I'm surprised that no one has suggested "slidewalks" already in use at
some air ports.

Dilettante

--- In spacesettlers, "Bob Hardman" wrote:

> I'm surprised that no one has suggested "slidewalks" already in use
> at some air ports.

Of course! Nice, wide ones, which is OK because you have all that
space you saved by not having autobahns.

> Dilettante

Xenophile (who *hopes* we can do better than cars and intersections
and traffic jams and..............)

> From: Bob Hardman [mailto:Bsanctuary@...]
>
> I'm surprised that no one has suggested "slidewalks" already
> in use at some air ports.

Yeah! Slidewalks! And tube-cars! And towers that look like flying saucers
at the top. And tights and capes with 8-inch high collars.

Now that I think of it, jet-packs never caught on due to their extremely
limited range. But in a habitat rotating for only 1/10th or 1/20th of a G,
they'd have the range needed to become practical.

Ahh... The vision is complete!

Regards,

Mike Combs

Why not the Moller Skycar ?? or a variant of, change it over to electric
engines with a fuel cell for power source.

could be very useful for emergency vehicles if nothing else, especially
in Island III's or Bernal Sphere's

Combs, Mike wrote:

One thing I have never really understood, is how gravity will work once
you are off the floor inside an O'Neil cylinder or Bernal Sphere ? I
don't mean just a little way off the floor but say 100 m or more up.

B

Combs, Mike wrote:

There is no gravity. If you were in a fixed position (relative to the
rim) with no velocity 100 m up, you would stay there until the wind or
orbital dynamics (your center of mass isn't the same as the colony's)
moved you to something you can grab.

On Tuesday, July 16, 2002, at 05:52 AM, Brett Sargeant wrote:

> One thing I have never really understood, is how gravity will work once
> you are off the floor inside an O'Neil cylinder or Bernal Sphere ? I
> don't mean just a little way off the floor but say 100 m or more up.
>
> B
>
> Combs, Mike wrote:
>
>>>
>>>
>>
>> Yeah! Slidewalks! And tube-cars! And towers that look like flying
>> saucers
>> at the top. And tights and capes with 8-inch high collars.
>>
>> Now that I think of it, jet-packs never caught on due to their
>> extremely
>> limited range. But in a habitat rotating for only 1/10th or 1/20th of
>> a G,
>> they'd have the range needed to become practical.
>>
>> Ahh... The vision is complete!
>>
>>
>> Regards,
>>
>> Mike Combs
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>

Space tourism could be our ticket to the stars. Save your pennies,
suborbital flights for $100,000 may start in 2005! See
http://www.spaceadventures.com/suborbital for details.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Just curious...

Could you move fast enough to push yourself into free fall? This
probably wouldn't be possibly just by running (although maybe in a
very low gee habitat it would be), but what about folks flying an
ultralight? Would you feel gravity once you were off the ground or
would you be in free fall? And what would this do to things like
landing? Would flying an ultralight in a habitat be something like
flying a small spacecraft, having to "match courses" with the ground
to land and things like that?

Mark

--- In spacesettlers@y..., Al Globus wrote:
> There is no gravity. If you were in a fixed position (relative to
the
> rim) with no velocity 100 m up, you would stay there until the wind
or
> orbital dynamics (your center of mass isn't the same as the
colony's)
> moved you to something you can grab.
>
> On Tuesday, July 16, 2002, at 05:52 AM, Brett Sargeant wrote:
>
> > One thing I have never really understood, is how gravity will work
once
> > you are off the floor inside an O'Neil cylinder or Bernal Sphere ?
I
> > don't mean just a little way off the floor but say 100 m or more
up.
> >
> > B
> >
> > Combs, Mike wrote:
> >
> >>>
> >>>
> >>
> >> Yeah! Slidewalks! And tube-cars! And towers that look like
flying
> >> saucers
> >> at the top. And tights and capes with 8-inch high collars.
> >>
> >> Now that I think of it, jet-packs never caught on due to their
> >> extremely
> >> limited range. But in a habitat rotating for only 1/10th or
1/20th of

Just go to the center (probably only a few hundred meters away) and
you'll be in free fall.

On Wednesday, July 17, 2002, at 08:02 PM, mgellis2 wrote:

> Could you move fast enough to push yourself into free fall? This
> probably wouldn't be possibly just by running (although maybe in a
> very low gee habitat it would be),

The dinosaurs were destroyed by an asteroid because they weren't
space-faring. It's almost as if Gaia then thought "Well, dinosaurs
worked pretty well, but space-faring is necessary. Maybe I'll should
try mammals this time." Humanity is now developing systems to detect and
deflect asteroids, and could build orbital space colonies to spread
beyond Earth to insure life would survive a planetary catastrophe.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Yes, but what about an ultralight (or helicopter, etc.)? I imagine
that when you run or jump, you are still connected to the habitat in
terms of having been moving along with it, so you'd drop back to the
ground. But if you are flying, say 50 m. above the ground, wouldn't
you sometimes just cancel out that momentum? Pressure from air and
wind, etc. would probably have some effect on you, but there isn't
really gravity, just the spinning interior surface of the habitat
whose rotation creates something like gravity.

Am I making sense? I apologize if I'm just missing something basic
here.

What would it feel like if this happened while you were flying an
ultralight, etc. inside a habitat? Would you just sort of feel
gravity drop away as you cancelled out your momentum? And then when
you landed, would you feel a sudden shock as "gravity" was "restored"
because you were now in contact with the surface again?

And how much effect would air and wind pressure have on aircraft in
these circumstances?

Anyone have any ideas about this?

Thanks.

Mark

--- In spacesettlers@y..., Al Globus wrote:
> Just go to the center (probably only a few hundred meters away) and
> you'll be in free fall.
>
> On Wednesday, July 17, 2002, at 08:02 PM, mgellis2 wrote:
>
> > Could you move fast enough to push yourself into free fall? This
> > probably wouldn't be possibly just by running (although maybe in a
> > very low gee habitat it would be),
>
> The dinosaurs were destroyed by an asteroid because they weren't
> space-faring. It's almost as if Gaia then thought "Well, dinosaurs
> worked pretty well, but space-faring is necessary. Maybe I'll
should
> try mammals this time." Humanity is now developing systems to detect
and

On Friday, July 19, 2002, at 08:31 AM, mgellis2 wrote:

> Yes, but what about an ultralight (or helicopter, etc.)? I imagine
> that when you run or jump, you are still connected to the habitat in
> terms of having been moving along with it, so you'd drop back to the
> ground.

You will not drop back to the ground. You will go in a straight line --
which will intersect the surface of the colony because it's concave.

The materials in one asteroid (the largest ) are sufficient to make
orbital space colonies with ~500 times the surface area of the Earth in
usable real estate. See http://lifesci3.arc.nasa.gov/SpaceSettlement/
for details.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

There are certainly some changes that one would have to get used to in
depending on centrifugal force as a substitute for gravity.

The only thing holding you to the "ground" in a cylinder is centrifugal
force. As soon as you stop moving in the same circular arc as you are when
you're on the "ground," there will be nothing acting on you to draw you back
to the ground. A jump into the air from a standing start won't cancel out
all your centrifugal force, so you will "fall" back to the "ground."

But if you use an ultralight or any other device or method to cancel out
your circular motion you'll just stay where you are (or more likely you'll
continue in a straight line until you hit something). So if you used an
ultralight to take off from the "ground," once you've become airborne you
can shut the thing off, because there's no gravity pulling you back toward
the "ground."
You'll just float along going in the same direction.

This does have potential design implications. What should be added to the
cylinder design to help people or things slow down if they happen to get up
there out of control, and are moving in a random direction with enough speed
to splat when they finally strike something?

--- In spacesettlers, "mgellis2" wrote:

> Yes, but what about an ultralight (or helicopter, etc.)? I imagine
> that when you run or jump, you are still connected to the habitat
> in terms of having been moving along with it, so you'd drop back to
> the ground. But if you are flying, say 50 m. above the ground,
> wouldn't you sometimes just cancel out that momentum? Pressure
> from air and wind, etc. would probably have some effect on you, but
> there isn't really gravity, just the spinning interior surface of
> the habitat whose rotation creates something like gravity.

Something like gravity, yes. But weirder.

http://lifesci3.arc.nasa.gov/SpaceSettlement/teacher/materials/ringwor
ld/

This will take you to a JAVA thingie that lets you simulate dropping
or throwing objects in an artificial-gravity-via-rotation
environment. Try dropping stuff with the view locked, then unlocked.

> Am I making sense? I apologize if I'm just missing something basic
> here.

I think so. I wish I knew better the answer, and how to say it so
that it would make sense.

Xenophile (if you throw it just right, it'll do a loop-de-loop...
WEIRD)

mgellis2 wrote:

> Yes, but what about an ultralight (or helicopter, etc.)? I imagine
> that when you run or jump, you are still connected to the habitat in
> terms of having been moving along with it, so you'd drop back to the
> ground.

Think about the air. The air rotates with the habitat.

Left to its own devices the air will speed up an object until
it moves at the same speed as the habitat at that altitude.

So even in free fall you will generally feel a constant
'gravity' force getting stronger and stronger until you pull
your parachute and land pretty normally.

So, hovering in a helicopter would mean that you get
normal gravity for that altitude.

> But if you are flying, say 50 m. above the ground, wouldn't
> you sometimes just cancel out that momentum?

Sometimes, if you fly in the right direction.

At any distance from the center the rotation gives the air
you're flying in a particular speed in a particular direction.
The air will follow the habitat, except at the
center where it stays still. This happens because air
is a viscous medium, and the drag of the buildings
means the air ends up rotating around.

Anyway, lets call that direction that the air is moving
'spinward' and the opposite direction 'antispinward'.

If you fly antispinward at the right speed- you actually
stop, but it wouldn't look like that, because the habitat
would be moving past you. But because you are really
stopped you will be in zerogravity in the cockpit. The
aeroplane will fly fairly normally, although you'd have to put
the stick forwards, because the aircraft doesn't weigh
anything, you don't need any lift!

If you fly spinward at the same speed relative to the ground
(assuming you keep the same altitude), you will get four times
earths gravity acting on you, and you'd have to pull back
on the joystick to account for the extra weight- that's
because the speed of the air and your airspeed add together
-you are going around twice as fast and the weight is
going to be in fact 4 times as much if you do the maths.

> Pressure from air and
> wind, etc. would probably have some effect on you,

Well, the aircraft will have to fight it's way through the
air- that's true. (Of course the air is still flowing past you
creating drag on the aircraft, so you'd need to leave the
engine running at all times, and you need to use the wings
to generate enough lift to keep the aeroplane in the air.

> but there isn't
> really gravity, just the spinning interior surface of the habitat
> whose rotation creates something like gravity.

Yes. It's your rotation that matters. Doesn't matter whether
you are moving relative to the air, it's the rotation relative
to someone outside that counts. Doesn't even matter if you
are rotating around a different center than the habitat- it's
the acceleration around your center that counts.

> Am I making sense? I apologize if I'm just missing something basic
> here.

You're on the right lines.

> What would it feel like if this happened while you were flying an
> ultralight, etc. inside a habitat? Would you just sort of feel
> gravity drop away as you cancelled out your momentum? And then when
> you landed, would you feel a sudden shock as "gravity" was "restored"
> because you were now in contact with the surface again?

It will vary depending on which direction you are flying in.
There's no sudden shock- it's entirely to do with whether you
are flying spinwards, antispinward or down the length of the
habitat and how fast you are going. Also, altitude effects it
as well.

> And how much effect would air and wind pressure have on aircraft in
> these circumstances?

Nothing special- same as normal. Air pressure will vary with
altitude, less so than on earth though. There may be some
unusual convection currents to deal with. The weight of the
plane will vary. The fuel supply for the aircraft might
need to be adjusted to be able to take zero-g, but that's about
it.

Also the bottom line is that the size of the effects depend
on the size of the habitat and how fast the plane flies.
Large habitats spin faster at the rim, so your plane may not
be able to fly fast enough to give you zero-g, atleast not
at near ground level.

Ok test, to see if you've really understood this ;-)

You take off in an aeroplane in an Island 3 habitat,
along the axis of the cylinder.

Your experienced gravity would be:

a) about normal gravity
b) about zero-g
c) negative gravity

You then turn antispinward, and you set your airspeed
to the same as the rim speed but in the opposite direction.
(Maintaining altitude.)

Your experienced gravity would be:

a) about normal gravity
b) about zero-g
c) about negative gravity

(Tricky one!) You then accelerate to twice the airspeed,
maintaining the same altitude in the same direction. What
gravity force would you feel:

a) about normal gravity
b) about zero-g
b) about negative gravity

> Thanks.
>
> Mark

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding
technological civilization?"
- Gerard O'Neill

--- In spacesettlers, Ian Woollard wrote:

> Ok test, to see if you've really understood this ;-)
>
> You take off in an aeroplane in an Island 3 habitat,
> along the axis of the cylinder.
>
> Your experienced gravity would be:
>
> a) about normal gravity
> b) about zero-g
> c) negative gravity
>
> You then turn antispinward, and you set your airspeed
> to the same as the rim speed but in the opposite direction.
> (Maintaining altitude.)
>
> Your experienced gravity would be:
>
> a) about normal gravity
> b) about zero-g
> c) about negative gravity
>
> (Tricky one!) You then accelerate to twice the airspeed,
> maintaining the same altitude in the same direction. What
> gravity force would you feel:
>
> a) about normal gravity
> b) about zero-g
> b) about negative gravity

Would you consider setting this up as a poll, and we can see how many
of us get these right? I *think* I know the answers, but I'm going
to wait and give mgellis2 a chance to answer first. After all, this
was posted in response to his question.

Xenophile (cooking up a few technical questions of his own)

You can mail me your answers direct if you want...
I'll get out my red pen ;-)

xenophile2002 wrote:

> --- In spacesettlers, Ian Woollard wrote:
>
>>Ok test, to see if you've really understood this ;-)
>>
>>You take off in an aeroplane in an Island 3 habitat,
>>along the axis of the cylinder.
>>
>>Your experienced gravity would be:
>>
>>a) about normal gravity
>>b) about zero-g
>>c) negative gravity
>>
>>You then turn antispinward, and you set your airspeed
>>to the same as the rim speed but in the opposite direction.
>>(Maintaining altitude.)
>>
>>Your experienced gravity would be:
>>
>>a) about normal gravity
>>b) about zero-g
>>c) about negative gravity
>>
>>(Tricky one!) You then accelerate to twice the airspeed,
>>maintaining the same altitude in the same direction. What
>>gravity force would you feel:
>>
>>a) about normal gravity
>>b) about zero-g
>>b) about negative gravity
>>
>
> Would you consider setting this up as a poll, and we can see how many
> of us get these right? I *think* I know the answers, but I'm going
> to wait and give mgellis2 a chance to answer first. After all, this
> was posted in response to his question.
>
> Xenophile (cooking up a few technical questions of his own)
>

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding
technological civilization?"
- Gerard O'Neill

--- In spacesettlers, Ian Woollard wrote:

> You can mail me your answers direct if you want...
> I'll get out my red pen ;-)

I'd do that, except that your e-ddress is given as ianwoollard@t...

I've not a clue as to what the t stands for. But I think I know the
answers to the qestions, and I'm happy about that, as many of the
things that come up on these subjects are simply (or complexly!) over
my head.

Xenophile (who wonders if this chopped-off e-mail addy thing happens
to everybody, and why)

From: "xenophile2002"
To:
Sent: Monday, July 22, 2002 6:56 PM
Subject: [spacesettlers] Re: That last mile
(...)

> Xenophile (who wonders if this chopped-off e-mail addy thing happens
> to everybody, and why)

It is one of your settings in your Yahoo Groups profile. You can choose to
make your e-mail public or hidden. I think that the default option is
hidden.

Lucio Coelho

Oh well, I get a tonne of junk mail at my e-ddress (e-ddress?
cute!) anyway:

ian.woollard@...

xenophile2002 wrote:

> --- In spacesettlers, Ian Woollard wrote:
>
>>You can mail me your answers direct if you want...
>>I'll get out my red pen ;-)
>>
>
> I'd do that, except that your e-ddress is given as ianwoollard@t...
>
> I've not a clue as to what the t stands for. But I think I know the
> answers to the qestions, and I'm happy about that, as many of the
> things that come up on these subjects are simply (or complexly!) over
> my head.
>
> Xenophile (who wonders if this chopped-off e-mail addy thing happens
> to everybody, and why)
>

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding
technological civilization?"
- Gerard O'Neill