Using Concrete to build space ships...

hello Thor,

>"You need the same mass no matter what you use as
>shielding. To get the same level of radiation as sea
>level on earth, you need 101kPa/9.8(m/s^2) = 10300kg
>of shielding per square meter. The moon
>miner's manifesto numbers are for a radiation level
>much higher than earth sea level. To reduce it to
>sea-level radiation, you would need four or five
>meters of regolith or ten meters of water."
>
>Thanks Ed for the detail.
>
>Correct me if I am wrong in this assessment:
>
>In the early stages of human space development life
>will be like mice hiding from the radiation/bone loss
>cat. Stay out in the open too long and you will get
>fried (caught) one way or another.
>
>The best shelters will always be the moon under enough
>regiolith to block anything short of an asteroid.
>Next best will be in some bulky structure either
>inside of an asteroid or on the side of it. Both will
>be built in place or the fuel costs will be
>extravagant.
>
>Astronauts will need very quick travel to the
>moon/asteriods to prevent getting fried. This means
>only high impluse propulsion systems and no round
>about means of getting there. Mass drivers and ion
>engines would not do this. Nuclear would leave wakes
>close to home - go have fun with the enviromentalists.

Sounds good to me.
>
>In this model the cheapest oxidizer is oxygen brought
>up from the moon and kerosene or hydrogen brought up
>from earth. Kerosene is nice since don't need to
>pressurize it or worry about boiling off if the sun
>shines on it.

When you use a solar sail carrier like I proposed, it should be
possible to deliver Water/permafrost/ice from satellites and to
whatever place you like.

So hydrogen and steam propulsion won on asteroids and comets and
transported to the place of usage will become the first choice of
transportation.

It will take some time to deliver but the carrier vessels would be
constantly out with their prospector landers and on the way back.

So staying with just carriers as I stated to TangoMan might not be a
good idea since this would reduce the costs of fuel a lot.

Frank