A satellite of initial mass
m0 is in a circular orbit of radius
R around a star of mass
M. The satellite travels through a vast cloud of dust that is stationary relative to the star. The satellite has a scoop of cross-sectional area
A facing its direction of motion, and it sweeps up and retains all the dust it encounters. The dust has a uniform mass density
ρ.
The satellite's engines provide a thrust force to keep the satellite in exactly the same circular orbit at a constant speed. What is the magnitude of the thrust force provided by the engines as a function of time
t after entering the dust cloud? (Assume the mass of the swept dust is much less than
M, and neglect the self-gravity of the dust cloud).