Asteroid use

>
> MW: If a 1000 tonne asteroid being transported to
> earth were to hit the Earth it would be the equivalent
> of a 2.5 megaton nuclear weapon. Obviously, such
> asteroids could be safely placed into Earth orbit. But
> would you trust dozens, if not hundreds of private
> companys to do this. What about asteroid
> transportation companies based in third world
> countries. An asteroid disaster would be a lot bigger
> than some damaged Liberian oil tanker. And the
> insurance cost would be-- astronomical-- if we
> attempted to place these asteroids in Earth orbit or
> even in Lunar orbit, IMO. And the environmental
> protest would make the anti-nuclear protest of 1970's
> look trivial.
>

a 1000 tonnes of steel is equal to a cube 5m on a side. A meteor
that big will produce a crater maybe 50 m in diameter. Its not equal
to a 2.5 megaton nuclear bomb. If you thin it is, I would like to see
the numbers to back it up.

> Mars, however, also has practically all of the natural
> resources necessary for human survival. And a much
> lower gravity well than the Earth. And there would be
> little protest about transporting hundreds of 1000 to
> 10,000 tonne asteroids into Marsian orbit every year
> to be processed. The satellite market is estimated to
> be worth about 20 trillion dollars in the next 20
> years. The manufacturing of satellites out of asteroid
> materials in Mars orbit would allow Mars to dominate
> this potential 20 trillion dollar industry.
>

Mars has none of the infrastructure ready, has no people for a market.
The moon would be a cheaper course than mars.

The $20 trillion satellite market everyone is talking about the total
value, not the value of the satellites. It includes the comminucation
value, the weather predicting value, and perhaps even power. It isn't
'the earth's population is going to spend 20 trillion on satellite
manufacturing'.

> >
> MW: Orbital telescopes would be a lot more expensive
> than lunar telescopes manufactured on the moon. And
> lunar telescopes would be easier to maintain because
> there would be people there already. A space telescope
> would be a lot more expensive to repair.
>

There are big assumptions being made here. How many people live on the
moon today? My belief is that where ever humans settle, that is where
the telescopes will be built.

> > MW: But as far as sending humans out to the asteroid
> > belt, it is obvious that the first place they should
> > go would be to Ceres, the largest of the asteroids.
> > Because of its large size (more than 2.7 million
> > square kilometers of surface area) and its extremely
> > low gravity, Ceres may well be the most valuable

The most obvious place to go is an asteroid that is deliberately
captured into earths orbit. in 1997 a asteriod was found that had
passed between earth and the moon about a month earlier. Had this
asteroid been found a month before its closest approach a project to
help the earth capture it was possible, and we had instant access to
space material a mere 50 000 km away.

Does nasa have such a plan on the books?

> >
> MW: Asteroids only 1 kilometer to 100 kilometers in
> diameter would probably be the most difficult to mine
> since they would be to heavy to transport into a
> planetary orbit and might be too small and to rugged
> to set up large facilities on its surface-- especially
> if their rotations are very fast. And the labor cost
> would be very high since you would have to find people
> willing to work in isolation in such environments.
>
Again this depends on its location. Ceres is further than mars. If
your going to hit ceres, why not phoebus and demos instead?

The rotation of an asteroid doesn't matter much. You find the line
through which it is rotating, and start mining along that line. Once
you have a deep hole along the axis, you start mining further from the
axis from the inside of your hole.

Bill