Long March 3B lofts ChinaSat 9A – third stage issue reported

by Rui C. Barbosa

Three days after the successful launch of the Huiyan (HXMT) X-ray space telescope, China was back in action with the launch of a new communications satellite from the Xichang Satellite Launch Center. Launch of Zhongxing-9A (also designated ChinaSat-9A) took place at 16:10 UTC using a Long March-3B/G2 (Chang Zheng-3B/G2) launch vehicle from the LC2 launch complex. However, the third stage suffered an issue, resulting in the satellite being placed in the wrong orbit.
Chinese Launch:

Operated by the China Satellite Communications Co. Ltd. (China Satcom), the Zhongxing-9A communications satellite was developed by the China Aerospace Science and Technology Corporation (CASC) based on the DFH-4 bus.

With an expected life time of 15 years and stationed at 101.4 degrees E, ZX-9A is equipped with 18x36MHz and 4x54MHz BSS Ku-band transponders to provide direct broadcast services for radio and TV transmission, digital film and digital broadband multimedia system as well as information and entertainment broadcasting market. The satellite launch mass is 5,100 kg.

Due to the issue with the third stage, the incorrect orbit will require some reworking of its immediate life in space. The spacecraft is classed as healthy.

The satellite was originally developed as Xinnuo 4 (Sinosat 4) and was due to be launched in late 2008, having been delayed to 2011. In 2010, the satellite was taken over by China Satcom and renamed ZX-9A (ChinaSat-9A). Reportedly parts produced for ZX-9A have been used for other satellites.

The DFH-4 (DongFangHong-4) platform is a large, next-generation, telecommunications satellite platform, with high capability output power and communication capacity ranking with international advanced satellite platforms.

The applications for the DFH-4 platform aren’t limited to high capacity broadcast communication satellites and can be used to tracking and data relay satellites, regional mobile communication satellites, etc.

The platform comprises propulsion module, service module and solar array. It has a payload capacity of 588 kg and an output power of 10.5 kW by the end of its lifetime. Its design lifetime is 15 years and its reliability by the end of lifetime is more than 0.78.

Based on versatility, inheritance, expandability and promptness principles and mature technology, the platform will reach a world advanced level to meet the needs of international and domestic large communication satellite markets.

The platform is equipped with 22 Ku-band transponders (four 54MHz and 18 36MHz), three receiver antennas, and two transmission antennas. With a designed operational life of 15 years, the DFH-4 can support the transmission of 150~200 TV programs simultaneously to ground users using a 0.45m antenna device.

The DFH-4 satellite also features strong capabilities against hostile disturbance and jamming. The satellite’s power supply includes two 6m solar panels.


Launch vehicle and launch site:

To meet the demand of international satellite launch market, especially for high power and heavy communications satellites, the development of Long March-3B (Chang Zheng-3B) launch vehicle was started in 1986 on the basis of the fight proven technology of Long March launch vehicles.

Developed from the Chang Zheng-3A, the Chang Zheng-3B is at the moment the most powerful launch vehicle on the Chinese space launch fleet.

The CZ-3B features enlarged launch propellant tanks, improved computer systems, a larger 4.2 meter diameter payload fairing and the addition of four strap-on boosters in the core stage that provide additional help during the first phase of the launch.

The rocket is capable of launching a 11,200 kg satellite to a low Earth orbit or a 5,100 kg cargo to a geosynchronous transfer orbit.

The CZ-3B/G2 (Enhanced Version) launch vehicle was developed from the CZ-3B with a lengthened first core stage and strap-on boosters, increasing the GTO capacity up to 5,500kg.

On May 14, 2007, the first flight of CZ-3B/G2 was performed successfully, accurately sending the NigcomSat-1 into pre-determined orbit. With the GTO launch capability of 5,500kg, CZ-3B/G2 is dedicated for launching heavy GEO communications satellite.

The rocket structure also combines all sub-systems together and is composed of four strap-on boosters, a first stage, a second stage, a third stage and payload fairing.

The first two stages, as well as the four strap-on boosters, use hypergolic (N2O4/UDMH) fuel while the third stage uses cryogenic (LOX/LH2) fuel. The total length of the CZ-3B is 54.838 meters, with a diameter of 3.35 meters on the core stage and 3.00 meters on the third stage.

On the first stage, the CZ-3B uses a YF-21C engine with a 2,961.6 kN thrust and a specific impulse of 2,556.5 Ns/kg. The first stage diameter is 3.35 m and the stage length is 23.272 m.

Each strap-on booster is equipped with a YF-25 engine with a 740.4 kN thrust and a specific impulse of 2,556.2 Ns/kg. The strap-on booster diameter is 2.25 m and the strap-on booster length is 15.326 m.

The second stage is equipped with a YF-24E (main engine – 742 kN / 2,922.57 Ns/kg; four vernier engines – 47.1 kN / 2,910.5 Ns/kg each). The second stage diameter is 3.35 m and the stage length is 12.920 m.

The third stage is equipped with a YF-75 engine developing 167.17 kN and with a specific impulse of 4,295 Ns/kg. The fairing diameter of the CZ-3B is 4.00 meters and has a length of 9.56 meters.

The CZ-3B can also use the new Yuanzheng-1 (“Expedition-1”) upper stage that uses a small thrust 6.5 kN engine burning UDMH/N2O4 with specific impulse at 3,092 m/s. The upper stage is able to conduct two burns, having a 6.5 hour lifetime and is capable of achieving a variety of orbits. This upper stage was not used on this launch.

Typical flight sequence for the CZ-3B/G2 sees the launch pitching over 10 seconds after liftoff from the Xichang Satellite Launch Centre. Boosters shutdown 2 minutes and 7 seconds after liftoff, separation from the first stage one second latter. First stage shutdown takes place at 1 minutes 25 seconds into the flight.

The separation between the first and second stage takes place at 1 minute 26 seconds, following fairing separation at T+3 minutes 35 seconds. Stage 2 main engine shutdown occurs 326 seconds into the flight, following by the shutdown of the vernier engines 15 seconds later.

The separation between the second and the third stage and the ignition of the third stage takes place one second after the shutdown of the vernier engines of the second stage. The first burn of the third stage will last for 4 minutes and 44 seconds.

After the end of the first burn of the third stage follows a coast phase that ends at T+20 minutes and 58 seconds with the third stage initiating its second burn. This will have a 179 seconds duration. After the end of the second burn of the third stage, the launcher initiates a 20 second velocity adjustment maneuver. Spacecraft separation usually takes place at T+25 minutes 38 seconds after launch.

The first launch from Xichang took place at 12:25UTC on January 29, 1984, when the Chang Zheng-3 (Y-1) was launched the Shiyan Weixing (14670 1984-008A) communications satellite into orbit.

The Xichang Satellite Launch Centre is situated in the Sichuan Province, south-western China and is the country’s launch site for geosynchronous orbital launches.

Equipped with two launch pads (LC2 and LC3), the center has a dedicated railway and highway lead directly to the launch site.

The Command and Control Centre is located seven kilometers southwest of the launch pad, providing flight and safety control during launch rehearsal and launch.

The CZ-3B launch pad is located at 28.25 deg. N – 102.02 deg. E and at an elevation of 1,825 meters.

Other facilities on the Xichang Satellite Launch Centre are the Launch Control Centre, propellant fuelling systems, communications systems for launch command, telephone and data communications for users, and support equipment for meteorological monitoring and forecasting.

Future Chinese launches:

The second half of 2017 will see a large increase in Chinese launch activities, starting with the expected launch of the Shijian-18 experimental communication satellite using the second launch of Long March-5 launch vehicle from the Wenchang Space Launch Center on July 2.

Equipped with LIPS-300 Ion engines for orbital maneuvering, the new satellite is based on the new DFH-5 satellite platform. The DFH-5 satellite platform is a large trussed satellite platform of new-generation, developed by China itself. Its technical specifications reached an advanced world level.

The DFH-5 has a launch mass of 8000 kg, of which the payload is 1500 kg, providing 18 kilowatts payload power, high load, high power, high heat dissipation, long life, scalability, etc., using a truss structure, high power distribution systems, advanced electronics and integrated multi-mode high-thrust electric propulsion and other advanced technology to meet the needs of communications and other devices.

The development of the DFH-5 platform will lead the technical innovation of the design and manufacture of spacecraft and other relevant areas, promoting the upgrading of the our large satellite platform, supporting the development of civil space infrastructure and aerospace equipment, and creating new advantages in international commercial satellite market competition.

A new pair of navigation satellites are expected to launch on July 15 and August 16 when China will launch the Zangheng-1, the Experimental Satellite on Electromagnetism Monitoring (ESEM).

The ESEM mission was proposed to be the first satellite of space-based geophysical fields observation system in China with a lot of application prospects in earthquake science, geophysics, space sciences and others. Together with Zangheng-1 there will be a number of small sats on board the Long March-2D launch vehicle, such as the Fengmaniu-1, Shaonian Xing and the ÑuSat-3 and ÑuSat-5 satellites and others.

A new communications satellite, Zhongxing-6C is expected to launch in September as well as a new pair of navigation satellites.

A new pair of navigation satellites will be launched in October and at the end of November when China conducts the ambitious Chang’e-5 lunar sample return mission.

The Chang’e 5 lunar probe is expected to land in the Mons Rümker in Oceanus Procellarum region, and to take moon samples back to earth at the end of the year. Maunch is expected around November 30.

Three new navigation satellites will be launched in December and others launches are expected, like the Fengyun-2H and Fengyun-3D meteorological satellites, the civilian remote sensing Gaofen-5 and Gaofen-6 satellites and the Algerian communications satellite.

Other launches are also expected in the Yaogan Weinxing series.

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