China launches another navigation satellite – End 2010 with record 15 launches

by Rui C. Barbosa

Ending a record breaking year, China launched its seventh satellite as part of their large navigation system via their Long March 3A – otherwise known as the CZ-3A Chang Zheng-3A (Y18) – launch vehicle. The launch of BeiDou-2 ‘Compass-I2’ took place from the Xi Chang Satellite Launch Center, in Sichuan Province at 20:20UTC on Friday.

Chinese Launch:

The satellite that was launched is the second BeiDou-2 IGSO (Inclined GSO) satellite of the system. This constellation of satellites will consist of 35 vehicles, including 27 MEO satellites, 5 GSO satellites and 3 IGSO. The satellites will transmit signals on the: 1195.14-1219.14MHz, 1256.52-1280.52MHz, 1559.05-1563.15MHz and 1587.69-1591.79MHz, carrier frequencies.

The BeiDou-2 was developed in the basis of the DFH-3 satellite platform and has an expected lifespan of eight years.

The Compass Navigation Satellite System (CNSS) is China’s second-generation satellite navigation system capable of providing continuous, real-time passive 3D geo-spatial positioning and speed measurement. The system will initially used to provide high-accuracy positioning services for users in China and its neighboring regions, covering an area of about 120 degrees longitude in the Northern Hemisphere. 

The long-term goal is to develop a global navigation satellite network similar to the USA’s GPS and Russia’s GLONASS.

Like the American and Russian counterparts, CNSS will have two kinds of services: a civilian service that will give an accuracy of 10 meters in the user position, 0.2 m/s on the user velocity and 50 nanoseconds in time accuracy; and the military and authorized user’s service, providing higher accuracies. The first phase of the project will see the coverage of the Chinese territory, but in the future the Compass constellation will cover the entire globe.

The previous BeiDou launch took place on October 31st when a Chang Zheng-3C orbited the ‘Compass-G4’ (37210 2010-057A) satellite.

This was the nineteenth flight of the CZ-3A Chang Zheng-3A launch vehicle. The CZ-3A is a three-stage liquid launch vehicle, which has inherited the mature technology of the CZ-3 Chang Zheng-3. An upgraded liquid hydrogen and liquid oxygen cryogenic third stage has been developed to enable CZ-3A performing greater geostationary transfer orbit (GTO) capability.

The CZ-3A is equipped with a more flexible and sophisticated control system which supports substantial attitude adjustments to orient the payloads before spacecraft separation and provides adjustable satellite spin-up rotation rate. It has paved the way for the development of CZ-3B Chang Zheng-3B and CZ-3C Chang Zheng-3C, and become the basic type of GTO launch vehicles.

The CZ-3A is mainly used for GTO missions; it also can be used for LEO, SSO and polar orbit missions, as well as dual-launch and multiple-launch missions. The launch capacity of the CZ-3A to GTO is 2,650 kg, the lift-off mass is 241,000 kg, the overall length is 52.5 meters, the diameter of first stage and second stage is 3.35 meters, the diameter of third stage is 3.0 meters, and the maximum fairing diameter is 3.35 meters.

The first stage and second stage of CZ-3A employ storable propellants, i.e. unsymmetrical dimethy1 hydrazine (UDMH) and nitrogen tetroxide (N­2O4), and the third stage uses cryogenic propellants, i.e. liquid hydrogen (LH2) and liquid oxygen (LOX).

On the first stage the CZ-3A uses a DaFY6-2 engine with a 2961,6 kN thrust, while the second stage is equipped with a DaFY20-1 main engine (742 kN) and four DaFY21-1 vernier engines (11.8 kN each). The third stage is equipped with two YF-75 engines (78.5 kN each).

The fairing diameter of the CZ-3A is 3.35 meters and has a length of 8.89 meters.

CZ-3A consists of rocket structure, propulsion system, control system, telemetry system, tracking and safely system, coast phase propellant management and attitude control system, cryogenic propellant utilization system, separation system and auxiliary system, etc.

The launch success rate of CZ-3A is 100 percent since its maiden flight on February 8, 1994 when it successfully launched two experimental satellites (the Shi Jian-4 and the Kua Fu-1, a DFH-3 model). And it was awarded the “Gold Launch Vehicle” title by China Aerospace Science and Technology Corporation in June 2007.

This was the 137th successful Chinese orbital launch, the 136th launch of a Chang Zheng launch vehicle, the 8th launch from Xi Chang in 2010, and the 15th orbital launch for China in 2010.

The Xi Chang 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 centre has a dedicated railway and highway lead directly to the launch site. The Command and Control Centre is located seven kilometers south-west of the launch pad, providing flight and safety control during launch rehearsal and launch.

Down range Tracking and Control stations of the launch center are located in Xi Chang City and Yibin City of Sichuan Province, and Guiyang City of Guizhou Province. Each of them houses tracking and measurement equipment for the powered phase of a launch vehicle flight.

Other facilities on the Xi Chang 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.

During 1993-1994 Xi Chang underwent extensive modernization and expansion, in part due to the requirements of the CZ-3 launcher family and in part to meet commercial customer needs.

The first launch from Xi Chang took place at 12:25UTC on January 29, 1984, when the CZ-3 Chang Zheng-3 (CZ3-1) was launched the Shiyan Weixing (14670 1984-008A) communications satellite into orbit. The launch of the new BeiDou-2 satellite was the 52nd successful orbital launch from Xi Chang.

New light on future plans:

China is affirming its place on the world space program. The recent visit of NASA Administrator Charles Bolden that led a small delegation to China is a sign of the growing importance of the Chinese roll in space. This visit increased mutual understanding on the issue of human spaceflight and space exploration, which can form the basis for further dialogue and cooperation in a manner that is consistent with the national interests of both countries.

Space Station in 2020:

China announced it had formally begun its manned space station program, which aims to complete construction of a relatively large manned space laboratory around 2020. China is aiming to develop and launch the first part of a space laboratory before 2016, focusing on breakthroughs in living conditions for astronauts and research applications, a spokesman inside the Chinese space program said.

Chinese plans to develop and launch a core cabin and a second laboratory module around 2020. These vehicles will be assembled in orbit around the Earth into a manned space station. The project is going to be built on the achievements of previous projects and continue to use the Shenzhou spacecraft and Long March F carrier rocket, and their launch and landing sites.

This project is part of the three-step manned space program, which involves developing the Shenzhou spaceships, technologies needed for docking and extra-vehicular activities, that is currently underway, and finally the construction of the space station.

China planned to launch two unmanned space modules, TG-1 Tian Gong-1 and Shenzhou-8, in 2011, which were expected to accomplish the country’s first space docking and were regarded as an essential step toward building a space station.

Tiangong-1, can eventually be transformed into a manned space laboratory after experimental dockings with Shenzhou-8, Shenzhou-9 and Shenzhou-10 spacecraft, with the last two carrying two or three astronauts each.

Commercial space:

Next year China also plans the launch of three commercial missions, launching into orbit the Eutelsat-W3C, the PakSat-1R and the NigComSat-1R communications satellites. PakSat-1R and NigComSat-1R, for Pakistan and Nigeria, are both based on the DFH-4 satellite platform.

China and Brazil will also continue with the mutual cooperation with the launch of the CBERS-3 remote sensing satellite.

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