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Orbital Decay (Read 3322 times)
shellandtube
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Orbital Decay
08/28/07 at 17:19:33
 
I was wondering how I might use grav sim to simulate orbital decay. For example a satellite falling out of orbit or on a larger scale over what time the moon might migrate towards and the collide with the earth is something slowed it down? Any ideas?
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The shortest distance between two points is a straight line, or is it?
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Tony
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Re: Orbital Decay
Reply #1 - 08/28/07 at 19:26:10
 
If you're using the Beta Version, the Autopilot had "continuous orientation".  Setting this to "retrograde" and then using the autopilot's "thrust" command will allow you to make an orbit decay.  The decay curve is not realistic, so you'd have to compute your desired curve and adjust the autopilot accordingly from time to time to match a real-life curve.
 
The Moon is currently spiraling away fromt the Earth.  It will continue until Earth is tidally locked to the Moon, similar to Pluto and Charon.  At that point, the Moon may migrate back towards the Earth due to solar tides.  But it will take much longer than the life of the solar system for it to reach Earth.  If it did have time, then it would start to fall apart after it crossed the Earth's Roche limit, and it would form a very impressive ring system.
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shellandtube
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Re: Orbital Decay
Reply #2 - 08/28/07 at 20:11:16
 
Thats what I tried originally and what i ended up with was the moon divebombing towards the earth perhaps i left the thrust on for too long. Shocked (Did make a nice pattern though!)
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EDG
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Re: Orbital Decay
Reply #3 - 08/28/07 at 21:05:15
 
Quote from Tony on 08/28/07 at 19:26:10:
The Moon is currently spiraling away fromt the Earth. It will continue until Earth is tidally locked to the Moon, similar to Pluto and Charon. At that point, the Moon may migrate back towards the Earth due to solar tides. But it will take much longer than the life of the solar system for it to reach Earth. If it did have time, then it would start to fall apart after it crossed the Earth's Roche limit, and it would form a very impressive ring system.

 
Is it possible to simulate this in GravSim? Maybe if you could somehow create say 100 objects all in the same orbit with almost identical orbital parameters? (so instead of having one object that is a planet, you have 100 "particles" that make up the planet). Would the effect on the individual particles effectively be the same as simulating "tides"?
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(formerly known as Mal)
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shellandtube
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Re: Orbital Decay
Reply #4 - 08/28/07 at 21:21:14
 
Mal I would suggest creating an object to be the center of your sphere. then creating objects to form a sphere around them.
eg.
inclination 180+/-100%
sma 1000km+/-100%
eccentricity 0
LAN etc as default.
Am trying this now
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shellandtube
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Re: Orbital Decay
Reply #5 - 08/28/07 at 21:42:41
 
Yes it works.
Created a sphere of particles with an effective diameter similar to the moon with a sma equal to the solar diameter orbiting around the sun. (!?!) The sphere broke up and has formed nearly a complete ring after only 3 days. I am now looking to see how stable it is long term.
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shellandtube
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Re: Orbital Decay
Reply #6 - 08/28/07 at 22:15:53
 
The only problem I can see with regards to accuracy is that all the particles are technically orbiting the center of mass of the sphere at the start of the simulation.
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