Long March 2D fires opening salvo in new weather observation constellation
China launched the first satellite of a new orbital meteorological constellation. The Yunhai-1 (01) was launched at 23:14 UTC by a Long March-2D (Chang Zheng-2D) launch vehicle from the LC43/603 launch complex of the Jiuquan Satellite Launch Center. The launch comes two days after the launch of the second Long March-11 launch vehicle carrying the XPNAV-1 pulsar navigation satellite and other small satellites.
Not much is known about the Yunhai-1 satellites, with no specifics provided by the Chinese media.
However, it is understood the satellite constellation was developed by SAST and will probably likely the clouds using radio occultation. Technically it will be used for the exploration of atmospheric environmental elements, space environment detection, disaster prevention and mitigation, and scientific experiments.
The Chang Zheng-2D launch vehicle – used for this mission – is a two-stage rocket developed by the Shanghai Academy of Spaceflight Technology. With storable propellants is mainly used to launch a variety of low earth orbit satellites.
The development of CZ-2D was started in February 1990. From 2002, to meet the demand of SSO satellites, the payload fairing of 3350mm in diameter and attitude control engine for second stage have been successfully developed; and the discharge of remaining propellant and de-orbit of the second stage have been realized. This launcher is mainly used for launching LEO and SSO satellites. It is characterized with high reliability, wide application and mature technology.
The CZ-2D can launch a 1,300 kg cargo in a 645 km SSO. The rocket is 41.056m long and the first, second stages and payload fairing are all 3.35m in diameter.
Its first stage is the same of the CZ-4 Chang Zheng-4. The second stage is based on CZ-4 second stage with an improved equipment bay. Lift-off mass is 232,250 kg, total length 41,056 meters, diameter 3.35 meters and fairing length 6.983 meters. At launch it develops 2961.6kN engine thrust.
The first stage has a 27.910 meter length with a 3.35 meter diameter, consuming 183,200 kg of N2O4 / UDMH (launch mass of the first stage is 192,700 kg). Equipped with a YF-21C engine capable of a ground thrust of 2,961.6 kN and a ground specific impulse of 2,550 m/s. Burn time is 170 seconds.
The second stage has a 10.9 meter length with a 3.35 meter diameter, launch mass of 39,550 kg and consuming 45,550 kg of N2O4 / UDMH. Equipped with a YF-24C cluster engine with a main engine vacuum thrust of 742.04 kN and a vernier engine with a vacuum thrust of 47.1 kN (specific impulses of 2,942 m/s and 2,834 m/s, respectively).
The CZ-2D can use two types of fairings depending of the cargo. Type A fairing has a 2.90 meters diameter (total launch vehicle length is 37.728 meters) and Type B fairing with a diameter of 3.35 meters – total launch vehicle length is 41.056 meters.
The first launch of the CZ-2D was on August 9th, 1992 from the Jiuquan Satellite Launch Center orbiting the Fanhui Shei Weixing FSW-2-1 (22072 1992-051A) recoverable satellite.
The Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – was the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.
The site includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.
Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. It is also the place from where all the Chinese manned missions are launched.
The LC-43 launch complex, also known by South Launch Site (SLS) is equipped with two launch pads: 921 and 603. Launch pad 921 is used for the manned program for the launch of the Chang Zheng-2F launch vehicle (Shenzhou and Tiangong). The 603 launch pad is used for unmanned orbital launches by the Chang Zheng-2C, Chang Zheng-2D and Chang Zheng-4C launch vehicles.
Once the launcher stages are ready on the test and verification facility, they are transported by truck to the launch pad where they are stacked together and the fueling umbilical’s are attached to the rocket. Technicians can access the different stages through the service platforms that embrace the launcher at the launch platform.
Other launch zones at the launch site are used for launching the Kuaizhou and the CZ-11 Chang Zheng-11 solid propellant launch vehicles.
The first orbital launch took place on April 24, 1970 when the CZ-1 Chang Zheng-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).