In December 2021, China launched its latest Shijian series satellite, the Shijian -6 05. The launch, with a Long March 4B marked the 400th mission of the Long March series launch rockets. Yes China is making a lot of launches every year. But not a lot of public information is available about the purpose of these satellites. Recently a Shijian-21 satellite was even observed making a grappling maneuver against a debris piece in low earth orbit. Let us take a closer look on this particular family of satellites.
What is the purpose of this Shijian satellite constellation?
The China Association for Science and Technological operates the Shijian 6 constellation, which is supposed to be a technology signal intelligence (SIGINT) constellation (CAST). The constellation presently consists of ten satellites and is used to monitor the effects of radiation on satellites as well as conduct a variety of clandestine experiments (5 batches of 2). The latest addition to the constellation before Shijian 6 Group 5 (Shijian-6 05) was in 2010, when a Long March 4B launched two satellites into orbit from the Jiuquan Satellite Launch Center in Inner Mongolia. Just like the Shijian 6 05, there is not much information available about a more “detailed mission” of the satellite group, and is one of the most populous satellite groups in the orbit.
Some more information about the Shijian constellation
The China Association for Science and Technological operates the Shijian 6 constellation, which is a technology signal intelligence (SIGINT) constellation (CAST). The constellation presently consists of ten satellites and is used to monitor the effects of radiation on satellites as well as conduct a variety of clandestine experiments (5 batches of 2). The latest addition to the constellation before Shijian 6 Group 5 was in 2010, when a Long March 4B launched two satellites into orbit.
The satellites were subcontracted to the Shanghai Academy of Space Flight Technology and the Dongfanghong Satellite Company, while CAST is the satellite operator. The satellites were developed around a pre-existing satellite bus, which is equipped with two solar arrays and batteries and has a mission lifespan of at least two years, according to these businesses. The Shijian 6 Group 5 satellites are suspected to be utilised for mostly electronic intelligence tests in reference to the public information supplied by China officially.
What is the Long March 4 rocket used to launch Shijian?
The Long March 4B which was used to launch the Shijian series, specifically the Shijian-6 05 in question, is a mid-range launch vehicle, 27.91 metres long and 3.35 metres wide. The fuel is unsymmetrical dimethyl hydrazine (UDMH), while the oxidizer is nitrogen tetroxide (N204). It features four YF-21C engines that run on the Gas Generator combustion cycle, which is more specifically a cluster of four YF-20 engines mounted together. The stage as a whole has a thrust of around 2,960 kN. (More about the Long March series rockets here.)
Other Shijian satellites – The Shijian-21 and its space maneuver
On a Long March-3B carrier rocket, the Shijian-21 was launched from the Xichang Satellite Launch Centre in southwest China’s Sichuan Province. The satellite will primarily be used to test and evaluate space debris reduction technology, according to NASA. The Long March series carrier rockets were launched for the 393rd time. This satellite approached a defunct Beidou-2 G2 navigation satellite in late December 2021, matching its orbit and rendezvousing with, then docking with the spacecraft. Then it moved the dead satellite into a graveyard orbit and detached from it. This maneuver was visible to several space observers as somewhat of a “grappling and pulling” of the dead satellite. (More about this Shijian-21 satellite and its space maneuver here.)
This technology and successful execution of it tells a lot about China’s determination and consistent progress in space exploration and asserting their dominance in space. This satellite technique even has been speculated to have far reaching implications and possible military applications possible in the future
Overall, little is known about the inconspicuous and questionable Shijian series satellites, most of these have been officially announced to be deep space exploration and recon satellites to test various technology and is mostly not commonly known to general public, hence much less and inaccurate information is all that is available about these satellites. Yes, most satellites in the Shijian family that made their mission and purpose public didn’t do anything that would be totally not in line with their claims, but as it is still unclear as to what the main objective of these satellites is, the mystery attracts a humble amount of attention worldwide. (More about future of China’s space missions here.)
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