Consider a satellite orbiting earth. Its distance from the sun is 1.5 X 1011 meters. The sun radiates with an average power output of 3.8 X 1026 watts. If its solar collecting panels have a total area of 20 square meters, what would be the radiation pressure on the solar panels and the force due to it? The intensity of the solar radiation equals the average solar power per unit area. Its value at the satellite is thus 1.3 X 103 watts per meter square. Assuming that the solar panels completely absorb all the incident sunlight, the radiation pressure on the solar panels equals the solar radiation intensity over the speed of light, which is 4.3 X 10-6 newtons per meter square. The radiation force is the product of radiation pressure and the area of the solar panels. Its value is calculated to be 8.6 X 10-5 newtons.