Dong Fang Hong 11

Also called SJ-2B (Shi Jian-2B) or PRC 9C

Designation	12845 / 81093D
Launch date	19 Sep 1981 - 21:28 UT
Launch site	Jiuquan, LA2B
Launch vehicle	FB 1 (#11)
Mission	Radar calibration test
Highly Elliptical Earth orbit:
Perigee / Apogee	232 x 1608 km
Eccentricity
Inclination	59.4 deg
Period	103.4 min

According to ref #7: 81093D= SJ-2

Prime contractor
Platform
Operator
Mass at launch	257 kg
Dry Mass	kg
Basic shape	balloon
Dimension (m)	dia: 4m
Equipment
Solar array
Stabilization
Propulsion
Payload	Space dust/debris experiments and electromagnetic background probing

Decay

17 Aug 1982

The SJ-2B was a passive radar calibration test satellite. A balloon with a diameter of 4 m was used as a guiding optical beacon connected with a metal ball with a diameter of 0.45 m using a 600 m silk rope, which was used for the radar's calibration.
The balloon expanded after it was placed into orbit because of sublimation and a little residual gas in it. The polyester-aluminum-plated surface of the balloon was very bright and guided the radar to find the metal ball in orbit. In the first 16 orbits, the Kashi station for 7010 radar and the Zijinshan Observatory in China acquired 5 targets in orbit and successfully carried out the radar calibration.

Ref.: #1, #7, #15, #113, #242 - update: 10.08.15