China orbits YaoGan-5 satellite via Chang Zheng-4B launch vehicle

by Rui C. Barbosa
China has launched a new remote sensing satellite from the Taiyuan Satellite Launch Center. The fifth satellite in the YaoGan series was orbited by a CZ-4B Chang Zheng-4B  launch vehicle at 03:22 UTC Monday morning.

According to the state media, and as is predecessors, the YaoGan-5 satellite will be used for scientific research, land resources surveying, crop yield estimate and disaster prevention and relief. The satellite was developed by the China Academy of Space Technology.

Once again the lack of information about this new bird and its late launch announcement raises the questions about its military nature. Announced as a remote sensing and disaster relief satellite series, the YaoGan satellites have an “obscure” mission.

The first YaoGan satellite (29092 2006-015A) was launched by a CZ-4C Chang Zheng-4C (CZ4C-1) from the Taiyuan Satellite Launch Center on April 27, 2006. At the time the details about this satellite were very rare but later it was said that this was the first Jian Bing-5 satellite, being equipped with the first space-based synthetic aperture radar (SAR).

The YaoGan-2 (31490 2007-019A) was launched on 25 May, 2007 by a CZ-2D Chang Zheng-2D (CZ2D-8) from the Jiuquan Satellite Launch Center. The details about this satellite were also rare, but some sources pointed that this could be an optical military observation satellite complementing the results of the YaoGan-1.
On November 12th, 2007 was launched the YaoGan-3 (32289 2007-055A) satellite by a CZ-4C Chang Zheng-4C (CZ4C-2) launch vehicle from Taiyuan. The Yaogan-3 was said to be the second Jian Bing-3 SAR satellite. Finally, on December 1st 2008 was the launch of YaoGan-4 (33446 2008-061A) by a CZ-2D Chang Zheng-2D from Jiuquan.

The CZ-4B Chang Zheng-4B launch vehicle was first introduced in May 1999. The rocket is capable of launching a 2200 kg satellite into a 900 km polar sun-synchronous orbit, developing 2960000 kN at launch. With a mass of 248470 kg, the CZ-4B is 45.58 meters long and has a diameter of 3.35 meters.

Developed by the Shanghai Academy of Spaceflight Technology, the CZ-4B is a three-stage launch vehicle that uses storable propellants. Its first stage is the same of the CZ-4A, being equipped with a YF-21B (four YF-20B engines with swinging nozzles). The second stage is an YF-22B and the third stage uses an YF-40.

According to, modifications on the CZ-4B included larger payload fairing, the replacement of the original mechanical-electrical control on the CZ-4 with an electronic control, an improved telemetry, tracking, control, and self-destruction systems with smaller size and lighter weight.

It also includes a revised nozzle design in the second stage for better high-altitude performance, 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 launch of the CZ-4B was on May 10, 1999 from the Taiyuan Satellite Launch Center orbiting the FY-1C Feng Yun-1C (25730 1999-025A) meteorological satellite and the SJ-5 Shi Jian-5 (25731 1999-025B).

This launch was the 10th orbital launch by China this year, the 115th Chinese orbital launch, the 27th orbital launch from the Taiyuan Satellite Launch Center, and the fourth orbital launch from Taiyuan this year.

Situated in the Kelan County on the northwest part of the Shanxi Province, the Taiyuan Satellite Launch Center is also known by the Wuzhai designation.

It is used mainly for polar launches (meteorological, Earth resources and scientific satellites). The launch center is equipped with a Mission Command and Control Center, a Technical Center and telemetry, tracking and communications centers. There are two launch complexes in Taiyuan.

The next Chinese launch will probably be the launch of the FY-2E Feng Yun-2E meteorological satellite from Xi Chang Satellite Launch Center that is scheduled to take place in the last 10 days of the year. The satellite will be launched by a CZ-2A Chang Zheng-3A rocket.

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