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-   -   7/17/2003: Earth's artificial satellites (http://cellar.org/showthread.php?t=3685)

Undertoad 07-17-2003 11:33 AM

7/17/2003: Earth's artificial satellites
 
http://cellar.org/2003/sats.gif

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. :D

dave 07-17-2003 12:26 PM

The background is actually white.

Conesus 07-17-2003 01:58 PM

:eek:

one earth 07-17-2003 03:03 PM

Georgia?
 
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. :D

dave 07-17-2003 04:54 PM

Quote:

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

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?

dave 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.

Undertoad 07-17-2003 06:32 PM

They'll all have to be realigned when the big asteroid hits the Earth.

Griff 07-17-2003 07:09 PM

Those sats will just be bugs in the teeth of The Big One.

xoxoxoBruce 07-17-2003 07:59 PM

Quote:

(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.)
Doh...Good one Dave. I not only didn't get it, I didn't even know it went by. :blush:

novice 07-17-2003 11:40 PM

What about 'good one' UT.
After all, it was his joke to begin with.

GlassJaw 07-17-2003 11:40 PM

I thought this looked familiar...
 
This reminded me of J-track 3D which allows you to roll around the planet and see where specific satellites reside, including the ISS, in real time.

Spy satellites! Hehehe, nice!

xoxoxoBruce 07-18-2003 05:17 PM

Quote:

What about 'good one' UT.
True, credit where credit is due. Kudo's UT!
I should have read the whole post first but since I'd seen the original on APotD, I just skimmed it and didn't realize it was a value added post....until I'd made a fool of myself, that is.:blush:

Annebonannie 07-24-2003 06:04 PM

"georgia satellites", c'mon guys!

Type it into a browser search bar and see what you get.

xoxoxoBruce 07-24-2003 08:56 PM

Welcome to the Cellar Anne.:D Hey, as least they're not indicated.

MaggieL 07-25-2003 10:01 PM

AMSAT OSCAR 40 was supposed to be in a Molniya-type orbit too, but the rocket motor intended to steepen the inclination failed, leaving it in basically a geosynchronous transfer orbit at about +- 5 degrees inclination. There's about half a dozen operating amateur radio satellites these days.

I don't know what color they are on the pic. :-)

see http://www.phil-mont.org/AO40/AO40Notes.html

xoxoxoBruce 07-26-2003 12:24 AM

Maggie, why did you put that gold man in space?

MaggieL 07-26-2003 02:09 PM

Quote:

Originally posted by xoxoxoBruce
Maggie, why did you put that gold man in space?
For comparison. Like the whale next to the little girl in "Cosmic View" (the book that inspired "Powers of Ten").

see http://www.vendian.org/mncharity/cos...es/page07.html

Or perhaps like http://mirror.wolffelaar.nl/zardalu.sytes.net/

xoxoxoBruce 07-26-2003 10:30 PM

OK, as long as it's not male bashing.:D


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