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Elliptic orbit

In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. [1]

Apsis

An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.

Asteroid

Asteroids are minor planets, especially those of the inner Solar System.

Babylonian astronomy

The history of astronomy in Mesopotamia, and the world, begins with the Sumerians who developed the earliest writing system—known as cuneiform—around 3500–3200 BC.

Barycenter

The barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον centre) is the center of mass of two or more bodies that are orbiting each other, which is the point around which they both orbit.

Butterworth-Heinemann

Butterworth–Heinemann is a British publishing company specialized in professional information and learning materials for higher education and professional training, in printed and electronic forms.

Cambridge University Press

Cambridge University Press (CUP) is the publishing business of the University of Cambridge.

Cartesian coordinate system

A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular directed lines, measured in the same unit of length.

Celestial mechanics

Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects.

Characteristic energy

In astrodynamics, the characteristic energy (C_3) is a measure of the excess specific energy over that required to just barely escape from a massive body.

Circular orbit

A circular orbit is the orbit with a fixed distance around the barycenter, that is, in the shape of a circle.

Comet

A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing.

Dwarf planet

A dwarf planet is a planetary-mass object that is neither a planet nor a natural satellite.

Ecliptic

The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.

Ellipse

In mathematics, an ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.

Free fall

In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it.

Gravitational two-body problem

←For further relevant mathematical developments see also Two-body problem, also Kepler orbit, and Kepler problem, and Equation of the center &ndash; Analytical expansions The gravitational two-body problem concerns the motion of two point particles that interact only with each other, due to gravity.

Halley's Comet

Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 74–79 years.

Hohmann transfer orbit

In orbital mechanics, the Hohmann transfer orbit is an elliptical orbit used to transfer between two circular orbits of different radii in the same plane.

Hyperbolic trajectory

In astrodynamics or celestial mechanics, a hyperbolic trajectory is the trajectory of any object around a central body with more than enough speed to escape the central object's gravitational pull.

Isaac Newton

Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, astronomer, theologian, author and physicist (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time, and a key figure in the scientific revolution.

Johannes Kepler

Johannes Kepler (December 27, 1571 – November 15, 1630) was a German mathematician, astronomer, and astrologer.

Kepler orbit

In celestial mechanics, a Kepler orbit (or Keplerian orbit) is the motion of one body relative to another, as an ellipse, parabola, or hyperbola, which forms a two-dimensional orbital plane in three-dimensional space.

Kepler's laws of planetary motion

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

List of orbits

The following is a list of types of orbits.

Molniya orbit

A Molniya orbit (a, "Lightning") is a type of satellite orbit.

Newton's law of universal gravitation

Newton's law of universal gravitation states that a particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Orbit equation

In astrodynamics an orbit equation defines the path of orbiting body m_2\,\! around central body m_1\,\! relative to m_1\,\!, without specifying position as a function of time.

Orbital eccentricity

The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.

Orbital elements

Orbital elements are the parameters required to uniquely identify a specific orbit.

Orbital mechanics

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft.

Orbital Mechanics for Engineering Students

Orbital Mechanics for Engineering Students is an aerospace engineering textbook by Howard D. Curtis, in its third edition.

Orbital period

The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.

Orbital speed

In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter or, if the object is much less massive than the largest body in the system, its speed relative to that largest body.

Orbital state vectors

In astrodynamics and celestial dynamics, the orbital state vectors (sometimes state vectors) of an orbit are cartesian vectors of position (\mathbf) and velocity (\mathbf) that together with their time (epoch) (t\) uniquely determine the trajectory of the orbiting body in space.

Parabolic trajectory

In astrodynamics or celestial mechanics a parabolic trajectory is a Kepler orbit with the eccentricity equal to 1.

Perihelion and aphelion

The perihelion of any orbit of a celestial body about the Sun is the point where the body comes nearest to the Sun.

Planet

A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.

Primary (astronomy)

A primary (also called a gravitational primary, primary body, or central body) is the main physical body of a gravitationally bound, multi-object system.

In astrodynamics and celestial mechanics a radial trajectory is a Kepler orbit with zero angular momentum.

Semi-major and semi-minor axes

In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter.

Similarity (geometry)

Two geometrical objects are called similar if they both have the same shape, or one has the same shape as the mirror image of the other.

Solar System

The Solar SystemCapitalization of the name varies.

Space debris

Space debris (also known as space junk, space waste, space trash, space litter or space garbage) is a term for the mass of defunct, artificially created objects in space, most notably in Earth orbit, such as old satellites and spent rocket stages.

Specific orbital energy

In the gravitational two-body problem, the specific orbital energy \epsilon\,\! (or vis-viva energy) of two orbiting bodies is the constant sum of their mutual potential energy (\epsilon_p\,\!) and their total kinetic energy (\epsilon_k\,\!), divided by the reduced mass.

Specific relative angular momentum

In celestial mechanics the specific relative angular momentum \vec plays a pivotal role in the analysis of the two-body problem.

Standard gravitational parameter

In celestial mechanics, the standard gravitational parameter μ of a celestial body is the product of the gravitational constant G and the mass M of the body.

Tundra orbit

A Tundra orbit (Russian: Тундра) is a highly elliptical geosynchronous orbit with a high inclination (usually near 63.4°) and an orbital period of one sidereal day.

Virial theorem

In mechanics, the virial theorem provides a general equation that relates the average over time of the total kinetic energy, \left\langle T \right\rangle, of a stable system consisting of N particles, bound by potential forces, with that of the total potential energy, \left\langle V_\text \right\rangle, where angle brackets represent the average over time of the enclosed quantity.

Vis-viva equation

In astrodynamics, the vis-viva equation, also referred to as orbital-energy-invariance law, is one of the equations that model the motion of orbiting bodies.

References

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