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
75 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
47 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
1answer
90 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 ...
7
votes
3answers
559 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 ...
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 ...
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
86 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
110 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
101 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)
2
votes
1answer
48 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
1answer
135 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
84 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
102 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
94 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 ...
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 ...
2
votes
2answers
273 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
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.
1
vote
1answer
145 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 ...
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
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 ...
3
votes
2answers
925 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
161 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 ...
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 ...
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
2answers
259 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 ...
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
139 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 ...
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 ...
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 ...
3
votes
2answers
108 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 ...
4
votes
2answers
115 views

Reasons for decaying orbit for satellites and spacecrafts

As per newton's law, unless a force is applies, moving objects will continue to move in a straight line. A satellite which speeds at around 17.5k mph would be travelling in a straight line considering ...
-1
votes
1answer
66 views

How could the lifetime of a low earth orbit satellite be extended [closed]

How could the lifetime of a low earth orbit satellite be extended? I am studying for a test and wish to know a few methods. Thanks. Edit: You are allowed to work with anything related to the ...
34
votes
3answers
4k views

Cooling a satellite

Satellites are isolated systems, the only way for it to transfer body heat to outer space is thermal radiation. There are solar panels, so there is continuous energy flow to inner system. No airflow ...
0
votes
1answer
410 views

Finding the potential energy of a geosynchronous satellite above earth [closed]

I am trying to find the gravitational potential energy of a 1kg geostationary satellite above the earth. So far: $E=mgh$, and $g=GM/r^2$ so substitution of $g$ into the energy equation gives: ...
0
votes
1answer
66 views

How did the Huygens probe use EM waves to measure wind speeds on Titan?

In the Wikipedia's article on Huygens spacecraft, it was mentioned that one of the experiments was to measure the wind speeds on Titan by Doppler wind experiment. To quote the exact lines, it was ...
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)?
1
vote
0answers
181 views

How to calculate orbital eccentricity from the ratio of satellites' velocities?

I have a problem with working out how to calculate the orbital eccentricity from the ratio of two satellites' linear velocities. We know that two satellites encircles the Earth in two elliptical ...
0
votes
1answer
85 views

Newton's gravity formulas for ellipses

A few times I've come across formulas, which are identical for circular and elliptical orbits, except that for the second ones you substitute $r$ with $a$, where $r$ is the radius of a circular orbit ...