Editing Trans-lunar injection (section)

=== Patched conics ===
TLI targeting and lunar transfers are a specific application of the [[N-body problem|n body problem]], which may be approximated in various ways. The simplest way to explore lunar transfer trajectories is by the method of [[Patched Conics|patched conics]].  The spacecraft is assumed to accelerate only under classical 2 body dynamics, being dominated by the Earth until it reaches the Moon's [[Sphere of influence (astrodynamics)|sphere of influence]].  Motion in a patched-conic system is deterministic and simple to calculate, lending itself for rough mission design and "[[Back-of-the-envelope calculation|back of the envelope]]" studies.