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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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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 ...
uhoh's user avatar
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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)?
ThePiachu's user avatar
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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
SE - stop firing the good guys's user avatar
13 votes
2 answers
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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 ...
uhoh's user avatar
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Why do these satellite antennas look so weird? (strangely shaped with little white dots...)

The NASA Spaceflight article Arianespace press onward with dual-passenger Ariane 5 launch shows a photo of Intelsat 39 during testing. The dish reflectors are strangely shaped: rather than being ...
uhoh's user avatar
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32 votes
6 answers
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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 ...
user's user avatar
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25 votes
3 answers
32k views

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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18 votes
3 answers
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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 ...
Stu's user avatar
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4 votes
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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 ...
uhoh's user avatar
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3 votes
1 answer
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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 ...
uhoh's user avatar
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7 votes
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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 ...
Elisa Fitri's user avatar
5 votes
2 answers
600 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 ...
Roger Wood's user avatar
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5 votes
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Are there any satellites in geosynchronous orbits that are neither geostationary nor 'wobbly geostastionary' (figure of eight geostationary)?

None of the examples in this question: Are there any satellites in geosynchronous but not geostationary orbits? are nothing like geostationary. They still stay above the one side of the earth. What ...
Matthew Christopher Bartsh's user avatar
4 votes
2 answers
425 views

SGP4 on Systems Tool Kit (STK); how to check if SDP4 deep space correction is implemented?

I am doing orbit propagation for a geostationary satellite which requires the deep space corrections of SDP4. See my previous question SGP 4 for Geostationary Satellite. I am using SGP4 on STK, but, ...
Elisa Fitri's user avatar
3 votes
1 answer
179 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 (...
uhoh's user avatar
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1 vote
1 answer
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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 ...
uhoh's user avatar
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17 votes
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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 ...
Coomie's user avatar
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13 votes
2 answers
12k 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?
Stu's user avatar
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9 votes
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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 ...
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8 votes
1 answer
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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 ...
Bob516's user avatar
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5 votes
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Computing GEO satellite's longitude from elevation/azimuth from a given latitude/longitude?

This question is a bit of a mix between satellite knowledge and math. Suppose I have the "look angles" (elevation and azimuth) for an otherwise unidentified geostationary satellite, and I would like ...
Mour_Ka's user avatar
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1 answer
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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 reportedly ...
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3 votes
1 answer
1k 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 ...
uhoh's user avatar
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3 votes
0 answers
177 views

Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v needed 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. ...
uhoh's user avatar
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14 votes
2 answers
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Have there ever been 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 ...
uhoh's user avatar
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10 votes
1 answer
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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 ...
senshin's user avatar
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1 answer
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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 ...
SF.'s user avatar
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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 ...
jkavalik's user avatar
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10 votes
1 answer
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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 ...
TildalWave's user avatar
9 votes
2 answers
853 views

How do stable equilibrium points work in GEO? If all geosynchronous spacecraft suddenly lost stationkeeping, would most "fall into" one or the other?

The (currently unanswered) question Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v to move from one to the other? (also see comments at Delta-v to move from GEO to ...
uhoh's user avatar
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8 votes
3 answers
10k views

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 ...
jazeboo's user avatar
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7 votes
2 answers
2k views

Does it economically cost the same to launch a satellite into LEO and GTO?

I was doing some research about how much $/kg it costs to launch a satellite into GEO. I came across several sources that lists info for LEO: https://ourworldindata.org/grapher/cost-space-launches-low-...
Yi Qiang Ji's user avatar
6 votes
1 answer
1k views

Are all or some geostationary satellites tidally locked to the Earth?

Satellites in geostationary orbit always remain above the same location on the Earth's surface, at an altitude of 35,786 kilometres (22,236 miles) above the equator. But I wonder whether they're also ...
LoveForChrist's user avatar
6 votes
4 answers
2k views

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. ...
Marmstrong's user avatar
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3 votes
1 answer
1k 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 ...
uhoh's user avatar
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1 vote
0 answers
185 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 ...
uhoh's user avatar
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1 vote
2 answers
149 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 ...
uhoh's user avatar
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25 votes
4 answers
4k views

Name for geostationary orbit around another planet

A geostationary orbit is a circular orbit in Earth's equatorial plane whose rotation period matches that of the Earth. The "geo" in "geostationary" means Earth, so is there another term to designate ...
usernumber's user avatar
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16 votes
2 answers
3k views

Why are obsolete geostationary satellites re-orbited above the geostationary belt?

That seems a bit counter-intuitive, because in an orbit above the belt, the satellite would eventually lose gain velocity, so its orbit would intersect the orbital plane of the geostationary ...
Mark's user avatar
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14 votes
1 answer
1k views

How many dead sats near GEO?

It's my understanding a geosynchronous satellite will put itself in a graveyard orbit just before it dies. How many dead sats are in GEO or in neighboring graveyard orbits? What is their total mass?
HopDavid's user avatar
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12 votes
1 answer
7k views

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 ...
Stu's user avatar
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12 votes
3 answers
3k views

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?
Hash's user avatar
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12 votes
3 answers
1k views

Is the risk of explosion-induced damage to operational spacecraft in GEO actually reduced substantially by raising Spaceway-1 by 300 km?

Engadget: DirecTV satellite is at risk of explosion due to battery issues Space News: DirecTV fears explosion risk from satellite with damaged battery say that the spacecraft must move 300 km above ...
uhoh's user avatar
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11 votes
2 answers
3k views

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.
sky's user avatar
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11 votes
2 answers
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What is the process for allocating GEO slots to commercial satellites?

Building off of this previous question, is there a more detailed summary anywhere of the process that a commercial satellite would have to go through to obtain a GEO slot? The documentation I have ...
M.A.H.'s user avatar
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10 votes
1 answer
2k 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 <...
cobarzan's user avatar
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9 votes
1 answer
2k 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?...
David says Reinstate Monica's user avatar
9 votes
1 answer
505 views

What is typical lifetime of GTO rocket stages before reentry?

Most of geostationary satellites are launched at geostationary transfer orbit (GTO) first by rocket's upper stage. Than satellites separate and circularize the orbit by own propulsion. The upper ...
Heopps's user avatar
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7 votes
1 answer
546 views

How could RCA Satcom III have been completely lost? (Or was it?)

This answer to What “missing satellite” was part of the story of CNN's debut? quotes the 1981 UPI Article The RCA Satcom III-R commercial communications satellite, designed to... as follows: The ...
uhoh's user avatar
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7 votes
1 answer
489 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 ...
peterh's user avatar
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