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stutefish
2007-Jan-22, 05:08 PM
So why not a disk, for interplanetary travel?

A central core comprising the main engine; with storage, living, and equipment spaces radiating outwards.

RCS thrusters around the outer rim, including thrusters to impart spin (roll?) for artificial gravity.

I'd say put the acceleration couches/nav porthole/storm cellar on top of the main engine, along the main thrust axis. The crew would stay there during powered flight, and then spin the craft while coasting so they could walk around the living quarters and lab areas.

Obvious problems (well, obvious to me, anyway), would have to do with questions like, "how big a radius can the disk have, before it flexes too much to maintain integrity under main thrust?", and, "how strong would the structure have to be, to maintain integrity while spinning?"

One huge problem solved would be the elmination of complex and weight-adding joints and apertures to allow portions of a craft to spin while the rest does not.

I'm sure the board can come up with more problems and solutions. Any takers? :)

MentalAvenger
2007-Jan-22, 06:24 PM
Accelerate edge-wise, coast flat-wise while spinning for artificial gravity.

galacsi
2007-Jan-22, 07:12 PM
An interplanetary ship does not need heavy thrust. it can be powered by ionic or plasmic motors.So structural problems can be kept at a minimum.

It can go edge on , and the edge can be fit with a shield.

Problem , the disk configuration is not very efficient to pack living space inside your ship. A sphere is better.

Then there is the dangers of having rockets motors just next crew's bunks inside the habitable part of the ship.

THe 2001 design is much better IMO.

stutefish
2007-Jan-23, 04:26 PM
For interplanetary travel (not interstellar, just between planets in our own solar system), I'm not sure a shield would be strictly necessary.

Also, what is a sphereship but several layers of disk-shaped "floors" of varying diameters? I suspect that the proper next step from a diskship would be a tubeship.

Maybe edge-on is a better way to do it, though. I hadn't given much thought to the proximity of engines to crew quarters.

However, I do imagine a series of concentric rings. The central core would be a kind of CSM stack, with an engine at the bottom and a flight deck/storm cellar at the top. Wrapped around the central core would be the fuel and air tanks. Wrapped around that inner ring of bulk consumables would be the electronics and storage cabinet rings. The outer ring would contain shirtsleeve environments: living spaces, observatories and labs, with the maximum useful gravity the spin can impart.

Perhaps the whole thing could be constructed skeletally, like a spiderweb, with the spaces filled in with inflatable hab modules or hardshell storage tanks and cabinets. Tough, flexible ribbed tubes acting as airtight gangways between central core and outer ring and all the storage spaces in between.

Thank you for your thoughtful responses.

JustAFriend
2007-Jan-25, 03:59 PM
Shape is irrelevant in space.

A Borg Cube is just as good as anything and right-angle cubes are easy to construct.

Woody-
2007-Jan-25, 05:50 PM
Shape is irrelevant in space.

A Borg Cube is just as good as anything and right-angle cubes are easy to construct.

Shape is not irrelevant.

If you want to use spin for "gravity" then some kind of sphere, tube, or wheel is better suited.

If you mount a high thrust engine then its better to have most of your mass along the centerline of the thrust.

If cost of materials is an issue then a sphere gives you the most volume per surface area.

I'm sure others will be along with more examples I haven't thought of.

publiusr
2007-Mar-02, 11:53 PM
A disk like airship might make a good outer moonbase. Walk around--and it won't rise like a balloon from the surface.

galacsi
2007-Mar-03, 01:42 PM
Time ago , i had the idea of a lunar habitat made in the form of a centrifuge turning around in a circular trench on magnetic levitation. The aim was to maintain a terrestrial gravity of 1 G .Pseudo gravity of 1G inside is vectorial combinaison of lunar gravity and centrifuge force.
A kind of shuttle on circular track around the centrifuge can match its speed and connect to it , then detaching and stopping , is used as an elevator for carryng goods and people from and out of the centrifuge habitat.
This can be buit in an asteroid too and may be more usefull because here native gravity is way too small.

Maksutov
2007-Mar-04, 12:49 PM
How about an interstellar Frisbee?

After all such forms have been proved to work on Earth.

Now, all that is needed is the initial spin vector and we're on our way!

The spin could be obtained by a slight deflection of the initial thrust.

The forward component would be achieved by thrusters or perhaps extraneous impellers.

The effect on the occupants would be multiple Gs, but if they were in a cryogenic state, it wouldn't be felt.

If the onboard electronics were smart enough, the spin rate could be decreased just before the release of the occupants from their cryogenic states.

With the possibility of the craft landing on an alien beach, well, that would be quite appropriate.

publiusr
2007-Mar-09, 10:57 PM
Do a search over at www.astronautix.com under ROOST, and you will see a drawing for an HLLV saucer concept. With super cooled hydrogen inside--it might just levitate like that little pill o' stuff they use for superconducting displays.

Let it skitter down a runway, build up speed, and run exhaust through MHD to get more altitude from a run-and-go.

trinitree88
2007-Mar-10, 12:29 AM
So why not a disk, for interplanetary travel?

A central core comprising the main engine; with storage, living, and equipment spaces radiating outwards.

RCS thrusters around the outer rim, including thrusters to impart spin (roll?) for artificial gravity.

I'd say put the acceleration couches/nav porthole/storm cellar on top of the main engine, along the main thrust axis. The crew would stay there during powered flight, and then spin the craft while coasting so they could walk around the living quarters and lab areas.

Obvious problems (well, obvious to me, anyway), would have to do with questions like, "how big a radius can the disk have, before it flexes too much to maintain integrity under main thrust?", and, "how strong would the structure have to be, to maintain integrity while spinning?"

One huge problem solved would be the elmination of complex and weight-adding joints and apertures to allow portions of a craft to spin while the rest does not.

I'm sure the board can come up with more problems and solutions. Any takers? :)

stutefish.
How about a diskship built on parameters that are a little different. First we'll remove the thrusters. Burning hydrocarbons or hydrazine produces an exhaust plume of CO2 and H2O, mixed with nitrogen oxides. That leaves contrails when you travel at altitude in atmospheres similar to the Earth's. Water vapor. Too visible.....needs to be a little more stealthy. Without a fixed airfoil, or a moveable airfoil, you'll need to develop something else to offset the weight of the craft. Since inertial accelerations are indistinguishable from gravitational ones...the principle of equivalence... manipulating the equivalence is essential.
The advantage of this is that the acceleration of the craft will involve all the nuclei of the external structure, plus all of the nuclei of the cargo within a few (c/ dimensions of the craft) seconds, simultaneously.. Since they all will "feel" the acceleration, 50-10,000 g's should be fine, even with humanoids onboard, as it is the gradient in the accelerations over the dimensions of the vehicle that causes the net forces felt by the passengers.
Odd, that's kind of the effect seen by some people regarding.....:shifty: :D , and of course, if you can manipulate inertial effects, you can by the same token manipulate gravitational effects.:think: pete.

stutefish
2007-Mar-10, 03:13 PM
LOL. nice idea, trinitree!

I had envisioned a ship that flew "face-on" to the direction of travel, rather than edge-on, which would raise some issues with atmospheric drag...

DaveC426913
2007-Mar-10, 03:46 PM
The disc spaceship, travelling face-on into the interstellar medium is a very efficient design for exposing its occupants to maximum radiation.

Cook until crisp and golden brown. Occupants are done when an inserted toothpick comes out dry.

trinitree88
2007-Mar-11, 02:17 PM
LOL. nice idea, trinitree!

I had envisioned a ship that flew "face-on" to the direction of travel, rather than edge-on, which would raise some issues with atmospheric drag...

Dave C has issues with radiation, which has been identified recently in Sci. American as the principle hazard to interplanetary, space, travel.
stutefish, you're worried about atmospheric drag.
By odd choice, magentic fields can push the atmosphere out of the way before the edge of the ship arrives...oxygen is a magnetic gas and will respond to strong fields, modifying supersonic shock waves. It was tried in the sixties on some reentry vehicles to facilitate communication during Gemini/Apollo missions, but without success.
Now if a limiting strength magetic field..~10 11Gauss were involved in the propulsion effect, it'd also deflect lots of the ISM, reducing radiation exposure. In order to function effectively, a small surface area would necessarily need a reversed effect to allow a local gradient for walking around inside. That of course, if possible would enable a beamed gradient, down and out through a portal....anyone or "thing" outside the ship, would be accelerated and directed into the portal....a "tractor" beam as it were.
Now, if you're out stargazing, and a black silent disk slips over the horizon and pauses above you, be careful, if a metallic voice says..."Step into the light". Sweet dreams. Pete.

DaveC426913
2007-Mar-12, 02:21 PM
Why would this star-faring generationship be going through any atmospheres???

DaveC426913
2007-Mar-12, 02:24 PM
By odd choice, magentic fields can push the atmosphere out of the way before the edge of the ship arrives
That may be true, but that doesn't solve your drag problem. In fact, it makes it worse. The magnetic field will serve as drag, requiring consequently more power from the ship to push it. In fact, since the magnetic field would effectively give the ship a much larger cross-sectional area pushing through the atmo, you've now made the effort required much greater.

stutefish
2007-Mar-12, 04:28 PM
I'm not actually worried about atmospheric drag; as I envisioned the diskship as a purely space-traveling vessel. Trinitree had brought up the idea of a disk-ship traveling edge-on for reasons of atmospheric drag. I had merely pointed out that the design I had in mind involved an axis of travel that would be very bad from an atmospheric drag point of view. What I didn't say at the time was that--as Dave pointed out--a true "space ship" doesn't have to worry about atmospheric drag anyway.

trinitree88
2007-Mar-12, 06:35 PM
That may be true, but that doesn't solve your drag problem. In fact, it makes it worse. The magnetic field will serve as drag, requiring consequently more power from the ship to push it. In fact, since the magnetic field would effectively give the ship a much larger cross-sectional area pushing through the atmo, you've now made the effort required much greater.

Dave. True, but given the basic premise of manipulation of the principle of equivalence, drag is kind of moot. The odd thing that always struck me was anecdotal reports from primitive tribes, Inuits, Papua natives, bushmen....and they would first describe an object that lifted without airfoils or rocket noise, and then describe aerodynamic antics that one would scant give credence to
occupants living through it....unless the same effect that attenuates the gravity field..(an acceleration), attenuates the inertial acceleration ,too, when the craft does it's kinematic dance.
This of course presupposes that one can actually do that, which has no experimental verification...as of yet.:think:

publiusr
2007-Mar-15, 10:27 PM
A craft with a massive central flywheel spun up by a nuclear craft that remains in Earth Orbit might be one way to supply electrical power--with the mass of the flywheel being a heavy duty battery itself. The disck has an inset dish always pointing back toward Earth, with gyros used to 'level off' while passing through any debris to present less of a cross section.


No reactors,and no solar collectors, radiators or other fragile protrusions sticking up like washerboards out from a trashcan/bus

Spinning fast enough, and you have M2P2 to boot. And artificial gravity. Maybe the flying disk isn't such a bad design after all.

publiusr
2007-Oct-12, 09:37 PM
Here is more information on potential diskships.

http://www.astronautix.com/craft/bonaucer.htm
http://www.astronautix.com/craftfam/lenicles.htm

A question. Would a submerged maglev system work, so as to avoid any landing gear? The landing strip would be a shallow lake or harbor. Water touchdown--and perhaps suspended in air while allowed to cool, then lowered to the water surface.

We all seen the levitating super conductor disks, so an all cryogenic HLLV saucer with some coils might do the same. Water is broken down for fuel, and also supports the craft.

Less violent than most splash-down recoveries or hitting the maglev rail hard...

For a heavier payload, a tether from a passing asteroid may assit in lofting such a disk shaped craft--which would lend itself to outsized, circular payloads like lenses, SPSS systems, etc. Such a wide craft might also be used as a base aor habitat on the moon.

http://www.liftport.com/component/option,com_smf/Itemid,58/topic,708.0