro-optical observation satellite on the military Jianbing-6 series.

Similar satellites were the Yaogan Weixing-2 (31490 2007-019A) that was launched on 25 May, 2007; the Yaogan Weixing-4 (33446 2008-061A) launched on December 1, 2008; the Yaogan Wexing-7 (36110 2009-069A), launched on December 9, 2009; and the Yaogan Weixing-11 (37165 2010-047A) launched on September 22, 2010.

All the satellites were launched by Long March-2D rockets from the Jiuquan Satellite Launch Center.

The Jianbing-6 electro-optical satellites carry high resolution optical sensors and reportedly have a resolution of between one to three meters and are placed in orbits that provide favourable illumination for the imaging missions.

This launch was the 211th Chinese orbital launch and the 199th successful one, being also the 199th launch of the Long March launch vehicle family.

It was also the 69th successful orbital launch from the Jiuquan Satellite launch Center, the sixth launch from this space center in 2014 and the 11th orbital launch for China this year.

Launch Vehicle and Launch Site:

The Chang Zheng-2D (Long March 2D) launch vehicle is a two-stage rocket developed by the Shanghai Academy of Spaceflight Technology. With storable propellants is mainly used to launch a variety of low earth orbit satellites.

The development of CZ-2D was started in February 1990. From 2002, to meet the demand of SSO satellites, the payload fairing of 3350mm in diameter and attitude control engine for second stage have been successfully developed; and the discharge of remaining propellant and de-orbit of the second stage have been realized. This launcher is mainly used for launching LEO and SSO satellites.

2014-11-20 11_06_16-Yaogan Weixing-24 - Long March 2D - JSLC - November 20, 2014The CZ-2D can launch a 1,300 kg cargo in a 645 km SSO. The rocket is 41.056m long and the first, second stages and payload fairing are all 3.35m in diameter.

Its first stage is the same of the CZ-4 Chang Zheng-4. The second stage is based on CZ-4 second stage with an improved equipment bay. Lift-off mass is 232,250 kg, total length 41,056 meters, diameter 3.35 meters and fairing length 6.983 meters. At launch it develops 2961.6kN engine thrust.

The first stage has a 27.910 meter length with a 3.35 meter diameter, consuming 183,200 kg of N2O4 / UDMH (launch mass of the first stage is 192,700 kg). Equipped with a YF-21C engine capable of a ground thrust of 2,961.6 kN and a ground specific impulse of 2,550 m/s. Burn time is 170 seconds.

The second stage has a 10.9 meter length with a 3.35 meter diameter, launch mass of 39,550 kg and consuming 45,550 kg of N2O4 / UDMH. Equipped with a YF-24C cluster engine with a main engine vacuum thrust of 742.04 kN and a vernier engine with a vacuum thrust of 47.1 kN (specific impulses of 2,942 m/s and 2,834 m/s, respectively).

The CZ-2D can use two types of fairings depending of the cargo. Type A fairing has a 2.90 meters diameter (total launch vehicle length is 37.728 meters) and Type B fairing with a diameter of 3.35 meters – total launch vehicle length is 41.056 meters.

The first launch of the CZ-2D was on August 9th, 1992 from the Jiuquan Satellite Launch Center orbiting the Fanhui Shei Weixing FSW-2-1 (22072 1992-051A) recoverable satellite.

Long March 4CThe Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – was the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.

The site includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.

Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. It is also the place from where all the Chinese manned missions are launched.

The LC-43 launch complex, also known by South Launch Site (SLS) is equipped with two launch pads: 921 and 603. Launch pad 921 is used for the manned program for the launch of the Chang Zheng-2F launch vehicle (Shenzhou and Tiangong). The 603 launch pad is used for unmanned orbital launches by the Chang Zheng-2C, Chang Zheng-2D and Chang Zheng-4C launch vehicles.

Other launch zone at the launch site is used for launching the Kuaizhou solid propellant launch vehicle.

The first orbital launch took place on April 24, 1970 when the CZ-1 Chang Zheng-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).

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