Questions tagged [satellites]

Satellite is a generic descriptor for any body that orbits a much larger body. The term commonly refers to objects orbiting planets, like artificial satellites and moons, but it can sometimes also refer to planets, small stars, satellite galaxies, and other objects.

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What is the precise ECI frame for two-line elements?

I am trying to reproduce an SGP4 test vector (page 80 of http://www.celestrak.com/NORAD/documentation/spacetrk.pdf), at epoch + 0 (TSINCE=0 in the output table). It should be purely about geometry, no ...
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Why does a satellite moving around earth in circular motion its speed is constant?

I do know the satellite's tangential velocity is always perpendicular to gravity, therefore its speed must remain unchanged, however, I have some confusion. If I separate both the tangential velocity ...
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Planetary motion considering natural satellite

Using Kepler's laws of gravitation we can determine the time period of a planet revolving around the sun. However, this excludes the gravitational effect due to satelite(s) orbiting around the planet. ...
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Why don't the satiltes fall into the earth? [duplicate]

Still, I don't understand how come the satellites won't fall into earth. I know the general explanation to this question is that the satellite's horizontal velocity is too fast that makes the gravity ...
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How close would a supernova be to endanger the astronauts on the ISS?

How close would a supernova be to endanger the astronauts on the ISS? Would Betelgeuse be close enough?
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Fastest possible space-probe

What is the fastest possible velocity a space probe can achieve using planetary orbits? has there been such a planetary alignment in the past 100 years?
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Regarding the objects in free fall in the ISS

There are lots of information about this topic, but I'm still greatly confused about something: Astronauts in the ISS are in free fall all the time because they have only gravity acting on them, but ...
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Why it takes more energy to pull satellite towards Earth than pushing it away?

Newton's law of motion states that satellite in orbit stays in orbit unless external force is applied, so we shall apply the force through it's thruster to deorbit. Strangely, it takes more energy to ...
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Is net force on a geostationary satellite, (when observer is standing just below it on earth) equal to '0'?

Since a geo stationary satellite appears to be at rest form earth, should not the net force acting on the satellite equal to $0$. Now since earth is a non-inertial frame we will have to apply a ...
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Are satellites doing free fall?

I was told that satellites are doing free-fall. But I don't think so, I think, assuming that the satellite is moving at a constant speed in a circular motion, the satellite does not do free-fall ...
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Cause of weightlessness [duplicate]

I'm a first year engineering student who is new to physics, so I apologize if my question is stupid. But in our statics course we are using the book "Engineering mechanics: statics" by R.C. Hibbeler ...
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Body dropped into orbit from Space Elevator

Istr that in Arthur C Clarke's The Fountains of Paradise it is stated that a body falling from a "Space Elevator" at an altitude of more than 16,000 miles will never hit the Earth, but (due to the "...
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Finding exposure time of a satellite camera

Note: I am not sure if this is the correct stack for this question I'm working on a cubesat project, specifically on the camera payload. I've been tasked to find the exposure time of a VIIRS ...
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Rotation of satellite at Lagrange point $L_1$

What rotations occur due to gravitation for a body placed/anchored at Lagrange point $L_1$ in the Sun-Earth system, which is an unstable equilibrium point? Is the rotation axis vector normal to the ...
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Are there any satellite orbit earth perpendicular to the sun and what is the name of this kind of orbit?

I think we could put satellite to orbit earth in such a way that it always see the sun. Which is orbiting along the path of earth orbiting the sun, like a wheel perpendicular to the sun I don't know ...
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Lisa Pathfinder Mission - interpretation of results (frequency)

In the results of the space mission Lisa Pathfinder is on the xx axis the frequency value. Where does this frequency come from? Does it come from satellite orbit frequency or mass vibration?
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Difference between Earth's magnetic field and Earth's gravitational field [closed]

I have a misconception about this. Are these really different? If so then how? And one more problem is that, whether satellites orbit around the Earth because of Earth's Magnetic Field or Earth's ...
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Is it really necessary for the orbital plane of a satellite to pass through the center of mass of the object around which it's orbiting?

Is it really necessary for the orbital plane of a satellite to pass through the center of mass of the celestial body around which it's orbiting? Does the answer depend on, whether the celestial body ...
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What is orbit that could place satellite to be always under the Sun?

I just thinking that, if we could place satellite to orbit earth in opposite direction of earth rotation, inverse of geostationary orbit. If we carefully choose a speed to sync with earth rotation, it ...
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Does gravitational force on a satellite only change the tangential velocity of the satellite?

I'm modelling an orbit of a satellite that has gravitational, drag and lift forces acting on it. Am I correct in stating that the orbit speed $V = \sqrt{GM/r}$ is just the tangential velocity of the ...
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Why do satellites orbit around the centre of a planet?

Why can satellites not orbit around the North or South Pole, instead of orbiting about the centre of the earth?
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How to decrease satellite's orbital radius?

According to the equation $v²=GM/r$ to decrease the orbital radius of a satellite currently in orbit, you'd want to increase its speed. However intuitively this doesn't make sense to me, surely if you ...
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Graphing time as a function of another variable [closed]

I'm sorry if this is not the correct place to post this, but it seems most applicable. I'm graphing the time for a satellite to decay, which depends on the altitude it orbits at, making time a ...
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Will it be possible to remotely determine the vertical temperature/pressure profile of an extrasolar atmosphere?

I was wondering why this equation seemed to work, but I guess no one has a good explanation so it is assumed to be a coincidence for now. Unfortunately, it could only be expected to work for "earth-...
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Acceleration of a satellite orbiting Mars

I am studying how a satellite would move in orbit around Mars. I have calculated the velocity of its movement. However, if the gravity of Mars is the only force affecting the movement of the satellite,...
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How does a single satellite like the upcoming BIOMASS use interferometry?

The future satellite BIOMASS, from the ESA, will supposedly use p-band frequency interferometry to detect changes in forests. By itself? How?
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Satellites orbiting around any planet's [closed]

Suppose a satellite is revolving around a planet with radius r. Now if we increase the value of r then the angular velocity and kinetic energy will decrease, but the total energy & potential ...
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Escape velocity and orbital velocity confusion

If orbital velocity is reduced when we want to put a satellite in a higher orbit, and if to achieve a lower orbit we need to increase it's velocity, then how come by increasing the speed of the ...
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Inextensible filament structure in gravitational field

Let $\gamma$ be a curve lying in a gravitational field with each point moving as an independent point mass. Formally, \begin{equation} \partial^2_t \gamma(u, t) = -\nabla U(\gamma(u, t)), \end{...
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Time dilation in satellites [duplicate]

Is the time dilation suffered by clocks in GPS satellites accurate to what is predicted by special relativity? By "accurate" I mean to ask if the numerical answer given by relativity equations match ...
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Satellite image anomaly

This is a satellite image of somewhere in West Texas: See the localized Red-Green-Blue feature on the road? What could have caused this?
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Geosynchronous satellites with polar orbit?

I know that satellites can go in polar orbits, but as far as I have read, this is only done by LEO satellites. I think it is possible to have geosynchronous satellites with polar orbits (near polar), ...
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Astronauts in spacecraft, they have to circle the earth many times a day, do they also have the illusion of the moon?

Astronauts in spacecraft, they have to circle the earth many times a day, do they also have the illusion of the moon? I don't think they have, because according to the theory, the illusion of the moon ...
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Satallite orbiting the earth [closed]

I need help understanding a question from my physics book. It goes like this: a communications firm wants to place a satellite in orbit so that it is always directly above the earth’s 45th ...
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How does light transfer momentum to a solar sail?

Last month the Planetary Society launched Solar Sail 2. After reading about it a bit I found that its a type of payload carrier that works on the principle of transfer of momentum from light. ...
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Sunlight on an object

I'm not entirely sure how I should be phrasing this question, but it's part of a project I'm working on. It's all about finding reflectivity by way of a telescope. We figured the first way to proceed ...
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Time dilation in a geosynchronous orbit

since gravity slows time, and velocity slows time, would observer A on the equator directly under observer B in a geosynchronous orbit experience time at the same rate? Time would slow on the surface ...
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How does the orbital radius affects the orbital velocity

I have a question says that "If the orbital radius of a satellite increase four times the orbital velocity will be ..." and the answer is that the velocity will be doubled !! We studied that orbital ...
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Change of orbit with tangential impulse

I see a similar question: Change of orbit with a radial impulse. The answer to that question seems fine to me. In the answer, mention is made of this similar question, but it is not fully treated. ...
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Trajectory of a satellite whose velocity is less than circular orbital velocity? [closed]

If the velocity of the satellite orbiting around a planet is reduced somehow...then what would it's trajectory looks like spiral(1) or elliptical(2) Or Does it depends on the  velocity it has(less ...
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Why aren't satellites disintegrated even though they orbit earth within earth's Roche Limits?

I was wondering about the Roche limit and its effects on satellites. Why aren't artificial satellites ripped apart by gravitational tidal forces of the earth? I think it's due to the satellites being ...
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Can satellites stay in orbit when the Earth is being accelerated?

In a TV show I'm watching, the people of Earth have decided to leave the solar system, and take Earth with them, so they've built a large number of powerful rocket engines on one side of the Earth (as ...
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Can we build a superconductor on the Moon and beam energy where needed? [closed]

Should we not build a superconductor facility on the moon ? We find a spot where the rays of the sun don’t provide heat. This should enable a superconductivity facility to operate due to the low ...
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Difference between Critical and orbital velocity

What is the difference between orbital and critical velocity of satallite ? I have read that critical velocity is constant value and it does not depend upon altitude. It only gives the velocity of ...
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Kepler's 3rd law: ratios don't fit data

I have been looking at satellite orbits around the earth, or any object around any planet in fact, and am trying to find the orbital radius, or semi major length of a given satellite. Kepler's third ...
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Kinematics and dynamics of a crashing satellite

A satellite in low, circular orbit around the Earth experiences drag (friction) and slowly spirals into Earth's atmosphere. It then enters the Earth's atmosphere, heats up catastrophically and burns ...
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Friction and satellites

There was this question we did in class. There is a satellite orbiting the Earth. It runs into some particles, and due to friction, the satellite loses speed. We were asked to predict what will happen ...
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If a satellite speeds up, does that make move farther away or closer?

If a satellite is in a stable circular orbit and goes about 41% faster (escape velocity) then it leaves its host forever. I get that. However, what if it speeds up by less than 41%? Intuitively, it ...
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How do microwaves communicate with satellites?

If microwaves only penetrate up to a few cm of food in a household appliance before being absorbed and transferring energy to water molecules, than how are microwaves able to communicate through long ...
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Number of GPS satellites required to give 100% coverage

I am a Belgian school student in sixth grade of secondary school (the Belgian equivalent of High school). Together with two class mates we were assigned to write some kind of essay about the Global ...

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