Will update with more pages as the day progresses. This one is an elaboration on the two-body problem we talked about last time (how a planet, or a satellite, orbits around another, larger body) and shows how the International Space Station is caught in something called “constant free-fall”, that is, balancing between gravity and velocity, centripetal and centrifugal forces.
EDIT: Newton’s Cannonball, or, how we actually place satellites in orbit around Earth. Depending on the initial velocity (in this case perpendicular to the Earth) of the object, this object will take on different trajectories around, or beyond, the centre of gravity, that is, our planet.
EDIT-2: The ideas behind operative space travel, using and abusing the gravitational fields of the celestial bodies in order to land and detach smoothly.