View source for Engineering:Tongxin Jishu Shiyan

{{Infobox space program
| name            = Tongxin Jishu Shiyan
| country         = {{flagicon|China}} People's Republic of China
| organization    = [[Organization:Shanghai Academy of Spaceflight Technology|SAST]]<br/>CAST
| purpose         = Reconnaissance
| status          = Active
| duration        = 2015–Present
| firstflight     = 12 September 2015
| successes       = 9
| failures        = 0
| launchsite      = Xichang Satellite Launch Center<br/>Wenchang  Space Launch Site
| launcher        = 
| native_name_a   = 通信技术试验
| native_name_r   = Tōngxìn Jìshù Shìyàn
}}

{{Short description|Chinese satellite program}}

'''Tongxin Jishu Shiyan''' ('''TJS''', {{Zh|s=通信技术试验|t=|p=Tōngxìn Jìshù Shìyàn|l=communication technology test}}) is a Chinese military [[Astronomy:Satellite|satellite]] program operating in [[Astronomy:Geostationary orbit|geostationary orbit]] (GEO). TJS satellites are manufactured by the [[Organization:Shanghai Academy of Spaceflight Technology|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 [[Engineering:Shiyan (satellite)|Shiyan satellite program]].<ref name=":2">{{Cite tweet|number=1077262393401577474|user=planet4589|title=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.|author=Jonathan McDowell|date=24 December 2018}}</ref>

Unlike traditional, non-military satellites where the Chinese government announces the satellite's name, mission, platform, [[Engineering:Launch vehicle|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.<ref name=":0">{{Cite journal |last=Clark |first=Phillip S. |date=January 2018 |editor-last=Becklake |editor-first=John |title=China's Shiyan Weixing Satellite Programme: 2004–2017 |url=https://www.bis-space.com/membership/chronicle/2018/Space-Chronicle-v71-Suppl.1-2018_xx83mf.pdf |journal=Space Chronicle: A British Interplanetary Society Publication |location=London |volume=71 |issue=1 |pages=23 |isbn=978-0-9567382-2-6}}</ref>

Although the true purpose of TJS satellites remains classified, satellite observers speculate these satellites provide early warning and [[Signals intelligence|signals intelligence]] ([[Signals intelligence|SIGINT]]) for the Chinese People's Liberation Army (PLA).<ref>{{Cite web |last=Krebs |first=Gunter D. |date=1 August 2022 |title=TJS 1, 4, 9 (Qianshao-3 1, 2, 3 ?) |url=https://space.skyrocket.de/doc_sdat/tjs-1.htm |website=Gunter's Space Page}}</ref><ref>{{Cite web |last=Krebs |first=Gunter D. |date=30 July 2022 |title=TJS 2, 5, 6 (Huoyan-1 ?) |url=https://space.skyrocket.de/doc_sdat/tjs-2.htm |website=Gunter's Space Page}}</ref>

== Classes ==
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.

=== Qianshao-3 ===
TJS-1, TJS-4, and TJS-9 satellites, launched in 2015, 2019, and 2021, maintain geostationary orbit over the [[Earth:Indian Ocean|Indian Ocean]]<ref>{{Cite web |title=TJS-1 |url=https://www.n2yo.com/satellite/?s=40892 |website=N2YO}}</ref> and [[Place:Micronesia|Micronesia]]<ref>{{Cite web |title=TJS-4 |url=https://www.n2yo.com/satellite/?s=44637 |website=N2YO}}</ref><ref>{{Cite web |title=TJS-9 |url=https://www.n2yo.com/satellite/?s=50574 |website=N2YO}}</ref> and are suspected to comprise the Qianshao-3 SIGINT satellite class ({{Zh|s=前哨|p=Qiánshào|l=Outpost}}).<ref name=":0" /><ref>{{Cite web |last=Krebs |first=Gunter D. |date=8 January 2022 |title=TJS 1, 4, 9 (Qianshao-3 1, 2, 3 ?) |url=https://space.skyrocket.de/doc_sdat/tjs-1.htm |website=Gunter's Space Page}}</ref> The Chinese government originally stated these satellites were designed to test [[Astronomy:Ka band|Ka-band]] [[Engineering:Broadband|broadband]] communication (27–40 GHz) but has not commented on the satellites since they achieved geostationary orbit.<ref>{{Cite news |last=Yu |first=Bai |date=12 September 2015 |title=China launches communication technology experimental satellite |work=Xinhua News Agency |url=http://news.xinhuanet.com/english/photo/2015-09/13/c_134618997_3.htm |url-status=dead |archive-url=https://web.archive.org/web/20170314075756/http://news.xinhuanet.com/english/photo/2015-09/13/c_134618997_3.htm |archive-date=14 March 2017}}</ref><ref>{{Cite web |title=GEO SIGINT - Qianshao / TJSW / Chang Cheng "Great Wall" |url=https://www.globalsecurity.org/space/world/china/geo-sigint.htm |website=Global Security}}</ref> In January 2017, novel reports of an antenna approximately 32 meters wide reinforced speculation of the satellite's potential SIGINT mission.<ref name=":0" /> Other Chinese sources suggest the Qianshao series are [[Engineering:Space-Based Infrared System|space-based infrared]] early warning satellites.<ref>{{Cite web |date=17 June 2020 |title=中国导弹预警卫星不输美俄 能在3万公里高空捕捉目标 |trans-title=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 |url=https://mil.sina.cn/zm/2020-06-17/detail-iirczymk7440485.d.html |website=Sina Military |language=zh}}</ref><ref>{{Cite web |title=前哨系列预警卫星 |trans-title=Outpost series of early warning satellites |url=https://zhuanlan.zhihu.com/p/79839379 |website=Zhihu Zuanlan |language=zh}}</ref>

=== Huoyan-1 ===
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."<ref name=":0" /><ref name=":1">{{Cite web |last=Krebs |first=Gunter D. |date=30 July 2022 |title=TJS 2, 5, 6 (Huoyan-1 ?) |url=https://space.skyrocket.de/doc_sdat/tjs-2.htm |website=Gunter's Space Page}}</ref> Launched in 2017, 2020, and 2021, these satellites are rumored to be of the Huoyan-1 ({{Zh|s=火眼|p=Huǒyǎn|l=Fire Eyes}}) program — China's first early-warning satellites in geosynchronous orbit.<ref name=":2" /><ref name=":0" /><ref name=":1" /> These purported Huoyan-1 series satellites remain fixed in orbit over the Indian Ocean, South China Sea, and Oceania.<ref>{{Cite web |title=TJS-2 |url=https://www.n2yo.com/satellite/?s=41911 |website=N2YO}}</ref><ref>{{Cite web |title=TJS-5 |url=https://www.n2yo.com/satellite/?s=44978 |website=N2YO}}</ref><ref>{{Cite web |title=TJS-6 |url=https://www.n2yo.com/satellite/?s=47613 |website=N2YO}}</ref>

=== 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.<ref>{{Cite web |last=Krebs |first=Gunter D. |date=8 February 2021 |title=TJS 3 / TJS 3 Subsatellite |url=https://space.skyrocket.de/doc_sdat/tjs-3.htm |website=Gunter's Space Page}}</ref> Said to have only had one [[Engineering:Payload|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 [[Engineering:Apogee kick motor|apogee kick motor]] (AKM), a final-impulse motor often discarded by satellites entering their terminal geostationary orbit.<ref name=":3">{{Cite AV media |url=https://www.youtube.com/watch?v=xx5zevd6AdU |title=TJS 3 Space Activities - Spacecast 15 |date=1 July 2019 |last=Hall |first=Bob |type=Podcast |language=en}}</ref> 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.<ref name=":3" /> Reinforcing suspicions, on Friday, 18 January 2019, the subsatellite maneuvered eastward over [[Place:Southeast Asia|Southeast Asia]] with the main TJS-3 satellite performing the same maneuver two days later.<ref name=":3" /> The two satellites continued to complete a number of synchronized maneuvers.<ref name=":3" />

Later in May 2019, capitalizing on the passing of the [[Astronomy:Terminator (solar)|day-night terminator]] which makes satellite tracking by [[Astronomy:Optical telescope|optical telescope]] impractical, the TJS-3 maneuvered far out of its orbit with its subsatellite taking its place shortly after.<ref name=":4">{{Cite news |last=Clark |first=Colin |date=28 October 2021 |title=US, China, Russia Test New Space War Tactics: Sats Buzzing, Spoofing, Spying |work=Breaking Defense |url=https://breakingdefense.com/2021/10/us-china-russia-test-new-space-war-tactics-sats-buzzing-spoofing-spying/}}</ref> 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".<ref name=":4" /><ref>{{Cite news |last=Jones |first=Andrew |date=5 November 2021 |title=An object is now orbiting alongside China's Shijian-21 debris mitigation satellite |work=SpaceNews |url=https://spacenews.com/an-object-is-now-orbiting-alongside-chinas-shijian-21-debris-mitigation-satellite/}}</ref> China has yet to acknowledge any secondary object associated with the TJS-3.<ref>{{Cite news |last=Clark |first=Stephen |date=18 October 2019 |title=China launches mysterious geostationary satellite |work=Spaceflight Now |url=https://spaceflightnow.com/2019/10/18/china-launches-mysterious-geostationary-satellite/}}</ref>

== Satellites ==
{| class="wikitable"
!Name
!Program
!Launch
!Function
!Orbital apsis
!Inclination
!SCN
!COSPAR
!Launch site
!Launcher
!Status
|-
|TJS 1
|Qianshao-3 1
|12 September 2015
|[[Signals intelligence|SIGINT]]
|35,770.9&nbsp;km × 35815.7&nbsp;km
|0.1°
|40892
|{{Cospar|id=2015-046A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 2
|Huoyan-1 01
|5 January 2017
|[[Engineering:Early warning satellite|Early warning]]
|35,769.0&nbsp;km 35,818.5&nbsp;km
|0.2°
|41911
|{{Cospar|id=2017-001A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 3
|Unknown
|24 December 2018
|Unknown
|35,788.0&nbsp;km  35800.0&nbsp;km
|0.1°
|43874
|{{Cospar|id=2018-110A}}
|XSLC
|[[Engineering:Long March 3C|Long March 3C]]
|Operational
|-
|TJS 3 (subsat)
|Unknown
|24 December 2018
|Unknown
|36,309.3&nbsp;km  36,369.9&nbsp;km
|1.1°
|43917
|{{Cospar|id=2018-110C}}
|XSLC
|[[Engineering:Long March 3C|Long March 3C]]
|Operational
|-
|TJS 4
|Qianshao-3 2
|14 October 2019
|[[Signals intelligence|SIGINT]]
|35.781.7&nbsp;km  35804.2&nbsp;km
|0.0°
|44637
|{{Cospar|id=2019-070A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 5
|Huoyan-1 02
|7 January 2020
|[[Engineering:Early warning satellite|Early warning]]
|6,780.9&nbsp;km  35,808.5&nbsp;km
|0.2°
|44978
|{{Cospar|id=2020-002A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 6
|Huoyan-1 03
|4 February 2021
|[[Engineering:Early warning satellite|Early warning]]
|35,789.0&nbsp;km  35,796.7&nbsp;km
|0.4°
|47613
|{{Cospar|id=2021-010A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 7
|Unknown
|24 August 2021
|Unknown
|35,788.8&nbsp;km  35,799&nbsp;km
|0.1°
|49115
|{{Cospar|id=2021-077A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 9
|Qianshao-3 3
|29 December 2021
|[[Signals intelligence|SIGINT]]
|35,787.8&nbsp;km  35,800.1&nbsp;km
|0.0°
|50574
|{{Cospar|id=2021-135A}}
|XSLC
|[[Engineering:Long March 3B|Long March 3B]]
|Operational
|-
|TJS 10
|Unknown
|3 November 2023
|Unknown
|Unknown
|16.96°
|58204
|{{Cospar|id=2023-169A}}
|WSLS
|[[Engineering:Long March 7|Long March 7A]]
|Operational
|}

== See also ==
{{Portal|Spaceflight|China
}}
* [[Engineering:Yaogan|Yaogan]]
* [[Engineering:Shijian|Shijian]]
* EKS (satellite system)

== References ==
[[Category:Satellite series]]

{{Sourceattribution|Tongxin Jishu Shiyan}}