From: Amara Graps (amara@amara.com)
Date: Sat Dec 22 2001 - 17:01:14 MST
>> >> Spike Jones wrote: ...if a solid motor is firing and something
>> >> goes wrong with the guidance system causing the back end to
>> >> flip around forward, a bunch of phlogiston and junk is sprayed
>> >> into orbit that could damage other satellites.
>>
>> Amara Graps wrote: That stuff can remain in orbit for a long time too.
>> (years and decades)
>Speaking of which, I thought of a mechanism whereby space debris
>could get into earth orbit from a sub-orbital solid motor burn. I got the
>idea from reading Amara's excellent PhD thesis.
Heh... (thanks!)
maybe start here, but I didn't consider below 2 R_Earth for this study:
http://www.mpi-hd.mpg.de/dustgroup/~graps/earth/
How would you define sub-orbital ... ? (LEO?)
>Suppose a solid motor exhaust plume does scatter some slag
>in a poorly-understood (by me anyway) von Karman vortex
>effect at the nozzle edge. The velocity of the particle could
>still be significantly sub-orbital, but suppose the particle carries
>a net charge,
likely
> Then the charged particle would interact with the solar
>wind,
solar wind where? which side of the magnetosphere? at 10 R_Earth ..?
see here:
http://www.mpi-hd.mpg.de/dustgroup/~graps/earth/magnetosphere.html
>perhaps getting accelerated to orbital speed. Then the
>particle could go neutral, as a direct result of interaction
>with charged particles in the Van Allen belts,
I'm confused.. Is your hypothesis saying the particle lost energy
from outside of the magnetosphere and traveled inwards (maybe
through the magnetotail or magnetopause) ?
>trapping a bunch
>of stuff in orbit, since the neutral junk would not then be carried
>away by the solar wind. All this from a *suborbital shot*.
>
>Wow thats kinda scary. Amara, could this happen?
summary: you think that might have a collection of neutral particles
trapped in the magnetosphere from this suborbital shot ?
First you need to define for me particle sizes: the submicron radius
particles take a long time (hours) to reach equilibrium charge potential,
so they get accelerated quickly out of the Earth's magnetosphere. The
larger particle sizes reflect better the Earth plasma conditions (their
larger size means larger surface area to the impinging ions and electrons),
and quickly reach equilibrium charge potential (the charging times vary
proportional to the size of the particle). The Earth's magnetosphere is
a very energetic (plasma-wise and magnetic-field-wise) place, and
particles are charged up constantly.
I don't recall how large the slag particles are (my notes are at work).
but I know that the alumninum oxide spheres from the solid rocket motors
can be submicron, and therefore, they accelerate the quickest (some
of these tiny particle can even leave the solar system).
The people who have done the most work on this topic are Antal Juhász
and Mihaly Horányi
Juhász, Antal, and Horányi, Mihaly," (1997), "Dynamics of charged space
debris in the Earth's plasma environment," J Geophys Res 102,
pages 7237-7246, April 1, 1997.
Juhász, Antal, and Horányi, Mihaly," (1999) Magnetospheric Screening
of Cosmic Dust", J Geophys Res 104, 12577-12583.
I was (and am) learning from these two: we were all using similar code,
except Antal's magnetic field is a lot more complete than mine (I used
a simple dipole for the Earth). Antal gave me the plasma data too for my
study (i.e. seen here: http://www.mpi-hd.mpg.de/dustgroup/~graps/earth)
Amara
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Amara Graps, PhD | Max-Planck-Institut fuer Kernphysik
Heidelberg Cosmic Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY
Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps
************************************************************************
"We came whirling out of Nothingness scattering stars like dust." --Rumi
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