Questions about "The High Frontier"

Quadibloc wrote:
Jonathan wrote:
Why do sci-fi writers assume we must move into space to survive???

Well, we do. Someday, a big asteroid is going to hit the Earth.

Unless we stop it from hitting Earth. We don't need to have offworld
colonies in order to do that; our current space launch capacity is
sufficient.

Even if it does hit Earth it's not likely to cause the extinction of the
human species. As a whole we're an extremely resilient species, and
there are lots of little sub-groups that are even more suited to
surviving than the average Joe (survivalist nutball enclaves with
stockpiles of tinned food, heads of state with their nuclear war
bunkers, ballistic missile sub crews, and so forth). You'll need
something really big to put humanity down for good and there just aren't
a lot of those out there.

Nothing lasts forever, so a species confined to only one place, no
matter how big that place is, will eventually die out.

The most pessimistic estimates I can recall reading recently are that
Earth will become uninhabitable due to water loss and increasing solar
output in about half a billion years. I doubt there will be humans
around by then whether we colonize other planets or not; Earth's doom is
a problem for our species' descendants to worry about (or to watch with
amusement).

The facts on the ground strongly suggest that as societies become
more advanced and affluent, the population growth slows to
sustainable levels.

Unfortunately, we don't *quite* have the resources to sustainably get
everyone affluent enough so as to stop population growth in time.

Source? There have been people predicting imminent Malthusian
catastrophes for hundreds of years. They've all been wrong so far.

If the goal is really to save humanity from the devastating effects of
global catastrophes, there are much cheaper and easier ways of doing
that. Better, too - spending a hundred billion dollars to find and
deflect a dino-killer asteroid saves billions of lives, whereas spending
it to establish a self-sufficient offworld colony saves a few dozen
(assuming it can actually be done for such a small amount). Even just
spending it to establish a deep bunker here on Earth would save more
lives, and make rebuilding afterward much easier to boot.

Personally, I'm all for the colonization of other planets. But I don't
think it's a good idea to use false pretenses to justify the exercise.

Bryan Derksen wrote:

Personally, I'm all for the colonization of other planets. But I don't
think it's a good idea to use false pretenses to justify the exercise.

It's become a community habit over the years, and is hard to break.

On Wed, 03 Oct 2007 22:02:32 -0000, Damien Valentine
wrote, in part:

I see what you're saying, but curiously, that wasn't something that
O'Neill brought up. How many editions was "High Frontier" printed
in? Are you reading the same one as I am?

The paperback edition was significantly different from the hardcover
edition, in that some of the calculations used to justify the idea as
plausible were omitted from the paperback edition - as it notes in its
preface.

But the book "Space Colonies" from the Whole Earth Catalog people is one
where a *variety* of viewpoints on the project, including those that
claimed that the terrorism danger would make it a non-starter, were
presented.

John Savard
http://www.quadibloc.com/index.html

On Sun, 07 Oct 2007 01:52:55 -0500, Pat Flannery
wrote, in part:
Wayne Throop wrote:
: Pat Flannery

: If we could just make it all-electric, we would be in business.
: Maybe a giant railgun to shoot it right into orbit. Okay, so we may need
: to train the crew to handle 500 or so gs on takeoff... :-)

Nah, just use a 300 km long rail.

Which leads to a interesting problem... at 300 km long the rail has a
significant curve in it to follow the curvature of the Earth's surface.
Toward the end of the acceleration run it may try to peel right off the
track, as from its point of view the track drops away from its direction
of movement. To deal with air friction during ascent at a shallow angle
it's going to have to come off the launcher at a velocity far higher
than orbital velocity.

Have the rail straight, and its far end about 25 miles up in the air.
That was the altitude at which the V2s levelled off, because now air
friction was a less serious problem.

This probably is wildly impractical, but a 25-mile-high structure that
lets one use electricity instead of the first stage of a rocket seems a
*lot* closer to being practical than a space elevator. It might be
buildable with the technology of 100 years in the future, instead of
100,000 years in the future.

John Savard
http://www.quadibloc.com/index.html

On Sun, 07 Oct 2007 14:42:32 -0500, Pat Flannery
wrote, in part:

But to deal with air drag during ascent you'll need to exceed that
velocity by a considerable amount,

Put the rail inside an evacuated tube. It shouldn't be too hard to pump
the air out, since there isn't much air at the far end anyways.

John Savard
http://www.quadibloc.com/index.html

On Thu, 11 Oct 2007 17:42:41 -0500, "Paul F. Dietz"
wrote, in part:
"Damien Sullivan" wrote in message
...

Both arguments are bogus; the real question is "what can space colonies
do for the people living in them?"

The more penetrating question is "what can space colonies do
for the people PAYING for them?"

On the overcrowded Earth of 2100, living space is at a premium. This
cannot be allowed to get worse, and must be reversed. This necessity has
led to only one married couple out of 100 being issued a permit to have
one child.

However, others may still have children provided the frozen embryo is
launched into space to a space colony, to be raised there - a small
rocket, of the kind used to launch a communications satellite, can send
thousands of these frozen embryos to the expanding cloud of space
colonies. Thus, the cost of having a child this way, a child who will be
part of the brighter future we are building for humanity, is affordable
to many.

Also, given the small size of microchips these days, many people have
themselves launched into space after they've uploaded. You would be
surprised at how much money you can make from day trading when you can
think at computer speeds, and don't need to go to the bathroom or eat.

What with petri dishes and all, this even allows people to arrange to
have and raise their own children without being one of the lucky permit
winners.

John Savard
http://www.quadibloc.com/index.html

On Mon, 08 Oct 2007 20:16:24 +0200, Matthias Warkus
wrote, in part:
Rand Simberg schrieb:

With associated losses.

With modern HVDC links, losses are negligeable, especially since there's
so much solar power to go around.

The loss of (usable) energy is hardly the problem.

The gain of heat, so hard to dissipate when one doesn't have convection
but only radiation to do the work, is the problem.

John Savard
http://www.quadibloc.com/index.html

"John Savard" wrote in message
...
On Sun, 07 Oct 2007 01:52:55 -0500, Pat Flannery
wrote, in part:
Wayne Throop wrote:
: Pat Flannery

: If we could just make it all-electric, we would be in business.
: Maybe a giant railgun to shoot it right into orbit. Okay, so we may
need
: to train the crew to handle 500 or so gs on takeoff... :-)

Nah, just use a 300 km long rail.

Which leads to a interesting problem... at 300 km long the rail has a
significant curve in it to follow the curvature of the Earth's surface.
Toward the end of the acceleration run it may try to peel right off the
track, as from its point of view the track drops away from its direction
of movement. To deal with air friction during ascent at a shallow angle
it's going to have to come off the launcher at a velocity far higher
than orbital velocity.

Have the rail straight, and its far end about 25 miles up in the air.
That was the altitude at which the V2s levelled off, because now air
friction was a less serious problem.

This probably is wildly impractical, but a 25-mile-high structure that
lets one use electricity instead of the first stage of a rocket seems a
*lot* closer to being practical than a space elevator. It might be
buildable with the technology of 100 years in the future, instead of
100,000 years in the future.

There is the slight complication that large tensile structures are easier
than large compressive structures.
The solution, of course, is to find a way to turn that 25-mile-high launcher
into a tensile structure... attach balloons to it!
Or maybe wings... could you rely on high-altitude winds to support a static
structure by aerodynamic lift?

-l.
------------------------------------
My inbox is a sacred shrine, none shall enter that are not worthy.

Wayne Throop wrote:

: Pat Flannery
: Which leads to a interesting problem... at 300 km long the rail has a
: significant curve in it to follow the curvature of the Earth's surface.
: Toward the end of the acceleration run it may try to peel right off the
: track, as from its point of view the track drops away from its direction
: of movement. To deal with air friction during ascent at a shallow angle
: it's going to have to come off the launcher at a velocity far higher
: than orbital velocity.

Pat, it would have to be one tough payload to ascend at a shallow angle
through the troposphere far faster than orbital velocity.


Well, first, you make sure the ejection end is as high as you
can get it, to minimize those losses. Second, if you only get
up to LEO velocity, you're never going to "pull up" from the
rail, though you'd end up with no force "downwards" onto the rail.

I like to imagine a west to east rail going up Mount Chimborazo. It's
proximity to the equator gives a .5 km/sec advantage right off the bat.
The air is thinner at the summit, so I believe the velocity ceiling set
by atmospheric friction would be higher. If a Chimborazo mass driver
were even able to impart 1 km/sec, that'd still be a helpful boost that
would substantially cut the reaction mass needed to achieve LEO.

Hop

"John Savard" wrote in message
...

On the overcrowded Earth of 2100, living space is at a premium. This
cannot be allowed to get worse, and must be reversed. This necessity has
led to only one married couple out of 100 being issued a permit to have
one child.

You must not be aware that the latest demographic projections have global
population topping out at 10 billion, and then actually going into a
decline.

However, others may still have children provided the frozen embryo is
launched into space to a space colony, to be raised there - a small
rocket, of the kind used to launch a communications satellite, can send
thousands of these frozen embryos to the expanding cloud of space
colonies. Thus, the cost of having a child this way, a child who will be
part of the brighter future we are building for humanity, is affordable
to many.

You might perform this experiment: Pick out about 10 friends, family
members, or coworkers. Outline your scenario, and then ask them how many
would pay 100,000 dollars (assuming they had it) to send off an embryo in
this fashion. Then ask them if they would pay 1 million dollars for a
property lot on an Island 1 habitat (along with passage for them and their
spouse).

My prediction: A fair number will say "no" to either scenario, but there
will be a big difference between those saying yes to the second scenario vs.
the first. That may provide a clue to which is most likely to come about.

Also, given the small size of microchips these days, many people have
themselves launched into space after they've uploaded. You would be
surprised at how much money you can make from day trading when you can
think at computer speeds, and don't need to go to the bathroom or eat.

"Uploading" is a future technology predicated on science we don't yet
understand. Science we already understand may lead to space transportation
systems much more economical than what you seem to be assuming.

--


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