G'day,

Had a chance to study the Kalpana One paper. Looks good to me but its a
shame to use artificial light for crop raising when theres so much natural
sunlight. Agricultural is by far you main power requirement. A way around
this is to attach solar collectors to the outside of the colony's hull and
divert the sunlight into the agricultural areas with fiber optics. This is
not new but is used in hybrid light systems.

see:

http://www.sunlight-direct.com/

http://www.ornl.gov/sci/solar/

That would cut power requirements from 300 megawatts to 50 megawatts. You
could then dump the powersat and intergrate solar electricity collectors on
a skirt at one end of the habitat.

ta

Ralph

At 03:10 PM 4/26/2006, you wrote:
>G'day,
>
>Had a chance to study the Kalpana One paper. Looks good to me but its a
>shame to use artificial light for crop raising when theres so much natural
>sunlight. Agricultural is by far you main power requirement. A way around
>this is to attach solar collectors to the outside of the colony's hull and
>divert the sunlight into the agricultural areas with fiber optics.

The exterior of the hull is rotating at 2rmp, giving you 1g away from the
colony. Of course, as you move away from the hull the force becomes greater.

I'd suggest doing a little of the medium-detail design before you decide
this works.

I couldn't find a publication date on this. Does anyone know?
We might invite the writers of the paper here to discuss it and answer
our questions.

Ralph wrote
>>... its a shame to use artificial light for crop raising when
>>theres so much natural sunlight. Agricultural is by far you
>>main power requirement. A way around this is to attach solar
>>collectors to the outside of the colony's hull and divert the
>>sunlight into the agricultural areas with fiber optics.

It does seem strange to allow sunlight into the habitable areas, but
use artificial light for agronomy. I wonder why was this was chosen?
Also, I can't see how sunlight enters the habitable area; From the
endcaps which are parallel to the sunlight's incoming direction, with
no mirrors?
With no light pipes or directed lighting, we must assume that all
lighting in the inner low-G decks is artificial. Again, with light
pipes, sunlight can be brought in anywhere, with no moving parts.
It'd be interesting to see a study of the relative mass and cost of
conventional electric lighting and light pipes for different
applications.

Al Globus wrote:
> The exterior of the hull is rotating at 2rmp, giving you 1g
>away from the colony. Of course, as you move away from the
>hull the force becomes greater.

Understood. Was this intended to rebut Ralph's suggestion for exterior
light collectors? Sure, they'd be under outward pull, but they could be
much smaller than the huge "petals" of O'Neill's Island 3.
One reason the Kalpana 1 designers might not like it is the need to
turn them away from the light-pipe inlets. Another suggestion comes to
mind: swing them only a bit so they direct light onto PV arrays instead
of the inlets.

I couldn't find a publication date on this. Does anyone know?
We might invite the writers of the paper here to discuss it and answer
our questions.

Ralph wrote
>>... its a shame to use artificial light for crop raising when
>>theres so much natural sunlight. Agricultural is by far you
>>main power requirement. A way around this is to attach solar
>>collectors to the outside of the colony's hull and divert the
>>sunlight into the agricultural areas with fiber optics.

It does seem strange to allow sunlight into the habitable areas, but
use artificial light for agronomy. I wonder why was this was chosen?
Also, I can't see how sunlight enters the habitable area; From the
endcaps which are parallel to the sunlight's incoming direction, with
no mirrors?
With no light pipes or directed lighting, we must assume that all
lighting in the inner low-G decks is artificial. Again, with light
pipes, sunlight can be brought in anywhere, with no moving parts.
It'd be interesting to see a study of the relative mass and cost of
conventional electric lighting and light pipes for different
applications.

Al Globus wrote:
> The exterior of the hull is rotating at 2rmp, giving you 1g
>away from the colony. Of course, as you move away from the
>hull the force becomes greater.

Understood. Was this intended to rebut Ralph's suggestion for exterior
light collectors? Sure, they'd be under outward pull, but they could be
much smaller than the huge "petals" of O'Neill's Island 3.
One reason the Kalpana 1 designers might not like it is the need to
turn them away from the light-pipe inlets. Another suggestion comes to
mind: swing them only a bit so they direct light onto PV arrays instead
of the inlets.

It will be published in 2006 in the beginning of may

At 06:46 PM 4/27/2006, you wrote:
>I couldn't find a publication date on this. Does anyone know?
>We might invite the writers of the paper here to discuss it and answer
>our questions.
>
>Ralph wrote
> >>... its a shame to use artificial light for crop raising when
> >>theres so much natural sunlight. Agricultural is by far you
> >>main power requirement. A way around this is to attach solar
> >>collectors to the outside of the colony's hull and divert the
> >>sunlight into the agricultural areas with fiber optics.
>
>It does seem strange to allow sunlight into the habitable areas, but
>use artificial light for agronomy. I wonder why was this was chosen?

To avoid using 1g area for agriculture. The size of the 1g area drives the
surface area, which drives the shielding, which drives the mass
requirements, which is probably the tallest pole.

>Also, I can't see how sunlight enters the habitable area; From the
>endcaps which are parallel to the sunlight's incoming direction, with
>no mirrors?

Diffusion and/or mirrors on the interior

> With no light pipes or directed lighting, we must assume that all
>lighting in the inner low-G decks is artificial.

Yes.

>Again, with light
>pipes, sunlight can be brought in anywhere, with no moving parts.
>It'd be interesting to see a study of the relative mass and cost of
>conventional electric lighting and light pipes for different
>applications.

A detailed trade is needed for light pipes vs electric lights. Since this
is awhile in the future, you might need to assume LED electric lighting --
which is much more efficient but might not be sufficiently powerful for
agriculture.

Issues include
-- size of collecting area
-- constraints on colony pointing
-- size of the routing cables/light pipes

The primary reason light pipes were not used on Kalpana One is because none
of us were familiar with the technology.

Here's a quick analysis:

Kalpana One agriculture assumes 50m^2 per person for high intensity
agriculture (continuous sunlight, optimal atmosphere, etc.). For 5,000
people that works out to 250,000m^2 of plants. Assuming you need full
sunlight (probably right within a factor of 2), this means 250,000m^2 of
collection -- or a square 500 m on a side.

Kalpana One's thermal design requires that the axis of the cylinder be
aligned with the solar system's north-south axis. Furthermore, the hull
exterior rotates at 2 rpm.

I don't know how one could attach a 500m on-a-side solar collector, or even
something half that size, to Kalpana One and keep it pointed at the sun.

Anyone else have a good idea?

At 06:46 PM 4/27/2006, you wrote:

The writer of the paper are Nittin arora (me) , my friend ankur bajoria.. we are students .. still undergraduates though,,, from india... and most important person is AL Globus sir.. he is the one who was responsible and still is for the growth of space coloniztion and he is also reponsible for KALPANA ONE ... we helped him as much as we could ... it was a team work .. but i am happy to see suggestions coming in... it would help evolve the desgin and make it more perfect.. and who knows one day maybe some of us will live in it :) .. all are welcome to ask us any questions..

r wrote: I couldn't find a publication date on this. Does anyone know?
We might invite the writers of the paper here to discuss it and answer
our questions.

Ralph wrote
>>... its a shame to use artificial light for crop raising when
>>theres so much natural sunlight. Agricultural is by far you
>>main power requirement. A way around this is to attach solar
>>collectors to the outside of the colony's hull and divert the
>>sunlight into the agricultural areas with fiber optics.

It does seem strange to allow sunlight into the habitable areas, but
use artificial light for agronomy. I wonder why was this was chosen?
Also, I can't see how sunlight enters the habitable area; From the
endcaps which are parallel to the sunlight's incoming direction, with
no mirrors?
With no light pipes or directed lighting, we must assume that all
lighting in the inner low-G decks is artificial. Again, with light
pipes, sunlight can be brought in anywhere, with no moving parts.
It'd be interesting to see a study of the relative mass and cost of
conventional electric lighting and light pipes for different
applications.

Al Globus wrote:
> The exterior of the hull is rotating at 2rmp, giving you 1g
>away from the colony. Of course, as you move away from the
>hull the force becomes greater.

Understood. Was this intended to rebut Ralph's suggestion for exterior
light collectors? Sure, they'd be under outward pull, but they could be
much smaller than the huge "petals" of O'Neill's Island 3.
One reason the Kalpana 1 designers might not like it is the need to
turn them away from the light-pipe inlets. Another suggestion comes to
mind: swing them only a bit so they direct light onto PV arrays instead
of the inlets.

Al Globus wrote:

>To avoid using 1g area for agriculture. The size of the 1g area drives the
>surface area, which drives the shielding, which drives the mass
>requirements, which is probably the tallest pole.
>
Hmm. Interesting point. Instead of using spherical endcaps which don't
have very usable surfaces, you could theoretically consider having
conical endcaps. Cone shapes are reasonably easy pressure vessels to
manufacture.

That way you could use them for agriculture- plants don't care as much
about low g.

Cone shapes also give you a way to evacuate in an emergency.

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Ian Woollard

> Hmm. Interesting point. Instead of using spherical
> endcaps which don't have very usable surfaces,

So I take it you would disagree with the points I made on 04-19? What
shortcomings do you see?

> you could theoretically consider having conical endcaps.
> Cone shapes are reasonably easy pressure vessels to manufacture.

Although cones would not have even distribution of the pressure load.

> Cone shapes also give you a way to evacuate in an emergency.

Hey, that was a point I should have made in favor of spherical end-caps
vs. flat. I remember Gerard O'Neill commenting to somebody that he
didn't really care all that much for the Stanford Torus design. When
pressed, one criticism he offered was that in an emergency requiring
evacuation, you would be dependent on elevators to get you up to the
spin axis. He was much more comfortable with designs which allowed
residents to get up to the spin axis on their own power.

Regards,

Mike Combs

--- "Combs, Mike" wrote:

> I remember Gerard O'Neill commenting to
> somebody that he
> didn't really care all that much for the Stanford
> Torus design. When
> pressed, one criticism he offered was that in an
> emergency requiring
> evacuation, you would be dependent on elevators to
> get you up to the
> spin axis. He was much more comfortable with
> designs which allowed
> residents to get up to the spin axis on their own
> power.
>

Elevators? Who says that the spokes have to be
straight?

http://i31.photobucket.com/albums/c398/robot_guy/torus.jpg

Ed Minchau
http://robot_guy.blogspot.com

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Ed Minchau

> --- "Combs, Mike" wrote:
>
> > I remember Gerard O'Neill commenting to somebody that he didn't
> > really care all that much for the Stanford Torus design. When
> > pressed, one criticism he offered was that in an emergency requiring

> > evacuation, you would be dependent on elevators to get you up to the

> > spin axis. He was much more comfortable with designs which allowed
> > residents to get up to the spin axis on their own power.
> >
> Elevators? Who says that the spokes have to be straight?
>
> http://i31.photobucket.com/albums/c398/robot_guy/torus.jpg

Yeah, another possibility is the 45degree angle spokes that we see on
Pat Rawlings' design used in "L5: First City in Space". At first I was
a bit puzzled by that, then it occurred to me that in addition to an
elevator or at least a powered people-mover (which I think you would
doubtless still have in any case) you could also have stairwells for
emergency use. But... these would be stairwells well over half a mile
long! Now granted, by the time you were halfway up, you'd weigh half as
much, and 2/3rds up, 1/3 as much, but still...

A person might make the point that with a Bernal Sphere or with
spherical end-caps on a cylinder, one would also have a considerable
uphill trek. But there are two points to make here. One: At the point
where "gravity" is the highest, the incline would be the least, and
vice-versa. Two: If all the residents of a space habitat are swarming
up to get away at the same time, better for them to have a wide,
two-dimensional surface to do it on. Some people might well tire and
have to stop. Vital for others to be able to pass them by and keep
going. If this instead was a long stairwell going up a tunnel, people
who have tired out might create clogs in the traffic which might
ultimately become difficult or even impossible to pass.

I'd say your curving spokes would share the sphere's or spherical
end-caps' advantage of a slope which starts out shallow and then only
becomes steep at low "gravity" heights, but might share the problems of
a 45degree angle spoke.

Regards,

Mike Combs

Combs, Mike wrote:

>>you could theoretically consider having conical endcaps.
>>Cone shapes are reasonably easy pressure vessels to manufacture.
>>
>>
>Although cones would not have even distribution of the pressure load.
>
Actually, it's quite easy to deal with that, you just taper the wall
thickness down towards the axis. The overall volume/mass ratio is the
same for a cylinder as a cone, and you get more surface area for the
same mass (since the volume/area ratio increases at smaller diameters
whilst the volume/mass ratio remains constant.)

At 07:15 PM 4/28/2006, you wrote:
>Al Globus wrote:
>
> >To avoid using 1g area for agriculture. The size of the 1g area drives the
> >surface area, which drives the shielding, which drives the mass
> >requirements, which is probably the tallest pole.
> >
>Hmm. Interesting point. Instead of using spherical endcaps which don't
>have very usable surfaces, you could theoretically consider having
>conical endcaps. Cone shapes are reasonably easy pressure vessels to
>manufacture.

The end caps need to be pretty blunt to avoid axis of rotation
instability. Both spherical and conical end caps are too long, to my
mind. For Kalpana One we felt that there should be a curved transition
from the side to nearly flat end caps. The exact details are TBD.

On 5/1/06, Combs, Mike wrote:
(...)
> Hey, that was a point I should have made in favor of spherical end-caps
> vs. flat. I remember Gerard O'Neill commenting to somebody that he
> didn't really care all that much for the Stanford Torus design. When
> pressed, one criticism he offered was that in an emergency requiring
> evacuation, you would be dependent on elevators to get you up to the
> spin axis. He was much more comfortable with designs which allowed
> residents to get up to the spin axis on their own power.
(...)

Although you could also use escape pods attached to the rim of the
torus. People would just embark, decouple and be shot through the
tangent of the rotation.

From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com] On Behalf Of Lucio de Souza Coelho

> On 5/1/06, Combs, Mike wrote:
> (...)
> > Hey, that was a point I should have made in favor of spherical
> > end-caps vs. flat. I remember Gerard O'Neill commenting to somebody
> > that he didn't really care all that much for the Stanford Torus
> > design. When pressed, one criticism he offered was that in an
> > emergency requiring evacuation, you would be dependent on elevators to
> > get you up to the spin axis. He was much more comfortable with
> > designs which allowed residents to get up to the spin axis on their own power.
>
> Although you could also use escape pods attached to the rim of the torus.
> People would just embark, decouple and be shot through the tangent of the
> rotation.

Somebody in the group made that very suggestion. O'Neill reminded us about the radiation shield which is outside of the pressure hull. The "escape pod" concept couldn't work with any design with either a stationary radiation shield, or one rotating at a different speed or in a different direction, which would rule it out for either a Stanford Torus or a Bernal Sphere. It would work for any design with integrated shielding (i.e. shielding which rotates with the habitat).

Regards,

Mike Combs

>From Al Globus
>> I don't know how one could attach a 500m on-a-side solar
>>collector, or even something half that size, to Kalpana
>>One and keep it pointed at the sun.

Ralph
> The habitat has that much area effectively facing the sun
>>at any one time.
> So cover the exterior with multiple colectors. Have a
>>look at the website they are not very heavy.

Multiple collectors means multiple the mass and cost for them. Maybe
not much of a concern, but it's there. They'd all track the Sun moving
across their sky, or they are fixed and designed to minimize losses
from poor angles.

The primary could be detached, directing light to secondaries on the
colony which funnel it into light conduits into the interior (much like
the Stanford Torus)
The secondaries could be practically anywhere on the exterior: Axial
("Hatbox), concentric (like the 45 degree windows on the Island One),
or possibly multiple inlets on the outer hull ("down" floor), and the
incoming light from the primary sweeps across them in turn. This
mightn't even have to mean a light source which moves with the colony
rotation: proper directing of the reflectors in the light conduits (or
mixing of input from different pipes if they're solid glass conductors)
and some diffusion could make it not noticeable for people or plants.

Further, like the Island One Bernal sphere, the primary could provide a
shadow for the radiators in some other configuration.

I'm trying mightily to keep in mind one of the most important
engineering principles: K.I.S.S. (keep it simple, stupid). Fight
Murphy's Law with every fundamental assumption you make. (Not just
idiot-proof, but Murphy or saboteur-proof as much as possible.) It's
not easy.
Are light conductors and separate mirrors simpler than a rectenna and
electric lights?
Hmmm...

On 01/05/06, Combs, Mike wrote:
> Somebody in the group made that very suggestion. O'Neill reminded us about
> the radiation shield which is outside of the pressure hull. The "escape
> pod" concept couldn't work with any design with either a stationary
> radiation shield, or one rotating at a different speed or in a different
> direction, which would rule it out for either a Stanford Torus or a Bernal
> Sphere. It would work for any design with integrated shielding (i.e.
> shielding which rotates with the habitat).

You could just build a little tunnel or rail pointing antispinward
into the habitat and use a 'retro rocket' to slow the escape pod,
before dropping into the gap between the habitat and the shielding.
Adding a gap costs *very* little extra material.

Once you're between the two, you can just jet around and leave via an
escape hole.

It's not very difficult.

> Regards,
>
> Mike Combs

-Ian Woollard

"Gravity is just a theory. We shouldn't be teaching it to children as
if were fact."
"Reunite Gondwanaland... Think of the children." - Mary Shafer

You asked for it :-)

Something I came up with a while ago, but never developed very far, was
an attempt, like Kalpana One, to compromise and find a good
configuration. I put some crude drawings in the "Photos" section of
this club.
I don't know if this link will work (you probably need to be signed
into Yahoo):

I assume integral shielding as concrete structure. Over a lot of the
hull, it doesn't even need to be full thickness, because things like
agronomy and machinery that don't need full protection for cosmic ray
secondaries can be below the 1G hab floor, and cumulative thicknesses
of structures protects the habitation areas adequately.
Just enough structure under the equatorial hab areas to stabilize the
rotation axis.

A quibble: in most sources I've seen, Lunar regolith has about the
perfect relative masses of metals for structure and rock for shielding.
What's the big fuss over minimizing it?
If we're assuming rock for shielding, you're going to need over 95%
rock by mass, whether you're mining a metal-rich asteroid or the Moon.
Also, for another quibble, I like to assume integral rock dust
shielding for colonies. Nothing gives you confidence like ~1.6 meters
of reinforced concrete/sintercrete for your colony hull.
Besides, we're not building one of these from the top of rockets from
Earth: we'll have access to large scale space resources, and what's
another few million tons?
Also, your design doubles the shielding accepted for the NASA Summer
Studies; ~10tons per sq meter. I live near Denver, at about 1.6km ASL,
where they settled on the shielding requirements (while I'm not at 1/2
atmospheric pressure, I am above half of the atmosphere's mass, so
about 5tons/m^2).

From this club's archives:
Review: "Concrete Space Colonies"

Nitin Arora wrote:

At 07:14 PM 5/1/2006, you wrote:

>I'm trying mightily to keep in mind one of the most important
>engineering principles: K.I.S.S. (keep it simple, stupid). Fight
>Murphy's Law with every fundamental assumption you make. (Not just
>idiot-proof, but Murphy or saboteur-proof as much as possible.) It's
>not easy.
>Are light conductors and separate mirrors simpler than a rectenna and
>electric lights (on Kalpana One)?
>Hmmm...

Separate, external mirrors introduces a lot of complexity. I don't like
them. If light pipes are to work, the simplest approach is to cover the
hull with collectors and pipe it into the colony. To decide if this is
better than solar cells (you'll need some of these anyway for emergency
power) will require a fairly detailed trade study (IMHO).

At 07:43 PM 5/1/2006, you wrote:
>we'll have access to large scale space resources, and what's
>another few million tons?

A lot of work to get it from there to here. Maybe not too much of a
concern for the 100th colony, but for the first one we need to minimize the
total mass of materials to be brought to the construction site. It is
probably the tallest pole in any orbital design.

> Also, your design doubles the shielding accepted for the NASA Summer
>Studies; ~10tons per sq meter. I live near Denver, at about 1.6km ASL,
>where they settled on the shielding requirements (while I'm not at 1/2
>atmospheric pressure, I am above half of the atmosphere's mass, so
>about 5tons/m^2).

Actually, the NASA summer studies called for 4.5 tons/m^2. But remember
that in Denver you are only exposed to cosmic radiation coming from the
sky. Everything coming from the other side of the Earth is blocked.

That said, I think 4.5 - 5 tons per m^2 is probably reasonable, subject to
further study. It doesn't really change much about Kalpana One, but it
does cut that mass in half and make everything about two times easier.

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Al Globus

> Separate, external mirrors introduces a lot of complexity.
> I don't like them.

This is a widely-held view, but I have a hard time seeing it. The light
pathways are sometimes complex, but I don't think this is the same as
being complex to build or operate.

When one has light as a power source, and wants light in the end, it
just makes more sense to me to use the light directly than to go the
PV-arrays/artificial-light-source route, with its two attendant
efficiency losses.

Regards,

Mike Combs

why would it have to be attached. a mirror of that size could focus
the light in to a receptor at the center of one end. light pipes are
basically glass tubes (several different methods of doing this) that
carry the light along the path you chose. if the mirror is frequency
specific to the visible light spectrum (meaning it only reflects
those frequency, and appears to be clear glass to all others), it
would not increase the heat of the station. the most likely method of
doing this is to have bundles of fiber-optics that can be split up
to send each fiber to its proper destination. when it arrives it
enters a different type tube, one that radiates the light outwards
though out its length. or it can exist the fiber in a point light
source style, similar to light bulbs.

one advantage of this system is that the light can be turned on and
off with easy, simply by blocking one end or the other. or it can be
redirected in to another area for its uses.

another advantage is that glass blocks ultraviolet radiation,
something that has been found to be detrimental to both animals and
plants. plants that are raised under sunlight with the ultraviolet
radiation block are bigger and less bitter than normal ones.

another advantage is that it requires little structure, being mostly
plastic.

--- In spacesettlers@yahoogroups.com, Al Globus wrote:
>
> The primary reason light pipes were not used on Kalpana One is
because none
> of us were familiar with the technology.
>
> Here's a quick analysis:
>
> Kalpana One agriculture assumes 50m^2 per person for high intensity
> agriculture (continuous sunlight, optimal atmosphere, etc.). For
5,000
> people that works out to 250,000m^2 of plants. Assuming you need
full
> sunlight (probably right within a factor of 2), this means
250,000m^2 of
> collection -- or a square 500 m on a side.
>
> Kalpana One's thermal design requires that the axis of the cylinder
be
> aligned with the solar system's north-south axis. Furthermore, the
hull
> exterior rotates at 2 rpm.
>
> I don't know how one could attach a 500m on-a-side solar collector,
or even
> something half that size, to Kalpana One and keep it pointed at the
sun.
>
> Anyone else have a good idea?
>
> At 06:46 PM 4/27/2006, you wrote:
> >I couldn't find a publication date on this. Does anyone know?
> >We might invite the writers of the paper here to discuss it and
answer
> >our questions.
> >
> >Ralph wrote
> > >>... its a shame to use artificial light for crop raising when
> > >>theres so much natural sunlight. Agricultural is by far you
> > >>main power requirement. A way around this is to attach solar
> > >>collectors to the outside of the colony's hull and divert the
> > >>sunlight into the agricultural areas with fiber optics.
> >
> >It does seem strange to allow sunlight into the habitable areas,
but
> >use artificial light for agronomy. I wonder why was this was
chosen?
> >Also, I can't see how sunlight enters the habitable area; From the
> >endcaps which are parallel to the sunlight's incoming direction,
with
> >no mirrors?
> > With no light pipes or directed lighting, we must assume that all
> >lighting in the inner low-G decks is artificial. Again, with light
> >pipes, sunlight can be brought in anywhere, with no moving parts.
> >It'd be interesting to see a study of the relative mass and cost of
> >conventional electric lighting and light pipes for different
> >applications.
> >
> >Al Globus wrote:
> > > The exterior of the hull is rotating at 2rmp, giving you 1g
> > >away from the colony. Of course, as you move away from the
> > >hull the force becomes greater.
> >
> >Understood. Was this intended to rebut Ralph's suggestion for
exterior
> >light collectors? Sure, they'd be under outward pull, but they
could be
> >much smaller than the huge "petals" of O'Neill's Island 3.
> > One reason the Kalpana 1 designers might not like it is the need
to
> >turn them away from the light-pipe inlets. Another suggestion
comes to
> >mind: swing them only a bit so they direct light onto PV arrays
instead

here's an idea that might be a bit far out for you. why not bring the
materials closer to the construction site before you begin.

allow me to use your imagination for a minute.

on approximately zero - 2 years, a small probe is launched. it
carries very little reaction mass, mainly for precision landing and
stuff. prior to this neo have been studied and a medium size one that
gives all the indications of having the best results is targeted. the
main payload of this probe is a large solar sail, with several
smaller ones also included. once in space it deploys one or more or
the sails and heads for the rondevu (sp?) with the target. it then
stabilzes the tumble using the smaller sails, deployed in choisen
areas. then it deploys the main, and begins to bring the neo into an
orbit that will allow it to be captured by the earth. once there, the
smaller ones are once again used to change its orbit and speed to put
it in the desired orbit for the station. it arrives about zero - 6
months.

at the same time as it is changing orbits a second probe is sent to
it, this one carring equipment to mine and smelt ores from the neo.
This includes a very large mirror to collect the suns heat and direct
it to the proper equipment. it also includes radiators to help get
rid of the heat from the metals and materials afterwords. most likely
this would be in a centerfuge that could be attached to the asteroid.
it would also include some basic metal working machines such as
rollers to make plates.

once the station was under construction the asteriod could be used
for living quarters for the construction crew.

--- In spacesettlers@yahoogroups.com, Al Globus wrote:
>
> At 07:43 PM 5/1/2006, you wrote:
> >we'll have access to large scale space resources, and what's
> >another few million tons?
>
> A lot of work to get it from there to here. Maybe not too much of
a
> concern for the 100th colony, but for the first one we need to
minimize the
> total mass of materials to be brought to the construction site. It
is
> probably the tallest pole in any orbital design.
>
> > Also, your design doubles the shielding accepted for the NASA
Summer
> >Studies; ~10tons per sq meter. I live near Denver, at about 1.6km
ASL,
> >where they settled on the shielding requirements (while I'm not at
1/2
> >atmospheric pressure, I am above half of the atmosphere's mass, so
> >about 5tons/m^2).
>
> Actually, the NASA summer studies called for 4.5 tons/m^2. But
remember
> that in Denver you are only exposed to cosmic radiation coming from
the
> sky. Everything coming from the other side of the Earth is blocked.
>
> That said, I think 4.5 - 5 tons per m^2 is probably reasonable,
subject to
> further study. It doesn't really change much about Kalpana One,
but it
> does cut that mass in half and make everything about two times
easier.

At 12:49 PM 5/18/2006, you wrote:
>why would it have to be attached. a mirror of that size could focus

One of the things Kalpana One tries to stay away from is large, co-orbiting
pieces of hardware that may collide with the colony. Basically, I don't
like catestrophic failure modes in active systems. I prefer minute to
minute survival to depend on passive systems, because they screw up less.

That said, as someone noted, the exterior hull of Kalpana One is about big
enough. One could cover most of it with light collectors and direct them
to the interior, at least in principle, although I doubt light pipes are as
easy to work with as electrical cables -- but I might be wrong. You need
some body-mounted solar cells for emergency power.

the nice thing about light in space, is that it can go a long ways
with little attenuation. it would be possible for the mirror to be
several miles away and still be aimed at the proper spot. Ive not
been able to find it on the net, but years ago, i heard about
something the Japanese had come up with. it was called a sunflower.
what it did was absorb the sunlight into a mixture of gasses, that
then sent a laser like beam comprised up of all the visible light
spectrum, though a light bundle. the light from these bundles could
be separated into many different rooms and into many different
floors. at that time they were using glass fiber optics, which could
send the light for miles. similar but cheaper systems using plastic
are suppose to be available for homes next year. these use plastic
fibers, which unfortunately can only carry the light for a few dozen
yards. light fibers are lighter, and more flexible than metal cables
used to carry electricity. they are also smaller and are more
resistant to problems caused by radiation.

--- In spacesettlers@yahoogroups.com, Al Globus wrote:
>
> At 12:49 PM 5/18/2006, you wrote:
> >why would it have to be attached. a mirror of that size could focus
>
> One of the things Kalpana One tries to stay away from is large, co-
orbiting
> pieces of hardware that may collide with the colony. Basically, I
don't
> like catestrophic failure modes in active systems. I prefer minute
to
> minute survival to depend on passive systems, because they screw up
less.
>
> That said, as someone noted, the exterior hull of Kalpana One is
about big
> enough. One could cover most of it with light collectors and
direct them
> to the interior, at least in principle, although I doubt light
pipes are as
> easy to work with as electrical cables -- but I might be wrong.
You need
> some body-mounted solar cells for emergency power.
>
> >the light in to a receptor at the center of one end. light pipes
are
> >basically glass tubes (several different methods of doing this)
that
> >carry the light along the path you chose. if the mirror is
frequency
> >specific to the visible light spectrum (meaning it only reflects
> >those frequency, and appears to be clear glass to all others), it
> >would not increase the heat of the station. the most likely method
of
> >doing this is to have bundles of fiber-optics that can be split up
> >to send each fiber to its proper destination. when it arrives it
> >enters a different type tube, one that radiates the light outwards
> >though out its length. or it can exist the fiber in a point light
> >source style, similar to light bulbs.
> >
> >one advantage of this system is that the light can be turned on and
> >off with easy, simply by blocking one end or the other. or it can
be
> >redirected in to another area for its uses.
> >
> >another advantage is that glass blocks ultraviolet radiation,
> >something that has been found to be detrimental to both animals and
> >plants. plants that are raised under sunlight with the ultraviolet
> >radiation block are bigger and less bitter than normal ones.
> >
> >another advantage is that it requires little structure, being
mostly
> >plastic.
> >
> >--- In spacesettlers@yahoogroups.com, Al Globus wrote:
> > >
> > > The primary reason light pipes were not used on Kalpana One is
> >because none
> > > of us were familiar with the technology.
> > >
> > > Here's a quick analysis:
> > >
> > > Kalpana One agriculture assumes 50m^2 per person for high
intensity
> > > agriculture (continuous sunlight, optimal atmosphere, etc.).
For
> >5,000
> > > people that works out to 250,000m^2 of plants. Assuming you
need
> >full
> > > sunlight (probably right within a factor of 2), this means
> >250,000m^2 of
> > > collection -- or a square 500 m on a side.
> > >
> > > Kalpana One's thermal design requires that the axis of the
cylinder
> >be
> > > aligned with the solar system's north-south axis. Furthermore,
the
> >hull
> > > exterior rotates at 2 rpm.
> > >
> > > I don't know how one could attach a 500m on-a-side solar
collector,
> >or even
> > > something half that size, to Kalpana One and keep it pointed at
the
> >sun.
> > >
> > > Anyone else have a good idea?
> > >
> > > At 06:46 PM 4/27/2006, you wrote:
> > > >I couldn't find a publication date on this. Does anyone know?
> > > >We might invite the writers of the paper here to discuss it and
> >answer
> > > >our questions.
> > > >
> > > >Ralph wrote
> > > > >>... its a shame to use artificial light for crop raising
when
> > > > >>theres so much natural sunlight. Agricultural is by far you
> > > > >>main power requirement. A way around this is to attach solar
> > > > >>collectors to the outside of the colony's hull and divert
the
> > > > >>sunlight into the agricultural areas with fiber optics.
> > > >
> > > >It does seem strange to allow sunlight into the habitable
areas,
> >but
> > > >use artificial light for agronomy. I wonder why was this was
> >chosen?
> > > >Also, I can't see how sunlight enters the habitable area; From
the
> > > >endcaps which are parallel to the sunlight's incoming
direction,
> >with
> > > >no mirrors?
> > > > With no light pipes or directed lighting, we must assume
that all
> > > >lighting in the inner low-G decks is artificial. Again, with
light
> > > >pipes, sunlight can be brought in anywhere, with no moving
parts.
> > > >It'd be interesting to see a study of the relative mass and
cost of
> > > >conventional electric lighting and light pipes for different
> > > >applications.
> > > >
> > > >Al Globus wrote:
> > > > > The exterior of the hull is rotating at 2rmp, giving you 1g
> > > > >away from the colony. Of course, as you move away from the
> > > > >hull the force becomes greater.
> > > >
> > > >Understood. Was this intended to rebut Ralph's suggestion for
> >exterior
> > > >light collectors? Sure, they'd be under outward pull, but they
> >could be
> > > >much smaller than the huge "petals" of O'Neill's Island 3.
> > > > One reason the Kalpana 1 designers might not like it is the
need

--- In spacesettlers@yahoogroups.com, Al Globus wrote:

> > Also, your design doubles the shielding accepted for the NASA
> > Summer Studies; ~10tons per sq meter. I live near Denver, at about
> > 1.6km ASL, where they settled on the shielding requirements (while
> > I'm not at 1/2 atmospheric pressure, I am above half of the
> > atmosphere's mass, so about 5tons/m^2).

> Actually, the NASA summer studies called for 4.5 tons/m^2. But
> remember that in Denver you are only exposed to cosmic radiation
> coming from the sky. Everything coming from the other side of the
> Earth is blocked.

> That said, I think 4.5 - 5 tons per m^2 is probably reasonable,
> subject to further study. It doesn't really change much about
> Kalpana One, but it does cut that mass in half and make everything
> about two times easier.

Al, we went through this very issue almost 3 years ago:

You're positing that the shielding requirement needs to be doubled
because the Earth is blocking half of the radiation. No. Imagine that
you are standing with a radiation meter in Denver. You take a reading.
The source of the radiation is coming from the sky above you (let's
discount sources in the Earth itself. The radiation reading is the sum
total of radiation that you have to address, not double the amount.

Now, imagine that instead of standing in Denver, we could erase the
mass of the Earth but leave atmosphere in place as an outer sphere
that enveloped the Earth. You're positing that the radiation level
would suddenly double because the mass of the Earth has been removed.
However, you're neglecting the role of the atmosphere on the other
side of the sphere - it would have attenuated the radiation level to
the same degree as the atmosphere above Denver, therefore there would
be little residual radiation left for the bulk of the Earth's mass to
block.

Therefore, the model for shielding should only account for a radiation
intensity that comes from one direction. In any Habitat, there will be
shielding all around the circumference which will envelop the Habitat
in the same fashion that the atmosphere envelops Earth.

Your shielding requirements can be halved back to the orginal Summer
Study requirements.

TangoMan

--- In spacesettlers@yahoogroups.com, "victoriatangoman"
wrote:

> Your shielding requirements can be halved back to the orginal Summer
> Study requirements.
>
> TangoMan

Looking through that comment thread, here are some comments from
Arthur and Lucio: