Abstract
The evolution of low Earth orbit satellites under the action of atmospheric drag and J2
oblateness perturbations has been widely investigated. Simple analyses describing the altitude decay of a circular orbit through energy arguments have also been widely available. This paper extends these simple analyses by providing compact analytic expressions for true anomaly and ascending node angle along with a more accurate expression for altitude decay. The resulting solutions then allow a fast and efficient method of investigating the orbital evolution of decaying, precessing circular orbits. Applications include the rapid evaluation of station-keeping budgets for both single platforms and the orbital evolution of satellite constellations. Passive station-keeping by continuous low thrust acceleration is investigated and shown to be naturally unstable.
