Press Release


First Quasi-Zenith Satellite MICHIBIKI
Completion of the Critical Operation Phase

September 19, 2010 (JST)

Japan Aerospace Exploration Agency (JAXA)

The Japan Aerospace Exploration Agency (JAXA) confirmed that the attitude control mode of the first quasi-zenith satellite "MICHIBIKI" was shifted to the regular control mode at 7:31 p.m. on September 19, 2010 (Japan Standard Time, JST). As the MICHIBIKI has already been injected into the drift orbit, JAXA completed its critical operation phase.
The satellite is in good health.

We will further control the orbit to place the satellite into the quasi-zenith orbit for about one week while carrying out the initial functional verification of the onboard mission devices in cooperation with organizations* that perform technological verifications for about three months.

We would like to express our profound appreciation to all related personnel and organizations who have supported and cooperated with the launch and tracking operation of the MICHIBIKI.


- Regular control mode : Attitude control mode through which the MICHIBIKI flies by directing its positioning antenna toward the Earth.
- Drift orbit : The last step orbit prior to the quasi-zenith orbit. The orbit altitude and inclination (angle against the equator) are equal to those of the quasi-zenith orbit, but the longitude of the center of the figure-8 orbit is not above Japan. After being injected into the drift orbit, it will take a few days to maneuver the satellite to have its figure-8 center above Japan, thus it will ultimately fly in the quasi-zenith orbit.
- Quasi-zenith orbit   : While the quasi-zenith orbit has the same orbit period of 23 hours and 56 minutes as the geostationary orbit, it can let a satellite stay over Japan longer by taking an elliptical orbit with higher altitude above Japan and flying in a figure-8 orbit.

* National Institute of Advanced Industrial Science and Technology (AIST), Electronic Navigation Research Institute (ENRI), Geospatial Information Authority of Japan (GSI), National Institute of Information and Communications Technology (NICT), Satellite Positioning Research and Application Center (SPAC)

** A movie in the following URL explains more about the quasi-zenith satellite orbit.