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Re: Re: starship-design: Private Asteroid Mining

In a message dated 9/15/97 1:37:25 PM, wharton@physics.ucla.edu wrote:

>Okay - sounds like turning an asteroid into useful material might not be so
>tough.  Next question: how expensive is it to send it to Earth orbit?
>I suppose there might be a few asteroids that come so close that it would
>only take the slightest nudge to put them in orbit around the Earth (or
>around the moon... maybe that would be safer if you miscaclulated?)
>But still, the average earth-orbit-crossing asteroid would probably take
>an awful lot of energy to do this.  I'm sure not as much as it would take
>to launch it into orbit, but is the price at all comparable?  Does anyone
>have a dollars/kilogram estimate for A) putting Earth materials into orbit
>twenty years from now and B) pulling asteroid materials into orbit twenty
>years from now.  Enquiring minds want to know...

Asteroids pass very close to earth all the time.  TO DAMB CLOSE!  NORAD
reports an average of 25 kiloton plus atmospheric explosions a year from
asteroids.  One a few hundred meters across skimed the upper air over New
Zealand a couple years back (would have been an H bomb sized blast if it
would have hit).

A kilometer or 2 per secound delta-V would place most in orbit.  Less if you
pick more carfully.  That compares to about 8-9 kilometer per seound to get
into earth orbit.  But since you can use local water and solar pumped rockets
for a steam rocket.  Sound lower the costs.

As for costs to orbit with near term equipment.  A kerosine oxegen single
statge to orbit should have fuel costs of about $20 per pound of cargo to
orbit.  Assuming heavy trafic to cur overhead costs that could run about
twice that for launch costs.  Of course their are some tricks you can pull to
cut that cost down by maybe a factor of 10, but it adds a lot systems

For comparison airline fare across the pacific runs about $10 a pound, and
the space shuttle costs about $30,000 a pound.