Questions tagged [geostationary]

Questions about orbits whose position in the sky remains the same for a stationary observer on the primary body.

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9
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1answer
885 views

Thrust and rotation strategy to circularize a standard GTO orbit using ion propulsion?

The previous question How much time does it take to circularize a GTO orbit using ion propulsion? has a good, quantitative answer based on a known delta-v. But I'm wondering how would you actually ...
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5answers
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If we build a space elevator from Earth surface to GEO, could I step off it at GEO and remain in GEO?

Ignore for a moment the question of whether building such a space elevator is practical. Let's also ignore the minute delta-v involved in "stepping off" something in orbit. If we were to build a ...
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3answers
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How closely spaced are satellites at GEO?

As the picture below (kind of) shows, there are lots of satellites in geostationary orbit. Couple this with the fact that certain longitudes are more desirable than others (like above North America or ...
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2answers
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Are any geosynchronous satellites visible with the naked eye?

It is very easy to spot LEO satellites during dusk or dawn. I am wondering if satellites further out in a geosynchronous orbit are also visible. Of course, if even possible, these would appear more ...
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2answers
449 views

At what magnitude would adjacent large geostationary communications satellites see each other?

Imagine I'm sitting on a geostationary satellite. I can see the Earth in front of me. It's about the size of a soccer ball at arm's length. To the left and right, I can see similar satellites in the ...
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2answers
1k views

What is the reason for the Ariane 5 launcher with Intelsat 29e losing altitude?

After reaching a peak altitude of 222 km the Ariane 5 launcher with Intelsat 29e starts to lose altitude. What is the reason for this trajectory? Youtube video Paper on Ariane 5
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2answers
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Are commercial communications satellites in GEO being constantly monitored by telescopes?

I was trying to look up GOES-17 in Spaceflight101 but got sidetracked in the search result and ended up reading this thread about AMC-9, which links to the YouTube video Rough cut video of AMC-9 ...
4
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1answer
461 views

What factors would make station-keeping of an Areostationary Mars satellite necessary?

This answer introduced me to the word Areostationary Orbit - (hint, comes from Ares), an orbit that would remain stationary above a point on the equator of Mars. The article mentions that ...
15
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1answer
35k views

What is the current cost per kg to send something into GSO/GEO?

I was reading this article and thought it was reasonably cheap, probably because I mistook LEO for GEO. What is the going rate to get something into GeoStationary Orbit and Geosynchronous Equatorial ...
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1answer
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At which point would two GSO/GEO satellites with similar orbital elements be closest to each other?

While I was answering another question on How closely spaced are satellites at GEO I came to realize I can't really word it with much conviction how two close proximity satellites in GEO/GSO orbits ...
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2answers
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How is the launch window decided for GTO launches?

What launch vehicle, spacecraft and target orbit parameters decide the time of launch to GTO for satellites destined for GEO? The target orbital slot is always in the same relative position to the ...
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1answer
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How much “wobble” does a typical geostationary satellite experience?

Recall that geostationary satellites are placed into an orbit which is designed to stay above a fixed point on the Earth's surface. If the Earth and the satellite were both spherical cows in an ...
10
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1answer
488 views

Do geosynchronous satellite launches require a tight launch window?

I thought only launches to rendezvous (resupply, repair, space station expansion etc) and direct launches into interplanetary trajectory require precisely timed launch window. Then I read: Geosync ...
8
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1answer
606 views

Are there cubesats in GEO?

This answer to the question How often do reaction wheels require desaturation, normally? says: One practical example I know of is for a 6U in GEO that is always sun pointed, there's a thruster ...
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4answers
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Orbital altitudes, are some better than others and why?

The geostationary orbit of about 35,786 km above mean sea-level allows satellites to rotate at the same speed as the Earth on its axis, making them seem as if they don't move relative to the ground. ...
8
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1answer
141 views

How are co-located satellites positioned relative to each other?

I'm trying to learn about co-located GEO satellites. When I first heard about them, coming from a planetary orbital mechanics background, the first thing I pictured was based on the epicyclic ...
4
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1answer
324 views

CZ-5 plus YZ-2 put SJ-17 in GEO - third stage or separate spacecraft?

CZ-5 = Long March 5 YZ-2 = Yuanzheng 2 SJ-17 = Shijian 17 Gunter's Space Page says: SJ 17 (Shijian 17) is a Chinese experimental satellite flown on the maiden CZ-5/YZ2 launch. It is ...
2
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0answers
66 views

Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v to move from one to the other?

This answer discusses a spacecraft in GEO using a two-impulse (circular → elliptical → circular) raise & lower maneuver to move (phase) itself by 180 degrees in longitude then return to synchrony. ...
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0answers
107 views

Can I transmit signals from a wristwatch to geostationary orbit?

In comments below this answer to the question Which satellites can hear emergency signals from Scott Kelley's watch? we are (or at least I am) trying to figure out definitively if a wristwatch can ...
37
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1answer
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Are there any satellites in geosynchronous but not geostationary orbits?

I know there are a lot of geostationary satellites out there, but I'm wondering - are there any geosynchronous satellites that are not geostationary (ie - have a notable inclination to their orbit)?
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1answer
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Geosynchronous orbits around other Solar System objects

Earth's geostationary orbit has many human-made satellites which have helped vastly with communications and research. Aside from this artificial collection, are there any other objects orbiting a ...
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3answers
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What is the maximum mass of a satellite that can be placed in GEO?

What is the maximum mass of a satellite that can be placed in GEO? Or can satellites of any mass be placed in GEO?
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1answer
872 views

How much is a geostationary satellite expected to deviate from the geostationary orbit?

I've read this already and some Wikipedia articles, but found no real estimates on how much does a satellite deviate from its standard location. Say that the standard sub-satellite point (SSP) is <...
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2answers
2k views

How do communication satellites remain positioned above a particular region?

From what I understand, an object has to keep moving in an orbit to not come crashing down to Earth. (The ISS is the first thing I think of for this.) How then, do satellites which are purpose built ...
6
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3answers
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Given the orbital radius of a satellite, how is the orbital period calculated?

I know I can find the orbit radius of a satellite from the equation: $$r=\sqrt[3]{\frac{T^2GM}{4 \pi^2}}$$ but what determines the orbit period $T$? If I assume a geosynchronous orbit, would that ...
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1answer
137 views

How do you calculate the lat and lon of a point on the earth using azimuth and elevation seen from a geostationary satellite?

I am given the longitude of a geostationary satellite and a pointing vector from the satellite in the form of azimuth and elevation angles looking from the satellite towards the earth (where zero ...
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2answers
10k views

How long does it take for a satellite to reach GEO?

Specifically for the SpaceX SES-8 mission going on right now. But, generally, how long does it take for a satellite to reach GEO at a minimum?
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1answer
181 views

What is the Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) Augmented Geosynchronous Laboratory Experiment satellite?

The Spaceflight Now article Multi-satellite payload hoisted into high-altitude orbit by Atlas 5 rocket includes the passage: The lower passenger is the Evolved Expendable Launch Vehicle (EELV) ...
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2answers
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Are there any CubeSats that have been launched into Geostationary (GEO/GSO) or Geostationary Transfer Orbit (GTO)?

There is one mission by GSFC/NASA - Shields-1 to be launched into GTO. Apart from that I couldn't find any other mission to GTO/GEO. It would be of great help if there is any information on this.
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1answer
386 views

Needed height from the release of a space elevator to get a stable elliptical orbit?

As we know, something released from around 36000 km height from a space elevator will remain in geostationary orbit around the Earth. Things released from lower will go into an elliptical orbit ...
6
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1answer
530 views

Delta-v to move from GEO to GEO

To move a satellite in geostationary orbit, 166°55′E, to the antipode, 13° 4' 3.2" W, what delta-V would be needed for this to be accomplished? As for time constraints, I do not know what are the ...
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1answer
1k views

How stationary is geostationary?

When a satellite is in geostationary orbit, it is supposed to stay above one spot of the earth and rotate around the earth at the same rate the earth spins. But how exact does that equality need to be?...
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2answers
256 views

What's the closest that an Apollo mission passed GEO on its way to the moon?

@Uwe's comment No astronaut ever visited geostationary orbit at 22-23k miles to maintain or deploy satellites. The Apollo astronauts just rushed by on their way to the Moon and back. below the ...
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4answers
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For which applications are LEO and GEO substitutable?

This article, this article, and this earlier question indicate that, given enough satellites in LEO, it's possible to substitute between GEO and LEO. The first article and the question have some ...
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1answer
359 views

What is OneWeb's constellation's “progressive pitch” and how does it avoid interference with Ku-band satellites in GEO everywhere on Earth?

The Wikipedia article section OneWeb satellite constellation; Design characteristics tells us: The satellites will operate in the Ku band, communicating in the microwave range of frequencies in the ...
3
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1answer
524 views

ViaSat's 18 kW solar array - largest ever for a commercial telecom satellite?

Now that the protests at Kourou Space Center in French Guiana are over, Arianne has launched both EutelSat 172B and ViaSat-2 as 2017-029A. While EutelSat 172B has a ...
3
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1answer
52 views

How does the “eccentricity-inclination vector separation” technique work for colocated GEO satellites?

This answer to How are co-located satellites positioned relative to each other? links to the paywalled paper Separation of Geostationary Satellites with Eccentricity and Inclination Vector with the ...
3
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1answer
49 views

SGP 4 for Geostationary Satellite

I have read some sources that say that SGP4 is for satellite which have orbital period less than 225 minutes. For orbital period more than 225 minutes, we should use SDP4 instead. I need a ...
2
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1answer
183 views

Why would the orbit of a satellite in GEO climb by 21 km in altitude over six months by itself?

This answer mentions several effects that tend to move geostationary satellites out of their "box" over time, but one really surprised me. According to the plot below (from there, but uncredited) the ...
2
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0answers
166 views

How have the 'gift' transponders on ISRO's GSAT-9 been used by other countries?

edit: It's been seven months. close to two years close to two years and seven months now, have any of the 'gift' transponders been used or at least tested yet by the gift recipient nation? The BBC ...
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1answer
96 views

What GEO relay satellite will the ISS use for end-to-end optical communication with a ground station?

This LEMNOS page on NASA's Explorations and Space Communications site says: The Integrated Laser Communication Relay Demonstration (LCRD) Low-Earth Orbit (LEO) User Modem and Amplifier Terminal (...
2
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1answer
82 views

Syncom-3 was the first geostationary satellite. Anyone know of a description of the onboard electronics?

I am interested in any description of the electronics on Syncom-3, the first geostationary satellite. I've been able to find quite a bit of general information. There was a pair of 2 Watt TWTs and ...
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2answers
92 views

How did Syncom-3 achieve eight stages of frequency doubling? I only see seven in the block diagram

@BlueCoder's nice answer to Syncom-3 was the first geostationary satellite. Anyone know of a description of the onboard electronics? mentions that the the master oscillator was doubled eight times to ...
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1answer
33 views

Point Ahead Angle Calculation between LEO-GEO Satellite (ISL Scenario)

So, I have got two reference TLE from 2 different Satellite in LEO-GEO, which are as follows: (1st TLE for LEO, 2nd TLE for GEO) ...
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1answer
181 views

How do Inmarsat 5 F4's beams correspond to all of these antennas and feeds?

note: This is an old-style @uhoh question meaning that it is a bit on the long side. In this case I think it really needs to be since the question is a bit complex; I'm trying to understand how all ...