Huanjing Disaster Monitoring Satellites
The environment and disaster monitoring satellite constellation was the first special satellite intended for strengthening environmental monitoring and reducing disasters. Chinese plans for the Huanjing (Chinese for 'environment') disaster monitoring system called for an eventual total of eight small satellites to be launched to form a constellation for all-weather, 24-hour monitoring and environment and natural disasters forecast, forming a complete image on China once every 12 hours. The first phase calls for three satellites, two of which are equipped for visible, infrared, and multi-spectral imaging. A third spacecraft will carry a S-band synthetic aperture radar (SAR) for continuous, all-weather imaging. Phase two will comprise 8 satellites, four imaging and four SAR, in orbit simultaneously. China is one of the two charter members, along with the U.S., of the international Group on Earth Observations (GEO). By 2009 GEO membership consisted of 74 governments and 52 intergovernmental organizations involved in environmental monitoring from space.
On 06 September 2008, China launched the first two of an eight-satellite optical and radar imaging constellation to support rescue and recovery from natural disasters. The 470-kg Huanjing-1A and Huanjing-1B Disaster Reduction and Environmental spacecraft were lofted into a high-inclination Sun-synchronous orbit by a Long March 2C rocket from the Taiyuan space center in Shanxi province. The constellation will fly in a planned formation to enhance the coordination of data return. Although designed for disaster monitoring, the satellites will provide daily images of China and other areas.
The two satellites launched on 06 September 2008 were both optical, each carrying two charge-coupled-device (CCD) cameras with 30-m resolution and a swath width of 700 km, an infrared camera with 150-m resolution and a swath width of 720 km, and an ultralight image-formation meter with 100-m resolution, a swath width of 50 km, and a spectrum resolution of 9 km. They were placed into sun-synchronous orbits in the same orbital plane of 97.95° at 650 km altitude, enabling them to covering all Chinese territory every 48 hours. The first two satellites had a design life of three years, but the Chinese plan to replace them when necessary.
The satellite launch was the first step to construct a constellation, which contributed to a technical support system for environmental protection integrating sky, space and land. It would provide a platform for pollution mitigation, ecological change, disaster monitoring, warning, assessment and emergency response. Additionally, the satellites would greatly enhance international exchange and cooperation in the field of environmental protection.
China's first two satellites dedicated to environment and disaster monitoring were delivered to their users on 01 April 2009. Both Huanjing-1A and Huanjing-1B have two charge coupled device cameras, with a 30-m resolution and a 720-km width, each on board, the State Administration of Science, Technology and Industry for National Defense said in a statement. The Ministry of Civil Affairs, in charge of disaster relief and reduction, and the Ministry of Environmental Protection are the users of the two satellites.
They can jointly form the image of China's entire territory in two days, "which not many other satellites with 30-m resolution cameras in the world can achieve", it said. This enables the two satellites to monitor a designated area repeatedly, fast and inform government agencies of the latest disaster development.
In February 2009, on the Australian government's request to help fight a rare forest fire, the satellites, then under-testing, provided images, Chen Qiufa, the administration chief, said. Luo Pingfei, vice-minister of civil affairs, said the two satellites would provide a stable, long-term data source to help China fight against disasters.
The two satellites will provide data through the soon-to-open Beijing office of the United Nations Platform for Space-based Information for Disaster Management and Emergency Response for global disaster reduction. The satellites launched atop the Long March-2C launch vehicle on 06 September 2008 passed in-orbit testing in February 2009.
As of 2009 China planned to launch a small radar satellite to work with these two optical satellites.
Long March-2C carrier rocket carrying an environment-monitoring satellite Huanjing-1C blasted off from the launch pad at the Taiyuan Satellite Launch Center in Taiyuan, capital of north China's Shanxi Province, 19 November 2012. The launch marked the completion of a plan initiated by China in 2003 to create a small environmental monitoring satellite constellation, according to north China's Taiyuan Satellite Launch Center. The HJ 1C satellite carries a S band (3.13 GHz) synthetic aperture radar which is to provide imagery with a best resolution of 20 metres. The satellite had a launch mass of 890 kilogrammes and will fly in a dawn/dusk sun synchronous orbit at an altitude of around 500 kilometres.
The radar satellite, based on the CAST-968 Satellite Bus, joined the other two operating optical satellites "Environment I" satellites, which were launched in September 2008, to form a network covering most of China's territory. This "2+1" formula will help provide scientific evidence for assessing natural disaster situations, emergency aid and reconstruction as well as enable China to monitor and forecast ecological changes, pollution and natural disasters around the clock.
Displaying synthetic aperture radar (SAR) images in combination with Vessel Monitoring System (VMS) tracking data, making it possible to identify illegal or undeclared fishing vessels remotely.
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