energy with respect to both radial distance and time allows us to find the rate of change of the radial distance with respect to time as per below.

:
:
:

The assumptions used in this derivation above are that the orbit stays very nearly circular throughout the decay process, so that the equations for orbital energy are more or less that of a circular orbit's case. This is often true for orbits that begin as circular, as drag forces are considered "re-circularizing", since drag magnitudes at the periapsis

1.Previous
3.Next