Actually, no. you don't need to disassemble and reassemble the modules at
every stop.
If you know which containers need to off-loaded and in what order, you
simply place the earliest containers to the outer edge, and later containers
towards the inside. Like properly loading a delivery van, you don't unpack and
repack a van at every stop. You may have to
re-arrange at some point as you pick-up spheres that are slated for
later delivery, but a 4-layer stack of spheres provides direct access to
29 spheres/modules out of 30 (4x4 (16), 3x3(9-1),2x2 (4) and 1x1 (1)),
the remaining 1 module in the center can be used for life support or as the
single "structural" sphere to hold the whole mass together. Larger
masses (a 5-layer pyramid has 55 units, a 6 layer pyramid has 91) will
have more inaccessable modules, but if you are shipping 91 at a time, chances
are that a large portion are being dropped at a single location, in which
case, entire layers are dropped off at once.
The advantages are that you aren't limited by the structure of the ship
- if a "standard design" ship has docking ports for 30 modules, you are
limited to shipping a maximum of 30 modules, if you want to ship 32, then you
need two ships. If you are only shipping 10 modules, then you are paying to
move supporting structure for 20 modules.
If you argue that you can just "strap on" a couple more modules, you then
essentially have the sphere module ship, so why limit yourself in the first
place?
All the designs I have seen for modular freight ships have either relatively
small connection points (the small ends of containers attached to a central
core) or have large attachment points, but then strap on containers to
containers to achieve a reasonable number of modules carried. If you can PSB
either design then the same reasoning justifies the sphere design which has
multiple small connection points and straps containers to containers.
A pyramid design ensures that each component is connected to at least 2 other
components and as many as 8. If a single structure fails, unless it is an
outer component, there are at least two other components taking up the slack.
Modern containers are rated to 24 metric tons of carrying capacity, but must
withstand being stacked up to 6 deep, meaning they
have to be designed to support over 150 metric tons (cargo + container
weight). Obviously people don't worry much about a single container failing
and causing 150 tons to drop through the bottom of the ship. The structure of
a future sphere will be designed to handle "appropriate" amounts of stress,
and like current containers, the owners will be responsible for their
structural integrity and liable for losses due to the failure of their
container.
The design of such freighters is to just move freight and that such
"commercial" freighters are not military ships, they will not be designed to
pull 10's of G's of acceleration, they are designed to move the largest amount
of cargo for the cheapest cost. Military transport ships may be built to a
different design driven by a different set of requirements (faster speeds,
higher acceration, greater structural strength).
For transport to ground side, you seem to be making the assumption that a
cargo module would be small enough to fit on a shuttle. I was
imagining larger masses - each module massing 1000-5000 tons (full)
each. I don't think it would be efficient to try to land 5000 tons of cargo in
a glider (for comparison a fully loaded 747 weighs 330 tons).
Each sphere could be packed with smaller "glider-friendly" modules of
10-100 tons inside. If there is any sort of queue to get containers
down to the surface, then it doesn't matter as much that it takes time to
fully unload a sphere as the limiting step will be the availablility of
gliders.
Modern container ships are only efficient at ports with the appropriate
facilties, and even then are limited by the number of cranes that can
reach the ship - I think large container ships can be serviced by 3-4
cranes, but it still takes days to unload a large container ship because there
are thousands of containers (I think the largest container ships
now carry about 6000 TEU's (twenty-foot equivalent units) each). Future
modular containers will only be as useful as the environment they are
used in allows - for instance if your cargo is going to Backwater Planet
with just a small space station and no regular cargo surface shuttle, then
your glider designed module costs you extra money to transport with no gain in
use. If your goal is to transport goods cheaply between systems, then the
additional cost of transporting modular structure around that isn't utilized
increases your transport costs.
Continuing to use the modern example for specialized environment,
container trucks are not the same as a standard haul tractor-trailer
trucks. Container trucks have added equipment to lift, attach and otherwise
manipulate a container which can contain up to 24 metric tons of goods, which
is additional equipment and weight that is not necessary if you are delivering
goods to the local delivery store. Most containers are delivered to warehouses
or manufacturing facilities, where the large quantity of goods inside are
unloaded, repackaged and then delivered by more conventional means.
Massive modular cargo movements will tend to be between major ports, with the
facilities to manipulate large quantities of modules in and out of the system.
It may take hours or days to unload a modular ship, but
that is not time wasted, as the freighter can re-fuel, grant shore-leave
or perform maintenance on the ship while modules are being shuffled around.
Larger freight companies may even maintain a fleet of extra engine
modules at major ports, allowing defective or low-fuel modules to be
switched out or extra modules added to a ship to increase its size
and/or speed. Re-fueling might be as simple a plugging a new fuel
module on while pulling the empty off the other side. Or in a more drastic
maneuver the command and maneuver modules will be popped off with their
current crew and a new ship (command and maneuver modules)and crew popped on
and sent on their way.
In addition, like modern large container ships, the large or super-large
modular ships will only ply major trade routes, where their efficiency (full
loads, massive quantities) can be realized. You would be unlikely to find any
type of modular freighter plying the small trade routes on a regular basis,
partly because of lower demand, and the lack of infrastructure to support a
modular system.
--Binhan
[quoted original message omitted]
> slack. Modern containers are rated to 24 metric tons of carrying
Obviously people don't worry much about a single container failing and causing
150 tons to drop through the bottom of the ship. The structure of a future
sphere will be designed to handle "appropriate" amounts of stress, and like
current containers, the owners will be responsible for their structural
integrity and liable for losses due to the failure of their container.
Indy, when you write a news item based on this happening, have it happen to
someone other than an AE company, please? <grin>
> "laserlight@quixnet.net" wrote:
A note on cargo's and containers if I may:
While the sphere is the best shape for mass 'bulk' cargos, this is only
(really) if it is a cargo with no 'inner' containers. (Bulk foodstuffs,
liquids, bulk ore, etc.) As the sphere does not allow a really efficient
loading of containers due to curved walls. (Dome folks have to deal with this
'fact' on a regular basis as most furnishings as well as storage items come
shaped in a square or rectangular shape:o)
The elongated hexagon shape is actually a good idea as most of it's internal
space is easily subdivided into smaller hexagons.
Another thought is 'stacked' hexagons that can be peeled off the 'stack' for
removal. All the hexagons have attachment points on one side for attachment to
the 'hardback' (backplane) of the ship and forward and aft attachments to
attach them to the 'stack' of the next container.
ISO (International, not Interstellar:o) containers come in an assortment of
'styles' depending on what they are to carry and how. The ones I usually
worked with were side-opening, in that one whole 'side' was a set of
doors that
could be opened to load/unload the container. (Ours were also
'wood-floored' to
allow us to nail dunnage and bracing to secure the cargo. Others had eyelet's
in the floor and ceiling for cargo straps or steel banding.) The others have
either end-doors or a combination of the two types. The 'frame of these
containers is a 'box' of steel beams with connectors at each 'joint' for
connecting to crane or truck mounted lifting devices and to interconnect with
other containers and the securing apparatus of the ship, truck, or rail car. I
should mention there is another type called the 'folding' ISO frame which is
basically a bottom frame and two end frames that can fold down when not
transporting cargo to allow storage and shipping.
As for 'getting-them-down' devices, with a fairly simple computer
control and inflatable drag break structure, (and parafoils) you could have
the containers themselves enter an atmosphere and land automatically. For an
interface
craft there are several ways to make a large 'cargo' up/downloader. (In
fact that is what one person called such an idea for transporting real 'bulk'
goods down
to Earth from space. The Downloader was a non-powered glider with the
cargo capacity of a standard supertanker. The idea was for getting the oil
from Titan to Earth:o)
One would be a crew compartment and engine compartment that is hexagonal in
shape and the same size as the 'stacked' modules mentioned above. Since FTs
background assumes 'gravitic' control and drives it would be simple to make an
engine module using the same dimensions of the cargo modules and use those to
lift and lower cargo containers.
C=crew or automated guidance section X=cargo module E=engine module
CXXEXXEXXE
No need for wings or heavy reentry equipment. And also ideal for airless
planets or space-to-space transfer craft.
On the other hand if you need wings and reentry equipment, there was an idea
of a 'flatbed' aircraft that was pursued in the mid 80s. It was found that the
drag of an aircraft as subsonic speeds was not all that effected whether the
body behind the nose section was streamlined or not. This lead to the idea of
a low-slung aircraft used for hauling cargo that was either NOT
streamlined at all, (the illustration I saw was a 747 sized aircraft hauling a
couple of large cranes and heavy earth movers literally rolled onto the
'flatbed' and strapped down and flown:o) or the possibility of a RORO
(Roll-On/Roll-Off)
container aircraft. Due to the 'hardback' being only the lower part of the
aircraft the need to fit a cargo into the fuselage constraints was less and
you could, (theoretically anyway) load larger amounts of cargo than the
standard aircraft 'volume' would allow. (The engines were mounted above the
wings rather than below. This is a usable method, and proven, just not used
much.)
A reentry craft could be made the same way. Large wings and a high angle of
attack entry would keep the heating on the lee side of the craft, (upper
portions) much lower and allow for an 'open' entry approach. Keeping the high
drag attitude until below hypersonic, (probably supersonic too) would keep the
cargo from experiencing significant heating.
Just some ideas and thoughts.
Randy
> From: ShldWulf@aol.com
The ISO bit was intentional. I know its international. After all, if I
remember, it was britisg rail who originated the container standardisaton idea
for its freightliner trains (20ft boxs, 8ft high).
Could be wrong.
BIF
In a message dated 11/20/2004 8:19:00 AM Mountain Standard Time,
> bifsmith207@hotmail.com writes:
Well, I think it's 8'6" high now, which was IIRC out of the USA... whatever, I
guess. (See here for various links and
background: http://www.alteich.com/tidbits/t040104.htm Good
stuff.)
I think the main question of the debate is how much cargo do people see
shipping between the stars, and of what value?
If you will be shipping bulk low-cost items, like (generally
speaking) ocean shipping today, then there will certainly be
much larger ships that may have more general schemes -- not just
individual containers, but whole sub-ships of containers.
Perhaps you even have a point where the FTL cargo drive actually
just hauls around system-only ships that move the cargo to their
final destination... the FTL tug drops off the system ships and picks up any
that are ready at a specified point in a given system. No need to waste time
with the FTL drive sitting idle... this also depends on how much you think an
FTL drive
costs to make and/or operate, and exactly how the FTL drive
operates.
Alternately, if there is relatively little cargo shipping, but it is high
value (sending the machines to make the bulk cargo on site, or to make more
machines, etc.) then cargo ships would be smaller and presumably better
protected. This doesn't *seem* to be the case, at least in the generic
background, but I don't think it is really called out specifically.
'Til later,
Aaron Teske
mithramuse@yahoo.com mithramuse@njaccess.com
> --- david smith <bifsmith207@hotmail.com> wrote:
> From: Aaron Teske <mithramuse@yahoo.com>
Containers come in varios hights. 8ft, 8ft6, 9ft and 9ft6, with different
leinths from 20 ft, 40 ft and the latest 45 ft (which with the lifting points
at 40 ft, the extra is 3 in over each side). Some containers only
come in 20 ft size, due to payload mass (tanks especially).
BIF
anything he say sould be taken in jest, yes realy, I mean it, it true, trust
me :-)
(model railways are useful sometimes, as the above data shows)