the.com/orbital mechanics
the physics of falling forever and calling it a career.
means the branch of physics governing how objects move under gravity in space, from moons to satellites to spacecraft.
from grew out of kepler's laws and newton's gravitation in the 1600s, refined for the space age when getting a rocket from here to there stopped being poetry and started being math.
speed upto slow down, you actually burn fuel forward
orbit shapeperfect circles are basically mythical, everything is an ellipse
hohmann transfercheapest route between orbits, invented by a guy in 1925
three bodyadd one more mass and equations stop having neat answers