Glossary
- Periapsis/Perigee: In an elliptical orbit, the point of the orbit closest to the planet
- Apoapsis/Apogee: In an elliptical orbit, the point of the orbit farthest from the planet
- Eccentricity: A Scalar of how non-circular an orbit is.
- ecc = 0 => circular orbit
- 0 < ecc < 1 => elliptical orbit
- ecc = 1 => parabolic orbit - this is an escape orbit
- ecc > 1 => hyperbolic orbit - this is an escape orbit
- Sub-Orbital: Any trajectory that will lead an object (rocketload of kerbals) back to the ground.
- Prograde: The "forward" direction of your orbital path. Since orbits are elliptical, it's actually
the tangent of the orbit where the ship is.
- Retrograde: The reverse of Prograde, "backwards".
- Zenith: "Up" in ground-relative coordinates, i.e. the direction your rocket points at when at the
launchpad, aka: "the highest point in the sky".
- Nadir: opposite direction of "Zenith".
- Δv: A change in velocity, it is positive, wether it is slowing down of speeding up.