China launched a new satellite for ocean observation from the Taiyuan Satellite Launch Center on Wednesday. Launch of the Haiyang-2B took place at 22:57 UTC from the LC9 Launch Complex. The new satellite was orbited by a Long March-4B (Chang Zheng-4B) launch vehicle.
The Haiyang-2 program represents the second generation of ocean observation and monitorization satellites, with the program being approved by the China National Space Administration on February 2007, for measurement of ocean dynamic and environmental parameters in the microwave region (permitting all weather observations).
The requirements call also for the collection of data on marine wind setup (wind vector), marine surface height, and SST (Sea Surface Temperature), along with aero-marine forecasts for the prevention and relief of disaster.
The design and development of the HY-2 series began in April 2007, with the program funded by the Chinese State Oceanic Administration. The satellites are operated by the National Satellite Ocean Application Service.
The Haiyang-2 satellites are part of a system consisting of ocean color remote sensing satellites, ocean dynamic environment satellites and ocean surveillance satellites. The color remote sensing satellites use infrared remote sensing technology to monitor ocean pollution and topography in shallow waters.
The Haiyang-2 dynamic environment satellites utilize microwave remote sensing technology to monitor ocean wind fields and ocean surface temperatures, and the Haiyang-3 ocean surveillance satellites will have the combined features of the Haiyang-1 and Haiyang-2 series.
Onboard the new satellite are several instruments. The radar altimeter will be used for ocean topography, determining significant wave height and wind speed measurements on the sea surface. The instrument operates in two frequencies: 13.58 GHz and 5.25 GHz), and permits nadir-only viewing along with continuous sampling along the track.
The DORIS instrument (Doppler Orbitography and Radiopositioning Integrated by Satellite) will be used for precision orbitography, measuring the Doppler shift of signals from ground stations.
The Laser Retroreflector Array will be used for space geodesy and precision orbitography, with the Microwave Radiometer being used for all-weather sea-surface temperature and wind, and total-column water vapor. Finally, the Scatterometer will be used for determining the sea surface wind vector.
The three-axis stabilized Haiyang-2B uses the CAST968 satellite platform developed by the DFH (Dongfanghong Satellite Corporation Ltd.), a spin-off company of CASC (China Aerospace Science &Technology Corporation). The satellite will operate on a 973 km sun-synchronous orbit.
The mission will have two orbital phases: during the first two years it will have a 14-day cycle and then one year with a geodetic orbit – a 168 day cycle with a 5-day approximate subcycle.
Previous satellite on the series, Haiyang-2A, was launched on August 15, 2011, using a Long March-4B launch vehicle from the Taiyuan Satellite Launch Center.
The feasibility study of the CZ-4 Chang Zheng-4 began in 1982 based on the FB-1 Feng Bao-1 launch vehicle. Engineering development was initiated in the following year. Initially, the Chang Zheng-4 served as a backup launch vehicle for Chang Zheng-3 to launch China’s communications satellites.
After the successful launch of China’s first DFH-2 communications satellites by Chang Zheng-3, the main mission of the Chang Zheng-4 was shifted to launch sun-synchronous orbit meteorological satellites. On the other hand, the Chang Zheng-4B launch vehicle was first introduced in May 1999 and also developed by the Shanghai Academy of Space Flight Technology (SAST), based on the Chang Zheng-4.
The rocket is capable of launching a 2,800 kg satellite into low Earth orbit, developing 2,971 kN at launch. With a mass of 248,470 kg, the CZ-4B is 45.58 meters long and has a diameter of 3.35 meters.
SAST began to develop the Chang Zheng-4B in February 1989. Originally, it was scheduled to be commissioned in 1997, but the first launch didn’t take place until late 1999. The modifications introduced on the Chang Zheng-4B included a larger satellite fairing and the replacement of the original mechanical-electrical control on the Chang Zheng-4 with an electronic control.
Other modifications were an improved telemetry, tracking, control, and self-destruction systems with smaller size and lighter weight; a revised nozzle design in the second stage for better high-altitude performance; a propellant management system for the second stage to reduce the spare propellant amount, thus increasing the vehicle’s payload capability and a propellant jettison system on the third-stage.
The first stage has a 24.65 meter length with a 3.35 meter diameter, consuming 183,340 kg of N2O4/UDMH (gross mass of the first stage is 193.330 kg). The vehicle is equipped with a YF-21B engine capable of a ground thrust of 2,971 kN and a ground specific impulse of 2,550 Ns/kg. The second stage has a 10.40 meter length with a 3.35 meter diameter and 38,326 kg, consuming 35,374 kg of N2O4/UDMH.
The vehicle is equipped with a YF-22B main engine capable of a vacuum thrust of 742 kN and four YF-23B vernier engines with a vacuum thrust of 47.1 kN (specific impulses of 2,922 Ns/kg and 2,834 Ns/kg, respectively).
The third stage has a 4.93 meter length with a 2.9 meter diameter, consuming 12,814 kg of N2O4/UDMH. Having a gross mass of 14,560 kg, it is equipped with a YF-40 engine capable of a vacuum thrust of 100.8 kN and a specific impulse in a vacuum of 2,971 Ns/kg.
Situated in the Kelan County in the northwest part of the Shanxi Province, the Taiyuan Satellite Launch Center (TSLC) is also known by the Wuzhai designation. It is used mainly for polar launches (meteorological, Earth resources and scientific satellites).
The launch center has two single-pad launch complexes, a technical area for rocket and spacecraft preparations, a communications center, a mission command and control center, and a space tracking center.
The stages of the rocket were transported to the launch center by railway and offloaded at a transit station south of the launch complex. They were then transported by road to the technical area for checkout procedures.
The launch vehicles were assembled on the launch pad by using a crane at the top of the umbilical tower to hoist each stage of the vehicle in place. Satellites were airlifted to the Taiyuan Wusu Airport about 300km away and then transported to the center by road.
The TT&C Centre, also known as Lüliang Command Post, is headquartered in the city of Taiyuan, It has four subordinate radar tracking stations in Yangqu (Shanxi), Lishi (Shanxi), Yulin (Shaanxi), and Hancheng (Shaanxi).