User:Garbera14

Hi, my name is Joyce, and this page of Wikipedia is for my study ole.

China's Space Strategy and Goals
China has clearly stated its ambition to become a global leader in space, and its leaders have been specifically assigned to China's space program. This is part of the country's efforts to strengthen its national strength and enhance its national interests. Therefore, artificial satellites are indispensable, and they are an important step in completing this plan. Previous developments have stalled due to poor infrastructure and technological limitations. This support is helpful for improving and standardizing the quality of parts, helping to create a mature space program. It can be said that artificial satellites provide a good the basis and required parameters. China is now able to receive, store, process and distribute data from 26 Chinese remote sensing satellites, which will promote China's integration of information.

DFH-2 1, 2 [DFH-2 Bus]
To meet China's domestic needs, they used their own technology to develop a satellite like the western geosynchronous orbit in the 1960s, which is configured as a DFH-2 Bus, and the main body uses solar energy and batteries to provide energy. The operating time of the two satellites was replaced by other series after 1990-1991.

DFH-2A 1, 2, 3, 4, 5 (ZX 1, 2, 3, 4 / ChinaSat 1, 2, 3, 4) [DFH-2 Bus]
The mass of this spacecraft in orbit is 441 kg, which is slightly lighter than the earlier period by 1-2 kg. It was successfully placed in geosynchronous orbit in March 1988, December 1988, December 1988, and February 1990. A total of 4 satellites were projected during this period. Unfortunately, the fourth satellite was lost on December 28, 1991, and only three satellites were left and renamed. The configuration is still DFH-2 BUS, the equipment is 2 c-band transponders, which are promoted by GF-5B, and the main body still uses solar energy and batteries as energy sources.

DFH-3 1, 2 (ZX 6 / ChinaSat 6) [DFH-3 Bus]
The satellite configuration is changed to DFH-3 Bus, and it is equipped with 24 c-band transponders, providing 6 TV channels and 18 communication transmission channels, and its mass is 2200 kg. There are two satellites in this phase. One of them was found to be lost due to a motor failure at the apogee kick. The second satellite was also launched on May 12, 1997. This satellite is ChinaSat6 and is currently operating normally.

Tiantong-1 01, 02, 03, 04
The specifics of this satellite are unknown. The only thing we know now is that this satellite carries an S-band transfer satellite payload and a large non-detachable dish antenna. The configuration is guessed to be DFH-4 bus.

ZX 1A, 1B, 1C (FH 2A, 2B, 2C) [DFH-4 bus]
This series of satellites are China’s second-generation military communications satellites. ChinaSat 1A was launched in 2011 and ChinaSat 1C was launched in 2015. For ChinaSat 1B, the official did not provide any information.

ZX 2A, 2B, 2C, 2D (ST 2A, 2B, 2C, 2D) [DFH-4 bus]
This series of satellites belong to the Chinese military's communications satellites, with advanced controllable technology that can ensure the safety of information transmission. ChinaSat2A was successfully launched in 2012, ChinaSat 2C in 2015, and ChinaSat 2D in 2019.

ZX 6C (ChinaSat 6C) [DFH-4 bus]
This satellite is manufactured by CAST, launched and provided services in 2019, and supports the uplink and downlink transmission of high-quality broadcast and cable television programs.

ZX 7 (ChinaSat 7) [HS-376]
This is the first Chinese satellite purchased from Boeing Satellite Systems International and launched in 1996. However, because of China's poor capabilities at the time, the satellite was in the wrong low orbit. Its purpose is to provide voice, data, TV signals and other communication services, which are no longer in operation today.

ZX 20, 20A (ST 1, 1B) [DFH-3 Bus]
This satellite is the most powerful data processing capability recorded in China so far and belongs to the military scope.

ZX 22, 22A (FH 1A, 1B) [DFH-3 Bus]
This configuration is DFH-3 Bus, which can provide c-band and UHF communication. The two satellites launched can also be called ChinaSat22 and ChinaSat22A. The first satellite was launched in 2001, the second satellite was launched in 2006, and it is still in operation.

DFH-2 Bus
Introduced in 1984, the communication payload consists of only two c-band transponders. This technology is equivalent to the intelsat-3 in 1960.

DFH-3 Bus
A communication satellite platform with limited capabilities. It consists of seven sub-systems. Through adaptive transformation, it can be used for communication and navigation satellites and deep space probes.

DFH-4 Bus
China's third-generation communications satellite bus, which is characterized by high power, large payload, and long service life. It is composed of propulsion module, service module and solar cell array. Its service life is at least 7 years longer than the previous generation.

HS-376
A platform from the United States, manufactured by Boeing Satellite Systems, and put into operation in 1980. It can be folded during its launch process to increase the use of space. Later, it has become more powerful through the development of new solar cells.

A2100A
It also called AS 2100, which was developed by The Lockheed Martin in 1996. Its characteristic is to reduce parts and simplify the structure while improving on-orbit reliability, reducing weight, and reducing costs. This series has a total of three different sizes, and this time China used the A2100A size in ChinaSat 5A, which can generate 1-4KW of power. There are other versions, the A2100A is the most basic size, and the larger the size function in the future, the ability is also strengthened.

SSL-1300
It has a powerful modular bus and has been put into use since 1989. Its modular structure can easily tailor spacecraft and is suitable for a variety of tasks.

Spacebus-3000A
The French communications satellite bus, originally developed by Arabsat, began to use in 1996, and was later ordered by China and used in ChinaSat 5B.

Spacebus-4000C2
This satellite bus is an enlarged version of the Spacebus-3000/4000B-class version. It has good flight capabilities, can execute safe manufacturing plans, can accommodate various payloads on different islands, and can adapt to future communication services. It is the first product in the world to launch an AOCS with a built-in star tracker.

Technology
In January 1984, China's first experimental communications satellite, the first operational satellite was launched into the sky. In March 1988, satellite communications capabilities were improved day by day. Prior to the development and launch of dedicated military communications satellites, China is likely to rent civilian transponders operating in the C-band and Ku-band, such as SinoSat and ChinaSat.

China also has dedicated military communications satellites such as ChinaSat-22, which was launched in January 2000, and is China's first dedicated military communications satellite. Weighing 2300 kilograms (kg), the satellite has been in operation for eight years and was replaced after the launch of the "Fenghuo 2" (ChinaSat-22A) in September 2006. (ChinaSat-20) was launched in November 2003 and is said to be equipped with a steerable spot beam to operate in the Ku band. In 2010, a follow-up satellite was launched from Xichang in 2015. Since 2017, China has also conducted verification tests on broadband (Ka-band) communication satellites. The SJ-20 satellite is an LM-5 missile launched from Wenchang in December 2019 and verified the new generation of communication satellite bus DFH-5. This DFH-5 is the heaviest satellite in China so far.

C-band
The C band (4 to 8 GHz) is used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones as well as some surveillance and weather radar systems. It is one of the main technologies in Chinasat.

Ku-band
The Ku-band is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). Ku-band VSAT can be used for high-speed applications such as voice, video, computer-to-computer data communications, and SCADA and mainframe workstations. A certain amount of delay can be reduced, and the value of receiving only video and data communication is increasing while the cost is reduced. In the future, computer-to-computer data communication will become an indispensable part.

UHF transponders
This is he subsystem that provides the connection link between the satellite's transmitting and receiving antennas. It is one of the most important subsystems of the space segment subsystem. The function for this transponder are transmit and receive information in the satellite.