Questions about "The High Frontier"

Michael Ash wrote:

Those people old enough to remember life before the Communists came to
power will rightly remember that it was a whole lot worse. The Japanese
were doing all kinds of terrible things and the Nationalists weren't
really very nice people either. Those people not old enough to remember
those times will still remember a nearly constant and extremely fast rise
in the standard of living and general conditions in the country. There are
probably some people with outspoken political beliefs who are quite
unhappy but for the most part the people there have no *reason* to want a
revolution, and every reason to avoid one. And while I'm as much a fan of
liberty and democracy as the next guy, I'd have a hard time saying that
they're wrong.


After the slaughter at Tienanmen Square, the survivors let out what the
big plan was:
1.) Students will seize the square and demand democracy.
2.) The government will overreact, and there will be a bloodbath.
3.) The farmers will come in from the countryside and overthrow the
government.
4.) With democracy established, the students would be the obvious
intellectual leaders of the new political order.
5.) All things would then be wonderful and happy.
Parts 1 and 2 worked like a charm.
You read this, and you don't know whether to laugh or cry at the
incredible naiveté of it.
After the millions of deaths in The Great Leap Forward, the last thing
the people in the countryside wanted to see was any sort of political
upset, and a return to mass starvation.
I think that China will probably evolve into a pretty free culture with
time; say in twenty years or so.

Pat

Greg D. Moore (Strider) wrote:

If we're building SPS, then we will have LOTS of workers and the ability to
build substational stations.



Given how far into the future the date of construction is, it might be
able to be built almost entirely by robots at far lower cost than
building living quarters and bringing up supplies for human workers.

Pat

Mike Combs wrote:
Seems to suggest that Winkler was being overly-conservative when he insisted
that anything over 1 RPM would be a mistake.


NASA did a study on this to determine the minimum diameter of a rotating
station where the crew wouldn't feel dizziness as they moved around in
it due to the perception of what "up" was, particularly in regards to
their inner ear.
IIRC, it was around 400 feet diameter for a 1g station.

Pat

Mike Combs wrote:
How many editions was "High Frontier" printed
in? Are you reading the same one as I am?


He can't be talking about The High Frontier, or any other book where the
author knows what he's talking about, as any such hole would still only mean
a blow-down time of many days (or weeks). Nobody's going to kill a large
population that way.

A mad bomber might manage to blow out a window pane or two (if he could get
at them). That's still a blow-down time measured in days; plenty of time to
implement repairs, and no cause for immediate evacuation.


It depends on the size of the habitat and the amount of air pressure it
has in it; not all of O'Neill's habitat designs were the size of Babylon
5*. Island One's living area consists of a sphere of 460 meters
diameter, and you blow a one meter diameter hole in the outside of that,
and the air is going to vacate it in well under a day...trying to fix
the hole has the problem of getting near the hole while trying to avoid
being sucked into it (the noise near the hole should really be
impressive also) by what's probably be like a tornado going into it, and
the extreme discomfort caused to the populace as the air pressure drops.
When Soyuz 11 depressurized through a valve around 1/2 inch in diameter,
the crew were incapacitated inside of ten seconds as the rapidly falling
air pressure burst their eardrums, caused their blood to start to boil,
and ruptured the alveoli of their lungs..
In the case of that 480 meter one at surface air pressure, you had
better hope you can get that repair crew to the hole inside of a minute
or two, as that's about all the time you are going to have before things
start getting very uncomfortable.

So no, the logic is neither straightforward nor ironclad that "living beyond
the Earth" = "certain fascism".


I'm just not keen on living in a giant tin can, fascism or not.

* Island Three was twenty miles long; four times as long as Babylon 5.

Pat

Pat Flannery wrote:

It depends on the size of the habitat and the amount of air pressure it
has in it; not all of O'Neill's habitat designs were the size of Babylon
5*. Island One's living area consists of a sphere of 460 meters
diameter, and you blow a one meter diameter hole in the outside of that,
and the air is going to vacate it in well under a day...

The timescale I get is about 50 hr, and that's assuming that the
pressure stays constant, which it won't; it will drop.

Hole has an area of 0.79 m^2, speed of sound is 340 m/s (presuming the
vessel is pressurized to 100 kPa), so the volume rate of efflux out the
hole is 270 m^3/s. Volume of the habitat is 5.1 x 10^7 m^3, so that's a
timescale of 53 hr.

That's still a short timescale, but that's a lot of time to do something
about it. And presumably if the size was really that small and such
holes were a serious concern, you'd have suits for everyone and/or an
air bunker of some time.

Not to mention that a 1 m diameter hole could really only be plausibly
caused by mischief.

When Soyuz 11 depressurized through a valve around 1/2 inch in diameter,
the crew were incapacitated inside of ten seconds as the rapidly falling
air pressure burst their eardrums, caused their blood to start to boil,
and ruptured the alveoli of their lungs..

Your blood doesn't boil, and you don't sustain any serious tissue injury
unless you hold your breath and/or clam your mouth and nose shut.

The _Soyuz 11_ accident doesn't really scale upward, because the cabin
is so tiny, and, if I recall correctly, it was in a place that they
could have done anything about anyway.

--
Erik Max Francis && && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM, Y!M erikmaxfrancis
The quickest way of ending a war is to lose it.
-- George Orwell, 1903-1950

Pat Flannery skreiv:
Eivind Kjorstad wrote:
Wouldn't it be easier to hang the hotel on a tether, with a counter-mass
on the other end, and spin it ? (the counter-mass can be a second hotel
if desired)

That way you can have as small a structure as you like, with very low
rpm, and still whatever gravity is needed to maintain health.

Difficult to dock with though. You could link up to the center of the
tether and slid down to the end you wanted, but the change in mass would
mean that the center of rotation would change,

Yeah, but not by much if all that slides is some passengers and some
deliveries. That's a tiny fraction of overall mass. If it's a problem
one would think it could be counteracted by having some movable mass
somewhere that can actively compensate. (say water that can be pumped
between two alternative tanks)

and the increase in overall mass slow its rate of rotation down
as the docking ship gets spun up.

No. If you're docking with the centre of rotation of a rotating object,
obviously you need to be rotating with the same rpm as the object prior
to docking.

This ain't even complicated, consider that if you use the station you
want to dock with as your frame of reference, all you need to do is to
stop rotating -in-that-frame. It's not as if we're talking a lot of
energy here anyway, it doesn't need much of a push to set say the
space-shuttle up for rotating around its axis at 0.5 rpm.

Alternative solution is to have a docking-statin at the middle that does
-not- rotate. This has a few advantages. First, it can have more than 2
docks, since they don't need to be precisely on the center. Second, you
could hav any other facilities that benefit from zero-G here at the
centre too.


Eivind Kjørstad

Erik Max Francis wrote:
Pat Flannery wrote:

It depends on the size of the habitat and the amount of air pressure
it has in it; not all of O'Neill's habitat designs were the size of
Babylon 5*. Island One's living area consists of a sphere of 460
meters diameter, and you blow a one meter diameter hole in the
outside of that, and the air is going to vacate it in well under a
day...

The timescale I get is about 50 hr, and that's assuming that the
pressure stays constant, which it won't; it will drop.
The math is over he
http://www.sff.net/people/geoffrey.landis/higgins.html
i want to see someone get near a 1 meter diameter hole with air getting
sucked into it at sonic velocities.

Hole has an area of 0.79 m^2, speed of sound is 340 m/s (presuming the
vessel is pressurized to 100 kPa), so the volume rate of efflux out
the hole is 270 m^3/s. Volume of the habitat is 5.1 x 10^7 m^3, so
that's a timescale of 53 hr.

That's still a short timescale, but that's a lot of time to do
something about it. And presumably if the size was really that small
and such holes were a serious concern, you'd have suits for everyone
and/or an air bunker of some time.

Not to mention that a 1 m diameter hole could really only be plausibly
caused by mischief.

That was my intention, and why I stated that I was secretly digging the
hole.
Long time back, a friend and I were designing a space habitat, and were
looking for some way to detect small leaks that meteor impacts or other
faults could case in the outside wall of it.
Here's what we came up with; The wall of the habitat would be broken
down into a inner and outer wall separated by a few inchs and this
subdivided into a grid work of airtight cells by the structure between them.
Each of these cells would have a pressure sensor in it, and be
pressurized to less than the internal pressure of the habitat.
If pressure in one of the cells started to drop, it meant that it was
venting into space due to a leak in its external wall; if pressure
started to rise, it meant there was a leak in its internal wall.



When Soyuz 11 depressurized through a valve around 1/2 inch in
diameter, the crew were incapacitated inside of ten seconds as the
rapidly falling air pressure burst their eardrums, caused their blood
to start to boil, and ruptured the alveoli of their lungs..

Your blood doesn't boil, and you don't sustain any serious tissue
injury unless you hold your breath and/or clam your mouth and nose shut.

Other than having your body swell to twice its natural volume,
convulsions, and having your circulatory system shut down of course:
http://www.sff.net/people/geoffrey.landis/vacuum.html


The _Soyuz 11_ accident doesn't really scale upward, because the cabin
is so tiny, and, if I recall correctly, it was in a place that they
could have done anything about anyway.

It was under the seats, and they had apparently figured that out by the
time they went unconscious, but it was too late to do anything about it
then.

Pat

Eivind Kjorstad wrote:
and the increase in overall mass slow its rate of rotation down
as the docking ship gets spun up.


No. If you're docking with the centre of rotation of a rotating object,
obviously you need to be rotating with the same rpm as the object prior
to docking.

You could have what grabs on to it be free rotating, and only it needs
be spun up to the speed of the tether during docking. Then gradually
spin up the ship to the rate of rotation of the tether by basically
using a clutch on the grab assembly, before starting to slide down the
tether to the end you want to reach. Unfortunately, if you use something
like a brake on it as you descend you are going to have to have the mass
of the ship be balanced someway on either side of the tether, or it's
going to Start twisting it as it descends.
It might make more sense to have the ship dock with the center of the
tether using a despun rotating grab assembly mounted on the tether
itself with a ring joint that things can be transferred through into a
pressurized chamber from where elevators carry it down to the crew areas
at the end.
This ain't even complicated, consider that if you use the station you
want to dock with as your frame of reference, all you need to do is to
stop rotating -in-that-frame. It's not as if we're talking a lot of
energy here anyway, it doesn't need much of a push to set say the
space-shuttle up for rotating around its axis at 0.5 rpm.


Although that's the way the Pan-Am space clipper docks in "2001", I
think it would more sense from a simplicity viewpoint to despin the
docking assembly than spin up the docking spacecraft.


Alternative solution is to have a docking-statin at the middle that does
-not- rotate. This has a few advantages. First, it can have more than 2
docks, since they don't need to be precisely on the center. Second, you
could hav any other facilities that benefit from zero-G here at the
centre too.


That makes more sense to me also; about the only problem you run into
then is getting the rotary joint to be large enough in diameter for
large cargo to pass through without leaking air.
It looks almost like something Escher would come up with, but Hermann
Noordung's* soler powered 1929 space station design uses a logarithmic
spiral set of stairs to allow a person at its center walk out to the
ring-shaped area where there is one gravity while staying heads-up at
all times. It also has a despun airlock at its axis to allow space ships
to dock with it easily: http://davidszondy.com/future/space/noordung.htm
Considering the timeframe this came out of, this was a downright
brilliant piece of work on his part.

* Real name, Captain Herman Pototc(nik

Pat

"Hop David" wrote in message
...
Mike Combs wrote:

... If one's society ultimately fails (or just consistently performs
poorly), it would have to be a result of its underlying philosophy. In a
space habitat, one could hardly blame resource depletion, an energy
crisis, population pressures, a crop failure, or inconvenient location.

I don't agree.

Should the cloud of habs spread through NEAs and the main belt, there will
be a wide spectrum of fortunes. Some colonies may be situated near a two
lobe asteroid, one lobe being nickel-iron rich in platinum group metals,
the other lobe having water, ammonia and lots of hydrocarbons. This could
be a very wealthy hab. Other habs may be eking it out near big chunks of
silicon.

Well, that gets us back to the "inconvenient location" part of what I said.
My point being of course that, unlike nations here on Earth which cannot
change their locations, orbital habitats will be able to adjust their orbit
to something more advantageous.


--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

"Pat Flannery" wrote in message
...

provided that a political upset on board doesn't lead to chaos and their
own destruction as the factions fight it out like two fish in a aquarium
striving to be the first to blow up the aeration system to put the other
at a disadvantage.

Not a very logical-sounding scenario to me. That said, I'd agree that
death-cults would be a thing to avoid.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn