7/17/2003: Earth's artificial satellites

Undertoad · 07-17-2003, 11:33 AM

A few days ago the Astronomy pic of the Day featured this in an animated GIF which showed all the satellites and then zeroed in on the International Space Station. I just pulled out one frame of the animation because I find it so fascinating.

It turns out that there are two common locations for satellites: low earth orbit just out of range of the atmosphere, and geostationary orbit, where the satellite stays over the same point on the equator. So the outer ring there is made up of the geostationary satellites which revolve around the earth at the same speed as the earth.

The color code:

blue = weather satellites
yellow = communication satellites
green = scientific satellites
cyan = navigation satellites
black = secret military satellites
not indicated = georgia satellites

OnyxCougar · 07-17-2003, 11:51 AM

What isn't shown are the thousands of pieces of "space debris". We've managed to litter not only our planet, but the space surrounding it.

And we talk about "colonizing" other planets? Please.

Conesus · 07-17-2003, 12:22 PM

black = secret military satellites
Heh, now that's funny. Especially on that black background.

07-17-2003, 12:26 PM

The background is actually white.

Conesus · 07-17-2003, 01:58 PM

one earth · 07-17-2003, 03:03 PM

Who knew that Georgia Tech could do that?

Next thing you know, old Jed's a millionaire....

xoxoxoBruce · 07-17-2003, 04:40 PM

Dave, look again with your good eye.

07-17-2003, 04:54 PM

Quote:

Originally posted by xoxoxoBruce
Dave, look again with your good eye.

Did you miss the joke?

perth · 07-17-2003, 04:56 PM

Quote:

Originally posted by dave

Did you miss the joke?

i must admit, it took me an embarassingly long time to get it.

~james

xoxoxoBruce · 07-17-2003, 05:14 PM

Since the gif background is black and the Cellar background is grey, yes, I missed it.

arz · 07-17-2003, 05:24 PM

Yes, the two most common are LEO (low earth orbit) and GEO (geosynchronous earth orbit).

There are many other orbits, however. The GPS constellation orbits at MEO - mid earth orbit. The black spy satellites in some cases have very odd-shaped orbits designed to swing them low over the surface and then head way out again.

xoxoxoBruce · 07-17-2003, 05:39 PM

Quote:

There are many other orbits, however

So that explains the scatter?

07-17-2003, 05:52 PM

(Secret military satellites are represented by black dots. The joke was the implication that there are so many of them represented in that image that you can't see the background.)

gossard187 · 07-17-2003, 05:53 PM

The fun one is called Molniya. Its tilted like 60 degrees from the equator and elliptical. Kinda difficult to launch geo from latitudes far from the equator (takes too much fuel). That and another problem with Geostationary is even at that distance from the earth, the poles look real flattened and nothing very north or south gets a good signal (alot of Russia, Sweden, Finland, etc).

as for the spy satellites, they are likely highly elliptical. They swoop down close (travelling much faster than when they are far away). The benefit is that even though people may THINK they know when it will pass, the satellite could technically make a small burn at the apogee and offset the time of overpass (would still be daylight though).

gossard187 · 07-17-2003, 05:55 PM

oh and if you dont know much about the GEO, the ring is a highly sought after place to be. so an international body (forget the name now) allocates the ring into sections. the sections are then taken by a different governing body (like the FCC) and their only rule is don't interfere with the next section over. So you can put as many satellites in that space as you want and use frequency bands as allocated.

07-17-2003, 11:33 AM	#1
Undertoad Radical Centrist Join Date: Jan 2001 Location: Cottage of Prussia Posts: 31,423	7/17/2003: Earth's artificial satellites A few days ago the Astronomy pic of the Day featured this in an animated GIF which showed all the satellites and then zeroed in on the International Space Station. I just pulled out one frame of the animation because I find it so fascinating. It turns out that there are two common locations for satellites: low earth orbit just out of range of the atmosphere, and geostationary orbit, where the satellite stays over the same point on the equator. So the outer ring there is made up of the geostationary satellites which revolve around the earth at the same speed as the earth. The color code: blue = weather satellites yellow = communication satellites green = scientific satellites cyan = navigation satellites black = secret military satellites not indicated = georgia satellites

07-17-2003, 11:51 AM	#2
OnyxCougar Junior Master Dwellar Join Date: Mar 2003 Location: Kingdom of Atlantia Posts: 2,979	What isn't shown are the thousands of pieces of "space debris". We've managed to litter not only our planet, but the space surrounding it. And we talk about "colonizing" other planets? Please. __________________ Impotentes defendere libertatem non possunt. "Repetition does not transform a lie into a truth." ~Franklin D. Roosevelt

07-17-2003, 03:03 PM	#6
one earth least significant bit Join Date: Mar 2003 Posts: 13	Georgia? Who knew that Georgia Tech could do that? Next thing you know, old Jed's a millionaire....

07-17-2003, 04:40 PM	#7
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	Dave, look again with your good eye. __________________ The descent of man ~ Nixon, Friedman, Reagan, Trump.

07-17-2003, 05:14 PM	#10
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	Since the gif background is black and the Cellar background is grey, yes, I missed it. __________________ The descent of man ~ Nixon, Friedman, Reagan, Trump.

07-17-2003, 12:22 PM	#3
Conesus hit of sunshine Join Date: Jul 2002 Location: San Francisco Posts: 8	black = secret military satellites Heh, now that's funny. Especially on that black background.

07-17-2003, 12:26 PM	#4
dave Guest Posts: n/a	The background is actually white.

07-17-2003, 01:58 PM	#5
Conesus hit of sunshine Join Date: Jul 2002 Location: San Francisco Posts: 8

07-17-2003, 05:24 PM	#11
arz Hand-of-Kindness Extender Join Date: Sep 2002 Location: So Cal Posts: 137	Yes, the two most common are LEO (low earth orbit) and GEO (geosynchronous earth orbit). There are many other orbits, however. The GPS constellation orbits at MEO - mid earth orbit. The black spy satellites in some cases have very odd-shaped orbits designed to swing them low over the surface and then head way out again.

07-17-2003, 05:52 PM	#13
dave Guest Posts: n/a	(Secret military satellites are represented by black dots. The joke was the implication that there are so many of them represented in that image that you can't see the background.)

07-17-2003, 05:53 PM	#14
gossard187 Caste-Away Join Date: Jan 2003 Location: Palo Alto Posts: 48	The fun one is called Molniya. Its tilted like 60 degrees from the equator and elliptical. Kinda difficult to launch geo from latitudes far from the equator (takes too much fuel). That and another problem with Geostationary is even at that distance from the earth, the poles look real flattened and nothing very north or south gets a good signal (alot of Russia, Sweden, Finland, etc). as for the spy satellites, they are likely highly elliptical. They swoop down close (travelling much faster than when they are far away). The benefit is that even though people may THINK they know when it will pass, the satellite could technically make a small burn at the apogee and offset the time of overpass (would still be daylight though).

07-17-2003, 05:55 PM	#15
gossard187 Caste-Away Join Date: Jan 2003 Location: Palo Alto Posts: 48	oh and if you dont know much about the GEO, the ring is a highly sought after place to be. so an international body (forget the name now) allocates the ring into sections. the sections are then taken by a different governing body (like the FCC) and their only rule is don't interfere with the next section over. So you can put as many satellites in that space as you want and use frequency bands as allocated.

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