Basics of Space Flight: Orbital Mechanics

We are actually very fortunate that the Earth is not very spherical, because without that satellites on the high inclination orbits like the polar orbits and the Molinya orbits would crash into the Earth. Due to perturbations of the Moon, high inclination orbits have a tendency to be pushed from low eccentricity to very high eccentricity. (This is known as the Kozai-Lidov mechanism.) However, the fact that the Earth's gravitational potential is not exactly spherical (it has a quadrupole moment)…

This type of learning material, lacking any desperate 'ELI5' oversimplifications and laying out the proper amount definitions and equations without having to resort to fancy animations to keep the -quite often indolent- reader engaged, is unfortunately scarce in today's web, as is evident from the website's layout. Here are two favorite readings for anyone willing to delve more into the subject: Orbital Mechanics for Engineering Students by Howard D. Curtis…

I'm not sure if I missed the wrong lecture somewhere in my math education, but seeing that diagram of the conic sections was definitely an "Aha!" moment, tragically. I'm coming from a background where I've taken multiple calculus classes...

See also more on orbital mechanics at the same website at http://www.braeunig.us/space/interpl.htm.