Re: We can meet all our needs through space development

On Jan 28, 8:18 pm, Einar <eina...@xxxxxxxxx> wrote:
On Jan 28, 6:42 pm, Willie.Moo...@xxxxxxxxx wrote:

On Jan 28, 4:12 pm, Einar <eina...@xxxxxxxxx> wrote:

That's why I went with an open loop system.  That system must be fed -
which needed 21,000 metric tons per day running through it to keep it
going.  Triple that amount to replace parts and account for processing
losses.

The initial 1,000 moonlets provide 134 years of support.  Of course in
that time everything will have been replaced and upgraded.
It takes a delta vee of about 8 km/sec to bring stuff from the
asteroid belt.

Hmm, I wonder if you are going from the assumption that most of the
asteroyds are solid rock through.

No. I'm assuming that a complete survey of the 300,000 small objects
in the solar system can be completed in a reasonable time, and those
best suited for whatever use was have for them will be brought into an
appropriate orbit.

You see, according to what I have
heard most of them are actually looselly bound by theyr own gravity
piles of rubble.

Some are,some are other things, others are something else. Whatever
is sent back to Earth orbit will have to be engineered and processed
for the voyage.

This apparently came from the realization that most
of the asteroyds appear to have got to litle density in light of theyr

Density is easy to compute. You measure the deflection of a smaller
body that flies by, and divide that by the observed volume.
Asteroidal densities range from something a little less than water to
something a little more. There's no guessing, data exists for Ceres,
and other of the larger minor bodies.

apparent composition. The solution to that conundrum appears to be
that there are empty spaces within as they are only weakly held
together rubble most of 'em.

Some are like this - others are not. In any event,it will be a major
program to work out the details of the transport mechanism I only give
in broad strokes here.

I suspect that most of them would come apart if anyone would attempt
to shift them.

Depends on the details of how its done. It wold be naive to think you
can move them without first processing them somehow. Even something
as simple as a net or bag - depending on the tensile forces involved.

This means that first we would have to do a very
thorough surwey

Yes. We would do that anyway to pick out the best for returning it to
Earth..

of the asteroyd belt, and only attempt to move the
minority which appear not to in theyr past to have been shatterd by a
collision. Such a surwey can naturally be done, but it will take some
time as the asteroyd belt is pretty voluminous.

It could be done rather rapidly if approached correctly.

Miminum energy rockets have delta vee equal exhaust velocity.  So,
propellant fraction of  63.21% -  so to recieve 21,000 metric tons per
day from the asteroid belt 57,000 metric tons per day must start out
from the ateroid belt - flowing from the asteroid belt  36,000 metric
tons a day is ejected at 8 km/sec.to provide propulsive force.

Ah, I was wondering what you were thinking of as the fuel. Lineral
accelerators I presume. But first we have to find which are solid rock
and which are rubble.

No, because methods can be developed for moving either of those. As I
said, of the 300,000 small bodies in the solar system, only 1,000 fo
the very smallest are needed - if they have the right composition. We
may process entire asteroids in transit to throw away the stuff we
don't need and keep the stuff we do.

That's 417 kg per second - Each kg/sec projected at 8,000 m/sec
requires 32 MJ/sec - so 417 kg per second needs 13.3 GW.   So a single
20 GW power satellite with appropriate optics can feed this ring of
satellites.

Here is an Article you may like:

A Solar Grand Plan
By 2050 solar power could end U.S. dependence on foreign oil and slash
greenhouse gas emissions
By Ken Zweibel, James Mason and Vasilis Fthenakishttp://www.sciam.com/article.cfm?id=a-solar-grand-plan

This is just one fault-point of many I could mentione with your
vision.

Not really, I said explicitly that 21,000 tons per day would be needed
by the ring to keep feeding earth indefinitely.  Failing that, I said
the system would run out of resources in 134 years from the initial
1,000 moonlets.

This all then depends on that the asteroyd can actually be used in
that fashion, doesn´t it?

Yes. If you are saying asteroids cannot be moved and cannot be used
in this fashion, its up to you to say why? Most of the material
needed is water - that can be formed into ice, and put inside a highly
reflective shell in vacuum. Ice boils nicely into steam and that can
easily be got up to 8,000 m/sec exhaust speed through a variety of
means using laser energy beamed to the payload.

This sounds more like one would hope that the world at 2099
might be like.

I think its possible to achieve this.  When you actually carry out the
engineering calculations you find that the needs are surprisingly
modest, given the return.

Well, remember it´s the things we didn´t reckon with that cath us.

I'm not proposing a single specific course of action, I am proposing a
vision of using the resources of interplanetary space and solar energy
to meet the needs of human industry. If one specific approach doesn't
work, another will. I have merely done the prelminary calculations on
the scale of the problem.

Humanity currently uses 15 TW - capturing 120 GW in space and beaming
to payloads in the asteroid belt, along with payloads entering Earth
orbit, would provide a stream of raw material from the asteroids
sufficient to feed everyone on Earth. This is rather remakrable.
This or that detail may have to work this or that specific way - we
don't know all those details yet before working them out - but to say
in the absence of any clear knowledge that there are definite show
stoppers - is being overly pessimistic. Given that there are few
alternatives - we owe it to ourselves to look at this more closely.

.
Write a schy fy book on this, a suggestion.

I'd prefer it not to be sci-fi - but that's just me.

Einar

thanks for your comments.  If you have any other fault points to
discuss I'd like to hear them.

Sure, se abow.

Einar

.

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