On May 07, 2007, at 05:03 UTC, Chris Smyth wrote:

> Boy am I out of date about space settlements! I wasn't even aware
> of the Kalpana One study until I saw the link today. I read the study
> revision (12 pages) and I'll need to go back to the original study to
> see what's in it.

It's essentially the same, but the calculation of rotational stability
in the original study was incorrect. As a result, the cylinder is
longer (and in reality, would have a tendency to tumble), where as in
the new study it is shorter and stable.

> One interesting comment in the study mentions using
> material from NEO's (Near Earth Objects) to provide the mega-tonnage
> of shielding needed for the settlement.

Yes -- and if that doesn't work out, lunar regolith could be used
instead.

> At the risk of sounding naive, I immediately thought of the earth
> crossing asteriod that is expected to come within about 20,000 miles
> of the Earth in 2029 (I think).

Apophis? IIRC, the delta-V from that is much greater than for some
other asteroids. Remember, it's not the distance that matter so much
as the change in velocity needed to move material from it into Earth
orbit (or wherever you want to use it).

Best,
- Joe

Joe Strout -- joe@...
Strout Custom Solutions

Yes JOE is right .. there was a mistake in the AIAA paper which he himself told us and it was corrected.

Thanks JOE never got a chance to say that to you, only AL sir told me and we corrected it.

Take care

Nittin arora
Georgia tech.

From: "joe@..."
To: spacesettlers@yahoogroups.com
Sent: Monday, May 7, 2007 8:01:52 PM
Subject: [spacesettlers] Kalpana One design (was Re: Rotating space colonies)

On May 07, 2007, at 05:03 UTC, Chris Smyth wrote:

> Boy am I out of date about space settlements! I wasn't even aware

> of the Kalpana One study until I saw the link today. I read the study

> revision (12 pages) and I'll need to go back to the original study to

> see what's in it.

It's essentially the same, but the calculation of rotational stability

in the original study was incorrect. As a result, the cylinder is

longer (and in reality, would have a tendency to tumble), where as in

the new study it is shorter and stable.

> One interesting comment in the study mentions using

> material from NEO's (Near Earth Objects) to provide the mega-tonnage

> of shielding needed for the settlement.

Yes -- and if that doesn't work out, lunar regolith could be used

instead.

> At the risk of sounding naive, I immediately thought of the earth

> crossing asteriod that is expected to come within about 20,000 miles

> of the Earth in 2029 (I think).

Apophis? IIRC, the delta-V from that is much greater than for some

other asteroids. Remember, it's not the distance that matter so much

as the change in velocity needed to move material from it into Earth

orbit (or wherever you want to use it).

Best,

- Joe

Joe Strout -- joe@...

Strout Custom Solutions

--- In spacesettlers, joe wrote:

> Apophis? IIRC, the delta-V from that is much greater than for some
> other asteroids. Remember, it's not the distance that matter so much
> as the change in velocity needed to move material from it into Earth
> orbit (or wherever you want to use it).

How does the delta-V from Apophis compare to the Moon? What sort of
asteroid is Apophis? What resources are available from it?

Well, I can probably look those last two up.

Then again, maybe not. It matters if it's a snowball, hunk of iron,
or carbon-rich lump.

the Delta V for apophis and others can be found at:
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

(99942) Apophis 2004 MN4 5.687 km/s
Moon: 6.0 km/s

B

Xenophile wrote:

--- In spacesettlers@yahoogroups.com, Nitin Arora
>
> Yes JOE is right .. there was a mistake in the AIAA paper which he
himself told us and it was corrected.
>
> Thanks JOE never got a chance to say that to you, only AL sir told
me and we corrected it.
>
> Take care
>
> Nittin arora
> Georgia tech.
>

Hi Nitin,

Being a technician and admitedly behind the times in space
settlement design I wonder if the inner workings of Kalpana One has
been re-analyzed since the days of the O'niel Cylinder and the
Stanford Torus studies. If memory serves me correctly, these included
some rather detailed analysis of mass balance and recycling
technologies.
I see a high LEO space settlement as a combination tourist
destination and transit point for space workers going and comming
from various work assignments such as servicing satelites, moon or
asteroid mining and construction activities related to building more
space infrastructure. In this respect it would be somewhat like the
small towns that spring up aronund major interstate intersections.
There would be a set of "local citizens" and a large number of
transients feeding the economy of the station. Of course fuel and
consummables resupply and spacecraft repair would be a big part of
the settlement economy.

Any thought on this?

Chris

On May 09, 2007, at 03:12 UTC, Chris Smyth wrote:

> Being a technician and admitedly behind the times in space
> settlement design I wonder if the inner workings of Kalpana One has
> been re-analyzed since the days of the O'niel Cylinder and the
> Stanford Torus studies.

The Kalpana One design began WAY after those studies. And it was just
re-analyzed in the last year or two (resulting in the revised paper
just posted).

> If memory serves me correctly, these included
> some rather detailed analysis of mass balance and recycling
> technologies.

Not all that detailed, but they did touch on that.

> I see a high LEO space settlement as a combination tourist
> destination and transit point for space workers going and comming
> from various work assignments such as servicing satelites, moon or
> asteroid mining and construction activities related to building more
> space infrastructure. In this respect it would be somewhat like the
> small towns that spring up aronund major interstate intersections.
> There would be a set of "local citizens" and a large number of
> transients feeding the economy of the station. Of course fuel and
> consummables resupply and spacecraft repair would be a big part of
> the settlement economy.

That all seems reasonable to me.

Best,
- Joe

Joe Strout -- joe@...
Strout Custom Solutions

This is an old thread, but it seems worthwhile to revisit it in order to
discuss some aspects if its design and purpose.

One of the first things that comes to mind are the complimentary
concepts - borrowed from the maritime industry (and the ISS) - of
compartmentalization and redundancy. Kalpana One is envisioned as a
series of concentric cylinders - the outermost being the 1g main living
area. The inner cylinders would serve as agricultural,
industrial/manufacturing, and storage areas. The innermost cylinder
would possibly provide zero-g recreation.

I would first propose that these nested cylinders have the engineered
capacity to be quickly sealed off from one another in all respects
(atmospherically, electrically and hydrologically) in the event that
there is a fire or significant mechanical failure or hull puncture.
Likewise, I would suggest the each of these nested cylinders be
segmented with the same capability to isolated individulal segments for
the same reasons. The number of isolating segments employed in each
nested cylinder would be dictated by the potential impact of the various
failure modes or emergency conditions anticipated. Due to its enclosed
atmosphere, an uncontrorled fire would probably be one of the major
concerns - as it is on ships and, especially, on submarines.

Rudundacy of critical systems is just common sense in any closed system.
In this regard redundancy means not only the ability to switch to
alternate pieces of equipment, but also the ability to reroute systems
around failed or isolated portions of the station. This would include
communications, computers, electrical power transmission and switching,
water supplies and piping, air supplies and ductwork, drainage systems
and pumps, cooling systens and waste heat radiator systems, etc. Due to
the potential for serious consequences of multiple (individual
component) failures, I would recommend double redundancy (two back-up
systems) for anything that might significantly effect the operation of
the station. To my mind this includes just about every system.

Any thoughts on this?

Chris

--- In spacesettlers@yahoogroups.com, joe@... wrote:

Only thought is that this, like an O'neil colony, is a massive undertaking and probably second or third generation habitat. In this thread we're discussing ways to get a Human rated habitat, rotating in some manner to provide weight for long term habitation, up and in operation quickly and, to the extent possible, inexpensively. I don't see the nested cylinders as fitting this scenario.
Victor

From: csmyth3025
Sent: Monday, September 27, 2010 8:12 AM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Kalpana One design (was Re: Rotating space colonies)

This is an old thread, but it seems worthwhile to revisit it in order to
discuss some aspects if its design and purpose.

One of the first things that comes to mind are the complimentary
concepts - borrowed from the maritime industry (and the ISS) - of
compartmentalization and redundancy. Kalpana One is envisioned as a
series of concentric cylinders - the outermost being the 1g main living
area. The inner cylinders would serve as agricultural,
industrial/manufacturing, and storage areas. The innermost cylinder
would possibly provide zero-g recreation.

I would first propose that these nested cylinders have the engineered
capacity to be quickly sealed off from one another in all respects
(atmospherically, electrically and hydrologically) in the event that
there is a fire or significant mechanical failure or hull puncture.
Likewise, I would suggest the each of these nested cylinders be
segmented with the same capability to isolated individulal segments for
the same reasons. The number of isolating segments employed in each
nested cylinder would be dictated by the potential impact of the various
failure modes or emergency conditions anticipated. Due to its enclosed
atmosphere, an uncontrorled fire would probably be one of the major
concerns - as it is on ships and, especially, on submarines.

Rudundacy of critical systems is just common sense in any closed system.
In this regard redundancy means not only the ability to switch to
alternate pieces of equipment, but also the ability to reroute systems
around failed or isolated portions of the station. This would include
communications, computers, electrical power transmission and switching,
water supplies and piping, air supplies and ductwork, drainage systems
and pumps, cooling systens and waste heat radiator systems, etc. Due to
the potential for serious consequences of multiple (individual
component) failures, I would recommend double redundancy (two back-up
systems) for anything that might significantly effect the operation of
the station. To my mind this includes just about every system.

Any thoughts on this?

Chris

--- In spacesettlers@yahoogroups.com, joe@... wrote:

I would think that the redundancies you mention, the ability to section off every section and have fully independent systems for each, and 2 back up systems for each to be excessive. But I can't say that for sure, I would just wouldn't want to start with the premise of uber costly/safety design that isn't actually necessary to do the job.

I would think that ISS, antarctic and submarine experiences and extrapolating further on potential problems we could come up with safety systems that do the job without overly burdening the budget or diverting from other parts of the station.

For example, a catastrophic fire or decompression could be answered with breathing masks stored in every location and the ability to seal each area to prevent spread. (Without the full independence for each section, in other words not independent bathrooms, heating/cooling, etc.) Then emergency teams would assess the situation and open/close as needed and suit up for repair/damage control.

On back up systems, I would think it would depend on the system, which would decide how much back up is needed. Do we need 2 back up toilets per working toilet? Maybe not, do we need 2 back up CO2 scrubbers per scrubber? Quite possibly.

Brooks

--- In spacesettlers@yahoogroups.com, "csmyth3025" wrote:

On 9/28/10 5:22 PM, Victor Smith wrote:

> Only thought is that this, like an O'neil colony, is a massive
> undertaking and probably second or third generation habitat. In this
> thread we're discussing ways to get a Human rated habitat, rotating in
> some manner to provide weight for long term habitation, up and in
> operation quickly and, to the extent possible, inexpensively. I don't
> see the nested cylinders as fitting this scenario.

I can't agree. Kalpana One (which I was involved in the design of)
included nested cylinders *because* they are inexpensive. You get
dramatically more usable "land" area without needing more pressure hull
and radiation shielding (which are the bulk of the mass in a habitat).

csmyth3025 wrote:

> I would first propose that these nested cylinders have the engineered
> capacity to be quickly sealed off from one another in all respects
> (atmospherically, electrically and hydrologically) in the event that
> there is a fire or significant mechanical failure or hull puncture.
> Likewise, I would suggest the each of these nested cylinders be
> segmented with the same capability to isolated individulal segments for
> the same reasons.

Making them all pressure shells -- and especially your second
suggestion, where the individual compartments aren't even vaguely round
-- would increase the cost quite a bit, I think.

It might be doable, and you still get the benefits of shared radiation
shielding, but it would certainly be worth looking at how much those
extra pressure shells increase the cost.

(I do like the added safety very much, though!)

> Due to its enclosed
> atmosphere, an uncontrorled fire would probably be one of the major
> concerns - as it is on ships and, especially, on submarines.

Subs are very small; this thing is big. I think a fire would be easier
to control there than it is on Earth, and there are probably cheaper
ways to accomplish that using pressure shells -- a sprinkler system, for
example.

Best,
- Joe

Your right, Victor. I picked up on an older thread from 2007 since it
was the only one I could find on this subject and since Kalpana One is,
as far as I know, the most recent study done on rotating space colonies.

The design basis for Kalpana One is a population of 3000. This 2006
study (revised in 2007 to correct an error related to rotational
stability) can be found here:

http://www.nss.org/settlement/space/2007KalpanaOne.pdf

The study addressed various considerations to arrive at what was felt by
the study group to be the most economical form for a space colony
supporting a population of 3000. They concluded that a cylinder with a
radius of ~250 meters (at the ground level of the main living quarters),
a length of 325 meters and a rotational rate of 2 rpm to provide 1g
artificial gravity would be most economical and practical.

An earlier 1977 study went in to greater detail concerning design
criteria for space colonies configured for populations of 100, 10,000
and 10^6. This NASA Ames Research Center study can be found here:

http://space.alglobus.net/spaceres/index.html

Section II-1 of this study addresses physical design criteria for these
various sized colonies. The area required per person for a 100 person
station would be ~79 m^2 according to the study group. This requirement
doesn't provide any area for agriculture, animals, or food processing.
For this reason I prefer to use the more generous allocation of ~157 m^2
per person for colonies of 10,000 which provides for these activities.

Assuming that a torus design is preferred for a small colony of ~100
population, the minimum radius for a 1g habitat floor level at 2 rpm is
actually 223.4 meters. [r=(9.8 m/sec^2)(900 sec^2)/4pi^2]

If a torus tube interior diameter of 15 meters is used as the width of
the habitable floor area then the space allocation of 157 m^2 per person
allows for a population of 134 [(446.8 m)(pi)(15 m)]. This is likely the
minimum sized "working" permanent space colony which can accomodate a
small transient population either outward bound for other destinations
or returning to Earth.

It's assumed that a colony of this type will have some economic base to
sustain itself. It may serve as a transportation hub (servicing
spaceships and providing a "rest stop" for their crews) or, perhaps,
serving as a base for construction personnel working on solar power
satellites.

Any thoughts on this scenario?

Chris

--- In spacesettlers@yahoogroups.com, "Victor Smith"
>
>... In this thread we're discussing ways to get a Human rated habitat,
rotating in some manner to provide weight for long term habitation, up
and in operation quickly and, to the extent possible, inexpensively. I
don't see the nested cylinders as fitting this scenario....

Assuming that if we can fabricate such a habitat then we must also have available sufficiently efficient heavy lifters and personnel lifters to routinely supply and provide transportation to the habitat, then, besides the occupations that you mentioned, 'as a transportation hub (servicing spaceships and providing a "rest stop" for their crews) or, perhaps serving as a base for construction personnel working on solar power
satellites', I could see inhabitants engaged in roles such as 'sweeping' the orbital debris from around the planet in small ships (it's likely that in addition to making Earth orbital space safer this debris could provide barterable/ recyclable materials of use to the habitat), acting as construction crew on either interplanetary ships or new habitats, given facilities external to the habitat, colonists might process metals and volatiles from asteroids harvested and brought into orbit near the habitat. Inhabitants of scientific persuasion will no doubt find that a great many innovative processes and products come out of their labs (the patents for which will doubtless go far toward bolstering the habitat economy). Other colonists, interested in exploration, will want to sign on as crew for various missions, leaving their families safely at home on the habitat. The aforementioned avocations are just those that readily occur to me, a layman/enthusiast. I'm certain that many more will manifest as this scenario becomes reality.

The stated mass requirements for the Kalpana 1 is 7 million tons (including shielding). The authors of the plan therefore specefied that the habitat must be assembled from materials derived from either the moon or NEO asteroid harvesting, either of which is going to require a whole infrastructure of its own. This is why I say that K-1 is, at best, a second generation habitat, and probably 3g.

From: csmyth3025
Sent: Wednesday, September 29, 2010 4:24 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Kalpana One design (was Re: Rotating space colonies)

Your right, Victor. I picked up on an older thread from 2007 since it
was the only one I could find on this subject and since Kalpana One is,
as far as I know, the most recent study done on rotating space colonies.

The design basis for Kalpana One is a population of 3000. This 2006
study (revised in 2007 to correct an error related to rotational
stability) can be found here:

http://www.nss.org/settlement/space/2007KalpanaOne.pdf

The study addressed various considerations to arrive at what was felt by
the study group to be the most economical form for a space colony
supporting a population of 3000. They concluded that a cylinder with a
radius of ~250 meters (at the ground level of the main living quarters),
a length of 325 meters and a rotational rate of 2 rpm to provide 1g
artificial gravity would be most economical and practical.

An earlier 1977 study went in to greater detail concerning design
criteria for space colonies configured for populations of 100, 10,000
and 10^6. This NASA Ames Research Center study can be found here:

http://space.alglobus.net/spaceres/index.html

Section II-1 of this study addresses physical design criteria for these
various sized colonies. The area required per person for a 100 person
station would be ~79 m^2 according to the study group. This requirement
doesn't provide any area for agriculture, animals, or food processing.
For this reason I prefer to use the more generous allocation of ~157 m^2
per person for colonies of 10,000 which provides for these activities.

Assuming that a torus design is preferred for a small colony of ~100
population, the minimum radius for a 1g habitat floor level at 2 rpm is
actually 223.4 meters. [r=(9.8 m/sec^2)(900 sec^2)/4pi^2]

If a torus tube interior diameter of 15 meters is used as the width of
the habitable floor area then the space allocation of 157 m^2 per person
allows for a population of 134 [(446.8 m)(pi)(15 m)]. This is likely the
minimum sized "working" permanent space colony which can accomodate a
small transient population either outward bound for other destinations
or returning to Earth.

It's assumed that a colony of this type will have some economic base to
sustain itself. It may serve as a transportation hub (servicing
spaceships and providing a "rest stop" for their crews) or, perhaps,
serving as a base for construction personnel working on solar power
satellites.

Any thoughts on this scenario?

Chris

--- In spacesettlers@yahoogroups.com, "Victor Smith"
>
>... In this thread we're discussing ways to get a Human rated habitat,
rotating in some manner to provide weight for long term habitation, up
and in operation quickly and, to the extent possible, inexpensively. I
don't see the nested cylinders as fitting this scenario....

Your point is well taken, Victor - but we need to distinguish between an
"orbiting space colony" and those facilities that will necessarily
precede its construction. I would put these predecessor facilities
(habitats, if you prefer) more into the category of construction shacks
or construction camps. These types of facilities will be needed, of
course - both on the Moon (the most likely source of raw and processed
construction materials) and in orbit (to effect the construction of the
station). The initial facilities on the Moon will likely develop into
lunar colonies in their own right - in much the same way that Boulder
City, Nevada has become a city with its own economic base despite its
purpose-built function as quarters for the workers (and in many cases,
their families) who were constructing the Hoover Dam (a 5-year project
that was in 1931-1936 located in an isolated and remote area).

I'm inclined to think that a 100-person orbiting space colony is about
as small a "village" as you could get. Anything smaller would most
likely be a corporate or government "purpose-built" facility. There will
no doubt be larger colonies built - such as Kalpana One - designed to
house 3000 people and more. In this respect, I agree that Kalpana One is
a 2nd or 3rd generation facility. A 100 person facility is a first
generation true orbiting space colony in my mind.

Constructing a Stanford Torus-type 100 person facility is a massive
undertaking. If one takes the 1977 Ames Research Center study for
shielding requirement for radiation workers (5 rem/yr) as a baseline
requirement (with shelters akin to "hurricane shelters" to weather
infrequent intense CME's from the Sun), the shell of the torus and, I
would think, the "spokes" as well, will have to be constructed with
about 2800 kg/m^2 "walls". As it turns out, this mass is equal to about
1 meter of "typical" concrete - which has a mass of about 2400 kg/m^3.
High density concrete is more than twice as dense as "typical concrete"
so a designed concrete shell one meter thick with a 3,000 kg/m^3 density
should be easily achievable. Likewise, glass for skylights (more likely,
lightwave guides) is about as dense as concrete (ranging from 2000
kg/m^3 to ~8000 kg/m^3). A one meter thick shell of reinforced concrete
and glass "skylights" seems a reasonable design point.

The amount of mass for this shell is tremendous. If one assumes that the
torus has, as I stated in my previous post, a radius at the main "deck"
of 223.4 meters and a "tube" diameter of 15 meters, the surface area
that must be covered is 66,146 m^2 [Area=(4*pi^2*a*r)+(4*pi^2*r^2),
where a=the inner radius of the torus and r=the radius of the torus
"tube"]. The mass of the shell of the torus alone comes in at a
staggering 198,438,178 kg.

If one assumes that the torus is connected to the central hub by three
15 meter diameter "spokes", the surface area of these spokes will be
30,522 m^2 [pi*15 m*215.9 m*3]. At 3000 kg/m^2 the mass of the spokes
adds another 91,566,430 kg.

By my calculation the mass of a 100 person Stanford Torus-type space
colony with three "spokes" adds up to about 290,004,600 kg. If we add
another 10,000,000 kg for the hub and miscellaneous structures that
brings the total up to about 300,000,000 kg, or about 300,000 metric
tons. This is a lot less than the 7 million metric tons for Kalpana One,
but it's still a huge amount of material.

I suspect that such a facility will probably be built by transporting
components (from the Moon, most likely) to the orbiting construction
site. In this regard I envision the components as sections similar to
the cylinder sections used to construct the English Channel tunnel.

Any comments on this scenario (or my calculations)?

Chris

--- In spacesettlers@yahoogroups.com, "Victor Smith"
>
...The stated mass requirements for the Kalpana 1 is 7 million tons
(including shielding). The authors of the plan therefore specefied that
the habitat must be assembled from materials derived from either the
moon or NEO asteroid harvesting, either of which is going to require a
whole infrastructure of its own. This is why I say that K-1 is, at best,
a second generation habitat, and probably 3g.

I may have over-stated my case, Brooks. If a Stanford Torus-type
facility with three "spokes" is proposed, the isolation I'm suggesting
would simply be bulkheads with (large but closable) access doors at the
junctures of the spokes and the torus, between these junctures and the
torus sections in between junctures, and between the spokes and the hub.
The air handling infrasructure, water recycling infrastruture, power
distribution systems, communication systems, and computing systems in
any one of the three sections should be designed to accomodate the needs
of that section and, if need be, an adjacent section (albeit at a
predetermined minimal level of performance).

I think the recent experience that the crew of the ISS had with a failed
ammonia pump illustrates the need for such redundancy. In a small
station there is little room for equipment or process breakdowns. As one
who works hands-on with pumps, piping, electrical and computer controls,
and system processes I can assure you that breakdowns will occur
(sometimes in the most unexpected ways). No matter how much thought is
put in to identifying which equipment and systems are "critical" - our
space dwellers will no doubt find that the malfunction of some mundane
piece of equipment, valve, electrical relay, section of pipe, or run of
cable has unanticipated consequences that they wont be able to fix
quickly or easily.

Chris

--- In spacesettlers@yahoogroups.com, "brooksn" wrote:
>
> I would think that the redundancies you mention, the ability to
section off every section and have fully independent systems for each,
and 2 back up systems for each to be excessive...
>
...On back up systems, I would think it would depend on the system,
which would decide how much back up is needed. Do we need 2 back up
toilets per working toilet? Maybe not, do we need 2 back up CO2
scrubbers per scrubber? Quite possibly.

csmyth3025:

> If one takes the 1977 Ames Research Center study for
> shielding requirement for radiation workers (5 rem/yr) as a baseline
> requirement ...
> , the shell of the torus and, I
> would think, the "spokes" as well, will have to be constructed with
> about 2800 kg/m^2 "walls".

Probably no need for shielding in the spokes. People would only make brief transits through them, not live in them.

Regards,

Mike Combs

I would agree with the vocations mentioned for the colony but I would add one more big one, tourism. It definitely doesn't inspire the exciting science based or exploratory visions most space enthusiasts have when we think of humanity expanding into space. But it is right now more economically viable as a human expanding space oriented industry then anything else we have going, except government of course. So I would add hotel workers and guests to the list of inhabitants.

Brooks

--- In spacesettlers@...m, "Victor Smith" wrote:

My only comment would be that the added costs that a lunar base would create would make it unlikely to be used, especially given small asteroids abound that could be picked with far more diverse resources and lower energy requirements.

Brooks

--- In spacesettlers@yahoogroups.com, "csmyth3025" wrote:

Agreed, question on the ISS design and future designs. My understanding is that the windows of the ISS are a cause for major heat loss, and the ammonia based radiators for the ISS are needed to remove excess heat. I've wondered for awhile now why both these issues are merged. If larger sturdier windows, placed on the trailing side of station for reduced micro impacts, were put on the station and retractable insulation was available to regulate the temperature couldn't this reduce the complexity of the station and give you a kick ass view to boot?

Brooks

--- In spacesettlers@yahoogroups.com, "csmyth3025" wrote:

The problem with an orbiting space colony in regard to maintaining
thermal balance is that, because it's located in the vacuum of space,
the people inside are essentially living in a thermos bottle. The only
heat loss they can expect is radiative heat loss. On the other hand,
they can expect external radiative heat gain from those portions of the
station that are in sunlight as well as internal heat gain from people,
motors, computers, lights, etc.

The amount of heat gain inside the station significactly exceeds the
radiative heat loss that the station dwellers can hope to achieve
through a solid meter of concrete or glass. For this reason, heat
rejection panels permanently shaded from sunlight and cooling loops
(central air conditioning for space dwellers) will be an integral - and
critical - part of the station's air handling systems. The number, size,
and placement of skylights, windows, and lightwave guides will be
determined by illumination needs and aesthetic benefit. The capacity for
external heat rejection by radiative panels will not be largely effected
by heat gain or loss through these panels - although they will be one of
the factors considered during the design of the cooling and air handling
systems.

Chris

--- In spacesettlers@yahoogroups.com, "brooksn" wrote:
>
> Agreed, question on the ISS design and future designs. My
understanding is that the windows of the ISS are a cause for major heat
loss, and the ammonia based radiators for the ISS are needed to remove
excess heat. I've wondered for awhile now why both these issues are
merged. If larger sturdier windows, placed on the trailing side of
station for reduced micro impacts, were put on the station and
retractable insulation was available to regulate the temperature
couldn't this reduce the complexity of the station and give you a kick
ass view to boot?

There seems to be a common misconception that mining and processing
marerials on asteroids is easier and cheaper than mining and processing
materials on the Moon. First, you have to find not only an asteroid
that's close by, but it must be the right kind of asteroid. If your
going to the Asteroid Belt to pick out the types of asteroids you want,
your going to have to expend a lot of energy to get there and even more
energy to get the material back to the vicinity of Earth.
If your going to try to snag a nearby asteroid that zooming past
somewhere relatively close to Earth, your going to have to expend a lot
of energy to accelerate to the asteroid's velocity and even more energy
to alter the asteroid's orbit.

Either way, your going to need just as many people, just as much
equipment, and just as much habitat space as if you were mining and
processing materials on the Moon.

Mining and processing asteroids may prove to be practical and profitable
once we've establish a robust near-Earth space infrastructure and
transportation system. Until then, I don't think there's any beneficial
trade-off to justify asteroid mining over lunar mining.

Chris

--- In spacesettlers@yahoogroups.com, "brooksn" wrote:
>
> My only comment would be that the added costs that a lunar base would
create would make it unlikely to be used, especially given small
asteroids abound that could be picked with far more diverse resources
and lower energy requirements.

csmyth3025:

> There seems to be a common misconception that mining and processing
> marerials on asteroids is easier and cheaper than mining and processing
> materials on the Moon.

Personally, I would expect them to be in the same ballpark, even for asteroids with marginally smaller round-trip delta-V's than the lunar surface.

> First, you have to find not only an asteroid
> that's close by, but it must be the right kind of asteroid.

But by the same token, we would have to situate our lunar mine where there was the right kind of materials we wanted close by. It's been suggested that we locate where Maria borders on Highland so that we have access to the two different major material types on the moon.

> If your
> going to the Asteroid Belt to pick out the types of asteroids you want,

I think we're safe in assuming that anyone arguing for asteroid mining over lunar is targeting the NEAs.

> If your going to try to snag a nearby asteroid that zooming past
> somewhere relatively close to Earth, your going to have to expend a lot
> of energy to accelerate to the asteroid's velocity and even more energy
> to alter the asteroid's orbit.

Moving the entire asteroid into a High Earth Orbit would be gravy, but we could start out much more modestly by simply retrieving a certain amount of material off the surface.

> Either way, your going to need just as many people, just as much
> equipment, and just as much habitat space as if you were mining and
> processing materials on the Moon.

Probably true.

> Mining and processing asteroids may prove to be practical and profitable
> once we've establish a robust near-Earth space infrastructure and
> transportation system. Until then, I don't think there's any beneficial
> trade-off to justify asteroid mining over lunar mining.

The major argument for asteroids over the moon is that a greater variety of materials is freely available, including carbon, hydrogen, and perhaps even enough nitrogen to be useful.

The major arguments for moon over asteroids is frequency of launch windows and much shorter travel times. An argument can be made that, unlike for the moon, a manned trip to an asteroid would require vehicles and life support capabilities not yet demonstrated.

I would additionally argue that if telepresence technologies improve rapidly, this might push us in a lunar direction.

But I'm sure both sources of material will get used.

Regards,

Mike Combs

On 9/30/10 7:45 AM, brooksn wrote:

> I would agree with the vocations mentioned for the colony but I would
> add one more big one, tourism. It definitely doesn't inspire the
> exciting science based or exploratory visions most space enthusiasts
> have when we think of humanity expanding into space. But it is right now
> more economically viable as a human expanding space oriented industry
> then anything else we have going, except government of course. So I
> would add hotel workers and guests to the list of inhabitants.

Indeed, I'd suggest that the first "real" space colony (with trees, open
water, etc.) will probably be a Disney resort, or something similar,
with lots of villas for guests to stay in, a nice little beach, and
plenty of restaurants and attractions. Most of the population would be
weekly guests, the rest being park employees.

Best,
- Joe

Your right, Mike. When we get to the detailed design stage of a project
of this scope, I'm sure the engineers will be looking at availability of
materials, standardization of construction techniques, cost of
transporting construction materials, etc. They may find that thin-walled
metallic spokes are more cost-effective. It's also possible that with a
robust production and transportation system for torus
structural/shielding sections already established, the cost of using the
same type of material and construction techniques for the spokes may be
preferable.

We're a long way from having to make detailed construction plans. First,
we need to establish a source of accessible raw material. We then need
to design and establish mining, processing, and fabrication falilities,
as well as a transportation system for the finished construction
components. The step-by-step plans for these preliminary activities are
- in themselves - an interesting topic of discussion.

Chris

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> csmyth3025:
>
> > If one takes the 1977 Ames Research Center study for
> > shielding requirement for radiation workers (5 rem/yr) as a baseline
> > requirement ...
> > , the shell of the torus and, I
> > would think, the "spokes" as well, will have to be constructed with
> > about 2800 kg/m^2 "walls".
>
> Probably no need for shielding in the spokes. People would only make
brief transits through them, not live in them.

On 9/30/10 12:51 PM, csmyth3025 wrote:

> Either way, your going to need just as many people, just as much
> equipment, and just as much habitat space as if you were mining and
> processing materials on the Moon.

Quite right. Having the materials at a constant distance from Earth is
a huge logistical advantage.

Also, for the objection that the Moon is lacking volatiles and
platinum-group metals: the latter are likely available in impact
deposits (and I expect we'll find them soon). And volatiles are turning
out to be more available then we thought.

Best,
- Joe

http://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1/

Reading the above article, "Windows are a tremendous heat leak", also it states that "MLI insulation does a double-duty job: keeping solar radiation out, and keeping the bitter cold of space from penetrating the Station's metal skin."

And then it goes onto the issue of heat exchangers and radiators. But if we were to design the station to use the windows for its heat loss and use different insulation so that we protect from radiation but reduce the 'thermos' effect we may reduce our need for external radiators. What am I missing here? I understand if the effect is small, then it would have a small effect. But right now they are saying the window is a tremendous heat leak, that's a strong statement. And the insulation is designed 'for' keeping heat in, but if use the windows and less effective insulation it would seem a win win.

Brooks

--- In spacesettlers@yahoogroups.com, "csmyth3025" wrote: