抄録
The spin decay of our first scientific satellite "Shinsei" (1971-080 A) seems to give a clear evidence to the statement that a spin-stabilized earth satellite suffers the spin decay resulting from energy losses in the form of eddy currents and/or magnetic hysteresis. The analysis of the spin decay is presented in this paper, together with the observed data. A close corelation is found between the rate of spin decay and the magnitude of geomagnetic field component normal to the spin axis. With the aid of the torque measurement using a torque-meter, it is concluded that the torque due to the magnetic hysteresis is negligibly small as compared to the one due to the eddy currents. The average torque acting on Shinsei in its orbit is estimated to be roughly 12 dyne-cm.
