A spherical satellite circling the sun is to be maintained at a temperature of 25°C. The satellite rotates continuously and is partly covered with solar cells having a gray surface with an absorptivity of 0.1. The rest of the sphere is to be covered by a special coating that has an absorptivity of 0.8 for solar radiation an an emissivity of 0.2 for the emitted radiation. Estimate the portion of the surface of the sphere that can be covered by solar cells. The solar irradiation can be assumed to be 1420 W/m2 of surface perpendicular to the rays of the sun.