Using Concrete to build space ships...

Hey there TangoMan,

>Date: Tue, 24 Feb 2004 05:44:42 -0000
>
>--- In ssi_list@... "Valens Agnitio"
>
> > Because of the masses involved, I don't think ion thrusters would
> > work. If we are looking at bringing in several hundred thousand
> > tons, what would an ion engine have to be like to move it in a
> > reasonable amount of time?
>
> > Val
>
>I've been watching this thread unfold and I'm really curious about
>something. When Frank started it he conceded that there were a
>number of drawbacks but he wanted to look at some potential benefits.
>
>OK.
>
>But now conversations are turning to propulsion and I'm wondering
>why no one has brought up the rocket equation.
>

Actually, in this instance, I was refering to moving any materials from
their asteroid source to the construction point. However, the idea we are
discussing is a reusable shell that could be put in a permanent orbit that
brings it close to both Mars and Earth at various points. This shell could
be met by a much lighter vehicle, which could then insert into this shell,
and ride it to Mars or Earth. The shell, cheaply constructed and with
minimal attitude control to maintain orbit, would provide heavy duty
shielding against radiation and micrometeors. The savings come from not
having to worry about heavy shielding, lowering the costs and increasing the
safety of Earth-Mars transit.

I hadn't thought of it before Frank brought it up, but it sure is an
interesting thought experiment.

>Building a spaceship from concrete will necessitate carrying more
>fuel to propel the ship. One would want to have the lowest dry mass
>possible. Radiation shielding could be achieved internally with
>hollow cylindrical tanks of water that double as repositories for
>ship water needs. There is no need to build up the mass of the ship
>with concrete for radiation protection.
>

I had thought of this idea before, and it seems a very good idea. However,
the shell idea takes it a step further, offering much more protection. This
is most useful when Earth-Mars transits become more routine. If practicle,
it would certainly be far better than an H20 shield.

Val

Take off on a romantic weekend or a family adventure to these great U.S.