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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Can a radially launched projectile orbit a planet?

Imagine a spherical planet with no atmosphere. A ball is launched radially with a velocity $v$, maintaining $\frac{v_e}{\sqrt2}<v<v_e $ and there is no other objects in the universe (Ideal two ...
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Atmospheric depolarization rate in case of a Earth-Space channel

I am trying to write a quantum simulator using netsquid, but i ran in the problem that there aren't really any resources, on how to calculate the depolarization chance of a quantum bit in the ...
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Why does atmospheric drag speed up satellites?

I've read that old satellites slowly lose altitude when encountering the very thin atmosphere, and strangely enough they speed up. My theory is that the work done by the drag force is insignificant in ...
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Dot product between relative velocity and relative position in orbital mechanics

Reading Curtis' book Orbital Mechanics I found this relation that confused me. $$ \underline{r}\cdot\underline{\dot{r}}=r\dot{r} $$ What happens, say, for a circular orbit where $\underline{r}$ and $\...
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How to calculate the gravitational force of a black hole outside event horizon at a given distance $r$? [duplicate]

Let $g_{bh}$ $[kg·\frac{m}{s^2}]$ be the force caused by the gravity of a black hole. How do we calculate the force $g_{bh}(r)$ outside event horizon $R_{Sch} = \frac{2GM}{c^2}$ onto a satellite with ...
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Why is Microgravity called “Microgravity”?

I find the term "microgravity" to be misleading, how was it coined? NASA provide this definition: Microgravity is the condition in which people or objects appear to be weightless. The ...
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Elliptical Orbits

Two astronauts are in the same circular orbit of radius R around the Earth, 180 deg apart. Astronaut A has two cheese sandwiches, while Astronaut B has none. How can A throw a cheese sandwich to B? In ...
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Why is the period of a geostationary satellite not exactly 1440 minutes?

When reading about Astra satellites on Wikipedia (https://en.wikipedia.org/wiki/Astra_1KR), I saw that the period of the Astra 1KR satellite, positioned at 19.2° E, is 1,436.1 minutes (source: NORAD ...
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Understanding the spatial resolution of a imaging sensor, should it evenly divide the overall image resolution?

I am reviewing the Landsat 1 satellite, specifically its Multispectral Scanner (MSS) imaging system. The system had the following specifications ...
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My question is about satellite motion and gravitation

Our teacher told us today: Suppose a satellite is moving around the earth in a circular orbit of radius $r$. Suddenly an external agent stops its motion so that its kinetic energy becomes zero but ...
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Radius of Circular orbit of a Satellite around Earth always constant (if Space was a perfect vacuum) WHY?

The way I see it: Assuming space is a perfect vacuum, a satellite should stay in circular orbit with CONSTANT RADIUS around earth forever but I think the radius should gradually decrease for the ...
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Confusion on Gravitation/Orbital Mechanics

In polar coordinates, we can write: $$\frac{d^2\vec{r}}{dt^2}=\frac{-GM}{r^2}\hat{r}=(2\dot{r}\dot{\theta}+r\ddot{\theta})\hat{\theta}+(\ddot{r}-r\dot{\theta}^2)\hat{r}$$ $$\frac{-GM}{r^2}=\ddot{r}-r\...
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Are fireballs in the wrong direction?

So I was just reading about satellites burning up in the atmosphere. The book pointed out that it wasn't the gravitational velocity (towards the earth) that caused objects to burn up (which makes ...
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Why aren't orbits transferred at the perigee?

In example 10.6 titled "Satellite Orbit Transfer 1" of Kleppner and Kolenkow the author says The most energy-efficient way to put a satellite into circular orbit is to launch it into an ...
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Is the delta-V value from Low Earth Orbit (LEO) to Low Mars Orbit (LMO) equal to the delta-V value from LMO to LEO at same altitudes?

Radius of Earth = 6378km Radius of Mars = 3397km Sun-Earth distance = 149597600km (1 AU) Sun-Mars distance = 227986742km (1.524 AU) LEO = LMO = 500km NOTE: Assuming Earth and Mars revolve the Sun in ...
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Satellite path dependence on velocity

How does a satellite planetary path depend on its speed and other factors. I want to know more about parabolic, elliptic and hyperbolic paths of satellite.
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Why is a projectile trajectory parabolic while that of a satellite elliptic?

I understand that the parabolic trajectory is an approximation of a more elliptical trajectory, since acceleration due to gravity is taken to be a constant for a projectile. However I'm intrigued to ...
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Satellite return ro Earth

When satellite is return from space orbit to earth how they lower the potential energy? Do satellite need to fire engines as they launch? How we apply energy conservation laws?
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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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1answer
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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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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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1answer
75 views

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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1answer
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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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1answer
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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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252 views

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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