-Z- (Z@Gundam.Com)
Tue, 04 Apr 2000 21:42:33 -0700


At 17:00 4/4/2000, you wrote:
>Sorry for dumb boring and random questions...
>
>Do we know where on the Moon are Von Braun City and Granada?

Von Braun City is located in the Cayley crater in Mare Tranquilitatis (Sea
of Tranquility), the site of the Apollo 11 landing. It's inn the lower
left quadrant of the Moon when viewed from the Northern Hemisphere and the
upper right quadrant when viewed from the Southern Hemisphere. The Moon's
poles are reversed relative to Earth so, from the Lunarian viewpoint, Von
Braun City is at 0.7N by 23.4E.

Granada is a bit more problematic. Tomino places it in the "Soviet
Mountains" on the far side of the Moon. It turns out that there's no such
place -- what the Russians designated as a mountain range in their 1959
Luna 3 photographs turned out to be a system of rays and the designation
was subsequently dropped from lunar cartography in 1979. The area is now
called the Lipsky Plain. Based on the location and size of the crater in
the animation, I'd place Granada in the Tsiolkovsky crater, 20S by 130E.

>What about the planetary mechanics of Solomon and A Bao A Qu? Do they
>orbit L5 and L2 respectively in the same manner as Luna2 orbit L3?

Yes. In fact, none of the colonies actually reside in the Lagrange point
proper, but in "halo orbits" approximately 10,000 kilometers across around
the point.

>Finally a Bunch is 2 colony cylinders right (according to Z's site)? And
>a Side consists of up to 80 Bunches. So how do these 160 cylinders of 6.4
>km diameter x 32 km diameter move around an Lagrangian point? If the 160
>cylinders go around the L point in a circle (ellipse) what's the physical
>meaning of a "Bunch"? Or the 2 cylinders in a Bunch orbit around each
>other (must be very slow) and the 80 Bunches orbit around the L point in a
>circle?

That's not exactly what I said. The O'Neill "High Frontier" concept
specified paired cylinders, so it seemed reasonable that "bunch" might
originally have referred to a pair of colonies. Whether or not that was
the case, a single colony cylinder has always qualified for that.

"Bunch" may simply be a made-up word or a Japanese word applied in a
somewhat different fashion, the way "sector" and "quadrant" have been
co-opted for zones of space that bear no resemblance to true geometric
sectors or quadrants in American SF.

Further complicating things, Tomino states in his Gundam novels that
"later" colonies were up to 45 km long. One of the illustrations in Gundam
Century, comparing a colony cylinder to Mount Everest, actually scales in
as such. All of the other illustrations, taken from High Frontier, use the
canonical (per O'Neill) 32 km figure.

As to the orbital dynamics, each cylinder spins on its long axis, which is
always in a straight line pointing at the Sun. Gyroscopic action keeps it
in this orientation. The spinning cylinders travel in a near-circular
orbit around the Lagrange point, presumably in a cluster -- that which we
call a Side would, by any other name, orbit just the same. (^_^) If any
of the cylinders are paired, they revolve around a common center midway
between the two, with a period of 1/60 their rotational periods, which
works out to one-half revolution per hour or one revolution every two hours.

Orbital period for a Side around the Lagrange point is one-third that of
the Moon around the Earth, about once every ten days.

>And er... I got an answer from -Z- before, but I can't find that email any
>more... How big and heavy are Solomon, A Bao A Qu and Axis? (I found
>Luna2 formerly know as Juno is 180 km wide from Mark's site).

That 180 km (112 mile) figure's the whittled-down mass of
Luna-II. Asteroid 3 Juno is presently 244 km (150 miles) across.

If I have any figures on the masses of the other asteroid bases, they're
packed away for the Duration.

>The Axis was propelled from the asteroid belt to the Earth-Moon region
>during 0086, and in 0093 it was propelled onto Earth. What was the Axis's
>orbit from 0087 to 0093? Was it being flew around the Earth-Moon region
>like a space ship?

Axis was in a station-keeping orbit with Jupiter, at the far side of the
Asteroid Belt -- the engines were simply to keep it in place against
Jupiter's ferocious tidal forces. These were presumably beefed up for the
trip to the Earth Sphere. Once in the Earth Sphere, it was used like a
missile to take out A'Bao'A'Qu (by then renamed Zedan's Gate) and the major
part of it was for a time on a collision course with Granada. Thereafter,
it appears to have replaced A'Bao'A'Qu as Side 3's last line of
defense. In January 0089 it's used as a missile again, this time against
Core 3.

>And finally, where was the Moon Moon Colony? Was it going around Earth in
>a higher-than-Moon orbit? Or was it in a highly ellipsoidal orbit that
>brings it close to Earth once in a blue moon?

My understanding, never confirmed, is that is was in orbit around the
Moon. The name was thus a double pun: the moon of the Moon and the "moon"
belonging to the Moons. The Moons were supposedly Sun-worshippers, so Moon
Moon was in an orbit that kept it always on a line between the Sun and the
Moon ... or so the story goes. I don't think that such an orbit is
possible without orbital correction. A polar orbit around the Moon's
terminator, precessing as the Moon rotates so that Moon Moon's parabolic
mirror always points Sunward, would be much more likely and not require any
orbital corrections.

-Z-

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