Density and temperature variation in the exosphere derived from the orbital decay of satellite TAIYO

The TAIYO (1975-014 A), the third scientific satellite of Japan was launched on Feb. 24, 1975 from the Kagoshima Space Center (K.S.C). It was an aeronomy satellite designed to study the relation between solar radiations and thermospheric structures. The initial mean orbital elements of TAIYO were follows; height of perigee 255.24 km, height of apogee 3135.51 km, period 120.32 minutes, inclination 31.560. As the mean perigee height of satellite was 250 km, those orbital elements were available to study the changes of exospheric density and temperature during the flight of satellite. As the local time of passage of perigee changed during the flight, we could obtain the variation of exospheric temperature which depended on the local time. We compared also with the Jacchia's model corrected with the K sub(p) index and the solar radio flux (F sub(10.7)). (auth.)