SECULAR EVOLUTION OF THE ORBIT OF A BALLOON SATELLITE.

The motion of a balloon satellite of the ″Echo-1″ type is considered with allowance for the light pressure exerted by the sun, the gravitational perturbations from the moon and sun, and the noncentrality of the earth's gravitational field. The solution of the limiting problem of two fixed centers is chosen as the zero approximation. Formulas are derived for predicting secular perturbations in the orbital elements of a balloon satellite over a period of 10 to 12 days.