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.

learn more… | top users | synonyms

-1
votes
1answer
25 views

Could gyroscopes be use to control orientation of satellite?

In the game space engineers, the player can control the angular movements of a spacecraft with gyroscopes. Just to be clear, the purpose of this gyroscope is not to measure rotation, but to actually ...
0
votes
1answer
27 views

How does the total change in energy being negative indicate the direction of the Force?

To be more precise consider the following situation: Suppose a satellite is orbiting at a distance of $r_1$ from the centre of the earth. After some time, rockets are fired such that the new distance ...
1
vote
0answers
28 views

Can a satellite be put into orbit such that it will always remain directly over a city? [duplicate]

Isn't it possible if we just set it high enough so that it's angular speed matches with the earth's? I think that the city must be on the equator to make this happen. Am I correct? Please can anyone ...
0
votes
1answer
76 views

Can a satellite remain directly over a city?

Is it possible to put an artificial satellite into an orbit in such a way that it will always remain direct over a city (I mean at any specific place)?
2
votes
2answers
279 views

If the ionosphere reflects radio waves then why use satellites? [closed]

Please explain the main physical advantages of using satellites for communication as I'm sure there are many.
0
votes
1answer
76 views

Speed of satellite when it falls freely on the surface of the earth [closed]

I am a high school student in my final two years before university. I have a question which I do not know how to approach. Any help would be appreciated. Thanks! "If an artificial satellite is ...
0
votes
1answer
56 views

Optimal time for satellite rocket launch considering moon gravity [closed]

As per this The Gravitational Force of the Earth and Moon on Each Other Moon is pulling us with a force equal to 1/300,000th of our weight. I have read this Is the fuel burn for a satellite launch ...
0
votes
0answers
38 views

Remote sensing reflectance

I am not getting something simple for reflectance for a lambertian surface when dealing with remote sensing applications. I am trying to derive the equation from ...
1
vote
0answers
23 views

Calculating satellites orbits [duplicate]

Do Newton's and Einstein's theory of Gravity differ very much when calculating satellites orbits. If they don't, in what areas do they actually differ?
1
vote
2answers
50 views

How does the decaying orbit of a satellite maintain its orbit as it descends, as opposed to crashing straight back to Earth?

I understand that as a satellite in low-Earth orbit experiences atmospheric drag, it is slowed down. Therefore it no longer has the velocity to maintain its orbit at that point, as per the orbital ...
0
votes
1answer
86 views

Why do the satellites revolves on a circular path around a planet at orbital velocity? [duplicate]

We know that there is a particular velocity with which a satellite will move in a circular orbit ( orbital velocity ) but if its velocity is more than the orbital velocity but less than the escape ...
1
vote
2answers
75 views

Calculating speed of satellite in vacuum?

Satellite speed is $35\ \mathrm{km/s}$ after burn for $500\ \mathrm{ sec}$ and after some days or months this speed is reduced automatically $34$, $33$, $32$ respectively. Questions: How the ...
1
vote
1answer
96 views

Conversion of satellite coordinates from ITRF to J2000

I have coordinates of various satellites in two coordinate systems: Cartesian coordinates in the international terrestrial reference frame (ITRF) RA / DEC in J2000 epoch, as derived from plate ...
6
votes
1answer
2k views

How to determine satellite position in J2000 from latitude, longitude and distance from Earth?

Due to my task of writing orbit prediction routines I am trying to understand the reference frames better and how to use them ( particularly for Earth orbits ). I think I get the idea of what ECI ...
1
vote
2answers
261 views

Collision of two satellites

In a theoretical situation in which two identical satellites travelling around the Earth in opposite directions collided head on so that there velocities relative to the earth both became 0, would ...
7
votes
3answers
561 views

Questions on the movie Gravity (2013)

To start off, I'm not a physicist but a programmer, and only had a few years of physics education in high school so I'm sorry if I'm asking a stupid question. I just finished watching the movie ...
2
votes
1answer
58 views

Why do tidal forces not violate conservation of energy? [duplicate]

Europa is an example of a satellite which is heated by tidal forces. The orbit is constant, so how is energy conserved on Europa?
0
votes
1answer
90 views

Relative speed of Geostationary satellite with respect to earth?

I was wondering whether relative speed of geostationary satellite with respect to earth is zero or not.Since angular velocity of satellite about earth is same as angular speed of earth about its own ...
1
vote
2answers
112 views

Does the International Space Station always travels in the same path?

From the 3d visualization http://www.satflare.com/track.asp?q=25544#TOP (the right image with the red line indication the path of the ISS) it looks like always the ISS takes the same path. Is it the ...
1
vote
1answer
60 views

Time dilation on Satellites due to GR

I am trying to determine the time dilation onboard a satellite (say GPS @ 20,000km) w.r.t an observer on the earth. I have already determined the special relativity component using: $$ t' = ...
3
votes
1answer
42 views

What happens when the Kepler Space Telescope 'catches up' to Earth?

Kepler is in an earth-trailing orbit with a period of 372.5 days, so it lags behind the Earth about a week each year. Doesn't that mean that, in about 52 years, we'll meet it from the other direction? ...
0
votes
1answer
104 views

Relation of orbital radius with linear velocity of satellite [closed]

If a planet is going around the sun in a circular orbit , and if suddenly (impulsively) it's orbital radius was increased , what would happen to the linear velocity of planet (With reason)
3
votes
2answers
1k views

What may be effect of air friction to the velocity of satellite?

What is the effect of air friction to the velocity of satellite? I have heard satellite's speed increases with air friction. But I'm in confusion how is it possible?
2
votes
1answer
49 views

Given an equation of an elliptical orbit, is it possible to find satellite´s speed at a certain point?

As the heading says: given an equation of an elliptical orbit, is it possible to find satellite´s speed at a certain point? I'm playing a bit with simulations of planets and satellites in the solar ...
1
vote
1answer
44 views

Can a natural satellite have a synchronous orbit?

I was thinking about space-elevators and large masses being put into geosynchronous orbit, when I considered the possibility of a natural satellite being in a synchronous orbit. I did a little digging ...
0
votes
2answers
60 views

Can two artificial bodies be built in space and be made to orbit each other?

Would it be possible to make artificial constructs (satellites) orbit each other? I looked at the gravitational laws, and nothing seems to suggest that this is not possible.
0
votes
1answer
136 views

What is the potential and kinetic energy of the international space station?

I know it's possible to calculate, but what formulas would I use to be as accurate as possible? I'd like to see how it works for something big and high like that.
0
votes
0answers
85 views

How does the orbital velocity of a satellite vary for distance between the surface of earth(nearly) and more?

My physics teacher told me its the same for any distance but the formula for orbital velocity is under root of Gm/R+H so it must vary ?
3
votes
1answer
104 views

The James Webb Telescope, why are there 5 levels of protecting foil?

From simple curiosity, does anybody know why there are around 5 layers of solar radiation reflecting foil on the James Webb Telescope, rather than one or two? Is it to save weight, or (probably) ...
1
vote
1answer
95 views

Why are GPS transmitting signals made so weak?

Twice this year, my car's GPS receiver got totally lost. It seemed the cause of this was heavy cloud, (because I can't think of any other reason), and the GPS stayed in "Recalculating" mode, until ...
1
vote
1answer
31 views

Vibrational noise for scientific apparatus on a satellite

Say we're running an experiment on a satellite in some earth orbit. For example, maybe we're imaging something with transmission electron microscope or we're catching atoms in ion traps --- really ...
23
votes
5answers
7k views

Build a ring around Earth, then remove the supports

What would happen if we decided to build a giant ring that managed to wrap around the whole world, end to end that was supported with pillars all along the ring and then the supports all suddenly ...
0
votes
2answers
40 views

Earth “satellite” breadcrumb: Have we ever placed an object orbiting our Sun and the Sun only?

Have we ever placed an object orbiting our Sun and the Sun only? like a breadcrumb of our orbit... I was reading about VLA for satellites and wouldn't this breadcrumb be a viable solution to create a ...
-1
votes
1answer
241 views

Calculate orbit height from tangential velocity

Is it possible to calculate the altitude of a satellite orbiting a planet, just from the planet's mass and the satellite's velocity, assuming that the satellite is in a perfect circular orbit? If so, ...
1
vote
1answer
146 views

Calculate orbital changes after acceleration

With the vis-viva equation I can calculate the orbital speed at any position on the ellipse. I want to calculate the opposite way. Assume a satellite with an apogee of 600km and a perigee of 400km is ...
8
votes
1answer
409 views

Cancelling special & general relativistic effects

We know that for a GPS we need to make a correction for both general and special relativity: general relativity predicts that clocks go slower in a higher gravitational field (the clock aboard a GPS ...
1
vote
1answer
66 views

Time flow difference for satellites [duplicate]

Clocks in satellites have to be adjusted due to the effects of relativity; but does time for satellites (GPS) flow slower, due to the relative motion, or faster, due to the weaker amount of ...
0
votes
0answers
19 views

from control torque to magnetic moment

I am designing a system which generates a magnetic field to make itself move in space (a cubesat with magnetorquers). This magnetic field is known as the magnetic control torque, i.e. it will torque ...
1
vote
0answers
33 views

What is the particle distribution in Saturn's Ring System?

In watching the scientifically scream-inducing film/movie 'Interstellar', there was a shot of the spacecraft moving through the Rings of Saturn. In this shot, and in every graphical representation of ...
3
votes
2answers
931 views

Why aren't satellites increasing speed because of gravitational acceleration?

Satellites orbiting the earth are experiencing almost as strong gravitation as we do, but they don't hit the earth because of their velocity outwards and the earth's curvature. But if they're ...
0
votes
1answer
164 views

Would Special Relativity Predict Time Dilation of a Geostationary Satellite Compared to an Observer on Earth?

Consider a geostationary satellite at some arbitrary distance above the Earth's equator and consider a person directly below it, standing on the Earth's equator. Both satellite and person exist on the ...
0
votes
1answer
67 views

Can you see a solar eclipse from the International Space Station?

Inspired by last week's solar eclipse, I'm wondering under what conditions one can see a total solar eclipse from the ISS. How often does it happen? I guess it doesn't last very long because of the ...
1
vote
1answer
54 views

Can small chunks of cosmic matter revolve around artificial satellites in space?

I have always studied that where there is a body with mass, there is gravitational pull. So can small chunks (or dust) of cosmic matter revolve around artificial satellites in space? Or rather are ...
0
votes
0answers
25 views

Transmitting to and from low earth orbit?

I'm a hobbyist and I'm currently thinking about building a Cubesat. I'm currently designing PCBs, casing, etc. I was wondering what variables are involved with sending data to and from 250km - 350km ...
0
votes
1answer
140 views

Are the value of velocity and height constant for geostationary satellite?

We know that generally for geostationary station T=24 hours, h=3.6x10⁴km, R=6400 km, and velocity is 3.1 km/s. I think this values are stationary for geostationary satellite. Let we want to place a ...
1
vote
1answer
330 views

Satellites and gravitation

A satellite with mass $m$ orbits a planet of mass $M$ in a circular path with radius $r$ and velocity $v$. Due to some internal technical failure, the satellite breaks into two, similar parts with ...
26
votes
3answers
3k views

How do we stabilise satellites so precisely?

Look at the Hubble Ultra Deep Field photo. The stars in it are on the order of 1 arcsecond across. To an order of magnitude, this is $10^{-6}$ radians in a $10\text m$ telescope which was held steady ...
0
votes
0answers
33 views

How long can a satellite stay in orbit? [duplicate]

Well, obviously billions of years if it is the moon. Or not very long if it is only 100km above the Earth, due to atmospheric drag. Also, how long it stays up would depend on density ie how much ...
0
votes
1answer
32 views

Regarding satellites and their 'safety'

Are satellites nowadays designed so that if one fails or its orbit degrades the scientists involved can send it various codes so that it will starts to 'beak-up' into smaller and smaller parts where ...
3
votes
2answers
110 views

Physics of tidal locking: can the process be underdamped?

Is it possible for a satellite undergoing the process to overshoot the required rotation rate for tidal locking? For example, if its rotation rate is being slowed, can it become slower than it needs ...