Astrodynamics

right|thumb|Variation of orbital eccentricity    

minimum speed needed for an object to escape the gravitational influence of a primary body

geosynchronous orbit with zero eccentricity at a fixed longitude and a nominally fixed latitude; common orbit for communications satellites

space-navigation technique

field of classical mechanics concerned with the motion of spacecraft

orbit around the barycenter of the Sun

satellite orbit with high inclination

elliptical orbit used to transfer between two circular orbits of different altitudes, in the same plane

mathematical equation describing the motion of a rocket

Hohmann transfer orbit used to reach geosynchronous or geostationary orbit

orbital maneuver

orbit of an astronomical body equal to that body's average rotational period

supersynchronous orbit where spacecraft are intentionally placed at the end of their operational life

observed deviation from predicted accelerations of the Pioneer 10 and Pioneer 11 spacecraft

orbital perturbations

'Delta-v''''' (also known as "change in velocity"), symbolized as {\Delta v} and pronounced , as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or landing on a planet or moon, or an in-space orbital maneuver. It is a scalar that has the units of speed. As used in this context, it is not the same as the physical change in velocity of said spacecraft.

the illusion of reversing trajectories in relation to specific vantage points

maneuver in which a spacecraft falls into a gravitational well, and then accelerates when its fall reaches maximum speed

propulsive maneuver used to arrive at the Moon

spacecraft propulsion system which uses electricity

measure in astronomy

temporary orbit used during the launch of a satellite or other space probe

use of propulsive system to change the orbit of a spacecraft

device that senses the direction to one or multiple stars

path on the surface of the Earth or another body directly below an aircraft or satellite

maneuver that moves a spacecraft from one orbit to another

parameter in the gravitational two-body problem

fuel-efficient orbital maneuver

orbit of Mars where the orbiting object remains over the same location on Mars' surface

maneuvers made to maintain a particular orbit

vector quantity in celestial mechanics

rotation of a satellite as it orbits

type of orbit around an astronomical body that lies close to its equatorial plane

oblate-spheroid-shaped region around a celestial body where the primary gravitational influence on an orbiting object is that body

changing the inclination of an orbiting body's orbit

spacecraft instrument that senses the direction to the Sun

A statite (a portmanteau of the words static and satellite) is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. Typically, a statite would use the solar sail to "hover" in a location that would not otherwise be available as a stable geosynchronous orbit. Statites have been proposed that would remain in fixed locations high over Earth's poles, using reflected sunlight to counteract the gravity pulling them down. Statites might also employ their sails to change the shape or velocity of more conventi

adjustment of the time-position of spacecraft along its orbit

collection of gravitationally determined pathways through the Solar System that require very little energy for an object to follow

measure of the excess specific energy over that required to just barely escape from a massive body

estimation of orbits of objects

spacecraft docking mechanism

orbit for an artificial satellite in which natural drifting due to the central body's shape has been minimized by careful selection of the orbital parameters

Periodic, three-dimensional circuit near the L1 and L2 points in the three-body problem

the science of space vehicle performance, stability, and control.

type of orbit that is farther away from the parent body than a synchronous orbit

method to calculate trajectory calculations for spacecraft

measure of the efficiency of a rocket based on its propellant's mass

type of low-energy spacecraft transfer

Determine an orbit from two position vectors and the time of flight