Automated Rendezvous and Docking of Spacecraft

| a | semi major axis of ellipse | |
| c | velocity of light | |
| C | spring constant | |
| D | damping constant | |
| e | eccentricity of orbit | |
| ? | error factor | |
| ? | angle between ecliptic and equatorial plane | |
| f | frequency | |
| F | force | |
| F i | coordinate frame | |
| ? | imposed force per unit of mass | |
| i | inclination | |
| m | mass | |
| ? | gravitational constant of Earth | |
| ? | true anomaly, angular position on orbit measured from perigee | |
| O i | origin of coordinate frame | |
| ?, ? | phase | |
| r | radius, orbit radius | |
| R, r | range | |
| t | time | |
| T | orbital period; time | |
| V | velocity | |
| ? V | velocity increment | |
| ?,? o | angular frequency of orbit | |
| ? | angular rate; argument of perigee | |
| ? | angle between vernal equinox and ascending node (see RAAN) |