Tongxin Jishu Shiyan (TJS, ) is a Chinese military

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

program operating in

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...

(GEO). TJS satellites are manufactured by the

China Academy of Space Technology The China Academy of Space Technology (CAST) () is a Chinese space agency and subordinate of China Aerospace Science and Technology Corporation (CASC). The agency was founded on 20 February 1968, and is the main spacecraft development and prod ...

(CAST) and launched from

Xichang Satellite Launch Center The Xichang Satellite Launch Center (XSLC), also known as the Xichang Space Center, is a spaceport of China. It is located in Zeyuan Town (), approximately northwest of Xichang, Liangshan Yi Autonomous Prefecture in Sichuan. The facility beca ...

(XSLC) in China's southern

Sichuan Province Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

. TJS is likely the

cover Cover or covers may refer to: Packaging * Another name for a lid * Cover (philately), generic term for envelope or package * Album cover, the front of the packaging * Book cover or magazine cover ** Book design ** Back cover copy, part of co ...

name for multiple geostationary military satellite programs and should not be confused with the similarly named Shiyan satellite program. Unlike traditional, non-military satellites where the Chinese government announces the satellite's name, mission, platform,

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pad, launch pads, supported by a missile launch contro ...

, and

launch site A spaceport or cosmodrome is a site for launching or receiving spacecraft, by analogy to a seaport for ships or an airport for aircraft. The word ''spaceport'', and even more so ''cosmodrome'', has traditionally been used for sites capable ...

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. Although the true purpose of TJS satellites remains classified, satellite observers speculate these satellites provide early warning and

signals intelligence Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ( ...

(

SIGINT Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ( ...

) for the Chinese

People's Liberation Army The People's Liberation Army (PLA) is the principal military force of the People's Republic of China and the armed wing of the Chinese Communist Party (CCP). The PLA consists of five service branches: the Ground Force, Navy, Air Force, ...

(PLA).

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

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

and

Micronesia Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...

and are suspected to comprise the Qianshao-3 SIGINT satellite class (). The Chinese government originally stated these satellites were designed to test

Ka-band The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centime ...

broadband In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. ...

communication (27–40 GHz) but has not commented on the satellites since they achieved geostationary orbit. In January 2017, novel reports of an antenna approximately 32 meters wide reinforced speculation of the satellite's potential SIGINT mission. Other Chinese sources suggest the Qianshao series are space-based infrared early warning satellites.

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." Launched in 2017, 2020, and 2021, these satellites are rumored to be of the Huoyan-1 () program — China's first early-warning satellites in geosynchronous orbit. These purported Huoyan-1 series satellites remain fixed in orbit over the Indian Ocean, South China Sea, and Oceania.

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. Said to have only had one

payload Payload is the object or the entity which is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of ...

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 The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's only independent space force. Along with its sister branch, the U.S. Air Force, the Space ...

as an

apogee kick motor An apogee kick motor (AKM) is a rocket motor A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, produ ...

(AKM), a final-impulse motor often discarded by satellites entering their terminal geostationary orbit. 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. Reinforcing suspicions, on Friday, 18 January 2019, the subsatellite maneuvered eastward over

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

with the main TJS-3 satellite performing the same maneuver two days later. The two satellites continued to complete a number of synchronized maneuvers. Later in May 2019, capitalizing on the passing of the day-night terminator which makes satellite tracking by

optical telescope An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electro ...

impractical, the TJS-3 maneuvered far out of its orbit with its subsatellite taking its place shortly after. 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". China has yet to acknowledge any secondary object associated with the TJS-3.

Satellites

References