China launched another orbital mission from its Jiuquan Satellite Launch Center using a Long March-2D (Chang Zheng-2D) launch vehicle. The launch took place at 23:40 UTC from Launch Pad 94 of the LC34 Launch Complex. The main payload for this launch was the mysterious Shiyan Weixing-6 satellite. Chinese press refers this satellite to be used for space environment detection and related technical tests.
At the time of launch, the identity of all the satellites launched on this mission was not known. Several co-passengers were launched on this mission and more information is now becoming clearer.
The launch included Tianping-1A and B, both based on the Pina satellite platform, will be used as accuracy calibration of ground monitoring and control equipment.
Another satellite, Tianzhi-1, was developed by the Software of the Chinese Academy of Sciences.
The Institute of Microsatellite Innovation of the Chinese Academy of Sciences, the 771 Institute of Aerospace 9th Institute, the Optoelectronics Institute of the Chinese Academy of Sciences, and the Xiguang Institute of the Chinese Academy of Sciences also participated in the development. The launch mass was 27 kg.
The TP-1A satellite – classed as one of the co-passengers.
Jiading-1, or OKW-01, is China’s first privately designed LEO (low Earth orbit) communications satellite. The satellite was developed by Shanghai Ok Space Co Ltd, the first domestic commercial space company, which is located in Shanghai’s Jiading district, and more than 30 invention patents have been applied for the construction of the satellite. Jiading-1 is the first to be developed for the new Xiangyun Satellite Constellation.
The operational mission of the satellite is to carry out technical tests for the constellation project. The full deployment of the Xiangyun Satellite Constellation in low Earth orbit, the first of its kind in China, is expected to be completed in 2020 and it is hoped that through increased ground coverage, the constellation will be able to lower costs and speed up operations in a number of fields, such as petroleum, coal, power transmission, and shipping.
The launch mass of the Jiading-1 satellite is 50 kg and it includes a messaging system with the capability of inter-operations with the messaging system available with the Beidou satellite navigation system. Spacecraft dimensions at launch were 700mm × 425mm × 500mm.
The first Shiyan satellite was launched on April 18, 2004, by a Long March-2C rocket from the Xichang Satellite Launch Center.
This was China’s first experimental digital imaging system capable of stereo Earth-terrain mapping, also testing the digital imaging capability for the then new generation of Chinese military reconnaissance spacecraft in development.
Similar to Shiyan-1, Shiyan-2 was launched on November 18, 2004, also from Xichang and using a Long March-2C launch vehicle. Shiyan-3 and Shiyan-4 were both launched from Jiuquan. Both satellites were experimental vehicles with digital imaging system capable of stereo Earth-terrain mapping. Shiyan-3 was launched on November 5, 2008, and Shiyan-4 was launched on November 20, 2011, and Shiyan-5 was launched on November 24, 2013.
The other known satellite to be on-board was the Tianzhi-1 satellite. This was China’s first software-based satellite.
literally translated from Chinese as “sky-based intelligence”, Tianzhi-1 is focused on software, carrying a small cloud computing platform and four domestically made smartphones, and unlike a single-mission traditional satellite, it develops aviation software for different satellites and has an app store for various aviation applications.
Tianzhi-1 has a high degree of intelligence which allows in-orbit processing of most satellite data, universal software development for in-orbit experiments and universal access to its real-time status through a phone app.
Developed by the Chinese Academy of Sciences, Tianzhi-1 is launched mainly to lay the foundation for a network and to test key technologies for the software-defined satellite system.
The project, supported by CAS’ Bureau of Major R&D Program, formally began in 2017.
The Long March-2D (LM-2D) launch vehicle 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 LM-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 the 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 by high reliability, wide application and mature technology.
The LM-2D can launch a 1,300 kg cargo in a 645 km SSO. The rocket is 41.056 meters long and the first, second stages and payload fairing are all 3.35 meters in diameter.
The first stage is the same as the Long March-4.
The second stage is based on LM-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 2961.6 kN 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 35,550 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).
Long March 2D via Chinese media
The LM-2D can use two types of fairings depending on 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.
Launch profile of the Long March-2D starts with engine ignition at 1.2 seconds before lift-off. Pitch over maneuver happens at 12 seconds into the flight and the end of the first stage ignition occurs at two minutes 33 seconds.
Stage separation and second stage ignition occur one second latter. At 3 minutes 34 seconds the two parts of the fairing separate from the second stage.
Second stage main engine cut-off takes place at 4 minutes 21 seconds and second stage Vernier engines cut-off takes place at 9 minutes and 10 seconds. Nominally payload separation takes place three seconds later.
The first launch of the LM-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 LM-2D can use the Yuanzheng-3 (YZ-3) upper stage. This is capable of restarting more than 20 times, and operating for more than 48 hours. It is equivalent to mainstream upper stages in the world in terms of performance, such as restart times, in-orbit operation time, independent digital control system, and adaptable behavior for various tasks.
The Yuanzheng-3 upper stage was developed to meet the urgent needs for launch vehicles brought by the growth of small satellites, satellite constellations, electric propulsion platforms, etc.
The YZ-3 can also be used on the Long March-4B launch vehicle.
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 as South Launch Site (SLS) is equipped with two launch pads: 91 and 94. Launch Pad 91 is used for the manned program for the launch of the Long March-2F launch vehicle (Shenzhou and Tiangong). Launch Pad 94 is used for unmanned orbital launches by the Long March-2C, Long March-2D and Long March-4C launch vehicles.
Other launch zones at the launch site are used for launching the Kuaizhou, Kaituo and the Long March-11 solid propellant launch vehicles.
The first orbital launch took place on April 24, 1970 when the Long March-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).