New Beidou Satellite Launched

China launched its fifth Beidou/Compass navigation satellite on Friday, April 13.  The initial orbital elements (inclination = 55.0°, eccentricity = 0.62, mean motion = 3.84 orbits per day) may indicate that this is not another GEO satellite but rather the first of the MEO satellites.

Meanwhile, it seems that NORAD had “lost” the 4th Beidou satellite for awhile. Launched on February 2, the satellite reportedly had a problem with a stuck solar panel which needed to be fixed before the satellite could be transitioned from its geostationary transfer orbit to its intended geostationary location. The last publicly released element set for this satellite had been dated 8 March 2007. Perhaps this was the day the Chinese started to move the satellite to its geostationary position.

NORAD released an element set for the satellite in its near geostationary orbit. NORAD is currently reporting the satellite to be in an inclined orbit (6.3°) with a sub-satellite longitude of about 144°E. The latest Beidou/Compass might not be heading for GEO but either to an inclined geosynchronous orbit or MEO, similar to that of GPS and GLONASS satellites.

The Chinese have talked about various Beidou/Compass options:

1. 4 GEO + 9 inclined (50°) geosynchronous
2. 4 GEO + 12 MEO (55° x 20,200 km)
3. 30 MEO (56° x 21,363 km)

In one of their ITU filings, the Chinese referred to some of the satellites as Compass-M.