Satellite atmospheric friction analysis · CAP 2005 #27
Physics · mechanics
Problem
A satellite orbiting Earth at low altitude experiences a retarding force because of collisions with the few molecules present in the upper atmosphere. The mass density ρ of the atmosphere at the satellite's altitude is about 10−12 kg/m³.
(a) Assume that in such collisions, the molecules become embedded in the solar panel. If the satellite is moving at speed v, find an expression for the maximum retarding force on the solar panel in terms of ρ and of the radius of the satellite's orbit. Make any other reasonable assumption.
(b) Estimate how much altitude the satellite might lose over one week because of this friction. If you make assumptions, do not forget to justify them briefly.
(c) Somebody claims that as the satellite loses altitude it also loses speed because of the friction. Comment briefly.