TJS (Satellite)

通信技术试验 Tōngxìn Jìshù Shìyàn
Program overview
Country	People's Republic of China
Organization	SAST CAST
Purpose	Rendezvous & Inspection (RPO), Missile warning, SIGINT
Status	Active
Program history
Duration	2015–Present
First flight	12 September 2015
Last flight	23 October 2025
Successes	20
Failures	0
Launch site(s)	Xichang Satellite Launch Center Wenchang Space Launch Site

TJS,Chinese:通信技术试验;pinyin:Tōngxìn Jìshù Shìyàn;lit. 'communication technology test') is a Chinese militarysatellite program operating ingeostationary orbit (GEO). TJS satellites are manufactured by theShanghai Academy of Spaceflight Technology (SAST) and launched fromXichang Satellite Launch Center (XSLC) in China's southernSichuan Province. TJS is likely thecover name for multiple geostationary military satellite programs and should not be confused with the similarly namedShiyan satellite program.^[1]

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

Although the true purpose of TJS satellites remainsclassified, satellite observers speculate these satellites provide early warning andsignals intelligence (SIGINT) for the ChinesePeople'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 theIndian Ocean^[5] andMicronesia^[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 testKa-bandbroadband 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 arespace-based infrared early warning satellites.^[11][12]

TJS-2, TJS-5, TJS-6 and TJS-7 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] Placeholder images used in the launch video depicts the satellites as being roughly analogus to theSpace Based Infrared System (SBIRS) of the United States.^[14] These purported Huoyan-1 series satellites remain fixed in orbit over the Indian Ocean, South China Sea, and Oceania.^[15][16][17]James Acton, co-director of the Nuclear Policy Program at theCarnegie Endowment for International Peace believes these satellites primary purpose is for missile warning based on their orbital slots and inclinations.^[18]

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.^[19] Said to have only had onepayload aboard during its 2018 launch, observers detected a secondary object separate from TJS-3 in orbit. The object was originally labeled by theUnited States Space Force as anapogee kick motor (AKM), a final-impulse motor often discarded by satellites entering their terminal geostationary orbit.^[20] 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.^[20] Reinforcing suspicions, on Friday, 18 January 2019, the subsatellite maneuvered eastward overSoutheast Asia with the main TJS-3 satellite performing the same maneuver two days later.^[20] The two satellites continued to complete a number of synchronized maneuvers.^[20]

Later in May 2019, capitalizing on the passing of theday-night terminator which makes satellite tracking byoptical telescope impractical, the TJS-3 maneuvered far out of its orbit with its subsatellite taking its place shortly after.^[21] 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".^[21][22] China has yet to acknowledge any secondary object associated with the TJS-3.^[23]

• Yaogan
• Shijian
• EKS (satellite system)

• Satellites of China
• Satellite series
• Reconnaissance satellites
• Signals intelligence satellites

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