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Author Topic: Spiral Orbit Trails  (Read 6146 times)

Maxpm

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Spiral Orbit Trails
« on: May 29, 2011, 03:57:41 PM »
If you observe Uranus and its moons orbiting our sun, the trails will make "spiral" patterns.  However, if you wait for Uranus to move 90 degrees more around the Sun, the moons' orbital planes will no longer be perpendicular to the planet's direction of travel.  Instead of moving around Uranus's trail, the trails of the moons will slice through it vertically.

Is there any way to correct this, so that the moons will make spiral trails for the entire orbit?  Is this even possible in real life?

Omnigeek6

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Re: Spiral Orbit Trails
« Reply #1 on: May 30, 2011, 12:30:20 AM »
If you observe Uranus and its moons orbiting our sun, the trails will make "spiral" patterns.  However, if you wait for Uranus to move 90 degrees more around the Sun, the moons' orbital planes will no longer be perpendicular to the planet's direction of travel.  Instead of moving around Uranus's trail, the trails of the moons will slice through it vertically.

Is there any way to correct this, so that the moons will make spiral trails for the entire orbit?  Is this even possible in real life?

To answer your first question: not that I know of; for the orbits to always be spiral-shaped, the orbits would have to precess at a constant rate (Orbital precession is best described as a change in Longitude of Ascending Node). As far as I know, there is not a way to do this in US2.

As for your second question: Some satellites have orbits like this: http://en.wikipedia.org/wiki/Sun-synchronous_orbit
What you are describing is equivalent to a Sun-synchronous orbit with the Ascending Node twisted 90 degrees.
However, these orbits have very low altitudes- on Earth, they lie within the LEO range. For most planets, this would be well inside the Roche limit. Although spacecraft and very small moons could have such orbits, large moons would break up.

One final note: the longer the parent planet's orbit, the farther out a sun-synchronous or spiral orbit can be. I don't know the exact math, but you could probably calculate how far out a planet would have to orbit for sun-synchronous orbits outside the Roche limit to be possible.


atomic7732

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Re: Spiral Orbit Trails
« Reply #2 on: May 30, 2011, 11:01:14 AM »
Wouldn't it be a change in the Longitude of perapsis/perihelion/periastron/perigee/perijove you get the point...?

Omnigeek6

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Re: Spiral Orbit Trails
« Reply #3 on: May 30, 2011, 04:25:59 PM »
Wouldn't it be a change in the Longitude of perapsis/perihelion/periastron/perigee/perijove you get the point...?

Do you mean Argument of Periapsis?

atomic7732

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Re: Spiral Orbit Trails
« Reply #4 on: May 30, 2011, 05:14:12 PM »
Yeah.

Omnigeek6

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Re: Spiral Orbit Trails
« Reply #5 on: May 30, 2011, 08:26:01 PM »
Precession of the AP will not make the orbit spiral.

Put a satellite in a near-circular polar orbit around Earth. Play with the AP slider and see what happens. (Have projected paths turned on).
Now play with the Ascending Node slider and see what happens.

Which of those would keep the orbital plane perpendicular to the direction of the planet's motion?

Dan Dixon

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Re: Spiral Orbit Trails
« Reply #6 on: June 13, 2011, 12:44:13 PM »
If you open up the simulation "Spacecraft - Voyager II & Uranus in 1986" you'll see that the orbits of the moons relative to Uranus are not always perpendicular to the Sun.

Is there any way to correct this, so that the moons will make spiral trails for the entire orbit?  Is this even possible in real life?

So I don't think there is a way to do this, baring some some other forces that caused the orbit on the moon to rotate its axis at a rate that happened to correlate to the orbit of the planet around the Sun.

swampyankee

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Re: Spiral Orbit Trails
« Reply #7 on: October 13, 2012, 03:58:46 AM »
Can this software model our solar system's planetary orbits in three dimensions as well (with spiral trails)? Or is the feature limited to only Uranus and its moons?

Thanks!

Dan Dixon

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Re: Spiral Orbit Trails
« Reply #8 on: October 13, 2012, 04:22:59 PM »
Not just Uranus; Universe Sandbox can model any orbit in three dimensions.