Tongxin Jishu Shiyan
Tōngxìn Jìshù Shìyàn
Program overview
CountryChina People's Republic of China
Program history
First flight12 September 2015
Launch site(s)Xichang Satellite Launch Center
Wenchang Space Launch Site

Tongxin Jishu Shiyan (TJS, Chinese: 通信技术试验; pinyin: Tōngxìn Jìshù Shìyàn; lit. 'communication technology test') is a Chinese military satellite program operating in geostationary orbit (GEO). TJS satellites are manufactured by the Shanghai Academy of Spaceflight Technology (SAST) and launched from Xichang Satellite Launch Center (XSLC) in China's southern Sichuan Province. TJS is likely the cover name for multiple geostationary military satellite programs and should not be confused with the similarly named Shiyan satellite program.[1]

Unlike traditional, non-military satellites where the Chinese government announces the satellite's name, mission, platform, launch vehicle, and launch site in advance, with TJS satellites the Chinese government announces airspace closures the day before and makes vague statements on the satellite's purpose after the launch.[2]

Although the true purpose of TJS satellites remains classified, satellite observers speculate these satellites provide early warning and signals intelligence (SIGINT) for the Chinese People's Liberation Army (PLA).[3][4]


Satellites under the Tongxin Jishu Shiyan cover appear to compose three separate classes, all in geostationary orbit and performing a military or intelligence mission. These include the purported Qianshao-3 SIGINT class, the Huoyan-1 early warning class, and an unknown class for TJS-3 and its subsatellite.


TJS-1, TJS-4, and TJS-9 satellites, launched in 2015, 2019, and 2021, maintain geostationary orbit over the Indian Ocean[5] and Micronesia[6][7] and are suspected to comprise the Qianshao-3 SIGINT satellite class (Chinese: 前哨; pinyin: Qiánshào; lit. 'Outpost').[2][8] The Chinese government originally stated these satellites were designed to test Ka-band broadband communication (27–40 GHz) but has not commented on the satellites since they achieved geostationary orbit.[9][10] In January 2017, novel reports of an antenna approximately 32 meters wide reinforced speculation of the satellite's potential SIGINT mission.[2] Other Chinese sources suggest the Qianshao series are space-based infrared early warning satellites.[11][12]


TJS-2, TJS-5, and TJS-6 satellites are, according to official Chinese statements "new generation high capacity experimental communications and broadcasting satellites" testing "high speed and multi-frequency wide-band data transfer."[2][13] Launched in 2017, 2020, and 2021, these satellites are rumored to be of the Huoyan-1 (Chinese: 火眼; pinyin: Huǒyǎn; lit. 'Fire Eyes') program — China's first early-warning satellites in geosynchronous orbit.[1][2][13] These purported Huoyan-1 series satellites remain fixed in orbit over the Indian Ocean, South China Sea, and Oceania.[14][15][16]

TJS-3 satellites

The third satellite of the Tongxin Jishu Shiyan program, TJS-3, is still largely shrouded in secrecy with observers unable to determine if the satellite performs an early warning or signals intelligence mission.[17] Said to have only had one payload aboard during its 2018 launch, observers detected a secondary object separate from TJS-3 in orbit. The object was originally labeled by the United States Space Force as an apogee kick motor (AKM), a final-impulse motor often discarded by satellites entering their terminal geostationary orbit.[18] The secondary object drew public intrigue when, on January 4 and January 11, 2019 (weeks after launch), the secondary object performed station-keeping maneuvers to maintain a synchronized orbit with the main TJS-3 satellite, uncharacteristic of a discarded AKM.[18] Reinforcing suspicions, on Friday, 18 January 2019, the subsatellite maneuvered eastward over Southeast Asia with the main TJS-3 satellite performing the same maneuver two days later.[18] The two satellites continued to complete a number of synchronized maneuvers.[18]

Later in May 2019, capitalizing on the passing of the day-night terminator which makes satellite tracking by optical telescope impractical, the TJS-3 maneuvered far out of its orbit with its subsatellite taking its place shortly after.[19] According to Jim Cooper, lead for space situational awareness for the space-tracking company COMSPOC, TJS-3 and its subsatellite were likely developing and validating tactics, techniques, and procedures (TTPs) for spoofing other nation's space situational awareness efforts which would mistake the subsatellite for its parent while the latter could "be off doing things that are potentially threatening".[19][20] China has yet to acknowledge any secondary object associated with the TJS-3.[21]


Name Program Launch Function Orbital apsis Inclination SCN COSPAR Launch site Launcher Status
TJS 1 Qianshao-3 1 12 September 2015 SIGINT 35,770.9 km × 35,815.7 km 0.1° 40892 2015-046A XSLC Long March 3B Operational
TJS 2 Huoyan-1 01 5 January 2017 Early warning 35,769.0 km × 35,818.5 km 0.2° 41911 2017-001A XSLC Long March 3B Operational
TJS 3 Unknown 24 December 2018 Unknown 35,788.0 km × 35,800.0 km 0.1° 43874 2018-110A XSLC Long March 3C Operational
TJS 3 (subsat) Unknown 24 December 2018 Unknown 36,309.3 km × 36,369.9 km 1.1° 43917 2018-110C XSLC Long March 3C Operational
TJS 4 Qianshao-3 2 14 October 2019 SIGINT 35,781.7 km × 35,804.2 km 0.0° 44637 2019-070A XSLC Long March 3B Operational
TJS 5 Huoyan-1 02 7 January 2020 Early warning 6,780.9 km × 35,808.5 km 0.2° 44978 2020-002A XSLC Long March 3B Operational
TJS 6 Huoyan-1 03 4 February 2021 Early warning 35,789.0 km × 35,796.7 km 0.4° 47613 2021-010A XSLC Long March 3B Operational
TJS 7 Unknown 24 August 2021 Unknown 35,788.8 km × 35,799 km 0.1° 49115 2021-077A XSLC Long March 3B Operational
TJS 9 Qianshao-3 3 29 December 2021 SIGINT 35,787.8 km × 35,800.1 km 0.0° 50574 2021-135A XSLC Long March 3B Operational
TJS 10 Unknown 3 November 2023 Unknown 35,764.5 km × 35,824.7 km 0.4° 58204 2023-169A WSLS Long March 7A Operational
TJS 11 Unknown 23 February 2024 SIGINT TBA TBA TBA TBA WSLS Long March 5 Operational

See also


  1. ^ a b Jonathan McDowell [@planet4589] (24 December 2018). "TJS-1 is thought to be a large GEO SIGINT, Qianshao-3; TJS-2 is thought to be the Huoyan-1 missile early warning test satellite. TJS-3 uses a less powerful launch vehicle than the first two so may be different again" (Tweet) – via Twitter.
  2. ^ a b c d e Clark, Phillip S. (January 2018). Becklake, John (ed.). "China's Shiyan Weixing Satellite Programme: 2004–2017" (PDF). Space Chronicle: A British Interplanetary Society Publication. 71 (1). London: 23. ISBN 978-0-9567382-2-6.
  3. ^ Krebs, Gunter D. (1 August 2022). "TJS 1, 4, 9 (Qianshao-3 1, 2, 3 ?)". Gunter's Space Page.
  4. ^ Krebs, Gunter D. (30 July 2022). "TJS 2, 5, 6 (Huoyan-1 ?)". Gunter's Space Page.
  5. ^ "TJS-1". N2YO.
  6. ^ "TJS-4". N2YO.
  7. ^ "TJS-9". N2YO.
  8. ^ Krebs, Gunter D. (8 January 2022). "TJS 1, 4, 9 (Qianshao-3 1, 2, 3 ?)". Gunter's Space Page.
  9. ^ Yu, Bai (12 September 2015). "China launches communication technology experimental satellite". Xinhua News Agency. Archived from the original on 14 March 2017.
  10. ^ "GEO SIGINT - Qianshao / TJSW / Chang Cheng "Great Wall"". Global Security.
  11. ^ "中国导弹预警卫星不输美俄 能在3万公里高空捕捉目标" [China's missile early warning satellite does not lose to the United States and Russia, and can capture targets at an altitude of 30,000 kilometers]. Sina Military (in Chinese). 17 June 2020.
  12. ^ "前哨系列预警卫星" [Outpost series of early warning satellites]. Zhihu Zuanlan (in Chinese).
  13. ^ a b Krebs, Gunter D. (30 July 2022). "TJS 2, 5, 6 (Huoyan-1 ?)". Gunter's Space Page.
  14. ^ "TJS-2". N2YO.
  15. ^ "TJS-5". N2YO.
  16. ^ "TJS-6". N2YO.
  17. ^ Krebs, Gunter D. (8 February 2021). "TJS 3 / TJS 3 Subsatellite". Gunter's Space Page.
  18. ^ a b c d Hall, Bob (1 July 2019). TJS 3 Space Activities - Spacecast 15 (Podcast).
  19. ^ a b Clark, Colin (28 October 2021). "US, China, Russia Test New Space War Tactics: Sats Buzzing, Spoofing, Spying". Breaking Defense.
  20. ^ Jones, Andrew (5 November 2021). "An object is now orbiting alongside China's Shijian-21 debris mitigation satellite". SpaceNews.
  21. ^ Clark, Stephen (18 October 2019). "China launches mysterious geostationary satellite". Spaceflight Now.