# How do solar flares degrade orbits?

What is the mechanism of solar flares that causes degradation of spacecraft orbits? The kind that deorbited Skylab?

The proton storm is fairly thin, its pressure shouldn't affect the kinetic energy. What other effects can cause that? Electrodynamic drag?

• Interesting graphs! It seems the drag at 400km orbit rises to equivalent of a 250km orbit during high solar activiy - and the density scale being exponential, that's over an order of magnitude. And speed->altitude loss is an exponential function again (craft entering "naturally" exponentially more dense atmosphere and losing velocity faster.) So, we're facing an $O(e^{e^x})$ scale phenomenon. – SF. May 12 '16 at 6:09