Astrodynamics

In astrodynamics delta-v is a scalar measure for the amount of "effort" needed to carry out an orbital maneuver, i.e., to change from one orbit to another. A delta-v is typically provided by the thrust of a rocket engine. The time-rate of delta-v is the magnitude of the acceleration, i.e., the thrust per kilogram total current mass, produced by the engines. The actual acceleration vector is found by adding the gravity vector to the vec ...

See also:

Delta-v, Delta-v - Astrodynamics, Delta-v - Games, Delta-v - External link

Read more here: » Delta-v: Encyclopedia II - Delta-v - Astrodynamics

Main article: Astrodynamics Astrodynamics is the branch of celestial mechanics concerned with the motion of rockets, satellites and missiles. It is based upon Newton's laws of motion, and law of universal gravitation. The formula for escape velocity is defined in astrodynamics as: Astrodynamics is also used to compute the position of a satellite at a given time, a problem first solved by Johannes Kepler, who computed the formula: This formula is commonly referred to as Kepler's equation, and can compute the time required for a satellite ...

See also:

Astrophysics, Astrophysics - History, Astrophysics - Observational astrophysics, Astrophysics - Theoretical astrophysics, Astrophysics - Astrodynamics, Astrophysics - Astrophysicists

Read more here: » Astrophysics: Encyclopedia II - Astrophysics - Astrodynamics

Astrodynamics is the study of the motion of rockets, missiles, and space vehicles, as determined from Sir Isaac Newton's laws of motion and his law of universal gravitation. It is a specific and distinct branch of celestial mechanics, which focuses more broadly on Newtonian gravitation and includes the orbital motions of artificial and natural astronomical bodies such as planets, moons, and comets. Astrodynamics is principally concerned with spacecraft trajectories, from launch to atmospheric re-entry, including all orbital maneuvers, ...

Including:

• Astrodynamics - Laws of astrodynamics
• Astrodynamics - Formulae for ellipse
• Astrodynamics - Historical approaches
• Astrodynamics - Kepler's equation
• Astrodynamics - Perturbation theory
• Astrodynamics - Modern techniques
• Astrodynamics - Conic orbits
• Astrodynamics - Transfer orbits
• Astrodynamics - The patched conic approximation
• Astrodynamics - The universal variable formulation
• Astrodynamics - Perturbations
• Astrodynamics - Non-ideal orbits
• Astrodynamics - Interplanetary superhighway and fuzzy orbits
• Astrodynamics - Reference

Read more here: » Astrodynamics: Encyclopedia - Astrodynamics

Until the rise of space travel in the twentieth century, there was little distinction between astrodynamics and celestial mechanics. The fundamental techniques, such as those used to solve the Keplerian problem, are therefore the same in both fields. Furthermore, the history of the fields is essentially identical. Astrodynamics - Kepler's equation. Kepler was the first to successfully model ...

See also:

Astrodynamics, Astrodynamics - Laws of astrodynamics, Astrodynamics - Formulae for ellipse, Astrodynamics - Historical approaches, Astrodynamics - Kepler's equation, Astrodynamics - Perturbation theory, Astrodynamics - Modern techniques, Astrodynamics - Conic orbits, Astrodynamics - Transfer orbits, Astrodynamics - The patched conic approximation, Astrodynamics - The universal variable formulation, Astrodynamics - Perturbations, Astrodynamics - Non-ideal orbits, Astrodynamics - Interplanetary superhighway and fuzzy orbits, Astrodynamics - Reference

Read more here: » Astrodynamics: Encyclopedia II - Astrodynamics - Historical approaches

Celestial mechanics is a division of astronomy dealing with the motions and gravitational effects of celestial objects. The field applies principles of physics, historically Newtonian mechanics, to astronomical objects such as stars and planets. It is distinguished from astrodynamics, which is the study of the creation of artificial satellite orbits. Celestial mechanics - History of celestial mechanics. Although modern analytic celestial mechanics starts 400 years ago with Isaac Newton, prior studies addres ...

Including:

• Celestial mechanics - History of celestial mechanics
• Celestial mechanics - Ancient Civilizations
• Celestial mechanics - Claudius Ptolemy
• Celestial mechanics - Johannes Kepler
• Celestial mechanics - Isaac Newton
• Celestial mechanics - Albert Einstein
• Celestial mechanics - Open problems
• Celestial mechanics - Examples of problems
• Celestial mechanics - Perturbation theory
• Celestial mechanics - External link

Read more here: » Celestial mechanics: Encyclopedia - Celestial mechanics

The orbital period is the time it takes a planet (or another object) to make one full orbit. There are several kinds of orbital periods for objects around the Sun: The sidereal period is the time that it takes the object to make one full orbit around the Sun, relative to the stars. This is considered to be an object's true orbital period. The synodic period is the time that it takes for the object to reappear at the same spot in the sky, relative to the Sun, as observed from Earth. This is th ...

Including:

• Orbital period - Relation between sidereal and synodic period
• Orbital period - Calculation
• Orbital period - Small body orbiting a central body
• Orbital period - Two bodies orbiting each other

Read more here: » Orbital period: Encyclopedia - Orbital period

Science (from Latin scientia - knowledge) refers to a system of acquiring knowledge - based on empiricism, experimentation, and methodological naturalism - aimed at finding out the truth. The basic unit of knowledge is the theory, which is a hypothesis that is predictive. The term science also refers to the organized body of knowledge humans have gained by such research. Most scientists feel that scientific investigation must adhere to the scientific method, a process for evaluating empirical knowledge under the w ...

Including:

• Science - What is science?
• Science - Scientific method
• Science - Philosophy of science
• Science - Mathematics and the scientific method
• Science - Goals of science
• Science - Locations of science
• Science - Science and social concerns
• Science - Scientific literature
• Science - Fields of science
• Science - Natural sciences
• Science - Social sciences
• Science - Holistic interdisciplinary and applied sciences
• Science - Environmental sciences
• Science - Etymology
• Science - External articles and references
• Science - Textbooks
• Science - News and articles
• Science - Resources
• Science - Further reading

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In astrodynamics or celestial mechanics a circular orbit is an elliptic orbit with the eccentricity equal to 0. It is an example of a rotation around a fixed axis: this axis is the line through the center of mass perpendicular to the plane of motion. Circular orbit - Circular acceleration. Transverse acceleration (perpendicular to velocity) causes change in direction. If it is constant in magnitude and changing in direction with the velocity, we get a circular motion. For this centripetal accelera ...

Including:

• Circular orbit - Circular acceleration
• Circular orbit - Velocity
• Circular orbit - Orbital period
• Circular orbit - Energy
• Circular orbit - Equation of motion
• Circular orbit - Delta-v to reach a circular orbit

Read more here: » Circular orbit: Encyclopedia - Circular orbit

An orbital node is one of the two points where an inclined orbit crosses a plane of reference (e.g. the equator for geocentric orbits, the ecliptic for heliocentric orbits). Nodes do not exist for orbits with inclination equal to zero (equatorial orbits or ecliptic orbits). The ascending (or north) node is where the object moves north from the southern hemisphere to the northern, the descending (or south) node is where the object moves back south. The line of nodes is the intersection of the object's orbital plane with the plane of reference, a ...

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The ecliptic plane is the geometric plane that contains the orbit of the Earth. The ecliptic is the intersection of the ecliptic plane and the celestial sphere. A more intuitive definition would be to say that the ecliptic is the apparent path of the Sun during a year as seen from Earth. The orbits of most planets in the Solar System lie very close to it. Seen from the Earth, this is a bisecting great circle, superimposed upon the celestial sphere, which contains the different points of the Sun's path, relative to the backgroun ...

Read more here: » Ecliptic: Encyclopedia - Ecliptic

Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. The study of cosmology is theoretical astrophysics at the largest scales. Because it is a very broad subject, astrophysicists typically apply many disciplines of physics including, but not limited to, mechanics, electromagnetism, statisti ...

Including:

• Astrophysics - History
• Astrophysics - Observational astrophysics
• Astrophysics - Theoretical astrophysics
• Astrophysics - Astrodynamics
• Astrophysics - Astrophysicists

Read more here: » Astrophysics: Encyclopedia - Astrophysics

Prograde motion is the rotational or orbital motion of a body in a direction similar to that of other bodies within a given system, and is sometimes called direct motion. Retrograde motion is in the contrary direction. The word 'retrograde' derives from the Latin words retro, backwards, and gradus, step. Prograde and retrograde motion - Two notations. The north orbital pole of a celestial body is defined by the right-hand rule: If you curve the fingers of your right hand a ...

Including:

• Prograde and retrograde motion - Two notations
• Prograde and retrograde motion - Retrograde orbits
• Prograde and retrograde motion - Retrograde rotation
• Prograde and retrograde motion - Retrogradation or apparent retrograde motion
• Prograde and retrograde motion - Examples
• Prograde and retrograde motion - Reference

Read more here: » Prograde and retrograde motion: Encyclopedia - Prograde and retrograde motion

In astronomy, an apsis (plural apsides "ap-si-deez") is the point of greatest or least distance of the elliptical orbit of a celestial body from its center of attraction (the center of mass of the system). The point of closest approach is called the periapsis or pericentre and the point of farthest excursion is the apoapsis (Greek απο, from), apocentre or apapsis (the latter term, although etymologically more correct, is much less used). A straight line drawn through the peria ...

Including:

• Apsis - Formulae
• Apsis - Terminology

Read more here: » Apsis: Encyclopedia - Apsis

In astrodynamics, for elliptic orbits the longitude of the ascending node is the angle between the reference direction (e.g. the vernal equinox) and the ascending node. It can be calculated from orbital state vectors as: (if then ) where: is the x-component of , is cartesian vector pointing towards the ascending node (i.e. the z-component of is zero). For equatorial orbits (i.e. orbits with orbital inclination equal to zero) is undefined. For com ...

See also:

Longitude of the ascending node, Longitude of the ascending node - Calculation from state vectors

Read more here: » Longitude of the ascending node: Encyclopedia II - Longitude of the ascending node - Calculation from state vectors

In astrodynamics mean anomaly can be calculated as follows: where: is the mean anomaly at time , is the start time, is the time of interest, and is the mean motion. Alternatively: where: is orbit's eccentric anomaly, is orbit's eccentricity. ...

See also:

Mean anomaly, Mean anomaly - Calculation

Read more here: » Mean anomaly: Encyclopedia II - Mean anomaly - Calculation

In astrodynamics, the inclination can be computed as follows: where: is z-component of , is orbital momentum vector perpendicular to the orbital plane. ...

See also:

Inclination, Inclination - Calculation

Read more here: » Inclination: Encyclopedia II - Inclination - Calculation

Most planets, including Earth, spin in the prograde sense: They spin in the same direction as they orbit the Sun (that is, their north rotational pole and north orbital pole point in similar directions, more or less in the direction of the Solar north pole). The exceptions are Venus, Uranus, and Pluto. Uranus rotates nearly on its side relative to its orbit. It has been described as having an axial tilt of 82° and a negative rotation of −17 hours, or, equivalently, of having an axis tilted at 98° and a positive rotation. Since current sp ...

See also:

Prograde and retrograde motion, Prograde and retrograde motion - Two notations, Prograde and retrograde motion - Retrograde orbits, Prograde and retrograde motion - Retrograde rotation, Prograde and retrograde motion - Retrogradation or apparent retrograde motion, Prograde and retrograde motion - Examples, Prograde and retrograde motion - Reference

Read more here: » Prograde and retrograde motion: Encyclopedia II - Prograde and retrograde motion - Retrograde rotation

In the ideal case m1 is useful payload and m0 − m1 is reaction mass (this corresponds to empty tanks having no mass, etc.). The energy required can simply be computed as Seemingly this is just the kinetic energy of the reaction mass and not the kinetic energy required for the payload, but if e.g ve=10 km/s and the speed of the rocket is 3 km/s, then ...

See also:

Tsiolkovsky rocket equation, Tsiolkovsky rocket equation - History, Tsiolkovsky rocket equation - Stages, Tsiolkovsky rocket equation - Energy, Tsiolkovsky rocket equation - Examples

Read more here: » Tsiolkovsky rocket equation: Encyclopedia II - Tsiolkovsky rocket equation - Energy

There are many different conceptions of the word "science". According to empiricism, scientific theories are objective, empirically testable, and predictive — they predict empirical results that can be checked and possibly contradicted. In contrast, scientific realism defines science in terms of ontology: science attempts to identify phenomena and entities in the environment, their causal powers, the mechanisms through which they exercise those powers, and the sources of those powers in terms ...

See also:

Science, Science - What is science?, Science - Scientific method, Science - Philosophy of science, Science - Mathematics and the scientific method, Science - Goals of science, Science - Locations of science, Science - Science and social concerns, Science - Scientific literature, Science - Fields of science, Science - Natural sciences, Science - Social sciences, Science - Holistic interdisciplinary and applied sciences, Science - Environmental sciences, Science - Etymology, Science - External articles and references, Science - Textbooks, Science - News and articles, Science - Resources, Science - Further reading

Read more here: » Science: Encyclopedia II - Science - What is science?

Utilizing the vis viva equation where, where: is the speed of an orbiting body is the standard gravitational parameter of the primary body is the distance of the orbiting body from the primary is the semi-major axis of the body's orbit The magnitude of the first delta-v at the initial circular orbit with radius r0 is: At rbSee also:

Bi-elliptic transfer, Bi-elliptic transfer - Calculation

Read more here: » Bi-elliptic transfer: Encyclopedia II - Bi-elliptic transfer - Calculation