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Issue 53

04 Flash Archive · Members Only

China Paper: Shi Jian (SJ) and Shi Yan (SY) Projects

A CASI paper reviews how China's Shi Jian series established operational practices while Shi Yan satellites served earlier technology-piloting roles.

Author Minhas Published July 31, 2022

28 Mar 2022: The Chinese Aerospace Studies Institute, part of the USAF Air University, published a short paper describing the history of Chinese experimental SJ and SY satellites up to 2013. Read the paper.

– “Shi Jian” indeed means “practice” but as a noun, such as “best practice”, or as in “put into practice.”

– Chinese linguists argue against translating “Shi Yan” as “experiment,” so “pilot” or “trial” are more applicable.

– Both the SJ and SY series have for decades contributed to what Beijing now refers to as the China High-resolution Earth Observation System (CHEOS).

– SJ satellites have primarily improved methods for radar and infrared payloads and SY vehicles have primarily enabled testing of other optical payloads.

– The SJ series has 30 more years of history and a corresponding larger variety in missions and payloads. It has also regularly played a role in establishing best practices for data transmission and communications, and on-orbit satellite constellation guidance and control.

– In 2013, after being jointly launched, the SJ-15 and Shi Yan-7 conducted their only publicly known rendezvous and proximity operation (RPO), which seemed to be coordinated.

– Information on these early launches illustrates that China’s focus for the SJ series was on establishing best practices and operational procedures to enable the development of China’s space program.

– To begin professionalizing Chinese space operators, engineers used lessons learned from the first four SJ satellites to publish Mandarin space operations manuals such as the Handbook of the Artificial Satellite Environment and Handbook on Low Earth Orbit Space Environment.

– The SJ series improved methods for satellite control after launch, a general requirement especially necessary for enhanced imagery with two satellites flying in formation.

– The first Shi Yan was initiated and designed by the Harbin Institute of Technology and launched in 2004, nearly 30 years after the start of China’s space program.

– Shi Yan-1 was China’s first stereoscopic imaging satellite for terrain mapping, and the first ten years of the series saw Shi Yan 1-5 focused on piloting as many payloads as possible, probably optical sensors, on one satellite close to 200 kg.

China has historically used the SJ series to establish operational best practices and procedures for systems or techniques already adopted. The SY satellites appear to play an earlier role in the space systems development process, piloting multiple new technologies on one satellite bus to develop an efficient payload-integration platform and determine payload applicability.

Shi Jian - usage: best practice or procedure.

Shi Jian - usage: best practice or procedure.

Shi Yan - usage: pilot or trial.

Shi Yan - usage: pilot or trial.