40th Anniversary of 2001:A Space Odyssey

"Jeff Findley" wrote in message
...
Docking at the outermost point would create a lot of force on the docking
mechanism. Ignoring that issue, you've still got the problem of the mass
of the shuttle throwing the rotating station out of balance.

I've considered that- I expect a number of liquid supply tanks, fuel,
oxygen, water, or whatever- which are kept partially empty. If a mass
imbalance occurs, then fluid is moved around to eliminate it.

I suspect the mass of the Clipper is a tiny fraction of the mass of the
station. However, any mass change that does not occur along the plane that
is perpendicular to and intersects the center of the axis of rotation will
also cause the axis to nutate.

Fluid transfer to maintain balance is likely to be commonplace on rotating
stations.


** Posted from http://www.teranews.com **

Scott Hedrick wrote:
I thought about this for Babylon 5, which has an even more complicated
docking sequence (particularly when someone is coming and going- you not
only have to roll, but also constantly thrust to the side, as if you were
orbiting the rotational axis of the station). You don't need to have the
entire hub to not rotate- you can have a ring that can derotate, with
grappling fixtures to hold the spacecraft, then gradually speed up until the
spacecraft is rotating at the same rate as the station. Then, pull it inside
and have it land. This completely eliminates compatability issues with alien
craft and makes docking far safer.


B5's main rectangular docking bay is on the center axis of the docking
sphere.
So it's basically a "2001" type operation.
Starfuries are ejected via centrifugal force from the rotating exterior
Cobra Bays, and return to the Cobra Bays via the main docking bay in the
docking sphere... and some large cargo ships dock to the de-spun spine
to deliver cargo, avoiding the main docking bay completely.
http://www.shipschematics.net/b5/ima...n_babylon5.jpg
The whole thing owes a lot to the Gerard O'Neill "Island 5" L-Colony
designs, but rationalized so that only part of the whole complex rotates
for artificial gravity.

Pat

On Wed, 30 Apr 2008 02:11:26 -0500, Pat Flannery
wrote:

Starfuries are ejected via centrifugal force from the rotating exterior
Cobra Bays,

....Pat, can you cite source on this one? IIRC, years ago in the B5
moderated-by-assholes group, he stated that there was an ejector
mechanism to overcome what Li'l Harlie claimed was a tendency for such
a centrifugal launch in zero-gee such as the one depicted to not throw
the Starfury out fast enough to eliminate the risk of sideways
movement and impacting with the hatchway.

(I did try to Google Group search for this one, but didn't come up
with the post in question, alas.)

OM
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OM wrote:

Starfuries are ejected via centrifugal force from the rotating exterior
Cobra Bays,


...Pat, can you cite source on this one? IIRC, years ago in the B5
moderated-by-assholes group, he stated that there was an ejector
mechanism to overcome what Li'l Harlie claimed was a tendency for such
a centrifugal launch in zero-gee such as the one depicted to not throw
the Starfury out fast enough to eliminate the risk of sideways
movement and impacting with the hatchway.


No source; it just looks like that's what they do after the launcher
forks swing to the down position for launch.
I imagine the launch forks could incorporate some sort of catapult
mechanism to hurl them out also, and now that you mention it, the speed
they leave the bays at does look high for centrifugal force alone given
the smaller diameter of the docking sphere and its lower gravity in
relation to the main station cylinder.
Looking at the drawings of it in the Babylon 5 Security Manual, gravity
in the Cobra bays should be around 2/3 to 3/4 that of the main cylinder,
so assuming the main part is at 1G, this would mean a drop velocity out
of the bay of around 21-24 feet per second, and the launch sequence
shows them going faster than that.

Pat

"Pat Flannery" wrote in message
news:mbOdnd5EO61WhoXVnZ2dnUVZ_j-dnZ2d@northdakotatelephone...
Starfuries are ejected via centrifugal force from the rotating exterior
Cobra Bays, and return to the Cobra Bays via the main docking bay in the
docking sphere...

THe problem being, of course, that unless they all eject simultaneously,
they will all be going in different directions, spreading out in a
fan-shaped pattern, and thus requiring fuel to get into formation. Unless
the fighters can be launched into the plane defined by where the enemy will
be when the fighters get there and where the launch bay is when the fighters
are launched, you have serious out-of-plane maneuvering to do, and it's a
negative if the enemy is approaching along the axis of rotation, since you
have to stop momentum away from the station and start from scratch.

One thing missing was a heavier bomber-type craft, like BG's Raptors. JMS is
brilliant, but he can't think of everything (and didn't have the money for
it, anyway).


** Posted from http://www.teranews.com **

On Apr 10, 11:39 am, (Derek Lyons) wrote:

What was shaky?

Practically everything about the Discovery for starters. (Note the
lack of cooling fins

Fins?

Radiators yes, but what good are "fins" in the usual array-of-parallel-
plates sense going to do without
some gas flowing between them? When all you've got is radiation,
surfaces facing each other
won't help much.

On Apr 10, 5:06 pm, Pat Flannery wrote:

If the astronauts try to jog around it like shown in the movie, then the
1/6 g is going to make them come clean off of the floor, like someone
trying to run on the Moon would experience.

So how come they could run around the non-rotating locker module of
skylab?

wrote:
On Apr 10, 5:06 pm, Pat Flannery wrote:


If the astronauts try to jog around it like shown in the movie, then the
1/6 g is going to make them come clean off of the floor, like someone
trying to run on the Moon would experience.


So how come they could run around the non-rotating locker module of
skylab?


In Skylab they were in zero g, so as they ran, centrifugal force stuck
them to the wall. IIRC, they were going at quite a clip in that little
run, so the force could have been pretty high. The curvature of the
inside wall of the station was pretty severe also, so that what would
normally be a bounce ran them feet first into the wall a little further
on. Also, their run lasted only a few seconds.
On the Moon of course you were dealing with a effectively flat surface,
and the astronauts quickly found out that "kangaroo bouncing" was a lot
more effective than running if you wanted to get around fast.
Discovery's centrifuge was of considerably larger diameter than the
inside of Skylab, but there still would be some "rise" ahead of you as
you moved around it, so maybe something like running could be done
(although the balance effects on the inner ear are going to be severe in
any movement in that small of a diameter centrifuge.)
The set was complex enough to begin with, but hooking the actor on wires
from its center of rotation and counterbalancing 5/6 of his weight might
have been interesting in regards to what running would be like, and I'm
half surprised Kubrick didn't try it just to see what it looked like.
In 2001 the centrifuge was spinning and the astronauts were stuck to the
outside walls when it was at rest.
This brings up something interesting - depending of which direction you
run around Discovery's centrifuge in, you are going to either get
lighter or heavier. Run in the reverse direction of its rotation and you
effectively lose weight as your rotation around its axis is slower than
its RPM rate. Run _with_ the direction of rotation, and the reverse is true.
Has anyone watched the movie to see in which direction he's supposed to
be running?
You could check out the rotation direction when he climbs up to the core
access corridor.
(If it helps, the centrifuge is located at the end of a tunnel directly
in back of the command deck and is aligned so that its axis of rotation
sits at ninety degrees to the length of the ship - if the command sphere
of the Discovery was the Earth, its front would be the North Pole, its
widest point the Equator, and its attachment to the rest of the ship the
South Pole. In the cutaway of it in my book, this puts the centrifuge
at somewhere around the equator to 20 degrees south latitude.
Surprisingly it is nowhere near the full diameter of the command sphere.)
In relation to the rotating set itself, he's obviously running against
its direction of rotation at the speed of its rotation, so he should be
weightless.
But the intention in the film might be that he's running _with_ its
direction of rotation, so he should be at 1/3 G.
At 1/3 G you might be able to do Earth-like running while running up the
curve of the centrifuge's interior.
That still doesn't explain how the people in the Lunar base are are
getting around in such a Earth-like way.

Pat

Scott Hedrick wrote:

THe problem being, of course, that unless they all eject simultaneously,
they will all be going in different directions, spreading out in a
fan-shaped pattern, and thus requiring fuel to get into formation. Unless
the fighters can be launched into the plane defined by where the enemy will
be when the fighters get there and where the launch bay is when the fighters
are launched, you have serious out-of-plane maneuvering to do, and it's a
negative if the enemy is approaching along the axis of rotation, since you
have to stop momentum away from the station and start from scratch.


They do not lack in fuel, as they are powered by high thrust ion engines
and each of the four Cobra bays launches it fighters as it rotates into
position toward the side facing the enemy.
Launching rate is around one Starfury per second.

One thing missing was a heavier bomber-type craft, like BG's Raptors. JMS is
brilliant, but he can't think of everything (and didn't have the money for
it, anyway).

There is a attack variant of the Starfury, the Thunderbolt:
http://www.shipschematics.net/b5/ima...hunderbolt.jpg
....but as B5 was intended to be a peaceful station it wasn't originally
equipped with these, as the Starfuries were considered adequate for self
defense. Later in the show, when things went to crap between Earth and
B5, they did get some Thunderbolts from defecting EarthForce Alliance
ships that joined their revolt.

Pat

"Scott Hedrick" wrote:


"Pat Flannery" wrote in message
news:mbOdnd5EO61WhoXVnZ2dnUVZ_j-dnZ2d@northdakotatelephone...
Starfuries are ejected via centrifugal force from the rotating exterior
Cobra Bays, and return to the Cobra Bays via the main docking bay in the
docking sphere...

THe problem being, of course, that unless they all eject simultaneously,
they will all be going in different directions, spreading out in a
fan-shaped pattern,

Nope - you just drop them sequentially as each bay comes in line with
the departure vector. This leaves 'em deployed in a very nice line.

I've never seen B5, but the above solution was used in another novel
(whose name currently escapes me).

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL