Astrodynamics is the branch of astronomy that deals with the motion of spacecraft and other celestial bodies. Its primary objective is to design and control spacecraft trajectories to achieve specific mission objectives.

The strong nuclear force is not a fundamental force considered in astrodynamics because it acts only at very short distances, such as those within atomic nuclei. The other three forces, gravitational force, electromagnetic force, and weak nuclear force, play significant roles in astrodynamics.

The equation of motion for a spacecraft in a central gravitational field is $F = GmM/r^2$, where $F$ is the gravitational force, $G$ is the gravitational constant, $m$ is the mass of the spacecraft, $M$ is the mass of the central body, and $r$ is the distance between the spacecraft and the central body.

The Hohmann transfer orbit is a maneuver used to transfer a spacecraft between two circular orbits in the same plane. It involves two impulses: one to raise the spacecraft's perigee to the apogee of the transfer orbit and another to lower the spacecraft's apogee to the perigee of the target orbit.

A gravity assist maneuver is a technique used to change a spacecraft's velocity, direction of motion, or both by utilizing the gravitational field of a planet or moon. It can be used to increase or decrease the spacecraft's velocity, change its direction of motion, or both.

Lambert's problem is a mathematical problem in astrodynamics that involves determining the trajectory of a spacecraft given its initial and final positions and the time of flight. It is used to design spacecraft trajectories for missions such as interplanetary transfers and rendezvous maneuvers.

A rendezvous maneuver is a series of spacecraft maneuvers used to bring two spacecraft together in the same orbit. It is often used to dock spacecraft together for crew transfer, cargo transfer, or other purposes.

Geostationary orbits are circular orbits that lie directly above the Earth's equator and have a period of 24 hours, which means that they appear to remain stationary over a fixed point on the Earth's surface. Geosynchronous orbits, on the other hand, are not necessarily circular and can be inclined with respect to the Earth's equator. They have a period of 24 hours or more, but they may not appear to remain stationary over a fixed point on the Earth's surface.

Lagrange points are locations in space where the gravitational forces of two or more celestial bodies cancel each other out. This creates a stable environment where spacecraft can be placed and remain in a fixed position relative to the celestial bodies. Lagrange points are often used for spacecraft that need to maintain a constant position relative to the Earth, such as communication satellites and weather satellites.

Ballistic trajectories are trajectories in which a spacecraft is not powered and follows a parabolic path under the influence of gravity. Powered trajectories, on the other hand, are trajectories in which a spacecraft is powered and can deviate from a parabolic path.

A phasing maneuver is a maneuver used to adjust the timing of a spacecraft's orbit. It is often used to ensure that two spacecraft arrive at a rendezvous point at the same time or to adjust the timing of a spacecraft's passage over a ground station.

A plane change maneuver is a maneuver used to change the inclination of a spacecraft's orbit. It is often used to transfer a spacecraft from one orbital plane to another or to adjust the inclination of a spacecraft's orbit to match that of another spacecraft.

An eccentricity change maneuver is a maneuver used to change the eccentricity of a spacecraft's orbit. It is often used to transfer a spacecraft from an elliptical orbit to a circular orbit or vice versa.

A semi-major axis change maneuver is a maneuver used to change the semi-major axis of a spacecraft's orbit. It is often used to transfer a spacecraft from one orbit to another with a different semi-major axis.