My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

On 25 fév, 10:24, " wrote:
My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

No, but the reverse would be true. Your toron would be
torn apart by the Moon and Earth tidal effect.

Do you know Larry Niven ?

You should read his "Ringworld"

André Michaud

On Feb 25, 1:20 pm, wrote:
On 25 fév, 10:24, " wrote:



My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

No, but the reverse would be true. Your toron would be
torn apart by the Moon and Earth tidal effect.

Do you know Larry Niven ?

You should read his "Ringworld"

André Michaud


Thanks, I'll check it out, partly to eat crow because I thought I had
an original idea, partly because it sounds fascinating.
And there wouldn't be any way to counter that tidal effect, like some
sort of avoidence orbit?

Ed Davidson

On 25 fév, 21:21, " wrote:
On Feb 25, 1:20 pm, wrote:



On 25 fév, 10:24, " wrote:

My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

No, but the reverse would be true. Your toron would be
torn apart by the Moon and Earth tidal effect.

Do you know Larry Niven ?

You should read his "Ringworld"

AndréMichaud

Thanks, I'll check it out, partly to eat crow because I thought I had
an original idea, partly because it sounds fascinating.

It is. One of his best novels.

But you're good since you didn't know of Niven's work.

And there wouldn't be any way to counter that tidal effect, like some
sort of avoidence orbit?

I don't think so.

André Michaud

wrote in message oups.com...

Do you know Larry Niven ?

You should read his "Ringworld"

André Michaud

Niven was taunted at a sci-fi convention with "The Ringworld
is unstable". He wrote a sequel to correct the instability using
thrusters on the rim.

http://www.amazon.com/Ringworld-Engi.../dp/0345334302

On Feb 25, 9:24 am, " wrote:
My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

1. Don't need a tube. Just need a ribbon, with an inner surface and an
outer surface. See "Ringworld".
2. Don't need domes. Just need walls on the sides of the ribbon.
Atmosphere will stay in place in centrifugal effect as long as it
can't flow over the sides. Structurally much simpler and probably
better to let the atmosphere work as intended. See "Ringworld".
3. The time of the "day" would be 28 days * (1/2)^(3/2) = 10 Earth
days, according to Kepler's laws. This means that the "nights" would
be 5x24 hrs or 120 hrs long. During this time, temperatures would fall
like a stone, even with an atmosphere, and even with the reflected
Earthlight. Likewise, the daylight hours would be 120 hrs long and the
temperatures would soar to inhospitable levels. Better to have the
ribbon circle a constant source of energy (the sun) and impose
artificial, shorter-cycle shadow-makers for night and day. See
"Ringworld".
4. Any circular orbit will either lie in the same plane as the Moon,
or will intersect the plane of the Moon's orbit. The first case means
that the Moon will be closer to one part of the ribbon than other
parts of the ribbon, forcing an elliptical distortion of the ring.
Because the orbital period of the moon is about three times longer
than that of the ribbon, this will cause some precession of the
flexing of the ring, from minor-axis to major-axis about every 7 days,
and the tensile strength of the ring will have to accomodate that. The
second case means that the ring will flex from circular to elliptical,
with a rather sudden and possibly cataclysmic perturbation, every two
weeks. Again, the tensile strength required to withstand that rather
harrowing few hourrs every fortnight is probably well beyond the
strength of known materials. Better to build it where there are no
other nearby orbiting objects to cause tidal forces. See "Ringworld".
5. There is also the small matter of finding enough materials to make
the ring. The Earth's crust is about 7 miles thick (averaged over
oceans and continents). The surface area is 200 million square miles,
yielding a volume of about 1.4 billion cubic miles of crust. Let's
assume that your ribbon is 3 miles thick, 10 miles wide, and 750,000
miles in circumference, yielding a volume of 22 million cubic miles of
crust, about 1.5% of that available in the whole crust, and about 20%
of the continental volume above sea level. It's an interesting
exercise to decide what continent on Earth would have to disappear to
supply the materials for this ring. See "Ringworld".
6. It's also an interesting exercise to see how much the rotation of
the Earth would have to change to elevate all this material and get it
rotating at a different speed. Think of an ice skater when she extends
her arms.

PD

On Wed, 27 Feb 2007, PD wrote:

On Feb 25, 9:24 am, " wrote:
My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron."
[cut]
4. Any circular orbit will either lie in the same plane as the Moon,
or will intersect the plane of the Moon's orbit.
[cut]
5. There is also the small matter of finding enough materials to make
the ring.
[cut]
It's an interesting
exercise to decide what continent on Earth would have to disappear to
supply the materials for this ring.

Moon - ring. One problem solves another!

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/...,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html

On Feb 27, 12:23 pm, "Timo A. Nieminen"
wrote:
On Wed, 27 Feb 2007, PD wrote:
On Feb 25, 9:24 am, " wrote:
My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron."
[cut]
4. Any circular orbit will either lie in the same plane as the Moon,
or will intersect the plane of the Moon's orbit.
[cut]
5. There is also the small matter of finding enough materials to make
the ring.
[cut]
It's an interesting
exercise to decide what continent on Earth would have to disappear to
supply the materials for this ring.

Moon - ring. One problem solves another!


Worked for Saturn! Let's start there! Job is half done already!
Now, if we can only get all those pieces of rock to stick together....

On Feb 27, 10:41 am, "PD" wrote:
On Feb 25, 9:24 am, " wrote:



My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

1. Don't need a tube. Just need a ribbon, with an inner surface and an
outer surface. See "Ringworld".
2. Don't need domes. Just need walls on the sides of the ribbon.
Atmosphere will stay in place in centrifugal effect as long as it
can't flow over the sides. Structurally much simpler and probably
better to let the atmosphere work as intended. See "Ringworld".
3. The time of the "day" would be 28 days * (1/2)^(3/2) = 10 Earth
days, according to Kepler's laws. This means that the "nights" would
be 5x24 hrs or 120 hrs long. During this time, temperatures would fall
like a stone, even with an atmosphere, and even with the reflected
Earthlight. Likewise, the daylight hours would be 120 hrs long and the
temperatures would soar to inhospitable levels. Better to have the
ribbon circle a constant source of energy (the sun) and impose
artificial, shorter-cycle shadow-makers for night and day. See
"Ringworld".
4. Any circular orbit will either lie in the same plane as the Moon,
or will intersect the plane of the Moon's orbit. The first case means
that the Moon will be closer to one part of the ribbon than other
parts of the ribbon, forcing an elliptical distortion of the ring.
Because the orbital period of the moon is about three times longer
than that of the ribbon, this will cause some precession of the
flexing of the ring, from minor-axis to major-axis about every 7 days,
and the tensile strength of the ring will have to accomodate that. The
second case means that the ring will flex from circular to elliptical,
with a rather sudden and possibly cataclysmic perturbation, every two
weeks. Again, the tensile strength required to withstand that rather
harrowing few hourrs every fortnight is probably well beyond the
strength of known materials. Better to build it where there are no
other nearby orbiting objects to cause tidal forces. See "Ringworld".
5. There is also the small matter of finding enough materials to make
the ring. The Earth's crust is about 7 miles thick (averaged over
oceans and continents). The surface area is 200 million square miles,
yielding a volume of about 1.4 billion cubic miles of crust. Let's
assume that your ribbon is 3 miles thick, 10 miles wide, and 750,000
miles in circumference, yielding a volume of 22 million cubic miles of
crust, about 1.5% of that available in the whole crust, and about 20%
of the continental volume above sea level. It's an interesting
exercise to decide what continent on Earth would have to disappear to
supply the materials for this ring. See "Ringworld".
6. It's also an interesting exercise to see how much the rotation of
the Earth would have to change to elevate all this material and get it
rotating at a different speed. Think of an ice skater when she extends
her arms.

PD

Hope I can convey this properly - imagine the Earth next to the
moon, a baseball next to a golf ball in an imaginary level line. The
ring on a vertical axis at the
center of the baseball, so that it just looks like a straight up and
down line. As the golf ball revolves around the baseball, the ring is
locked in the same position
relative to the golf ball. Wouldn't that avoid any gravitational
effect from the golf ball?

Ed

On Feb 27, 8:34 pm, " wrote:
On Feb 27, 10:41 am, "PD" wrote:





On Feb 25, 9:24 am, " wrote:

My knowlege of physics and engineering is very limited, but I'm hoping
my questions will be of enough interest
to you that I get a considered reply. I'm working (as a hobby) with
this 3D Graphics/Sci-Fi concept of a manmade Torus object on a
planetary scale, call it "Toron." Just to simplify the presentation,
I'll speak in present tense
as if this thing already exists (no, I'm not about to take poison and
lie down to wait to join my buddies up there)
Also, obviously, there has to be an acceptance that there will be
fabulous breakthroughs in technology in the
future. Even with this kind of latitude, do these ideas make you
cringe and say, "yeah, sure"?
Toron encircles the Earth at approximately half the distance to the
moon. It's ten miles in diameter, like a ten-
mile-thick tube surrounding the planet. The outer half of the tube is
enclosed, housing docking ports, mechanical
works, supply stations, etc. The inner half, constantly facing Earth,
is enclosed by an immense transparent
or transluscent dome, each section of which is 4.5 miles wide and 20
miles long. These domes, along with
most of the other materials making up Toron, are manufactured in
plants on other bodies of the solar system.
There are approximately 15,000 dome sections.
Underneath the dome is a platform on which an artificial Earth surface
is built, 3 miles under the apex of the
dome. There are rivers, mountains, rain, there is animal life. If
you look overhead, there is our planet, basking in sunlight or a
magnificent crescent, always in the center of the sky. There are all
these things, that is, if centrifugal
force can be substituted for gravity. Also, would an object of this
size and in this location have any effect
on the motion and tides of the Earth and Moon?

1. Don't need a tube. Just need a ribbon, with an inner surface and an
outer surface. See "Ringworld".
2. Don't need domes. Just need walls on the sides of the ribbon.
Atmosphere will stay in place in centrifugal effect as long as it
can't flow over the sides. Structurally much simpler and probably
better to let the atmosphere work as intended. See "Ringworld".
3. The time of the "day" would be 28 days * (1/2)^(3/2) = 10 Earth
days, according to Kepler's laws. This means that the "nights" would
be 5x24 hrs or 120 hrs long. During this time, temperatures would fall
like a stone, even with an atmosphere, and even with the reflected
Earthlight. Likewise, the daylight hours would be 120 hrs long and the
temperatures would soar to inhospitable levels. Better to have the
ribbon circle a constant source of energy (the sun) and impose
artificial, shorter-cycle shadow-makers for night and day. See
"Ringworld".
4. Any circular orbit will either lie in the same plane as the Moon,
or will intersect the plane of the Moon's orbit. The first case means
that the Moon will be closer to one part of the ribbon than other
parts of the ribbon, forcing an elliptical distortion of the ring.
Because the orbital period of the moon is about three times longer
than that of the ribbon, this will cause some precession of the
flexing of the ring, from minor-axis to major-axis about every 7 days,
and the tensile strength of the ring will have to accomodate that. The
second case means that the ring will flex from circular to elliptical,
with a rather sudden and possibly cataclysmic perturbation, every two
weeks. Again, the tensile strength required to withstand that rather
harrowing few hourrs every fortnight is probably well beyond the
strength of known materials. Better to build it where there are no
other nearby orbiting objects to cause tidal forces. See "Ringworld".
5. There is also the small matter of finding enough materials to make
the ring. The Earth's crust is about 7 miles thick (averaged over
oceans and continents). The surface area is 200 million square miles,
yielding a volume of about 1.4 billion cubic miles of crust. Let's
assume that your ribbon is 3 miles thick, 10 miles wide, and 750,000
miles in circumference, yielding a volume of 22 million cubic miles of
crust, about 1.5% of that available in the whole crust, and about 20%
of the continental volume above sea level. It's an interesting
exercise to decide what continent on Earth would have to disappear to
supply the materials for this ring. See "Ringworld".
6. It's also an interesting exercise to see how much the rotation of
the Earth would have to change to elevate all this material and get it
rotating at a different speed. Think of an ice skater when she extends
her arms.

PD

Hope I can convey this properly - imagine the Earth next to the
moon, a baseball next to a golf ball in an imaginary level line. The
ring on a vertical axis at the
center of the baseball, so that it just looks like a straight up and
down line. As the golf ball revolves around the baseball, the ring is
locked in the same position
relative to the golf ball. Wouldn't that avoid any gravitational
effect from the golf ball?

Ed

I understand what you're trying to convey, but now you have a
spectacular problem of material stresses, not to mention that the
centrifugal force that generates your pseudogravity will vary
enormously around the ring. Here's why.

Let's build a ring just 300 miles above the earth. We could do this by
sending up a million or so space shuttles into orbit. What holds the
Space Shuttle in orbit is gravity. Specifically, there's a
relationship between the radius of the orbit and the time of the orbit
due to gravity. For the Space Shuttle, it's an hour and a half; for
the moon, further out, it's 4 weeks. But if you put a million Space
Shuttles in the same path, one just behind the other at 16,000 mph,
they would all follow each other merrily in a ring, without touching
each other. Then you could tie them all together with pipes (or pieces
of baling twine) in a big ring and you'd have your little Ringworld.
Now if one of the Space Shuttles got to be faster, it would have to
move to a nearer orbit to stay in a circle; if one of the Shuttles got
to be slower, it would have to move out to a further orbit to let
gravity keep it in a circle. That again is Kepler's law. The fact that
this ring of Space Shuttles could be tied together with string is what
makes the Ringworld concept feasible, and it's the delicate balance
between speed and radius that earns stability.

But now imagine a set of Space Shuttles that *isn't* following the
circumference of the orbit, ring-around-the-rosie-style. Imagine that
there is a ring of Space Shuttles, as you describe, that more or less
looks like a line of longitude, a great circle that passes over North
and South poles, and which rotates as though pivoted on an axis
through the Earth's poles. One of those Space Shuttles will be the one
over the equator, and it will be going at 16,000 mph, so that it
orbits in an hour and a half, gravity doing the work of keeping it in
a circular orbit. But what about the Shuttle that is poised over the
North Pole. It doesn't have *any* speed. It's just slowly spinning
around, turning once every hour and a half. Unfortunately, gravity is
still at work, and there is nothing holding that Space Shuttle up, and
in reality it would do exactly what you'd expect a Space Shuttle 300
miles up would do -- it'd fall like a stone. Oh, of course you could
hold it up with braces from neighboring shuttles, but now you're not
talking twine, you're talking serious steel to hold up a Space Shuttle
in the air. Oh, and the neighboring Space Shuttles aren't traveling at
16,000 mph either. They're turning in tight little circles around the
pole, relying on *their* neighbors to hold them up. In fact, the only
Shuttles that seem to be in balance are the ones on the equator, and
now you're expecting to create a rigid structure that can hold a Space
Shuttle in the air that is 10 miles wide and 6000 miles long. You'll
find that a pole with an aspect ratio of 600:1 is not very rigid.

OK, you say, so what we need to do is have a *combined* motion, so
that ring is *both* revolving around the circumference, ring-around-
the-rosie-style, *and* spinning on an axis through the poles. Now the
Space Shuttle that happens to be passing over the North Pole at a
given moment is still going at 16,000 mph, and we've restored the
radius vs. speed relationship. But notice that because the whole ring
is rotating on that pole-to-pole axis, that Shuttle over the pole will
have to constantly be steering (that is, firing its engine) toward the
left to follow the ring's spin. Worse, the Shuttle that happens to be
passing over the equator has to move toward the pole at 16,000 mph AND
around the equator at 16,000 mph, for a combined speed toward the
northeast at 22,400 mph -- and now that's too fast to remain in a
stable orbit 300 miles up. So now you need a rigid structure -- again
6000 miles long and 10 miles wide -- to keep that Shuttle from flying
out of orbit.

The stresses in the structure required to perform this kind of
maneuver are much, much greater than the tidal perturbation caused by
the Moon, and the latter is also catastrophic.

But I'm glad you asked.

PD