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[help] Satellite orbit question
I swear this went through Link Salad in the last year or two, but I cannot run it down.
Is there a stable configuration for extremely long-term orbits (millennia or more) for artificial satellites? I recall reading that at least one satellite has been placed in such an orbit. I’m trying to sort out if that’s true, and if so, is there a name for such an orbit?
Why, yes, this is rocket science.
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Posted: 5:33 pm Sat December 11 2010 |
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I will point out that the laws of physics do not distinguish between natural and artificial objects and clearly the moon’s orbit is super stable.
Absolutely true. But most manmade satellites do not have long-term stable orbits, I believe because they are too close to the upper atmosphere and experience drag.
Yes, orbital height is a constraint. Not only is there drag, but the earth’s gravitic pull goes up by the square as you get closer, requiring more force orthogonal to that to keep you from spiralling downward.
How high or low the orbit needs to be is a function of what it is trying to do (comms satellites are typically lower than weather ones IIRC) and how hard its owners want to conceal it.
Also, are you asking with reference to an arbitrary planet or specifically with respect to earth? Both the moon and all the junk we have thrown up there will factor into this.
Specifically, with the moon, we have what is called the three body problem, see:
http://en.wikipedia.org/wiki/Trojan_point#Stability
for details on that.
Actually, it’s for a fictional planet roughly of Earth-mass but with no major moon. (So the LaGrange points will be different, relying only on the solar interaction.)
Going out with a NASA boffin tonight. I’ll ask.
Thank’ee!
Sent you the best reply I had from the kind folks at Baen’s Bar. I sent it in a message on Facebook…
In a geosynchronous orbit, an artificial satellite would be a decent fraction of the moon’s distance from Earth. I imagine that would be a stable orbit where the satellite experiences little drag.
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