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originally posted by: InfiniteTrinity
a reply to: neutronflux
So, EchoStar 1 completes one orbit of earth’s mass
So it doesnt orbit around the Earth then?
It obviously doesnt otherwise you would have said Earth instead of Earth's mass.
Why dont you just admit that it doesnt orbit around the Earth.
If it stays above a specific point then it is not moving around the Earth, and thus, not orbiting the Earth. Remember from the last 300 times?
EchoStar I
EchoStar I is a communications satellite operated by EchoStar. Launched in 1995 it was operated in geostationary orbit at a longitude of 77 degrees west for 12 or 15 years. The company has approved the transfer of the 77 degree west orbital position to QuetzSat as of September 22, 2010.
en.m.wikipedia.org...
Station-keeping in geostationary orbit
en.m.wikipedia.org...
For geostationary spacecraft, thruster burns orthogonal to the orbital plane must be executed to compensate for the effect of the lunar/solar gravitation that perturbs the orbit pole with typically 0.85 degrees per year.[3] The delta-v needed to compensate for this perturbation keeping the inclination to the equatorial plane amounts to in the order 45 m/s per year. This part of the GEO station-keeping is called North-South control.[4]
The East-West control is the control of the orbital period and the eccentricity vector performed by making thruster burns tangential to the orbit. These burns are then designed to keep the orbital period perfectly synchronous with the Earth rotation and to keep the eccentricity sufficiently small. Perturbation of the orbital period results from the imperfect rotational symmetry of the Earth relative the North/South axis, sometimes called the ellipticity of the Earth equator. The eccentricity (i.e. the eccentricity vector) is perturbed by the solar radiation pressure. The fuel needed for this East-West control is much less than what is needed for the North-South control.
To extend the life-time of ageing geostationary spacecraft with little fuel left one sometimes discontinues the North-South control only continuing with the East-West control. As seen from an observer on the rotating Earth the spacecraft will then move North-South with a period of 24 hours. When this North-South movement gets too large a steerable antenna is needed to track the spacecraft. An example of this[when?] is Artemis.[citation needed]
To save weight, it is crucial for GEO satellites to have the most fuel-efficient propulsion system. Some[which?] modern satellites are therefore employing a high specific impulse system like plasma or ion thrusters.
Barycenter
en.m.wikipedia.org...
In astronomy, the barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον center[1]) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. It is an important concept in such fields as astronomy and astrophysics. The distance from a body's center of mass to the barycenter can be calculated as a two-body problem.
center of mass
en.m.wikipedia.org...
In physics, the center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion.
In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe. In the case of a distribution of separate bodies, such as the planets of the Solar System, the center of mass may not correspond to the position of any individual member of the system.
The center of mass is a useful reference point for calculations in mechanics that involve masses distributed in space, such as the linear and angular momentum of planetary bodies and rigid body dynamics.
In orbital mechanics, the equations of motion of planets are formulated as point masses located at the centers of mass. The center of mass frame is an inertial frame in which the center of mass of a system is at rest with respect to the origin of the coordinate system.
Orbital elements
en.m.wikipedia.org...
Orbital elements are the parameters required to uniquely identify a specific orbit.
The traditional orbital elements are the six Keplerian elements, after Johannes Kepler and his laws of planetary motion.
When viewed from an inertial frame, two orbiting bodies trace out distinct trajectories. Each of these trajectories has its focus at the common center of mass. When viewed from a non-inertial frame centred on one of the bodies, only the trajectory of the opposite body is apparent; Keplerian elements describe these non-inertial trajectories. An orbit has two sets of Keplerian elements depending on which body is used as the point of reference. The reference body is called the primary, the other body is called the secondary. The primary does not necessarily possess more mass than the secondary, and even when the bodies are of equal mass, the orbital elements depend on the choice of the primary.
Two elements define the shape and size of the ellipse:
Eccentricity (e)—shape of the ellipse, describing how much it is elongated compared to a circle (not marked in diagram).
Semimajor axis (a)—the sum of the periapsis and apoapsis distances divided by two. For circular orbits, the semimajor axis is the distance between the centers of the bodies, not the distance of the bodies from the center of mass.
Two elements define the orientation of the orbital plane in which the ellipse is embedded:
Inclination (i)—vertical tilt of the ellipse with respect to the reference plane, measured at the ascending node (where the orbit passes upward through the reference plane, the green angle i in the diagram). Tilt angle is measured perpendicular to line of intersection between orbital plane and reference plane. Any three points on an ellipse will define the ellipse orbital plane. The plane and the ellipse are both two-dimensional objects defined in three-dimensional space.
Longitude of the ascending node (Ω)—horizontally orients the ascending node of the ellipse (where the orbit passes upward through the reference plane, symbolized by ☊) with respect to the reference frame's vernal point (symbolized by ♈︎). This is measured in the reference plane, and is shown as the green angle Ω in the diagram.
The remaining two elements are as follows:
Argument of periapsis (ω) defines the orientation of the ellipse in the orbital plane, as an angle measured from the ascending node to the periapsis (the closest point the satellite object comes to the primary object around which it orbits, the blue angle ω in the diagram).
True anomaly (ν, θ, or f) at epoch (M0) defines the position of the orbiting body along the ellipse at a specific time (the "epoch").
The mean anomaly is a mathematically convenient "angle" which varies linearly with time, but which does not correspond to a real geometric angle. It can be converted into the true anomaly ν, which does represent the real geometric angle in the plane of the ellipse, between periapsis (closest approach to the central body) and the position of the orbiting object at any given time. Thus, the true anomaly is shown as the red angle ν in the diagram, and the mean anomaly is not shown.
The angles of inclination, longitude of the ascending node, and argument of periapsis can also be described as the Euler angles defining the orientation of the orbit relative to the reference coordinate system.
Note that non-elliptic trajectories also exist, but are not closed, and are thus not orbits. If the eccentricity is greater than one, the trajectory is a hyperbola. If the eccentricity is equal to one and the angular momentum is zero, the trajectory is radial. If the eccentricity is one and there is angular momentum, the trajectory is a parabola.
originally posted by: InfiniteTrinity
a reply to: neutronflux
Ok Neutronflux do geostationary satellites orbit around the Earth like you and your peers have been claiming or do they not?
Yes?
or
No?
I mean you guys literally said this so you should be able to answer with a yes or no, right?
originally posted by: InfiniteTrinity
Ok, Neutronflux, would you tell your friend that he is right when saying that geostationary satellites orbit around the Earth?
Or just tell me, do they orbit around the Earth or not.
Yes/no will suffice.
No reason to not answer this question.
originally posted by: InfiniteTrinity
a reply to: neutronflux
I have no problem discussing every aspect of your post, after we get closure on the current subject. So do geostationary satellites orbit around the Earth like you and your peers have been claiming for pages and pages?
Yes or no?
Stop embarassing yourself.
originally posted by: InfiniteTrinity
Well its clear to everyone that geostationary satellites dont orbit around the Earth then.
originally posted by: InfiniteTrinity
Ok, Neutronflux, would you tell your friend that he is right when saying that geostationary satellites orbit around the Earth?
Or just tell me, do they orbit around the Earth or not.
Yes/no will suffice.
No reason to not answer this question.
originally posted by: InfiniteTrinity
a reply to: neutronflux
I already told you Neutronflux. Your posts doesnt say wether or not it orbits around the Earth or not. That was the topic for 20 pages. It is irrelevant wether your post is false because your whole post is irrelevant.
Yes or no Neutronflux?
Stop embarassing yourself.
Another example. The moon actually doesn’t “orbit” around the earth.
I will also say yes a satellite in earth orbit, orbits the earth.
An orbit is a regular, repeating path that one object in space takes around another one.
originally posted by: InfiniteTrinity
a reply to: captainpudding
I will also say yes a satellite in earth orbit, orbits the earth.
Now say something relevant. The topic was geostationary satellites. Not satellites in general.
And once more, from NASA
An orbit is a regular, repeating path that one object in space takes around another one.
Now does a geosationary sat move around the object Earth? No it doesnt. Its geo stationary.
Rofl.
Okay fine a satellite in geostationary orbit around the earth is in orbit around the earth.