Shi Jian 4 (SJ 4)

SJ 4 [CAST]

SJ 4 (Shi Jian 4) was a satellite to monitor the space radiation environment and its effects in an elliptical orbit.

SJ-4 was built by CAST. The spin stabilized spacecraft had a mass of 397 kg with a diameter of 1.6 m and a height of 2.1 m.

The satellite was equipped with six instruments:

• EED (High Energy Electron Detector)
• EPS (High Energetic Proton and Heavy Ion Detector)
• ESA (Electrostatic Analyzer)
• SEEM (Dynamic Single Event Effect Monitor)
• SEUM (SRAM Single Event Upset Monitor)
• SPM (Surface Potential Monitor)

The satellite was launched from Xichang on the maiden flight of the CZ-3A rocket and was put into a geosynchronous transfer orbit of 210 km × 36125 km with an inclination of 28.6º. It operated for about six months.