Large Space Colonies and Large Disasters

The recent mass tragedies in Asia ask the question how safe will large
cylinder colonies be? The destruction of one of these could also lead
to the loss of several hundred thousand lives. How safe are they
against natural and man made attacks?

My reference design is 4 km in diameter, and has a non-rotating
external shield. The shield and the rotating cylinder each provide 5
tons per m2 of protection.

The shield would absorb small meteorites. The first layer of the shield
would be steel or chobham (tank) armour about 70mm thick (0.5 tons per
m2). This would stop small projectiles and break up larger ones. There
would then be a 100m gap (in which there would be water and oxygen
storage tanks), and then 4 tons per m2 of foamed slag, about 10m thick.
Impacts broken up by the outer shield would impact over a large area.
(This middle shield weighs almost 40% of total colony mass, and is why
there is no such thing as unwanted mass from NEOs etc). Any fragments
which broke through this layer would travel a further 50m to the inner
shield, which would have a similar consistency to the outer shield.

A further 50m separate the inner shield from the rotating cylinder
itself. This will be a massive structure in itself to hold in the air
pressure - perhaps 1 metre thickness of aluminium or carbon fibre,
topped by earth and gravel, houses and buildings.

As a final defence, every apartment can be sealed, in the event of
atmosphere loss, or even complete destruction of the main structure.
The apartments can support occupants for several days / weeks.

How robust is this to various threats? An initial analysis below
implies that the worst threats are man made, and unless we live in a
utopia, a shielded structure would be a wise precaution. This to my
mind would rule out the original O'Niell habitat designs. The multi
shield structure would protect against terrorists (Bin Laden's
successors will target the colonies), but not against a full war.

SMALL METEORITES (up to a few cm): These will be absorbed by the outer
shell. Any holes will be regularly filled in.
MEDIUM METEORITES (10cm to 1m): These will annihilate themselves
against the outer shell, but create a cloud of debris which will impact
the middle shield, possible causing damage to the LOX and Water tanks.
LARGE METEORITES (1m): These pose a threat, but would be detected
before hand. They should be intercepted a few km away from the station.
For very large meteorites, the colony could be moved. (However, since a
pair of colonies weighs 2 billion tons, it would normally be easier to
move the "asteroid".) The ability to move asteroids is a
prerequisite for the colony.
ORBITAL DEBRIS: Will typically be travelling slower than meteorites, so
will not normally be a problem.

PROJECTILE WEAPONS: These would have the effect of a medium meteorite
SUICIDE PILOTS: If terrorists tried to crash a rocket into the
structure, what would the effect be? At a closing speed of km/s, an
orbiter sized object could penetrate all three shield layers. Missile
defence needed?
ATOMIC BOMB: Exploded against the outer shield. A 1 Megaton bomb would
radiate the middle shield (100m away) with 30 tons TNT equivalent per
square metre. I'm not sure what this is in J/m2, but I think the
middle shield would be vaporised. What then? Would the plasma block
further radiation from reaching the inner shield?
Should we increase the distance between the middle and outer shields?
200m would make the middle shield 4 times more effective -a 1 Megaton
bomb would probably be survivable. An extreme load would be put on the
colony bearings - these need to be flexible enough to prevent the
pressurised cylinder impacting the shield.
PENETRATING ATOMIC WARHEAD: This is about the worst threat. The bomb
would penetrate the outer shield, and explode upon impact with the
middle shield. Would a powerful laser defence be of use?
ATOMIC BOMB against external structures: This could easily wipe out the
external structures, cutting power and light to the colony. If the
coupling with the neighbouring, counter-rotating colony is intact, then
the cylinder speeds could be wound down to provide several weeks of
emergency electricity supply. If the coupling is broken, then several
days supply could be provided, by de-spinning against the shield.
INTERNAL EXPLOSIONS - A suitcase full of TNT would not threaten the
structure, and delicate areas would be made very difficult to reach.
Some airport style controls would be needed to ensure nuclear weapons
couldn't be brought inside the pressure vessel.
CHEMICAL ATTACK - The interior is so vast, it is difficult to imaging
this having a colony wide impact. As mentioned above, residential
apartments can also be sealed.
BIOLOGICAL ATTACK - A threat, as for Earth cities. However, the
station is naturally quarantined. There would need to be fairly
stringent controls at points of departure to the colony.
What other threats are there?
What other defences are needed?

Alex Terrell wrote:
The shield would absorb small meteorites. The first layer of the shield
would be steel or chobham (tank) armour about 70mm thick (0.5 tons per
m2).

Nit; Burlington armor, often mis-named Chobham, is not producable in
that thin a layer, isn't really solid layers anyways,
and is woefully misapplied to hypervelocity impact problems.

Aluminum is as good as anything here. Steel, if more available,
will do just fine.


-george william herbert

"Alex Terrell" wrote in message
oups.com...
The recent mass tragedies in Asia ask the question how safe will large
cylinder colonies be? The destruction of one of these could also lead
to the loss of several hundred thousand lives. How safe are they
against natural and man made attacks?

My reference design is 4 km in diameter, and has a non-rotating
external shield. The shield and the rotating cylinder each provide 5
tons per m2 of protection.

The shield would absorb small meteorites. The first layer of the shield
would be steel or chobham (tank) armour about 70mm thick (0.5 tons per
m2). This would stop small projectiles and break up larger ones. There
would then be a 100m gap (in which there would be water and oxygen
storage tanks), and then 4 tons per m2 of foamed slag, about 10m thick.
Impacts broken up by the outer shield would impact over a large area.
(This middle shield weighs almost 40% of total colony mass, and is why
there is no such thing as unwanted mass from NEOs etc). Any fragments
which broke through this layer would travel a further 50m to the inner
shield, which would have a similar consistency to the outer shield.

A further 50m separate the inner shield from the rotating cylinder
itself. This will be a massive structure in itself to hold in the air
pressure - perhaps 1 metre thickness of aluminium or carbon fibre,
topped by earth and gravel, houses and buildings.

As a final defence, every apartment can be sealed, in the event of
atmosphere loss, or even complete destruction of the main structure.
The apartments can support occupants for several days / weeks.

How robust is this to various threats? An initial analysis below
implies that the worst threats are man made, and unless we live in a
utopia, a shielded structure would be a wise precaution. This to my
mind would rule out the original O'Niell habitat designs. The multi
shield structure would protect against terrorists (Bin Laden's
successors will target the colonies), but not against a full war.

SMALL METEORITES (up to a few cm): These will be absorbed by the outer
shell. Any holes will be regularly filled in.
MEDIUM METEORITES (10cm to 1m): These will annihilate themselves
against the outer shell, but create a cloud of debris which will impact
the middle shield, possible causing damage to the LOX and Water tanks.
LARGE METEORITES (1m): These pose a threat, but would be detected
before hand. They should be intercepted a few km away from the station.
For very large meteorites, the colony could be moved. (However, since a
pair of colonies weighs 2 billion tons, it would normally be easier to
move the "asteroid".) The ability to move asteroids is a
prerequisite for the colony.
ORBITAL DEBRIS: Will typically be travelling slower than meteorites, so
will not normally be a problem.

PROJECTILE WEAPONS: These would have the effect of a medium meteorite
SUICIDE PILOTS: If terrorists tried to crash a rocket into the
structure, what would the effect be? At a closing speed of km/s, an
orbiter sized object could penetrate all three shield layers. Missile
defence needed?
ATOMIC BOMB: Exploded against the outer shield. A 1 Megaton bomb would
radiate the middle shield (100m away) with 30 tons TNT equivalent per
square metre. I'm not sure what this is in J/m2, but I think the
middle shield would be vaporised. What then? Would the plasma block
further radiation from reaching the inner shield?
Should we increase the distance between the middle and outer shields?
200m would make the middle shield 4 times more effective -a 1 Megaton
bomb would probably be survivable. An extreme load would be put on the
colony bearings - these need to be flexible enough to prevent the
pressurised cylinder impacting the shield.
PENETRATING ATOMIC WARHEAD: This is about the worst threat. The bomb
would penetrate the outer shield, and explode upon impact with the
middle shield. Would a powerful laser defence be of use?
ATOMIC BOMB against external structures: This could easily wipe out the
external structures, cutting power and light to the colony. If the
coupling with the neighbouring, counter-rotating colony is intact, then
the cylinder speeds could be wound down to provide several weeks of
emergency electricity supply. If the coupling is broken, then several
days supply could be provided, by de-spinning against the shield.
INTERNAL EXPLOSIONS - A suitcase full of TNT would not threaten the
structure, and delicate areas would be made very difficult to reach.
Some airport style controls would be needed to ensure nuclear weapons
couldn't be brought inside the pressure vessel.
CHEMICAL ATTACK - The interior is so vast, it is difficult to imaging
this having a colony wide impact. As mentioned above, residential
apartments can also be sealed.
BIOLOGICAL ATTACK - A threat, as for Earth cities. However, the
station is naturally quarantined. There would need to be fairly
stringent controls at points of departure to the colony.
What other threats are there?
What other defences are needed?


Colonies would become , one hopes, numerous ( there's safety in numbers!
Secondly a good safeguard would be distance; at a reasobnable distance from
Earth ( eg hundreds of thousands of kilometres or more) there would be days
or weeks during which any vehicle headed towards it from earth could be
monitored. or assessed and if suspect nudged gently away from the Colony.

Remember also the lessons of history - a people dispersed is very hard to
annihilate. Hitler and Heydrich tried their worst - but could not overcome
this basic fact of life.

It could become de rigeur to park any incoming vehicle whose bona fide is
not absolutely established a few hundred kilometers from the Colony, so that
it could be subject to inspection by "customs" officials from the Colony.

It is easier for instance to park avehicle approaching aSpace colonuy than
it is, forinstance,to park increasing civilian jets in midair!

Beyond this of course Colonies would probably be able to deploy self
repairing nano-robots , and be able to seal parts of themselves off from
pressure leaks

In other words the judicious use of time and distance could provide extra
layers of warning and security?

In article ,
Michael Martin-Smith wrote:

snip

Beyond this of course Colonies would probably be able to deploy self
repairing nano-robots , and be able to seal parts of themselves off from
pressure leaks

One of the Rosinante novels (still one of the better space-
colony series out there, even though it is 20-odd years old) touched
on a potential application of those: at one point someone invests a
colony by having their cargo of repair-bots replace all the control
chips on the colony's mirror with chips the invading ship can command.

Given computer viruses, I predict that one hobby in a mileau
with cheap, plentiful repair-bots will be to illicitly reprogram them
to do amusing (to the programmer) things.

I wonder about inadvertent exchanges of 'bot populations, if
these things are small and numerous.
--
http://www.cic.gc.ca/english/immigrate/
http://www.marryanamerican.ca
http://www.livejournal.com/users/james_nicoll

Alex Terrell wrote:
The recent mass tragedies in Asia
ask the question how safe will
large cylinder colonies be?

As safe as large cruise ships, carrier ships, and so on.

But if you want to compare the recent events with using space colonies
as the analogy.

Think of thousands and thousands of space colonies suddenly got
irradiated by a very lethal space radiation. Maybe a solar flare would
be a good choice of an analogy.

The destruction of one of these could also lead
to the loss of several hundred thousand lives.

I just don't get it with people's fascination with numbers. Somehow,
some people think one person's death is less significant than the death
of a billion people.

How safe are they against natural and man made attacks?

First rule, don't rely on history books.

(snip some stuff about colony shielding)

(snip some stuff about sealed apartement)

The problem is that usually in an emergency situation, rescue effort
have a hard time helping people in many different places, usually
people are just told to come into one place so can help be distributed
there.

Maybe all apartements should be essentially self-contained spaceships,
should the colony loss air or even damaged heavily beyond repair, all
of the apartements then can maneuver themself out of the colony and
move into a specific rendezvous point, where the survivors then can be
picked up.

How robust is this to various threats?
An initial analysis below implies that
the worst threats are man made, and
unless we live in a utopia, a shielded
structure would be a wise precaution.

The problem is that... the recent tsunami incident is not man made, and
it cause huge problems in comparison of any recent man made event.

Unless of course you're implying that the recent tsunami incident is
man made.

This to my mind would rule out
the original O'Niell habitat designs.

How about the mushroom type starbases from Star Trek?

The multi shield structure would
protect against terrorists
(Bin Laden's successors
will target the colonies),

Well... Bin Laden is just a made up puppet to be used as a scapegoat.

So are you trying to say that in the future, builder of these space
colonies will then intentionally damage or even destroy these colonies
and then blame it on their made up puppets?

The other problem is that a terrorist is someone who terrorize, he
doesn't have to necessary make any physical harm at all.

(snip some stuff about asteroids and projectiles)

Correct. Sueffiecient protections and countermeasures are needed.

but not against a full war.

I'm quite suprised that so far no one has mentioned any intentional
attempt to aim a space colony at a planet or another colony.

But then again, any attempt to do so in real life would be very
noticeable and intercept immediately, unless it's intentionally
allowed.

SUICIDE PILOTS: If terrorists tried to crash a rocket
into the structure, what would the effect be? At a
closing speed of km/s, an orbiter sized object could
penetrate all three shield layers. Missile defence needed?

You mean like when Japanese pilots piloted their Ohka rocket planes
into allied warships?

Well... Human pilots are quite error-ridden, and most kamikaze attempts
usually end in failures, and even the ones that succeed failed to
eliminate the target.

To successfully to do something like that, you need an automatic pilot
without any person involved in the piloting and defense free enviroment
(no one trying to stop it), like what happened in 11th September 2001.
Now... For actually destroying the target, that's another matter.

In other words, a stray rocketship would only succed at puncturing the
colony, and probably will cause it to loss its air.

To destroy the space colony, as in to completely make it fall apart,
you need to put explosives at strategic places.


(snip some stuff about atomic bombs)

Probably won't do much damage unless aimed at critical areas and they
probably already had the software "Missile Command" installed at the
colony.


INTERNAL EXPLOSIONS - A suitcase full of TNT
would not threaten the structure, and delicate
areas would be made very difficult to reach.
Some airport style controls would be needed to
ensure nuclear weapons couldn't be brought
inside the pressure vessel.

I don't think that you should compare it an airport, think of more like
a seaport.


CHEMICAL ATTACK - The interior is so vast,
it is difficult to imaging
this having a colony wide impact.
As mentioned above, residential
apartments can also be sealed.

Same as below.

BIOLOGICAL ATTACK - A threat, as for Earth cities.

Yes, but not to Earth itself.

However, the station is naturally quarantined.
There would need to be fairly stringent controls
at points of departure to the colony.

I think that the officials probably will just seal the entire colony
until the threat diminish.




Michael Martin-Smith wrote:
Colonies would become , one hopes, numerous
( there's safety in numbers!

Well... There are numerous coastal communities in the Indian ocean,
does that help them from the tsunami?

Of course, there are many communities around Earth, and NOT just at the
Indian ocean's coast lines.

Remember also the lessons of history -

History? Which one? His history, her history, their history, and so on.

a people dispersed is very hard to
annihilate.

A.k.a. breed like mad and populate the earth and the universe.

Surely people who don't want the human population to climb will hate
that solution.

Hitler and Heydrich tried their worst -
but could not overcome this basic fact of life.

Please, Hitler and so on are just a bunch puppets, why bother
mentioning them?

It could become de rigeur to park any incoming
vehicle whose bona fide is not absolutely established
a few hundred kilometers from the Colony, so that it
could be subject to inspection by "customs" officials
from the Colony.

Well... Think of like a seaport.

Of course, the fact is that space is like the ocean, so some sea stuff
can probably also applied in space.

It is easier for instance to park
a vehicle approaching a Space colonuy than it is,

Just use the same regulation that is currently use for sea going vessel
entering a seaport, it's no different than that.

for instance, to park increasing civilian jets in midair!

Nah... They can do that. The problem is that if one of them run out of
fuel and crash, the airport will lose income on landing fee, gate fee,
fuel fee, and so on.

Beyond this of course Colonies would probably be
able to deploy self repairing nano-robots ,
and be able to seal parts of themselves off from
pressure leaks

Well... The best way would be to make a colony in sections. So even if
one section is damaged or even destroyed, the other sections would be
quite fine. Then the damaged or destroyed section can be repaired or
rebuild or even just let it the way it is.

On 1 Jan 2005 11:44:02 -0800, "Alex Terrell"
wrote:

snip
What other threats are there?

A MAJOR solar flair, would fry all on board, unless the station had
it's own magnetic shield strong enough to deflect the charged
particles, like the spaceship Pegasus had.

What other defences are needed?

Defence against cosmic rays.



Christopher
+++++++++++
"Never take anything for granted."

Benjamin Disraeli

I specifically stated that the shielding protection is 10 tons per m2.
This would provide protection against all solar flares and cosmic rays,
better than Earth's atmosphere. With this level of shielding, no
magnetic field is needed.

I've only heard of Chobham. Perhaps this is a British variant? I guess
all manufacturers keep the laminate armour compositions as a not so
closely guarded secret.

Are you sure about 70mm (or more accurately, 0.5 tons / m2) being too
thin? This is about the thickness of tank top armour.

As for aluminium, it's not so good against thermal weapons such as
lasers. For this I'd revise the outer layer to 1cm tungsten, backed by
6 cm steel. Perhaps a layer of copper to distribut heat, though I
suspect steel is good enough.

"Alex Terrell" wrote in message
oups.com...
The recent mass tragedies in Asia ask the question how safe will large
cylinder colonies be? The destruction of one of these could also lead
to the loss of several hundred thousand lives. How safe are they
against natural and man made attacks?


(snip)

Alex, nothing imaginable by life, for life, could be more a definition of
survival and prosperity (more a definition of safety and security) than
spreading out into the Universe in redundant proprietary concentrations.
Thus expansion and growth.

It's a matter of percentages, Alex. On one, single, world; on one, single,
island; in one, single, worldlet so to speak, the odds approach dead
certainty you will lose 100% of the population eventually to some titanic --
all encompassing of that "one, single," world -- catastrophe, whether from
within or from the outside. It is only a matter of time and the fact of
change.

Spreading out ever broader in space and ever deeper in life, getting ever
more redundant and ever more proprietary, does not guarantee that you will
not lose all to some titanic overall catastrophe. It only means that overall
catastrophe has to get vastly greater, geometrically and/or exponentially
greater, to destroy all.

Spreading out is a fundamental of survival and prosperity. Getting more
redundant is a fundamental of survival and prosperity. Getting more
proprietary is a fundamental of survival and prosperity. There is more than
one dimension to survival and prosperity, and space colonization addresses
them all. "We're in it for the species, boys and girls!" "Species," both
singular and plural. "Grow or die." "March or die."

There is no way we can make life--life itself--immortal. But we can
diminish the fact of mortality by increasing the odds of survival and
prosperity via expansion and growth, via spread of life, from the Earth. The
fate of life in any and every singularly closed environment is "determined."
The fate of life in expanding and growing plurality (in every sense of the
word) in an open frontier is "indeterminate."

Brad

On 2 Jan 2005 10:17:14 -0800, in a place far, far away,
made the phosphor on my monitor glow in such a
way as to indicate that:

I just don't get it with people's fascination with numbers. Somehow,
some people think one person's death is less significant than the death
of a billion people.

Yes, with good reason. To think otherwise would indicate a lack of
understanding of the meaning of word "significant."