링크 : http://www.sinodefence.com/strategic/spacecraft/yaogan2.asp

China press briefly reported on 25 May 2007 that the ChangZheng family of space launch vehicles had successfully conducted its 99th flight, sending two satellites into space. The ChangZheng 2D launch vehicle, which was launched from Jiuquan Satellite Launch Centre at 15:12 local time (07:12 GMT) on 25 May 2007, carried the Remote Sensing Satellite 2 (YaoGan WeiXing 2) designed by China Academy of Space Technology (CAST, also known as 5th Space Academy), as well as a pico-satellite designed by Zhejiang University for scientific experiment.

According to the Chinese reports, the Remote Sensing Satellite 2 was intended for “scientific experiments, land survey, crop yield assessment, and disaster monitoring”. While the specific purpose and design of the satellite is unknown, judging from the highly brief report, it is almost certain that this satellite is associated with military missions.

China launched a similar satellite known as Remote Sensing Satellite 1 (YaoGan WeiXing 1) on 27 April 2006. The satellite was later identified as the JianBing 5 synthetic aperture radar (SAR) satellite operated by the PLA for military reconnaissance role. The new satellite launched on 25 May could well be a similar design.


DongFangHong-4 (DFH-4) Communications Satellite

Last updated: 14 May 2007

The DongFangHong 4 (DFH-4) is China’s third-generation large-capacity communications satellite. It is also China’s first indigenous direct broadcasting system (DBS), which can transmit data to users without the need for ground station rebroadcast. The primary contractor for the programme is China Aerospace Corporation (CASC), with the European company Alcatel Alenia providing some of its communications satellite technologies.

The DFH-4 weights 5,100kg and is three-axis stabilised. The satellite is equipped with 22 Ku-band transponders (four 54MHz and 18 36MHz), 3 receiver antennas, and 2 transmission antennas. With a designed operational life of 15 years, the DFH-4 can support the transmission of 150~200 TV programmes 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.

If being used for military purpose, the DBS satellite offers a capability for distributing information to the lowest echelon in a battlefield. Potentially the satellite can transmit data (maps, pictures, and enemy deployments) on demand to small units, each to receive orders and situational information using a manpack receiver.

Development of the DFH-4 began in 2002. The first DFH-4 satellite, known as Sinosat 2 (or XinNuo-2 in its Chinese name), was intended to provide direct broadcast TV services for users in China mainland, Hong Kong, Macau, and Taiwan during the 2008 Beijing Olympic Game. The satellite was originally scheduled to be launched in 2005, but the launch was postponed due to technical reasons. On 28 October 2006, the Sinosat 2 was successfully launched by a CZ-3B space launch vehicle from Xichang Satellite Launch Centre (XSLC). However, the satellite’s solar panels and antenna failed to deploy, causing the RMB200 million (~US$25 million) satellite totally unusable. The satellite was last known to be stationed in GEO at 92.2 deg E.

A second DFH-4 satellite known as NIGCOMSAT-1 for Nigeria was successfully launched from Xichang on 14 May 2007. This was the first time that Chinese space contractors provided a packaged service including satellite design, manufacturing and launch for a foreign customer. As a part of the deal worth a total of US$311 million, the satellite will provide telecommunications, broadcasting, and broadband services for Nigeria.

A new DFH-4 satellite SinoSat 4 is scheduled to be launched in late 2008 to replace the failed SinoSat 2.