Dynamics of an Earth Ring

Before anybody gives me that look...this question is totally in the
context of a "what if" kind of hypothetical scenario.

Suppose an asteroid somehow, through some super, far future
engineering achievement has been captured into orbit around the Earth.
Now suppose we want to carve it out by detonating a series of missiles
that incrementally hollow their way into the body of such an asteroid.
The material excavated out of the body would create a thin ring system
around the Earth, as I try to illustrate he-

http://uk.geocities.com/aa_spaceagen...arth-ring.html

My main concern with such a project is one of SAFETY. I'd like to know
what a *safe* perigee (minimum) altitude would be necessary to prevent
orbital decay of ring material. I don't want any material from my
hypothetical ring system coming down toward the Earth under any
circumstances. Would the ring material be contained in a narrow plane
of fixed orbital incline, or would it scatter over time? What about
interactivity with particles trapped in the Van Allen radiation belts?
Is there any learnings from the Voyager studies (and now Cassini
studies) of Saturnian rings that could be used to predict the long
term stability of such a *hypothetical* ring system around the Earth
in the future?

Abdul Ahad

"AA Institute" wrote in message
om...
Before anybody gives me that look...this question is totally in the
context of a "what if" kind of hypothetical scenario.

Suppose an asteroid somehow, through some super, far future
engineering achievement has been captured into orbit around the Earth.
Now suppose we want to carve it out by detonating a series of missiles
that incrementally hollow their way into the body of such an asteroid.
The material excavated out of the body would create a thin ring system
around the Earth, as I try to illustrate he-

http://uk.geocities.com/aa_spaceagen...arth-ring.html

My main concern with such a project is one of SAFETY. I'd like to know
what a *safe* perigee (minimum) altitude would be necessary to prevent
orbital decay of ring material. I don't want any material from my
hypothetical ring system coming down toward the Earth under any
circumstances. Would the ring material be contained in a narrow plane
of fixed orbital incline, or would it scatter over time? What about
interactivity with particles trapped in the Van Allen radiation belts?
Is there any learnings from the Voyager studies (and now Cassini
studies) of Saturnian rings that could be used to predict the long
term stability of such a *hypothetical* ring system around the Earth
in the future?

Abdul Ahad

I think the moon would prevent the ring from forming properly
Alasdair
--

erect featherless biped
www.digitalmystic.co.uk

Alasdair ) wrote:



: "AA Institute" wrote in message
: om...
: Before anybody gives me that look...this question is totally in the
: context of a "what if" kind of hypothetical scenario.
:
: Suppose an asteroid somehow, through some super, far future
: engineering achievement has been captured into orbit around the Earth.
: Now suppose we want to carve it out by detonating a series of missiles
: that incrementally hollow their way into the body of such an asteroid.
: The material excavated out of the body would create a thin ring system
: around the Earth, as I try to illustrate he-
:
: http://uk.geocities.com/aa_spaceagen...arth-ring.html
:
: My main concern with such a project is one of SAFETY. I'd like to know
: what a *safe* perigee (minimum) altitude would be necessary to prevent
: orbital decay of ring material. I don't want any material from my
: hypothetical ring system coming down toward the Earth under any
: circumstances. Would the ring material be contained in a narrow plane
: of fixed orbital incline, or would it scatter over time? What about
: interactivity with particles trapped in the Van Allen radiation belts?
: Is there any learnings from the Voyager studies (and now Cassini
: studies) of Saturnian rings that could be used to predict the long
: term stability of such a *hypothetical* ring system around the Earth
: in the future?
:
: Abdul Ahad

: I think the moon would prevent the ring from forming properly

Saturn has several moons and its rings don't seem to mind. I don't doubt
that the moon would have an effect but prevent the forming? No, I don't
believe that.

Eric

: Alasdair
: --

: erect featherless biped
: www.digitalmystic.co.uk

"Alasdair" . uk wrote in news:cjgn48
:




"AA Institute" wrote in message
om...
Before anybody gives me that look...this question is totally in the
context of a "what if" kind of hypothetical scenario.

Suppose an asteroid somehow, through some super, far future
engineering achievement has been captured into orbit around the Earth.
Now suppose we want to carve it out by detonating a series of missiles
that incrementally hollow their way into the body of such an asteroid.
The material excavated out of the body would create a thin ring system
around the Earth, as I try to illustrate he-

http://uk.geocities.com/aa_spaceagen...arth-ring.html

My main concern with such a project is one of SAFETY. I'd like to know
what a *safe* perigee (minimum) altitude would be necessary to prevent
orbital decay of ring material. I don't want any material from my
hypothetical ring system coming down toward the Earth under any
circumstances. Would the ring material be contained in a narrow plane
of fixed orbital incline, or would it scatter over time? What about
interactivity with particles trapped in the Van Allen radiation belts?
Is there any learnings from the Voyager studies (and now Cassini
studies) of Saturnian rings that could be used to predict the long
term stability of such a *hypothetical* ring system around the Earth
in the future?

Abdul Ahad

I think the moon would prevent the ring from forming properly
Alasdair

There is currently a ring around earth. If you ever look at a 3-D type
map of satelites, (like J-Track 3D
http://science.nasa.gov/RealTime/JTr.../JTrack3D.html)
you'll see that the satellites in geostationary orbit make a nice ring
around earth :-)

There's a couple gotchas to this statement...first J-Track blows up the
relative size of the dot of light relative to the earth to many, many,
many times the actual size of the spacecraft, so it appears more
populated than it is (true...real rings aren't solid, but this is pushing
it). I heard once jupiter had a very small ring that we only discovered
when we sent probes in close to it...anyone know more info about this?

Also, all these man made satellites have position keeping thrusters, to
compensate for things like the moon. I have no idea as to what would
happen to this "ring" if they suddenly just turned them all off, but I
don't think anything major would happen very fast.

Also, all these man made satellites have position keeping thrusters, to
compensate for things like the moon. I have no idea as to what would
happen to this "ring" if they suddenly just turned them all off, but I
don't think anything major would happen very fast.

I've changed my mind about 20,000 km as a *safe* perigee height, as it
will endanger geostationary satellites orbiting in a constellation at
35,700 km.

If the perigee of the asteroid's orbit is 40,000 km and say the apogee
is 200,000 km then that may be a safe option. If the apogee goes much
above 250,000 km then there's the Moon's perturbing influence to worry
about, since it orbits at around 380,000 km.

Great, now all I need to do are some 'back of the cigarette packet'
calcs that show the Delta-V requirements to achieve a capture.

I hope no one gets too alarmed by all this... it's just some fun
calculations over a fun idea, which may or may not come to fruition
one day (depending if there's public support).

Abdul

In article ,
(AA Institute) wrote:

If the perigee of the asteroid's orbit is 40,000 km and say the apogee
is 200,000 km then that may be a safe option. If the apogee goes much
above 250,000 km then there's the Moon's perturbing influence to worry
about, since it orbits at around 380,000 km.

There's ALWAYS the Moon's perturbing influence to worry about. Have you
ever done any three-body problems? There's a reason they can't be done
analytically, you know. Especially when one of the objects is massive
enough to cause tides on the other object from 225,000 miles away, as
well as influence menstrual, mating, spawning and behavioral patterns of
a good deal of the life on it.

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net

Herb Schaltegger wrote in message ...
In article ,
(AA Institute) wrote:

If the perigee of the asteroid's orbit is 40,000 km and say the apogee
is 200,000 km then that may be a safe option. If the apogee goes much
above 250,000 km then there's the Moon's perturbing influence to worry
about, since it orbits at around 380,000 km.

There's ALWAYS the Moon's perturbing influence to worry about. Have you
ever done any three-body problems?

Not really, but I do fully appreciate that anything other than 2-body
does not have a 'closed' analytical solution. (If you've ever been in
a 'love triangle' then you'll know exactly what I mean!)

There's a reason they can't be done
analytically, you know.

I wonder if NASA or other space authorities have done any ring
modelling around the Earth... perhaps the question never cropped up
before. I certainly think a twisted idea like carving out an asteroid
in orbit is probably outside the normal *appropriate* rules of conduct
in spaceflight research!

I expect it's something they will have to study in the future. No
matter what kind of orbital colony you establish, their effluence will
need disposal into space and sooner or later you'll end up with a ring
around the habitat scattered along its orbit around the Earth. Any
micrometeroid impacts will also result in a scattering of debris over
hundreds of years.

Especially when one of the objects is massive
enough to cause tides on the other object from 225,000 miles away, as
well as influence menstrual

You don't think the woman's cycle could be a coincidence?

Abdul

Herb Schaltegger wrote in message ...
In article ,
(AA Institute) wrote:

If the perigee of the asteroid's orbit is 40,000 km and say the apogee
is 200,000 km then that may be a safe option. If the apogee goes much
above 250,000 km then there's the Moon's perturbing influence to worry
about, since it orbits at around 380,000 km.

There's ALWAYS the Moon's perturbing influence to worry about. Have you
ever done any three-body problems? There's a reason they can't be done
analytically, you know. Especially when one of the objects is massive
enough to cause tides on the other object from 225,000 miles away, as
well as influence menstrual, mating, spawning and behavioral patterns of
a good deal of the life on it.

I'm serious that a ring will be created around the Earth at some point
in the future and I need some equations to simulate the event. I want
to be able to analytically demonstrate the long term stability of such
a ring system and all I get is joke after joke on this thread...

I will try more analytical groups like sci.math and physics.

Abdul

(AA Institute) wrote:

Great, now all I need to do are some 'back of the cigarette packet'
calcs

Is this still allowed? Make sure you are in an approved and designated
area. Victims of passive calculation will seek redress.

Martin Frey wrote in message . ..
(AA Institute) wrote:

Great, now all I need to do are some 'back of the cigarette packet'
calcs

Is this still allowed? Make sure you are in an approved and designated
area. Victims of passive calculation will seek redress.

Ha ha very funny... Say, I don't smoke, do you have a spare fag packet
that I can borrow please, Martin?

(I'd also appreciate some help in calculating the fuel requirements
and all those interplanetary ballistics stuff!)

AAI