Questions tagged [orbit]

Questions regarding the mechanics or attributes of objects falling 'around' other objects, thereby orbiting them.

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2
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1answer
122 views

Space and Newton laws

I've read some articles which explain that we can't totally rely on Newtonian gravity concepts for understanding the motion of objects in space. My question is how the use of relativity helps us to ...
2
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1answer
43 views

Geocentric latitude and longitude of sub-satellite point

I was trying to derive the expressions for the geocentric latitude and longitude of the sub-satellite point using Keplerian elements. The final equations connecting the combination of the Keplerian ...
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1answer
225 views

Why don't spacecraft get left behind once in deep space?

On earth, I know that if I throw a tennis ball straight up while in a car, it comes straight back down thanks to Newton's first law. The ball, the air in the car, and myself are all moving at a speed, ...
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1answer
84 views

How to identify an object in orbit last night?

I saw an object last night (November 24, 2019) in the sky that was rather unusual and am curious about what it might have been. It had the luminosity and speed of movement across the sky (generally ...
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1answer
104 views

Could we reverse gravitational slingshot a fast object to slow it down and capture it in an orbit?

I have heard of plans to capture an asteroid in an orbit around the earth, to have it close by so that we could study it more easily. Such objects can have very high velocities, (I assume) possibly ...
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4answers
6k views

How did the USSR track Gagarin's Vostok-1 orbital flight? Was tracking capability an issue in the choice of orbit?

For the USA's Mercury flights, a number of tracking stations were installed around the globe. John Glenn's first orbital flight was tracked with them, plus a number of ships. (Tracking stations used ...
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0answers
52 views

Earth Rotational Vector and Orbital Inclination

I'm doing a project regarding orbital launches and i'm kinda confused about how to calculate orbital inclination from launch sites. I've simplified my model so I can ignore fuel and the rocket ...
2
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3answers
208 views

What is the gravitational acceleration of the Sun?

What is the gravitational acceleration of the Sun? I've seen numbers such as 274 m/s2, but that doesn't make sense to me seeing that relatively weak sources of spacecraft thrust such as Electric ...
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1answer
77 views

How to calculate 𝛥𝑣 that required to change orbit with same radius but different inclination?

How could I calculate the total 𝛥𝑣 required to change the inclination of a Geostationary orbit to another circular orbit with an inclination of 30° and the same radius? (The sidereal day is used for ...
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2answers
234 views

What information can I get if an elliptical orbit intersecting a circular orbit of radius 𝑟 and velocity of ellipse is equal to velocity of circular?

How can I approach solving the question below? Consider an elliptical orbit intersecting a circular orbit of radius $r$ as shown below. If $v_{ellipse} = v_{circular} = v $, find: True ...
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2answers
480 views

Velocity of a rocket needed to get to Mars

At 2:16 in this video, Don Pettit says he used the Rocket Equation to determine the velocity of the rocket needed to travel to Mars, which was 16 km/s. I am not sure as how he did it though, and was ...
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4answers
4k views

How does a Spacecraft change its orbit?

I am a high school student. I saw the latest Indian spacecraft "CHANDRYAANN 2", which was in orbit around the Earth for 14 days..... I am so curious to know how a spacecraft changes its orbit. I ...
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2answers
142 views

Do satellites in orbit undergo translational motion or rotational motion, when initially they are not given any additional spin?

Regarding the proposed duplicate: Thought the proposed duplicate has a similar titIe, I have read those answers and this question requires a different answer. We know satellites orbit around Earth, ...
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37 views

When will ISS return to approximately the same projected location on Earth's surface?

The ISS sailed over my country, Sri Lanka on the eve of yesterday (14th October), and there was some news coverage on the event. While the reporting wasn't particularly scientific or even factual (I'm ...
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1answer
38 views

How to deteremine the angle between Sun and 2 probes?

I have the orbital position and velocity and the orbital parameter of 2 spacecraft at LEO, how to define the angle between Sun - Probe 2 - Probe 1 in ECI frame (If you imagine at a point sun then ...
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1answer
72 views

Issue with SGP4 modelling from scratch in MATLAB

I am trying to develop the code from this source , this research paper and from this too as same as bibliography of that aforementioned source. So, here as you can see at page 14, they have defined ...
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0answers
19 views

Velocity Vector Transformation for Point Ahead Angle and Doppler Shift Calculation for Inter-Satellite Link

So, I have the Radial and Tangential Velocity Vector (like in Figure 1) and also the Cartesian coordinate of 3D velocity vector. For reference, you can see in this link. Where, $o_{dot}$ vector matrix ...
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2answers
115 views

How does the orbit of the Voyager and New Horizons probes manage to get into interstellar space?

I understand that every probe launched has been launched into an orbit. The further you want to go into the solar system, the faster it needs to be moving. And everything orbits the sun until it finds ...
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2answers
174 views

What is the closest distance SpaceX's Tesla Roadster (Starman) will ever be to Mars?

Elon Musk's own personal Tesla Roadster launched on the Falcon Heavy in November 2018 and unfortunately overshot the orbit of Mars. This short animation shows the trajectory of SpaceX's Roadster. It ...
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2answers
147 views

When calculating the future orbit of an artificial Earth satellite, is the Moon's gravity significant or insignificant?

Imagine a mathematician is plotting the future orbit of a satellite to be launched and put in orbit around the Earth. When they are making their calculation, is the moon so far away and the ...
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2answers
106 views

Do satellites inject into a Hohmann transfer orbit in Low Earth Orbit or in Solar orbit?

Lets say we have a satellite wanting to go to Mars. Do satellites such as MAVEN inject into a Hohmann transfer orbit while in Earth's orbit, or do they go out of Earth's Sphere of Influence into solar ...
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1answer
170 views

Where in orbit was Michael Collins when the LM landed?

In the NPR podcast On Apollo 11 Anniversary, A Former Crew Member Reflects On The Lunar Trip Scott Simon interviews Michael Collins. Near the beginning is this exchange: SIMON: We asked the man who ...
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1answer
347 views

A spacecraft is travelling at X units per hour. But relative to what exactly? Does it depend on orbit? How?

If I am walking, the ground is stationary, and I move X units/hour relative to the ground. If I am in low-earth orbit, then I am still moving X units/hour relative to the ground, only its a much ...
4
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1answer
133 views

Can a Space Telescope orbit so it was always in the shadow of the Earth?

Imagine you have a space telescope that had temperature sensitive instruments. (Like the Spitzer Space Telescope). In order to maintain a cool temperature - you want it always to orbit in the shadow ...
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1answer
671 views

Why does the eccentricity vector equation always equal -1?

This is the eccentricity vector equation, $$e=\frac{1}{\mu}[(v^2-{\mu \over r})r-(r \cdot v)v]$$ $$e=|e|$$ Now this equation is written differently from many different sources but they essentially ...
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0answers
116 views

Orbiting clock visible with the naked eye

Does anyone remember from the 1980s or possibly early '90s in the UK news a (serious) story about contructing a huge orbiting clock so that people would be able to look up at the sky to read the time ...
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32 views

Tools for testing look angle generator?

I'm looking for a software test tool with a specific capability: Given the lat/long/altitude of a point on the ground and the az/el/range from that spot to a point in space, generate a TLE for a ...
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5answers
3k views

How could a satellite follow earth around the sun while staying outside of earth's orbit?

I'm wondering if its possible for a satellite to follow earth around the sun while staying outside of its orbit. I wondering for the sake of space based solar infrastructure or just something ...
3
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2answers
269 views

Why was the Energia’s payload capacity to lunar orbit greater than its payload capacity to geosynchronous orbit?

The Energia rocket, developed in the 1970s and 1980s to launch the Soviet Buran space shuttle, had the second-highest payload capacity (100 tonnes to LEO) of any rocket ever flown (and the highest-...
3
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1answer
118 views

Tiny orbital body detection

What technology would be required to detect a coconut-sized sphere in Earth orbit, at the average altitude of communications satellites?
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0answers
32 views

Special Case Constellation Analysis Approach: Walker Constellation with Circular (e = 0) orbit in LEO

I am familiar with the general approach to propagate orbits using orbital parameters, and how to account for basic J2 perturbations. I am looking to perform some analysis on large walker ...
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1answer
96 views

PIR application as a sun sensor

Is there any history or merit to using a PIR (Pyroelectric ("Passive") InfraRed Sensor) as a sun sensor for determining the attitude or position of a Satellite?
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0answers
115 views

Recalculate Orbital Elements after a ΔV

I would like to write a program able to simulate a keplerian orbite given an initial position and velocity (r0, v0) and able to manage accelerations in different directions. To simulate the orbit, I ...
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2answers
134 views

How many stages needed for a launch ? How to plan a launch

I am looking on how to find out how many stages are needed to reach a certain orbit. I come across equations to compute the height reach by a stage of a certain time. On the other hand I don't find ...
5
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1answer
752 views

How precise must a satellite's orbit be?

I was thinking about the question on solid upper-stages and my feeling that a liquid upper-stage would allow a more precise orbit. But... how precise does an orbit actually have to be? I guess I mean ...
5
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1answer
114 views

Reference to understand the notation of orbital charts

To address various orbital evolutions of spacecrafts, some particular orbital charts are taken into account. For example, the following is used to depict how a chaser reaches a target: The only thing ...
4
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1answer
94 views

How would off-apsis burn effect the angle and position of new apoapsis

Let's say you have an elliptical orbit, if you burn prograde at the periapsis, you extend the apoapsis by some factor(according to vis-viva equation). But if you burn prograde on somewhere during the ...
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1answer
109 views

On the dynamics of two connected objects located at different circular orbits

I'm just thinking about the qualitative and quantitative implications of a hypothetical orbital problem, but what I ended up does not make sense as it should. In particular, assume that two objects ...
28
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6answers
9k views

Do simulator games use a realistic trajectory to get into orbit?

In videogames (such as KSP or Spaceflight simulator) people put rockets in orbit with the following procedure: Turn on the engines and move vertically for a bit. Start a roll program to turn the ...
3
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4answers
176 views

Could we build a sunlight regulator to orbit the sun and help with global warming? [duplicate]

like less sunlight around the poles would be good. if we put it in orbit close to the sun we may not need it to be that large. we can keep it in good position with RF cavity thrusters and mini ...
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0answers
25 views

Where will BioSentinel be relative to Earth while running experiments?

The Space.com article In 2020, NASA Will Send Living Things to Deep Space for First Time Since Apollo describes (among other things) the BioSentinel spacecraft, and links to a NASA BioSentinel fact ...
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0answers
133 views

ECI to LVLH transformation [duplicate]

I am working on a transformation of ECI coordinates to LVLH (Local Vertical Local Horizontal) coordinates in order to calculate satellite maneuvers. Does anybody know how should I approach the problem?...
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2answers
1k views

Have any humans orbited the Earth in anything other than a prograde orbit?

As per the title, have any humans been launched into an orbit around the Earth which is anything other than prograde? E.g. retrograde or polar.
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3answers
4k views

Why use a retrograde orbit?

I've been looking around and saw on What is the highest inclination orbit ever attained from a Cape Canaveral launch? a question about launching into retrograde orbit. Of course, due to range safety ...
5
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1answer
70 views

Trouble deriving rectangular components of acceleration of satellite in orbit around Earth with J2 consideration

I am trying to derive the rectangular components of acceleration for a satellite in orbit, with Earth oblateness in consideration, in order to use the RK4 method to find the updated position and ...
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3answers
449 views

How much of a rocket's energy is used to achieve altitude vs horizontal velocity?

Given how it is significantly easier to achieve suborbital spaceflight, I was wondering about how a rocket spends its energy budget. If you magically could launch a rocket from 0 km/s but from an ...
3
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1answer
158 views

Have there been any spacecraft with an ecliptic Earth orbit?

Have any spacecraft (manned or unmanned) orbited the Earth in the same plane as the Sun? (Please read the question carefully. It is not an orbit centered around the Sun, nor an equatorial orbit.)
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1answer
847 views

How to calculate density of unknown planet?

Having approached an unknown planet, a spaceship went in a low circular orbit. Would astronauts be able to determine the average density of the planets using only a watch
2
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1answer
275 views

Argument of Perigee for a circular orbit

For a perfectly circular orbit (e=0), how is the argument of perigee defined?? Thanks.
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2answers
240 views

Where can I find examples of orbital state vectors?

I'm currently trying to write a program that can calculate orbital trajectories. The goal is to take any orbital state vector (position, velocity) and convert it into Keplerian orbital elements, or ...