Greeting to the list,

I have just sent a long post off about a super sized habitat, while I was
putting the long post together I replied to a post from Robert which only
needed a short answer, he was mixing this super habitat with the ring-world
in the book, a problem that comes from having more than one conversation
going on at once. So in the back of my mind I had the image of the
ring-world going around a star and this made me think of other posts where
people had discussed putting a ring around the world. Now I do not think
that is a good idea for a lot of reasons, a solid ring of habitats around
Earth could be a disaster waiting to happen but what about other planets or
moons. Then while on an evening walk with my lovely wife (hello Lan, light
of my life :-) I had another idea, so here goes.
How about we build a ring in geo-sync (Luna-sync?) around the moon or a
moon, say Titan out at Saturn. The ring could be built in orbit, whatever
orbit was decided on, there is no need for it to stay directly over one
patch of ground, in fact with higher and lower orbits you could have
multiple rings, sorry Wheels (in the long post to Ian Woollard I needed
something to call this kind of hyper habitat, ring was being used for so
many things it was confusing, If anybody has a good name Im open to
suggestions). These could not be 15,000Km wide, that would make them bigger
than the moon they orbit and that makes things complicated but even at
1,000Km wide (still bigger than a lot of moons) it is a big structure. There
a number of way to do this so below is a far from complete list, no doubt
with many problems and errors, feel free to add, correct or criticise if
needed. On that point some of the ideas here are not going to be the most
practical ideas but some are fun and some worth looking at just because
there are different, some numbers are rounded.

Number 1: The super railroad system.

You find a moon without an atmosphere and around the equator or some other
great circle you build a large wide track from one kilometre up to 100km
wide and you have a train that travels around the track at speeds that give
you negative 1G, that is people stand on the roof of the train. For
example a track around Enceladus, a moon of Saturn would be a maximum of
around 500Km (504.2 if you want to be picky), you would have to have the
train travelling at 5,683 Km/hr, a single trip around the moon in 995
seconds (16.58 min) you would be held to the roof of the train with 1G the
normal gravity of the moon (0.0115G) so up your speed to 5,712 Km/hr, a trip
of 990 seconds and you will overcome the small gravity of the moon. This
track is going to need to be held down well to withstand the forces exerted
on it. Enceladus has a mean density of just 1.61 grams per cubic centimetre,
only half again as dense as water, this moon may be mostly ice and hard to
anchor to. Mind, would you need to anchor to the ice that well, it would
depend on the design of the train. Consider a tube, in vacuum, it sits on
the towers spotted around the moon Enceladus, inside the tube is a train,
this train is as long as its circular track so that the front and back are
in contact. The speed of the train pushes it up against the to top of the
tube (made of that good old standby CNT or some other super strong stuff,
from now on when I talk about some super cable, this is what I mean), the
tube does not need to be held down to the track that well, the tube itself
handles the strain. The train is 500Km in diameter so the track is 1,575Km
long (it stands a few meters above the surface). At 1,575Km long and 50Km
wide we have 78,750 Km sq a good size habitat. This could be done on any
body with no atmosphere, if you want to avoid air resistance problems (of
course the tube could be air tight, so you could do it here on Earth).

The biggest problem that I see here is that if it fails it fails big, you
would need to use something like mag-lev to stop problems with bearings or
any material contact, that would be very bad.

Number 2: The super railroad system in orbit.

The hyper-habitat in my other posts that got me thinking about different
types of habitats is the direct father of this one. Rather than a 15,000Km
long, 5,000Km wide super-hab spinning around a central axle, we reduce the
size of the hab and put the moon/planet in the middle (put this around Mars
and watch certain people go nuts, okay, sorry to any Mars types out there, I
do love you guys, really, we all want space, I just wish you could see our
side as well, though if you are reading this, you probably can ;-) On some
of the smaller moons you may even be able to run cables from the poles,
attached to a spindle. If we keep using Enceladus and have the Wheel move
out to a radius of 1,500Km or 1,250Km above the surface and spinning
(orbiting? Not really it is way above orbital speed) at once per 2,450
seconds, 13,849Km/hr you get just under 1G. At 9,425Km long and say 200Km
wide we have 1,885,000 Km sq, a pretty big habitat but really just the same
as number 1, just bigger.

Number 3: The tidal, orbital array.

For this we need a big planet, so lets stay with Saturn, its late here so
Im not going to bother with complex maths but if anybody else wants to do
it, I would be interested.
I should start by saying that the genesis of this idea started with Robert
and his belt of habitats around the Earth.
We begin by building a lot, a real lot of habitats, they are long tubes,
several thousand kilometres long and maybe a hundred kilometres wide, they
do not have to be cylinders, a ball on a stick design would do. You have a
large ball on top, a long (thin) tube (maybe only 100 metres wide) but
thousands long with a second ball on the bottom (not as big as the top one,
I think that would work). You put the habitat into orbit and have the centre
of mass at the orbit you want. Tidal forces will keep the tube straight and
the bottom will be orbiting slower than normal so you will not be in
freefall, if you are at the right distance from the planet you should have a
good percentage of normal gravity, the top ball will be orbiting faster than
normal and you should have a force pushing you out, if it is long enough you
might get a full 1G, pointing out. Now you attach lots of these together
until Saturn has a second ring, I have no idea of how large this would be or
what kind of square meters you would be looking at. Really Im not sure this
would work the way I think, the maths really needs to be done.

Well its getting late here and I have had a long day, so I think that this
is enough to go on with for now.

As a final personal note, it is now about quarter past one in the morning
and for us here in Australia the 11th of September has past, for you in
America it is just starting, I vividly remember 5 years at about this time I
sat watching the TV and not believing what I was seeing, when I first saw
the news flash at the bottom of the screen saying that a plane had hit the
first tower, I assumed it was a light plane, I turned over the channel and
saw the damage and could see that it was no light plane, I saw the second
plane hit and the towers come down, I didnt know how to react. My
sympathies to all those who lost love ones on that day and also to those who
didnt. No matter what your argument with somebody, that was not politics or
religion, it was murder. You didnt deserve it.

Darren Brown
Canberra
Australia

On 9/11/06, Darren wrote:
(...)
> Number 3: The tidal, orbital array.
>
> For this we need a big planet, so lets stay with Saturn, its late here so
> Im not going to bother with complex maths but if anybody else wants to do
> it, I would be interested.
> I should start by saying that the genesis of this idea started with Robert
> and his belt of habitats around the Earth.
> We begin by building a lot, a real lot of habitats, they are long tubes,
> several thousand kilometres long and maybe a hundred kilometres wide, they
> do not have to be cylinders, a ball on a stick design would do. You have a
> large ball on top, a long (thin) tube (maybe only 100 metres wide) but
> thousands long with a second ball on the bottom (not as big as the top one,
> I think that would work). You put the habitat into orbit and have the centre
> of mass at the orbit you want. Tidal forces will keep the tube straight and
> the bottom will be orbiting slower than normal so you will not be in
> freefall, if you are at the right distance from the planet you should have a
> good percentage of normal gravity, the top ball will be orbiting faster than
> normal and you should have a force pushing you out, if it is long enough you
> might get a full 1G, pointing out. Now you attach lots of these together
> until Saturn has a second ring, I have no idea of how large this would be or
> what kind of square meters you would be looking at. Really Im not sure this
> would work the way I think, the maths really needs to be done.
(...)

This would work the way you think - actually it is much like the
"needle worlds" that Clarke describes in "3001". They were in fact
bamboo-like orbital elevators many kilometers thick composed of hollow
segments that could be used as habitats. Your design is simpler (and
shorter) in the sense that it is just a "tidal habitat" without
accumulating the function of space elevator.

(As a side comment, I am not sure that you could get this on Saturn
without having the lower end inside the rings, but I have not done the
maths either.)

--- In spacesettlers, Darren wrote:

> My sympathies to all those who lost love ones on that day and also
> to those who didnt. No matter what your argument with somebody,
> that was not politics or religion, it was murder. You didnt deserve
> it.
>
> Darren Brown
> Canberra
> Australia

I know that I can not speak for ALL Americans, but I can speak as AN
American when I say: thank you.

Lucio ;

I have been doing a lot of thinking about the types of habitats that we may
have one day. I have no doubt that at first we are going to have a lot of
small things, perhaps something like the banded torus, a design that can be
expanded as the need for more room makes itself felt. The beauty of this
kind of design is that we can start small and build up from there. But as
the space manufacturing facilities we have mature and we gain experience in
how to build, then there is going to be more variation in the designs,
people will start to build habitats not because it is the cheapest or the
most efficient design for a given place and job but because it is a design
they like. The question is will (or should I say WHEN will ) the cost of
habitats ever drop down to the point where a single company or developer can
have one built for later resale or how about a single person building a
small habitat as a single dwelling (Mike Combs has a good story about this,
sorry the name escapes be but it also has pirates, I am a fan Mike)

>On 9/11/06, Darren > wrote:
>(...)
>> Number 3: The tidal, orbital array.
>>
>> We begin by building a lot, a real lot of habitats, they are long tubes,
>> several thousand kilometres long and maybe a hundred kilometres wide, they
>> do not have to be cylinders, a ball on a stick design would do. You have a
>> large ball on top, a long (thin) tube (maybe only 100 metres wide) but
>> thousands long with a second ball on the bottom (not as big as the top one,
>> I think that would work). You put the habitat into orbit and have the centre
>> of mass at the orbit you want. Tidal forces will keep the tube straight and
>> the bottom will be orbiting slower than normal so you will not be in
>> freefall, if you are at the right distance from the planet you should have a
>> good percentage of normal gravity, the top ball will be orbiting faster than
>> normal and you should have a force pushing you out, if it is long enough you
>> might get a full 1G, pointing out. Now you attach lots of these together
>> until Saturn has a second ring, I have no idea of how large this would be or
>> what kind of square meters you would be looking at. Really Im not sure this
>> would work the way I think, the maths really needs to be done.
>(...)
>
>This would work the way you think - actually it is much like the
>"needle worlds" that Clarke describes in "3001". They were in fact
>bamboo-like orbital elevators many kilometers thick composed of hollow
>segments that could be used as habitats. Your design is simpler (and
>shorter) in the sense that it is just a "tidal habitat" without
>accumulating the function of space elevator.
>
>(As a side comment, I am not sure that you could get this on Saturn
>without having the lower end inside the rings, but I have not done the
>maths either.)

Good to hear that it would work, possible that it would need to be in the
rings, problem there. Of course Saturn is just one big planet, I passed by
Jupiter because of the radiation but with the right shielding you could get
away with it. Then there is the other two giants and they may just be the
best option, to avoid the small rocks that are going to be in orbit around
these big boys, put it in to polar orbit most of the time you would be out
of the way of any small debris. While this design is fun and could be
impressive to see in orbit, would anybody ever build it? Other designs might
just be so much better that it is not practical to do these, shame really, I
would love to see a belt of these in orbit, hell, Id love to see any
habitat in orbit.

Darren

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

> The question is will (or should I say WHEN will ) the cost of
> habitats ever drop down to the point where a single company or
> developer can have one built for later resale or how about a single
> person building a small habitat as a single dwelling (Mike Combs
> has a good story about this, sorry the name escapes be but it also
> has pirates, I am a fan Mike)

Thanks. This is a reference to "Miranda and the Space Pirates"
http://members.aol.com/howiecombs/havnrock.htm.

Actually, in the story, a collection of four or five clans, consisting
of several families apiece, begin building habitats in the Belt. I
don't think I ever put a total number on the population, but imagined it
was something approaching a hundred people.

In assuming such a small number could build their own habitat, I assumed
3 things:

1. That vacuum vapor deposition would make the major part of building a
habitat much less labor-intensive than the kind of construction methods
we more typically think about.

2. That a century of advancement in robotics would make the job consist
mostly of directing robots through their tasks.

3. That self-replicating systems would enable a small group to ramp up
from modest beginnings to any level of industrial throughput desired.

Regards,

Mike Combs

> The question is will (or should I say WHEN will ) the
>cost of habitats ever drop down to the point where a
>single company or developer can have one built for later
>resale or how about a single person building a small
>habitat as a single dwelling

Aside from his propensity for assuming that we'll find ways to adapt
healthfully to zero-G living, I like Marshall Savage's single family
homes on the Moon.
There's also this (another suggestion for clustered habitats -I don't
know if this was brought up in that thread)
http://www.nas.nasa.gov/About/Education/SpaceSettlement/Nowicki/SPBI1G
H.HTM

>From the book "Interstellar Migrations and the Human Experience" I
learned that the most common population most everywhere humans have
set up as a nation, is 500, broken up into maybe 25 tribal villages
of 25 people. Maybe ten of fifty, but fifty people is rather a large
number to integrate into a single family grouping.

Mike Combs wrote
>in the story, a collection of four or five clans,
>consisting of several families apiece, begin building
>habitats in the Belt. I don't think I ever put a total
>number on the population, but imagined it was something
>approaching a hundred people.
> In assuming such a small number could build their own
>habitat, I assumed... vacuum vapor deposition... robotics
>... self-replicating systems

I consider SRS to be another unobtainium whiz-bang assumption. It
seems possible, but we don't know how to do it and we don't know
if/when several breakthroughs will allow it (A strong hint we have is
that the only way it's been done in the past is biological, and tell
me that isn't messy)
I doubt that a macrolife colony of 500 will be self-sufficient and
self replicating -unless one of these magic building techniques comes
about. Maybe not 5000. Too many little things go into each industry
that's required to make even a small thing.
Too many skills needed, and a self-teaching library conmputer
(that'll survive any real stretch of time) is another piece of magic.
History is messy, and it's almost too extravagent an asumption to
me, that it'll be any different.
All this is one reason I like Nomadic interstellar cometary colonists
as the long-run bet. It's extremely chaotic, and it assumes that a
large population with a widespread industrial infrastructure (not
near K=2, but at least using all the capabilities of a couple of
planet/mooon systems & many asteroidal colonies at least).
Little colonies could get lost in the Oort cloud, and they're still
within a few days communication of anywhere.

But I suppose it is harder to write stories based in this kind of
world. I've toyed with trying to write it into adventure games in the
GURPS RPG system which I could convince people to play in... S.F.
authors love a widget where you use techno-jargon, push a button, and
a thing is built and ready to use in the story, or the scene of
action is moved instantly instead of the mess of building or moving
the old-fashioned way. Everybody wants to get right to the action,
instead of role-playing all the deals with sub-contractors spread
across 500 cubic AU of space, and shipyard problems, etc.

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of John Frazer

> I consider SRS to be another unobtainium whiz-bang assumption.
> It seems possible, but we don't know how to do it and we don't
> know if/when several breakthroughs will allow it (A strong hint
> we have is that the only way it's been done in the past is
> biological, and tell me that isn't messy)

Oh, I don't know. It's easy for me to imagine a system that scoops up
soil, smelts out metals and silicon, builds all of the components of its
own construction, assembles a duplicate, and then copies its operating
system. A couple of important points are:

1. Having 100% closure would be great, but even an
only-partially-complete self-replication of 90 or 95% total system mass
would be a tremendous leg up. Past a point, O'Neill felt that
partially-self-replicating systems were an important requirement for
High Frontier.

2. Such a system would not necessarily require AI. Present computers
running current "follow this looping program line-by-line" software
could handle this. Bacteria don't have much in the way of intelligence,
but they are able to self-replicate.

Frankly, I expect macro systems capable of self-replication much sooner
than I expect nanotech replicators.

But one cautionary comment that I make to those who want to start
setting up replicators on the moon next year is that we'll see
replicators being unleashed on terrestrial deserts well before we see
them on the moon.

Regards,

Mike Combs