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Other Designations: China Brazil Earth Resource Satellite. Manufacturer's Designation: CBERS. Code Name: Zi Yuan. Class: Earth. Type: Landsat. Destination: Sun Synchronous Orbit. Nation: China. Agency: CAST/INP. From 1985 China and Brazil jointly developed a sun synchronous imaging satellite bus, the Zi Yuan-1 (Resouce-1) based on the Shi Jian 3 design. The joint project was externally referred to as CBERS (China Brazil Earth Resource Satellite) with China contributing 70% of the program cost. Originally launches were planned for 1996 and 1999 but there was a three year delay. The spacecraft had overall dimensions of 2 m by 3.3 m by 8.3 m with a 1.1 kW capacity, single solar array and was to operate in an 800-km sun-synchronous orbit with a 26-day repeating ground track pattern.
The Earth observation payload included three primary sensors (the first two of Chinese origin):
- CCD Camera: Five bands (0.51-0.73 micrometer, 0.45-0.52 micrometer, 0.52-0.59 micrometer, 0.63-0.69 micrometer, and 0.77-0.89 micrometer); 20-m resolution; 113 km swath
- IR Multi-Spectral Scanner: Four bands (0.50-1.10 micrometer, 1.55-1.75 micrometer, 2.08-2.35 micrometer, and 10.40-12.50 micrometer); 80-160-m resolution; 120-km swath
- Wide-Field Imager: Two bands (0.63-0.69 micrometer and 0.76-0.90 micrometer); 260-m resolution; 900-km swath.
Zi Yuan-1 also carried a Data Collection System and a Space Environment Monitor. The China-Brazil Earth Resources Satellite was jointly built by CAST/Beijing and INPE/Brazil. The spacecraft was controlled from both Chinese and Brazilian ground stations. CBERS-2 was under construction at the Brazilian National Institute for Space Research (INPE), and was originally to be launched in October 2001.
China and Brazil signed an agreement in September 2000 to develop two second-generation China-Brazil Earth Remote Sensing satellites (CBERS-3 and -4). The satellites were to include a significant improvement in the imaging resolution of the High Resolution CCD Camera (resolution of 5 meters vs. CBERS-1's 20 meters). The two countries would also study joint development of geostationary meteorological satellites and a telecommunications satellites based on the CBERS bus.
The sun-synchronous orbital bus developed for CBERS and the CBERS-3 imager may have been used for the military ZY-2 satellite, which was placed in a lower orbit for higher resolution imaging. The ZY-2 reportedly had over three times the resolution of the ZY-1. Typical orbit: 634 km circular orbit, 98 deg inclination. Length: 3.30 m (10.80 ft). Maximum Diameter: 2.00 m (6.50 ft). Span: 8.30 m (27.20 ft). Mass: 1,450 kg (3,190 lb). Associated Launch Vehicle: CZ-4B.
ZY Chronology - 1999 October 14 - ZY-1 - Launch Site: Taiyuan. Launch Vehicle: CZ-4B. Mass: 1,540 kg (3,390 lb). Perigee: 773 km (480 mi). Apogee: 774 km (480 mi). Inclination: 98.60 deg.
China-Brazil Earth Resources Satellite. China's first earth resources satellite, known as ZY-1, weighed 1,540 kilograms. Chief designer was Chen Yiyuan. The satellite, a joint project of China and Brazil, was designed to gather information on the environment, agriculture and urban planning through remote sensing images and data transmitted to China, Brazil and other countries. Planned lifetime was two years. The satellite circled the Earth 14 times a day and the groundtrack repeated after 26 days. By 23 February 2000 it had taken more than 20,000 high quality images. It was formally handed over for operational use on March 2 2000. The High Resolution CCD Camera had a resolution of 20 meters in the visible spectrum. The camera could point up to 32 degrees to either side of vertical, imaging the earth's surface stereoscopically. After 177 days the Wide Field Imager failed in early May 2000. Other devices, including the high resolution CCD camera, continue to work normally.
- 2000 September 1 - ZY-2 - Launch Site: Taiyuan. Launch Vehicle: CZ-4B. Perigee: 489 km (304 mi). Apogee: 501 km (311 mi). Inclination: 97.41 deg. Period: 94.43 min.
The ZY-2 (Ziyuan-2 ('Resource-2'), while disguised as a civilian earth monitoring system, was actually code-named Jianbing-3 and was China's first high-resolution military imaging satellite. The cover story of the official Xinhua news agency was that the civilian remote sensing system would be used primarily in territorial surveying, city planning, crop yield assessment, disaster monitoring and space science experimentation. However the satellite was placed at a much lower altitude than the ZY-1 satellite and US intelligence sources indicated that it was a photo-reconnaissance satellite for exclusively military purposes, such as targeting missiles at US and Taiwanese forces. The new satellite was believed to employ digital-imaging technology and to have a resolution of 2 m or less. The satellite was designed and built by the Chinese Academy of Space Technology and was developed indigenously. It was said to be more advanced than earlier sensing satellites and was expected to have an orbital life of two years. The camera provided more than three times the resolution of the ZY-1 earth resources satellite. The Zi Yuan 2 satellite may have used the CBERS Sino-Brazilian bus of the earlier ZY-1. However it was also said to be of new design and demonstrated the capability to maneuver in orbit, adjusting its orbit after launch. In October 2000 Chinese scientists denied that the ZY-2 satellite had a military mission. It was said to be a remote-sensing satellite equipped with CCD cameras and an infrared multispectral scanner that could only identify objects on the ground with a resolution of several dozen meters to 1 km.
- 2002 October 27 - ZY-2 - Launch Site: Taiyuan. Launch Vehicle: CZ-4B. Perigee: 470 km (290 mi). Apogee: 483 km (300 mi). Inclination: 97.40 deg. Period: 94.10 min.
JB-3 2 was nominally a Chinese (PRC) remote sensing satellite, although US intelligence sources indicated it had primarily an intelligence imaging mission. JB-3 2 was the name adopted by the USSPACECOM. Most news reports from China and elsewhere use different names: ZY-2B (acronym for ZiYuan-2B, translated as Resource-2B), and Zhong Guo Zi Yuan Er Hao, translated as China Resource 2. No information was available on the instruments onboard the JB-3 2, but officially it was intended 'for territorial survey, environment monitoring and protection, urban planning, crop yield assessment, disaster monitoring, and space scientific experiments'. The initial orbital parameters of this sun-synchronous satellite were period 94.1 min, apogee 483 km, perigee 470 km, and inclination 97.4°.
Bibliography and Further Reading
- Gertz, Bill, Washington Times, "Chinese 'civilian' satellite a spy tool", August 1, 2001.
- Wen-Rui Hu, Editor, Space Science in China, Gordon and Breach Science Publishers, China, 1997.. ISBN: 9056990233. More at amazon.com...
- Johnson, Nicholas L; and Rodvold, David M, Europe and Asia in Space 1993-1994, USAF Phillips Laboratory, Kirtland AFB, NM 80907, 1995.. Comprehensive survey of Russian, Chinese, and European launchers and spacecraft.
- McDowell, Jonathan, Jonathan's Space Report (Internet Newsletter), Harvard University, Weekly, 1989 to Present. Essential internet newsletter recording worldwide weekly space events. Accessed at: http://www.planet4589.org/jsr.html.
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