China has launched the first of a news series of oceanographic satellites, with the HaiYang-2A (HY-2A) launched at 22:57UTC on August 15. The launch was carried out by a Long March 4B (Chang Zheng-4B) launch vehicle from the Taiyuan Satellite Launch Center, as the Chinese ramp up their impressive launch rate.
Yet Another Chinese Launch:
This mission was originally schedule to take place in 2009. However, it was delayed for unspecified reasons. Another delay – albeit only a day – was also required due to unacceptable weather conditions at the launch site.
The new ocean dynamic environmental HaiYang-2 satellite series is a very important piece of China’s civil spacecraft program. The satellite will be used to monitor ocean wind fields, sea levels and temperatures, waves, currents, tides, and storms in order to provide disaster and weather forecasting information.
Instruments onboard include a microwave imager (microwave brightness temperature), a dual-band radar altimeter (working on Ku-band and C-band) – used to measure sea levels and wind speeds – and Ku-band radar scatterometer for measuring the sea surface wind field.
The design and development of the HY-2 series began in April 2007, with the program funded by the Chinese State Oceanic Administration. HY-2 will be operated by the National Satellite Ocean Application Service.
The HaiYang-2 satellites are part of a system consisting of ocean colour remote sensing satellites, ocean dynamic environment satellites and ocean surveillance satellites. The colour remote sensing satellites use infrared remote sensing technology to monitor ocean pollution and topography in shallow waters.
Two satellites in this series were launched: the HY-1A HaiYan-1A (27430 2002-024A) was launched at 0150UTC on May 15, 2002 by a Long March 4B (Y5) launch vehicle from the Taiyuan Satellite Launch Center LC1 launch complex (together with the FY-1D Feng Yun-1D meteorological satellite), while the HY-1B HaiYan-1B (31113 2007-010A) was launched at 0327UTC on April 11, 2007 by a Long March 2C/2 (Y18) launch vehicle from the same launch site.
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.
HaiYang-2A – built by the China Academy of Space Technology (CAST) -will operate on a 963 km sun-synchronous orbit. The mission will have two orbital phases: on 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.
This was the 145th successful Chinese orbital launch, the 144th launch of a Chang Zheng launch vehicle, the 33rd successful orbital launch from Taiyuan (the 1st in 2011) and the eighth orbital Chinese launch in 2011.
The CZ-4B Chang Zheng-4B launch vehicle:
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 back-up 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. The CZ-4B Chang Zheng-4B launch vehicle was first introduced in May 1999 and was also developed by the Shanghai Academy of Space Flight Technology (SAST), based on the CZ-4 Chang Zheng-4.
The rocket is capable of launching a 2,800 kg satellite into low Earth orbit, developing 2,960,000 kN at launch. With a mass of 249,000 kg, the CZ-4B is 45.80 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 introduce on the CZ-4B 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 system.
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 Chang Zheng-4B uses UDMH/N2O4 for all three stages. The first stage uses a YF-21B motor consisting of four 75,000kg thrust YF-20B thrust chambers motors with swinging nozzles. The second stage is similar to that of the CZ-3A, with a YF-24F rocket motor consisting of one 75,000kg thrust YF-22B main motor with fixed nozzles, and a YF-23F swivelling vernier motor with four chambers motors (4,700kg thrust in total). The third stage is a specially designed unit powered by a 98kN YF-40 rocket motor.
The Taiyuan Satellite Launch Center:
Situated in the Kelan County on 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 center is at a height of 1400-1900m above sea level, and is surrounded by mountains to the east, south and north, with the Yellow River to its west.
The annual average temperature is 4-10 degrees C, with maximum of 28 degrees C in summer and minimum of -39 degrees C in winter.
TSLC is suitable for launching a range of satellites, especially for low earth and sun-synchronous orbit missions. The center has state-of-the-art facilities for launch vehicle and spacecraft testing, preparation, launch and in-flight tracking and safety control, as well as for orbit predictions.
(Images via ChinaDaily.cn, MilEastDaily.com Global Security.net)