orbital decay (1 Viewer)

[bos1234]

The total mechanical energy, E , of a satellite in a stable orbit is the sum of its kinetic and potentiol energies.

It can be shown that

How did they obtain this formula?

And why does a satellite lose altitude if it is slowed down?

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MODS put latex on this site!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[xiao1985]

it seemed to be a formula for potential energy. and the formula should be Ep = -GmM/r, not /2

a satellite at a particular altitude need to travel at a particular velocity for it to maintain ciricular motion(to find what this velocity is, equate gravitation force with centripetal force)

upon losing speed, you can look at it as that the satellite effectively gets "dragged" in by the earth. More precisely speaking, at a slower velocity, a circular orbit is only stable at a higher altitude. But the satellite maintains its altitude, hence it can no longer undergoes circular motion, and hence undergo orbital decay