| 实践 Shíjiàn | |
| Program overview | |
|---|---|
| Country |  People's Republic of China |
| Organization | China Academy of Space Technology (CAST) |
| Purpose | Unknown, varied |
| Status | Active |
| Program history | |
| Duration | 1971–present |
| First flight | 3 March 1971 |
| Last flight | 27 September 2024 |
| Successes | 38 |
| Failures | 5 |
| Launch site(s) | |
| Vehicle information | |
| Launch vehicle(s) | |
Shijian (simplified Chinese: 实践; traditional Chinese: 實踐; pinyin: Shíjiàn; lit. 'Practice', abbr. "SJ") is a series of satellites built and operated by the People's Republic of China. Some Shijian-series satellites have drawn significant concerns from the United States government and space observers who cite unannounced launches, undisclosed sub-satellites deployed in orbit, unusual orbital maneuvers, and demonstrated rendezvous proximity operations (RPO) including the close inspection and towing of other satellites.[1][2][3][4]
Little is known about the series and what differentiates it from other experimental satellite series launched by China such as the Chuangxin (Chinese: 创新; pinyin: Chuàngxīn; lit. 'Innovation') series or Shiyan (Chinese: 实验; pinyin: Shíyàn; lit. 'Experiment') series.[5] The China Aerospace Studies Institute of the United States Air Force asserts that Shiyan-series satellites play an earlier role in the systems development process testing various new technologies on a single bus while Shijian-series satellites are used to develop operational best practices and optimize the technologies previously tested on Shiyan-series satellites.[6] In this regard, "Shijian" should be translated as "best practice", or "put into practice" while "Shiyan" ought to be translated as "experiment", "pilot", or "trial".
- ^ Dickinson, General James H. (21 April 2021). United States Space Command Presentation to the Senate Armed Services Committee U.S. Senate (PDF) (Report). Archived (PDF) from the original on 26 August 2022. Retrieved 2 September 2022.
- ^ Roberts, Thomas G. (31 March 2021). "Unusual Behavior in GEO: SJ-17". Aerospace Security, Center for Strategic and International Studies (CSIS). Archived from the original on 1 September 2022. Retrieved 2 September 2022.
- ^ Tiwari, Sakshi (17 February 2022). "Strangling Like A Python, China Says Its Powerful 'Robotic Snake' Can Crush Enemy Satellites Like Never Before". The Eurasian Times. Archived from the original on 1 September 2022. Retrieved 2 September 2022.
- ^ Jones, Andrew (27 January 2022). "China's Shijian-21 towed dead satellite to a high graveyard orbit". SpaceNews. Archived from the original on 3 February 2023. Retrieved 2 September 2022.
- ^ Chia, Henry (7 December 2021). "What we know about China's Shijian-class satellites". asiaMARKETS. Archived from the original on 28 August 2022. Retrieved 2 September 2022.
- ^ Burke, Kristin (28 March 2022). "Initial Analysis of Two Chinese Satellite Series: Shi Jian and Shi Yan" (PDF). China Aerospace Studies Institute (March 2022). Archived (PDF) from the original on 2023-10-07. Retrieved 2023-12-02.