Good evening all. Though there have been many quite informative posts upon the elemental concepts of orbital mechanics and spaceflight, and also taking into account OhioBob's wonderful website, I chanced upon this page while browsing JPL today. While taking into account the risk of over-saturation upon the subject, it occurred to me that many might enjoy and benefit from this link;
http://solarsystem.nasa.gov/basics/bsf4-1.php
I cannot claim credit for offering any illumination of my own, but I hope that some few might enjoy the presentation of this information. It is clearly written for a wider audience, and is a bit less "mathy" than a specialist website, though it does indeed contain a link to OhioBob's site for those who wish to get deeper into the numbers.