Using Concrete to build space ships...

> Part of my proposal was using a solar sail carrier craft to
transport
> smaller prospectors and their payload.
> The prospectors would fly but mainly between carrier and asteroid.

Where will the solar sails come from? How many would you need?

> So for the building phase transportation would be cheap.

It will be cheap if you somehow manage to get untold thousands of
these 1 km in diameter solar sails into oribt, and then to the
asteroid. Who's going to pay to get them into orbit?

> As the building material transportation would be cheap we could
build
> the cycler on the earth-sun libration region were the sun and earth
> gravitation outweighs each other.

I think you still need to demonstrate that building material
transportation will be cheap rather than just asserting it will be
so.

Also, I'm unclear as to the advantage of hauling all of this
material back to L1. Why do so? How much energy is required to
maintain position at L1?

> So we have gravity assisted slingshot propulsion for free
acceleration
> of the cycler available which could be additional supported through
> the cyclers thrusters. Just doing the first push and the craft will
> start accelerating.

Accelerating is fine, but you need both directional control and
control over the magnitude of acceleration. There is a limit to how
much momentum exchange one can realize from a slingshot.

I haven't seen any calculations that claim that you're going to get
over 4 km/sec boost in velocity. Can you provide some info on this?

> The standstill which you see as a disadvantage has the advantage
> that you need a lot less energy to point to the exact orbit youll
> like as you would need to change the inertia of a fast moving
> asteroid already influenced through earth gravitation when we
> would get to it.

Can you reword this because I'm not sure of what exactly you're
trying to say.

Your 200,000 tonne cycler will have to increase it's velocity by
4.3km/sec to get to a Mars orbit.

KE = 0.5 mv^2 ------> 0.5 * (200,000,000 kg)(4,300 m/s)^2 = 1.85 *
10^15 Joules

Now let's find an asteroid of 4,000,000 tonnes mass. TWENTY TIMES
HEAVIER. It is moving at a velocity of 4 km/sec in a nearby orbit.
It will need a delta-v of 0.3 km/sec in order to get into the cycler
orbit.

KE = 0.5 (4,000,000,000 kg)(300 m/s)^2 = 4.5 * 10^14 J.

You'll need TEN TIMES more energy to get your cycler into the proper
orbit than it would take to get a asteroid that is TWENTY TIMES more
massive into the same orbit. Or to put it another way, for the same
amount of energy you're proposing to use I could find an asteroid
that has the approximate period and velocity and move that asteroid
into the proper orbit and have TWO HUNDRED & FIVE TIMES the mass to
work with.

All of that EXCESS mass can serve as reaction mass in a mass driver
in order to change the orbit. Or if it is ice, then that can be
burned as rocket fuel. We don't need to send up fuel from Earth to
bring the vessel (or asteroid) into a cycler orbit. The asteroid
provides the fuel. It's free.

How can you get cheaper than free?

TangoMan