Orbits and Propagators - AGI

Diseño de Vehículos Espaciales 1DVE1‐T07‐492‐body propagators• 2‐body propagator assumptions:– satellites travel high enough above the atmosphere so that the drag forceis small– the satellite won’t perform manoeuvres (we can ignore any thrust)– we only consider the motion of the satellite close to the Earth– we can ignore the gravity of the Sun, the Moon or anything else– compared to Earth’s gravity, other forces e.g. solar radiation pressure,electromagnetic fields, etc. are negligible– the mass of the Earth is much, much larger than the mass of thespacecraft– the Earth is spherically symmetrical with uniform density (so assume it is apoint mass)• A 2‐body propagator does not need numerical integration in a forcemodel. The model allows for closed‐form solution, with the only need fora numerical technique to solve Kepler’s equation