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97 votes
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Are there any satellites in geosynchronous but not geostationary orbits?

Are there any satellites in geosynchronous but not geostationary orbits? Yep, lots! Apparently there are various advantages to being synchronous even when oscillating wildly in position above/below ...
uhoh's user avatar
  • 149k
38 votes

In what state are satellites left in when they are left in a graveyard orbit?

If the satellite is close to the Earth, a last bit of fuel is used to de-orbit it so that it burns up. If it is farther out, it is moved to a retirement orbit out beyond the used orbits. The last ...
zeta-band's user avatar
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30 votes
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Teleporting an object into geosynchronous orbit

I'm afraid you are incorrect. An object on the equator of Earth has a velocity of ~460 m/s. A satellite in geosynchronous orbit has a velocity of ~3000 m/s. You may be confused by the fact that both ...
Organic Marble's user avatar
25 votes
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Why are obsolete geostationary satellites re-orbited above the geostationary belt?

Orbits at the altitude of GEO are stable for very long times (millions of years). There is no significant decay of the orbital height due to some kind of drag, so the risk of these satellites ...
asdfex's user avatar
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25 votes
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Is an Earth synchronous (?) polar orbit possible?

A polar orbit can be geosynchronous and always follow the same path, but that path cannot be straight along a meridian. If the orbit passes on top of both poles, then the orbit lies on a plane ...
BlueCoder's user avatar
  • 2,113
23 votes

In what state are satellites left in when they are left in a graveyard orbit?

A satellite that is retired ordinarily and not expected to reenter will be passivated. The aim here is to minimize the amount of energy stored in the spacecraft, ideally it will be a dead rock ...
niwax's user avatar
  • 381
21 votes
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What are the benefits of supersynchronous transfer orbits?

This is a partially copied answer from this closely-related question: The other answerer focuses on the straight-up dV savings which occur when you're launching from a very inclined launched site. I'm ...
Anton Hengst's user avatar
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20 votes

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

Actually, it makes a lot of sense to raise the orbit of end-of-life geostationary satellites: Coming from Earth you have to cross through a lower orbit to transfer from low earth orbit to a ...
1337joe's user avatar
  • 7,206
18 votes

Have there ever been cubesats in GEO?

tl;dr As of June 2019, there are zero CubeSats in GEO The Union of Concerned Scientists has a great database of satellites orbiting the Earth, the smallest satellite that they have in GEO orbit is the ...
Mark Omo's user avatar
  • 5,291
17 votes
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What is Earth's apparent magnitude from geosynchronous orbit?

Interesting question! tl;dr mag -22 maximum, no particular danger except UV because it's still quite a large extended source (not concentrated to a point). Easy part first: Surface brightness for ...
uhoh's user avatar
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16 votes
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Difference between Tundra and Molniya orbits?

They are definitely not identical. Tundra is geosynchronous; period = 1 day. The eccentricity allows it to spend most of the time over a region of Earth off the equator, something not possible for ...
SF.'s user avatar
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14 votes
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Do satellite uplink/downlink signals spread or leak into space?

They have to spread their signal. Also, it requires a really big dish to not spread your signal at all. Imagine that there was no spreading at all. The dish would have to be pointed exactly at the ...
PearsonArtPhoto's user avatar
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13 votes
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Why would a space elevator / structure need to be in Geosynchronous orbit?

I've read a bunch on space elevators and from what everyone is saying, it would be required that the elevator is in geosynchronous orbit. The center of gravity of a space elevator would need to be at ...
David Hammen's user avatar
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10 votes

Do satellite uplink/downlink signals spread or leak into space?

As an example, an antenna 10 m wide has a beam width of 0.14 degrees at 14 GHz (where I've taken the beam width as the -3 dB point). At 36,000 km (geostationary orbit), a beam sent by this antenna ...
Hobbes's user avatar
  • 128k
10 votes
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Have there ever been cubesats in GEO?

Edited update: Have there ever been cubesats in GEO? Yes, 5 in the period 2021-2023. As of 2023, there are two operational cubesats in GEO, and three that were operational in GEO: Ascent, launched ...
blobbymcblobby's user avatar
9 votes

What are the benefits of supersynchronous transfer orbits?

As the comments discuss, inclination is the missing variable in the equation. The standard geostationary launch that you are thinking of looks something like this: geostationary transfer orbit (GTO) ...
BrendanLuke15's user avatar
8 votes
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How can space junk be dangerous at geosynchronous orbits?

If everything is going in the same orbit, that's true, anything impacting will be a low speed. However, there's a few things to consider. Two large low-speed objects impacting can cause damage. The ...
PearsonArtPhoto's user avatar
  • 121k
8 votes
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Why do geosynchronous satellites appear to oscillate in North-Southward direction? How to I trace out their path on the surface of the earth?

Let's first look at a typical orbit first for comparison. Note that the object being orbited could be anywhere. Note that it spends a time both above and below the equator. A few things about a ...
PearsonArtPhoto's user avatar
  • 121k
8 votes
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How do geosynchronous orbits follow the tilt of the earth?

Geostationary satellites don't. Or more actually - the tilt remains the same in relation to "distant stars" and the seasons on Earth - the latitude at which Sun is in zenith - changes due to Earth ...
SF.'s user avatar
  • 55k
8 votes

A black cube 1 mile per side appears in geosynchronous orbit around the earth. Who would spot it and how would they do it? How easy would it be?

The initial detection would almost certainly be a ground based telescope that could no longer see a particular star (because there is a giant cube in the way, cf. occultation). From that point, once a ...
Oscar Smith's user avatar
7 votes

Teleporting an object into geosynchronous orbit

As Organic Marble indicates, you'd have insufficient orbital velocity. However, even if you haven't increased the orbital velocity with your teleport, you have increased the orbital energy by ...
Phil Frost's user avatar
  • 1,033
7 votes
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Why do the geosynchronous TDRS satellites have this distribution of inclinations?

Please have a look at the "Onboard Orbit Computations" chapter on the "ACS Without an Attitude" book by Harold L. Hallock Gary Walter David G. Simpson Christopher Rouff. https://...
Eviatar.E's user avatar
  • 958
7 votes

What is a typical satellite solar panel mass?

Solar array designs vary a lot and need to be tailored to the mission they will power, so the specific power ratings (power per mass of the array—higher is better!) vary a lot as well. In addition to ...
Tom Spilker's user avatar
  • 18.3k
7 votes

A black cube 1 mile per side appears in geosynchronous orbit around the earth. Who would spot it and how would they do it? How easy would it be?

Remember, the moon is black, or at least almost as dark as fresh asphalt (the moon reflects about 7% of incoming light, compared to 5% for asphalt). It's just brightly lit against a truly dark ...
Mark Foskey's user avatar
6 votes

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

There is a very nice article about the synchronized variation of the debris motion at GEO, available here. Authors give an example of the 'well-known GEO stable plane, which is a fixed point of ...
prop-a-gator's user avatar
6 votes

Computing a new TLE following a delta-v impulse?

Do you really want to compute a new TLE, or just a new orbit? The TLE format itself is a significant problem, so it's best to avoid if possible. If you just need to look for changes in the orbit ...
Ryan C's user avatar
  • 7,962
5 votes

Is it possible to deliver enough LEO satellites with one launch to substitute for one in GEO?

In one launch? That depends on the mass of the satellites. Most rockets can deliver (roughly) 2x as much payload to LEO as they can to GEO. So your LEO satellites would need to be 1/50 the weight of ...
Hobbes's user avatar
  • 128k
5 votes

Why do geosynchronous satellites appear to oscillate in North-Southward direction? How to I trace out their path on the surface of the earth?

I suggest building a 3D model to understand it. Start with a nice disk, such as a paper plate or the cardboard packaging of a frozen pizza. Mark the center and draw regularly spaced radial lines (“...
JDługosz's user avatar
  • 539
5 votes
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How big (broad) is GEO orbit?

There are different answers according to the context. Firstly though it is worth pointing out that the part of the question "and still be in a stable, useful GEO orbit" is not so clear in terms of ...
Puffin's user avatar
  • 9,644

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