From: wolfone@ccwf.cc.utexas.edu (Patrick Chester)
Newsgroups: talk.environment
Subject: Re: Space Poop
Date: 8 Sep 92 23:57:53 GMT
Reply-To: wolfone@ccwf.cc.utexas.edu (Patrick Chester)
Distribution: na
Organization: The University of Texas at Austin, Austin TX
Originator: wolfone@sneezy.cc.utexas.edu

In:
>Article 7955 of talk.environment:
>From: bj368@cleveland.Freenet.Edu (Mike E. Romano)
>Newsgroups: talk.environment

>Since 1957 more than 3,300 launches have produced 7,000 trackable objects
>currently in orbit, equalling more than 3,000 tons of man made material.
>Of these 7,000 catalogued objects the US and USSR have produced approx
>3,300 each.  The rest are from Europe and other countries.
>Of these 7000 catalogued objects only 400 are operational satellites.
>The rest of this number include abandoned or nonfunctioning satellites,
>upper stages, and fragments including lens covers, separation bolts,
>and clamp bands.
>Further, there are from 30,000 to 70,000 smaller objects larger than 1
>cm which have not been catalogued.  Any pieces in this size range can
>damage spacecraft.
Looks like you did your research on the items above. At least it matches
info I've found out.

>Through the effect of air drag these objects continue to lose altitude
>and eventually rain down to earth.
And most will burn up in the atmosphere. These objects carry a LOT of
velocity. As the friction from the air increases as the object falls, the
energy in these objects will be released as heat and will melt/vaporize
the offending piece of space junk before it hits the ground. Its the few big
pieces of space junk you have to worry about. By the way, natural objects fall
to earth every day in the form of meteors. Go look it up in the library.
  
>Objects above the geo stationary orbit of 1000 km will remain there for
Excuse me? I thought GEO was at approx. 22000 miles (35200 km) above
the planet. Please take the time to research such things and you will seem 
more credible. Post to sci.space for any questions. There are quite a few
people there with the information to help you. If they can't help you they
can tell you where to find that information. From NASA for example.

>about 1000 years during which time they will orbit the earth more than
>5 million times, posing a constant risk of collision with functioning
>spacecraft.
I don't know if an object at GEO would stay in orbit for that long. It might
stay there longer. But you made another error. An object at GEO completes
one orbit in approx. 24 hours. Since this matches the rotation of the planet
the object appears to be stationary above the Earth. One orbit per day equals
(1 * 365.25 (avg Earth year)) 365.25 orbits per year. Times one thousand
years equals 365250 orbits. Of course, this doesn't take into account any
abberations in Earth's rotation through the Moon's influences; but since
I can't do that kind of math (calculus---ugh :) I won't.

Anyway, since those objects will stay at that point for quite awhile, the only
problem I see is room for more satellites at GEO. But all you have to do
is go up there and clear up the junk. A problem of engineering not science.
Correct me if I'm wrong about this, please.       
>Interactive collisions in earth orbits will eventually generate sufficient
>debris to create a dense Debris Belt and prevent further space launchings.
I think you are refering to something more like a Debris Ring around the
planet. But since the formation theories of rings and belts seem similar I can
accept that name for it. You'd need the mass of a small moon to get enough
matter to form even a thin ring around the planet. Even if we launched that 
much mass up (or carted it in from the Asteroid Belt) a ring would be unlikely
unless all of the matter came from the same general location and vector. You
see, planetary rings are formed from moons that stray too close and are torn
apart by tidal forces. All the junk in space was launched from different points
on the Earth and put into different orbits. The only way for that junk to form 
a ring would be if a small moon orbiting close to Earth (but not too close)
wore to "shepherd" the objects w/ its gravitational influence. Like several
moons around Saturn maintain some of the rings. As I've said before, look up
the relevant data. I did.
>Some scientists also predict than a sufficient amount of such debris will
>begin to significantly reduce solar radiation and affect global climate.
As I've noted before, I don't think we can get enough mass up there to do
that. You'd probably be better off starting a nuclear winter or crashing
an asteroid into one of the oceans to start such a cooling effect.
>-- 
>            Mike Romano     Univ. Calif. Berkeley

Sorry if this sounded like a flame. I didn't intend it.
-- 
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Patrick Chester            |"The earth is too fragile a basket in which to keep
wolfone@ccwf.cc.utexas.edu |  all your eggs." Robert A. Heinlein
claypigeon                 |"The meek shall inherit the earth. The rest of us
(Destroyer Fiend)          |  are going to the stars." Anonymous
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