In the absence of disturbances, an Earth orbiting satellite will follow a Keplerian orbit, which is a regular ellipse with Earth at a focus. However, in reality, there are many additional factors such as gravity field irregularities, Earth magnetic field interactions with satellite magnetic residual and induced magnetic field, solar radiation pressure, the gravitational influence of other celestial bodies and atmospheric drag, which disturb satellite orbits and deflect them from the classic Kepler ellipse fixed in inertial space. Generally, these orbital disturbances are relatively minor over the short-term of a few orbits. However, for low Earth orbiting satellites, atmospheric drag is the dominant factor, causing a satellite to gradually lose altitude (orbital decay) and eventually enterer the dense lower layers of the Earth's atmosphere, where is burned up. Even for fairly high altitudes, this decay can be fairly rapid. This effect can also be used for planned destruction of defunct satellites so as not to add to the space debris problem. This study develops simple models and simulators for satellite atmospheric drag orbital decay prediction. The simulator can be used for satellite orbital decay assessment and studying its effects.
