Dong Fang Hong 09

Launch data:

Spacecraft data:

Photo of the SJ-2 spacecraft (image credit: CAST)

Top view of the deployed SJ-2 spacecraft (image credit: CAST)

Sensor complement:

• The payload of about 100 kg included four instruments for space debris probing:
  • MMW (Millimeter Wave) Radar. The objective is to detect debris of size 3-10 cm or larger by remote sensing methods in the altitude range of 600 to 1300 km. The instrument provides measurements with a velocity resolution of <50 m/s; a direction resolution of <±1 arcsec; the time resolution is <1 s; SNR = 6.9 dB. The instrument has dimensions of 400 mm x 350 mm x 350 mm, a mass of 50 kg, and a power of 120 W.
  • IP (Impact Detector). The objective is to collect particles and impacting radiation (light) signals. The instrument consists of a charge detector and a light detector, each with different collecting apertures and different viewing directions. The charge detector collects particles in the mass range of 10-7 to 10-15 g, a size range of 0.05 to 50 ?m, and a velocity resolution of <10 km/s. The instrument mass is 6 kg (6 W power). - The light detector collects particles in the mass range of 10-3 to 10-7 g, a size range of 50 ?m to 0.5 mm, and a velocity resolution of <10 km/s. The instrument mass is 5 kg (power 4 W).
  • Large Sensitive Array (located at the back of the solar panel). The objective is to detect the total impact effect by measuring the change of the resistance. The instrument has dimensions of 1010 mm x 1010 mm x 600 mm, a mass of 7 kg and a power consumption of 6 W.
  • Optical Monitor. The objective is to monitor the surface change of the two solar panels (caused by debris impacts). The instrument uses four CCD cameras which are located inside the spacecraft.

End of life

Mission details:

• SJ-2 spacecraft is spin-stabilized and sun-pointing with a total mass of 250 kg. The main body of the satellite is an octahedral pyramid with a side length of 1.2 m and an outer diameter of 615 cm. Four deployable solar wings are attached to the top of the minisatellite.
• China launched the three spacecraft of the SJ-2 series (SJ-2, SJ-2A, and SJ-2B) on one launch vehicle (FB-1 or Feng Bao 1) on Sept. 20, 1981 (UTC). This represented the first multiple spacecraft launch of China and was considered as a great success with regard to space vehicle tracking, separation and control.