[abra0]

> MTG-S1 is the first geostationary meteorological sounder satellite to fly over Europe

I was confused for a minute on how it's both _geostationary_ and _over Europe_ -- you can't be geostationary if your orbit is not over the equator!

Turns out[1] the MTG-S1 satellite is in fact geostationary and parked at exactly 0°00'00"N 0°00'00"E (off the coast of Ghana), 42164 km up from the center of Earth, it's just pointing at Europe at an angle.

1 - https://space.oscar.wmo.int/satellites/view/mtg_s1

[progbits]

I had doubts about the "parked at exactly 0°00'00"N 0°00'00"E", thinking it was over Null Island just because the data wasn't updated yet and it was showing uninitialized values.

But you are right, [1] confirms "0° longitude".

[1] https://user.eumetsat.int/resources/user-guides/mtg-in-opera...

[dmurray]

That specifies its position to about 30 metres of precision.

Presumably it's an intentional choice to put it at such a round number, rather than any scientific benefit over it being, say, 10km west or east.

[slow_typist]

Geostationary satellite are usually kept within in a cube of 100 km. That’s less than 1/10 degrees. For earth observation it shouldn’t matter much.

[dmurray]

So there could reasonably be dozens [0] of satellites "parked at exactly 0°00'00"N 0°00'00"E". Definitely an unnecessary level of precision.

[0] A few sites give 10km as a standard minimum separation for geostationary satellites. That theoretically allows a thousand of them in the 100km cube, but I am guessing a lattice of them every 10 km in all 3 dimensions would not be manageable.

[slow_typist]

I don’t think that is a management problem but the mechanics will work against you and you would squander too much of the precious fuel if you stack’em in three dimensions.

But some geostationary satellites are close enough so that there can be failover without adjusting receiving antennas on the ground.

So you can of course keep them dense around the equator. Probably very close down to hundreds of meters (if not less) if you coordinate the station keeping. After all the forces that push or pull the satellites out of orbit (tidal forces and particle streams) should be very similar for close neighbours. Problem is that you have to share the bandwidth of the up- and downlink then because the dishes of the groundstations cannot focus so sharply.

Given that, and redundancy put aside, one bigger satellite with more payloads would usually be cheaper than two smaller ones without any disadvantages.

[complex_pi]

NOAA/NASA (USA), EUMETSAT (European organization), JMA (Japan), KMA (Korea), and CMA (China) all have a geostationary satellite (one or more actually). So, northern hemisphere countries, but the coverage is global thanks to the fact that you need to be, as you say, above the equator.

[thmsths]

I am surprised they would pick 0 for the latitude, it seems that most of Europe, whether it's the land or the people is east of that. Maybe some important weather systems develop over the Atlantic and they want to track that?

[labster]

It’s exactly that. In fact, information propagates along with the winds. If you don’t observe upstream, you instead propagate an information hole. Each new model run incorporates the output of the previous run to preserve sparse weather information. It’s not that there are few observations, it’s that Earth is really big.

[lucb1e]

How the heck is 0,0 still available! Was nobody interested in this position before for any purpose?

Is there a way to list what's all in geostationary orbit (either stationary at the equator, or at which longitudes they commonly cross through the equator)? Edit: found https://en.wikipedia.org/wiki/List_of_satellites_in_geosynch... (geosynchronous is a superset of geostationary). The closest is H2Sat at 0.5°. Article notes: "Some of these satellites are separated from each other by as little as 0.1° longitude [or] approximately 73 km". Trickier than keeping them apart is apparently getting a narrow enough communications beam width. /edit.

How long until we can see this ring above the equator from the ground? Although I guess the thickness would rival Saturn's rings and we would probably not be able to make it out even if the sats were shoulder to shoulder. We do see satellites from the ground when the sun hits them right, but those are typically around 1000x closer

[ecef9-8c0f-4374]

0°00'00"N 0°00'00"E the country where all the scammer live