# A problem with starship design...



## Vertigo (Sep 11, 2011)

This sort of follows from another thread; now I have a calculator for interstellar journey times i have come up with a design problem.

First of all I am assuming no FTL here and also something along the lines of a ramjet so we don't have to carry the horrendous quantities of fuel involved.

Now if we can achieve 1g acceleration then we can still get places pretty quickly (measured in ship time rather than observed time). For example a 40 lightyear journey (starting and finishing stationary) would take around 7 apparent years (almost 42 observed years). All is well, until we arrive at our destination and take up orbit about a planet. Suddenly we are in zero-g. If we are going to stay a while (as is likely) that is going to be a big problem. Spin the ship? Problem is that you will have to completely re-configure the interior as your "gravity" is now outwards instead of along the axis. On top of that, the size of your ramscoop to achieve 1g would be so big it is probably not feasible anyway.

Now if we shift things down a bit and go for an acceleration of .2g we can still get places reasonably quickly; that 40 lightyear journey will now be around 23 apparent years. However .2g is not going to be very comfortable or good for our health, so we spin the ship to give us artificial gravity. This solves the problem for the end of our journey; we just maintain the spin. However the problem is now during the journey. You have your outward 1g acceleration from the spin and a .2g acceleration along the axis. Now 2g is not a lot but it is the equivalent of say a bus accelerating from 0 to 60kph (~37mph) in around 8.6 seconds which means everyone will be permanently leaning forward and stuff will tend to slide off tables and such. Not very pleasant if you have to deal with it for 23 years. If everything was angled slightly to compensate for this the problem would reappear when you go into orbit at the end.

Does anyone have any bright ideas how you might get around this?


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## Metryq (Sep 11, 2011)

In one of James P. Hogan's books (_Voyage From Yesteryear_ ?) the author describes a toroidal habitat section divided into segments, like railroad cars with flexible joints in between. When the ship is in freefall, the segments are oriented with "down" perpendicular to the axis of the ship (like Space Station V in _2001: A Space Odyssey_). Under drive, the segments rotate by varying degrees (based on ship thrust) until "down" is almost sternward. The vectors add together.

Hogan used a similar concept in _Endgame Enigma_ where a fake space station was set up on Earth. The toroidal habitat had a floor banked like a racetrack, and the habitat spun a bit faster than 1G to compensate for actually being on Earth. (The prisoners being held in this simulated space station were told they were recovering from an illness, which is why they felt heavy and lethargic.)

I went to a traveling "VR arcade" back in the early '90s. Among the games was a centrifuge like that used for training pilots. The rig had two spherical pods. One pod featured a race car game, the other a fighter plane. The gamer would climb in. As the centrifuge accelerated, the game screen posted a "standby" notice. The default acceleration was at about 45 degrees, pressing the gamer's butt into the seat. Once the game began, the pod rolled in sync to the game activity to drive the built-up G straight into the back of the seat, down into the seat, or even laterally from side-to-side. This rotating pod rig gave "instant" response, rather than slow build-up or -down of Gs by varying the armature. That is, the ride spun at the same speed the whole time, only the pod changed orientation.


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## Vertigo (Sep 11, 2011)

Interesting Metryq I can see how that would work and answers all the needs of my question. Unfortunately it doesn't help my particular problem as I am thinking in terms of habitat style ships. Vast cylinders such as hollowed out asteroids and this solution wouldn't work with them. It seems to me I must be missing something here since there have been plenty of books with such ships but then maybe the authors are conveniently ignoring this aspect of it. Oh well I shall have to think some more on this 

I wonder how high the acceleration could go without it being significantly noticable. .1g would be the equivalent of accelerating from 0 - 60kph (37mph) in about 17 seconds. That's a pretty gentle acceleration; a reasonably fast car could do it in about 2 seconds. I wonder if that would be enough to be conscious of leaning into it?

Another way of looking at it would be that for an acceration of .1g it would be like standing on a 5.7 degree slope. Hmmmmm...


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## Metryq (Sep 12, 2011)

Vertigo said:


> maybe the authors are conveniently ignoring this aspect of it.



Bingo. It works for space stations freefalling in orbit, but the moment you apply thrust, you have problems. The filmmakers for _2010_ ignored a reverse case of this problem when _Leonov_ was strapped to _Discovery's_ back. Obviously, _Leonov's_ habitat had to be stopped, yet there is a scene with Floyd and Curnow snacking on some crackers and discussing the up-coming launch. They are slouched in casual poses in an obviously gravitated environment. Oops.

Arthur C. Clarke's _Rama_ had a higher cliff face on the "southern" shore of the Cylindrical Sea, and the ship accelerated gently enough not to flood the southern continent. But overall, I'd say authors are ignoring this. 

If you're imagining a cylinder, perhaps the interior is "terraced"? (Imagine it like a bunch of the aforementioned toroids in a stack, where each toroid might be a "county" or other division. The main highway would naturally surround the core, but not run directly through the central axis—that's for the ramjet.)

Unless you want to introduce stasis fields, or Cavorite, you don't have many choices.

Postscript: Clarke's _Rama_ used some kind of exotic "impulse engine"—the large, black cones on the southern wall. Although the ship did not use the kind of reaction motors we understand, that did not suspend the laws of physics for the contents of the ship.


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## Ursa major (Sep 12, 2011)

Metryq said:


> Arthur C. Clarke's _Rama_ had a higher cliff face on the "southern" shore of the Cylindrical Sea, and the ship accelerated gently enough not to flood the southern continent. But overall, I'd say authors are ignoring this.


It's a while since I read _Rendezvous with Rama_ (and its not-in-the-same-class sequels), so I can't recall what happened with regard to inertial and gravitational effects. Wouldn't you need an equally high northern cliff face to cope with deceleration?


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## Metryq (Sep 12, 2011)

Ursa major said:


> Wouldn't you need an equally high northern cliff face to cope with deceleration?



The obvious answer is that _Rama_ would flip over before a deceleration maneuver. This is a given with most spacecraft engine designs.


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## Vertigo (Sep 12, 2011)

Ursa I think not as, if I recall correctly, Rama had to flip over to decelerate so the thrust would always be in the same direction.

Metryq, even with the terrace idea each terrace would have a different apparent slope whether you are accelerating or parked. However...

I think I have a solution; two actually, which could be combined.

The first is easiest to implement. Assuming the .2g of my example which gives an apparent slope of 5 degrees (I tried this and 5 degrees is really quite noticeable). However if the habitat was built so that it flares out towards the front of the ship with a 2.5 degree flare, then under acceleration there would be an apparent slope of 2.5 degrees one way and parked 2.5 degrees the other way. Much less noticeable than 5 degrees. The the effect could be made still less noticeable by creating a "rolling landscape" inside the habitat. One side benefit is that in the case of a large hollowed out asteroid, the thinner rear end of the ship would allow for "underground" factories/storage etc in the thicker "hull" at that end. Also, if for example you figure you will spend more time parked than travelling, the angle could be adjusted slightly in favour of being parked or vice versa if more time is spent travelling. Houses would still be a little odd - they would always have a tilt of 2.5 degrees one way or the other (however see below).

The second solution is to use Metryq's James P Hogan approach. We can't apply this approach to the whole habitat but we could put the buildings "underground". Not a bad idea anyway; maximise the "ground" area for the biosphere. These buildings could then float in cradles so that they will rotate automatically to give a true perpendicular "down". Obviously the motion would need to be heavily damped; don't want to get seasick in your house! It wouldn't really be a massive difficult job as the "cradle" would only have to allow for a few degrees of movement.

Finally both of these solutions could be combined giving what would, I think, be an acceptable approach. I also like the idea of having a "river" going along the length of the habitat that flows one way under acceleration and the other when parked 

Edit: Metryq snuck in first with his post.



> This is a given with most spacecraft engine designs.


Not in the case of ramjets - they always face the same way... ah... blast, that blows the flared idea. In the case of ramjets it would have to be Metryq's idea only. Then under acceleration the floor of the habitat would appear to slope one way, under deceleration the other way and when parked it would appear flat.


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## Ursa major (Sep 12, 2011)

Metryq said:


> The obvious answer is that _Rama_ would flip over before a deceleration maneuver. This is a given with most spacecraft engine designs.





Vertigo said:


> Ursa I think not as, if I recall correctly, Rama had to flip over to decelerate so the thrust would always be in the same direction.


I've done my best to flush the contents of the sequels from my mind (yes, I disliked them that much), so I couldn't recall whether the reversing manoeuvre had been described (or mentioned).



Vertigo said:


> The second solution is to use Metryq's James P Hogan approach. We can't apply this approach to the whole habitat but we could put the buildings "underground". Not a bad idea anyway; maximise the "ground" area for the biosphere. These buildings could then float in cradles so that they will rotate automatically to give a true perpendicular "down". Obviously the motion would need to be heavily damped; don't want to get seasick in your house! It wouldn't really be a massive difficult job as the "cradle" would only have to allow for a few degrees of movement.
> 
> Finally both of these solutions could be combined giving what would, I think, be an acceptable approach. I also like the idea of having a "river" going along the length of the habitat that flows one way under acceleration and the other when parked


I can't help thinking that it would be just as easy to have above-ground buildings that can adjust to the changes in acceleration. (Apart from anything else, what's the point of have a huge "open" habitat if you have to live "underground"?) If the maximum change in orientation is ±5°, you would only have to provide a small area on two sides of a building that would be submerged/revealed as appropriate. Whole rows of building could be arranged at right angles to the direction of acceleration/deceleration, their extent only limited by the curvature of the habitat.


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## Vertigo (Sep 12, 2011)

Well I must admit Ursa I had wondered about that as well, and I agree it somehow seemed _wrong _to put the houses underground, factories maybe having the houses on the surface seems much nicer. 

I guess over the size of a house you would end up with a step down on one side and a step up on the other. In fact if you always placed the doors at the "rotation" point on the side following the direction of acceleration then you wouldn't even need a step. The only small disadvantage is that arrangement would be slighlty less stable and you might need to give the house a "keel" so it wasn't top heavy (bit embarrassing if your house suddenly flipped upside down in the middle of a dinner party ). 

I don't really want to use power/hydraulics or whatever to tilt the house and would rather it found it's natural tilt to suit the conditions. Maybe lock into that position once the habitat is in a steady state. But not a big problem and I think this could be a workable solution. Least ways, I can't think of a better one.


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## Metryq (Sep 12, 2011)

> *Vertigo* wrote: Not in the case of ramjets



I said "most," not "all."



> *Ursa major* wrote: so I couldn't recall whether the reversing manoeuvre had been described (or mentioned).



In _Rendezvous with Rama_ the alien ship maneuvers only once, shortly before its perihelion passage. _Rama_ dropped in from deep space, and one Earth ship used others as boosters in order to catch up with it. One of the Earthmen was exploring the southern continent in an ultra-light flyer when static discharges from _Rama's_ drive cones knocked him out of the air. I recall that extra-high cliff on the southern shore of the Cylindrical Sea because the downed Earthman had to jump from it to rescuers in a boat below.



> what's the point of have a huge "open" habitat if you have to live "underground"?



An excellent point. Why "waste" so much interior space with a "sky," unless it is found to have compelling psychological effects on the travelers, and/or serves as an atmosphere reservoir at the same time? I suspect that people long accustomed to living in artificial habitats would not "need" wide open spaces. Still, there is nothing preventing capable engineers from making a segmented toroid as tall and wide as they like. In fact, breaks between the segments might make induced winds easier to control. (Remember the hurricane in _Rama_ when the sea melted.) If a revolving torus or cylinder is tall enough, there might be a great disparity between the spin at ground level and at altitude.


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## mike1366 (Sep 12, 2011)

Three possible solutions that are more 'outside the box':

1) Flat-packed spacestation

Does your ship have to serve both functions - starship and spacestation?  Could you have your spacestation 'flat packed' for the journey and then construct it at the other end?

2) No spacestation

Or a very high risk option would be to have no spacestation at all. You'd  need to ensure that your target system had the right raw materials and  then carry the engineering equipment to build your spacestation when you get there.

Of course, you'd be totally stuffed if it turned out you couldn't use the raw materials...

There'd be a time limit on both these options. You'd need to be able to deploy the spacestation quickly before the crew suffered too much from the effects of zero-g. 

Or how about:

3) Genetic engineering

Engineer your crew for zero-g. But then of course they couldn't explore the planet. D'oh!


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## Vertigo (Sep 12, 2011)

> I said "most," not "all."


Yeah I know 

Whilst I could see making whole sections rotate like that as being practical for a smaller ship, I am definitely thinking more along the lines of Rama (of course my particular interest does not negate the general thrust of the question). But I think using the same sort of principle on a per house basis would work just fine.

I am thinking of a habitat around 20-30km long and 10km diameter. And weather is something I still need to research. I haven't fully figured out how the atmosphere will behave. Will it behave in the same way as it would with normal gravity? In which case at the central axis where it would be null-g the air pressure would be the equivalent of a 5000m mountain; breathable but you would be liable to altitude sickness and would not be able to exert yourself much without breathing gear. I have always thought all these ideas of flying in that area for sport, using the low gravity would be confounded by the low pressure giving less lift (not to mention being blinded by the main habitat lighting!)

How heat is applied to the habitat would greatly effect weather obviously. I actually thought you might deliberately create a temperature gradient both for variety but also to create an airflow along the length allowing the air to be (slowly) scrubbed and ensure it is free of alien microbes/spores etc.

Mike: I think that for smaller ships that might be the solution if you are planning to stick around for a while. I reckon that you would always be able to mine some asteroid in pretty much any system you go to. Carrying that much extra material would be a terrible waste. Alternatively if the ship is built in a modular way it might not be too unreasonable to make it "come apart" and be put back together as a space station.

Obviously for my very large habitat ships this would not be a good solution.

Oh and another thought. If using ramjets you may well have to manage the the deceleration to keep it low enough to be acceptable. Under acceleration your effective thrust is your engine thrust minus the drag and there is still considerable doubt as to whether you could actually generate more thrust than that drag. I believe this is still very much in the uncertain area of this technology. However this in turn suggests that the without the main engines running the decelerating drag may actually be considerably greater than your effective acceleration thrust and therfore you would have to reduce your ramscoop magnetic field to bring the deceleration down to reasonable values.


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## Metryq (Sep 12, 2011)

Mike's suggestion of re-engineering the travelers crossed my mind, but I did not think Vertigo wanted to go in that direction. Then again, isn't it possible the travelers would have been engineered before reaching starship technology? You want to talk about "thinking outside the box," then don't simply place modern man into a futuristic setting. Look at the world-wide changes just due to "monolithic circuits." (e.g. How many older sci-fi tales have ships with ENIAC-sized computers with binary lights, or perhaps even human calculators for astrogation?)

Imagine early space engineers essentially committed to living the rest of their lives in space as they build the first habitats. They might welcome cybernetic augmentation: immunity to freefall deterioration, greatly minimized life support needs (which would also translate in longer time in a vacuum), etc. As the need for such augmented people expanded, the technology would evolve rapidly and become more refined. Ultimately, people who were not space engineers might desire some of the subtler augmentations—built-in telephonic communication, life-like artificial limbs and enhanced senses, while electro-stimulation of muscles and/or nanotechnology controlled atrophy in the main body.

(Side note: Ever wonder how _Star Trek_'s Dr. McCoy can give someone a generic shot and then wave a "magic wand" over their body to make repairs? Perhaps he is injecting nanites, and the "magic wands" are controllers issuing commands to the tiny machines. Just a thought.)

Augmented people need not "give up" their reproductive abilities. _Mars Plus_, the sequel to _Man Plus_, described later generation cyborgs as subtly augmented humans, while Roger Torroway had been a brute chopping block job.

Maybe you should ask yourself what the people are like before you start designing a starship for them.


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## Vertigo (Sep 12, 2011)

Cities in Flight still had them using slide rules for computation! 

But yes I take your point Metryq, though I personal choice is not to go for heavy personal modification along those lines. A link to the computer network certainly but not the full cyborg route. I don't feel it would be necessary with remote robot control and my gut feel is that the majority would not want to. Though I am fully aware the case can be argued either way. 

The mind link thing is an interesting one. I'm not sure we will ever be able to "send thoughts" to a computer or whatever, I suspect the thought process is just too complex. However I do think it very feasible that at least the optic and auditory nerves could be tapped into and sound and images dumped directly into them. However communication back to the computer would need to be by voice, which would then be picked up by your own ears and auditory nerves and so could be sent back to the computer.

My gut feel is that there may be sub-cultures that do significant augmentation but that the majority would not, as in something like Reynolds Revelation Space.

This is all good stuff though thanks for the excellent suggestions!


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## Metryq (Sep 12, 2011)

Vertigo, I've never written a sci-fi story. These threads are a fun exercise, and I pick up a few titles along the way. (Sure, there are threads recommending works, but threads like this are more focused on given subjects.)

While I find cyborg augmentation interesting, I don't know if I'd be tempted to do it myself, even if the technology were advanced enough to make limbs "equal to" or better than natural limbs. Greater strength and speed would be a plus, but could senses be designed to satisfy a person? For example, seeing in the dark via infrared or light amplification would be very neat, but would the cybernetic eyes be "just as good" as natural eyes under normal conditions? (e.g. No loss in resolution as a trade-off for the night vision.)

One of the things I like about _Ghost in the Shell_ (in its various flavors) is the mix of augmented people. Motoko Kusanagi, tactical leader of Section 9, is a full-body cyborg, and not by choice (at least according to _GitS:SAC_). Some of the stories suggest that her senses, including touch, are far better than human. Yet Togusa, a former cop and least augmented of the group, has considered body augmentation to increase his speed and accuracy, but is afraid he'd lose contact with his wife and daughter through digitized senses. He is satisfied with a "cyberbrain" implant, that is equivalent to today's smartphones, and a bit more.

I suggested the Dr. McCoy connection to show how subtle "augmentation" might be. Perhaps the crew of the _Enterprise_ have nanites in their blood all the time, getting a fresh supply as old ones are used up or metabolized out. The nanites might aid in fighting disease while visiting so many planets, but otherwise be rather passive until stimulated by a medical technician's "magic wands."

Another thing to consider: back when many of the sci-fi greats were written, the idea of being in contact 24/7, or being able to get information at a moment's notice did not exist for most people—even officials. Yet Heinlein's _The Moon Is A Harsh Mistress_ made a big deal of it. I see an old cell phone in a movie now—the size of a small briefcase or as "small" as a brick—and I have to laugh. I lived through this change, and the results now seem second nature. Many people no longer wear watches because they have a cell phone with them.

It is actually such changes I meant to consider when designing your traveler culture. Say if a traveler is knocked unconscious in a fight, or kidnapped, telemetry will tell someone they are in trouble, what kind, and where. Of course, you don't want to short circuit any interesting plot turns by making them impervious. (Roddenberry rejected the idea of a "panic button" on the _Star Trek_ communicators to beam one back to the ship.) But something like the _GitS_ cyberbrain could be helpful. (e.g. Language translation services when interfacing with another culture. Such services might be as subtle as biometrics, like knowing that a native's respiratory rates are climbing, thus showing excitement, or possibly anger. A traveler may not know which it is, but the info may be helpful.)


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## Vertigo (Sep 12, 2011)

I too have never written story but I thoroughly enjoy the exercise of world building. The worrying thing is that I'm rapidly building up a couple of stories for the "world" now but I really don't think I have the skill to tell them  And I'm also not sure I have the time/commitment to learn those skills 

What you are describing there is exactly the sort of "augmentation" that I imagine. I think some sort of nanite style medicine is a very likely future technology and I had imagined the computer links I envisage (linked to the optical and auditory nerves) would also be useable for locating and possibly some diagnosis; at least determining if the person is injured/unconscious. 

I figured on some sort of nanite style thing for the optical/auditory nerves; something that would tap into individual nerves and transmit what it detects and/or superimpose signals it receives. I also figure that such a mechanism could learn relatively easily; present a series of known images to the person progressing from simple to complex and compare the signals being sent by the eyes. It might take a little while but if the receiving computer is smart enough it could just monitor for a while until it is confident that it has the signals properly decoded and then it would be ready to transmit to the person as well as receive.

A similar mechanism on the auditory side would allow a smart enough computer to translate on the fly and "speak" the translation back into your auditory nerves. Talking in another language would be a lot harder though!

However as I said before I rather baulk at going down the full cyborg route.

One thing I can't decide is whether anti-agathics are likely to be nanite style - whizzing around "cleaning" up and "repairing" cells with damaged DNA - or whether it is more likely for them to be genetic in nature - "installed" at birth/conception, designer baby style. I actually think the latter is more likely and I suspect it's not too far off (though not soon enough for an old git like me ).


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## Metryq (Sep 12, 2011)

If you go with nanites, you can come up with rules that are both "realistic" and conducive to good storytelling. For example, have the nanites routinely found in any traveler's blood programmed for a low level of intervention, such as defending against any foreign substances (like white cells, with perhaps a mild ability to neutralize toxins). This would make the travelers more robust, but not impervious. 

Given a serious injury, such as radiation poisoning, or physical trauma, the nanites may require "authorization" from a Dr. McCoy-style "magic wand" or perhaps a command device the travelers wear while going dirtside. Why? Because the cure may be just as bad—if not worse—than the injury. For example, nanites on overdrive might induce a killing fever, and/or overconsume healthy body tissue to maintain the army of nanites, as well as fix damaged tissue. Given the severity of the injury, it would be up to the individual to authorize potentially life-threatening nanite response (or even the degree of the response), versus waiting until better facilities are available.

Nanites also suggest an atomic or at least molecular level of matter control that would be helpful during interstellar flight—given power and the proper raw material (asteroid ship?), nanotech might produce _almost_ anything.

On the subject of sensory signals: have you seen the movies _Brainstorm_ and _Strange Days_, or read the books _The Multiplex Man, Realtime Interrupt_, and _Bug Park_? You mentioned a traveler being able to receive translations of a native language, but not being able to speak it. Suppose augmentation allowed partial control of a traveler's nerves, thus allowing a cyberbrain to speak using the traveler's own voice and mouth? For the traveler, such a skill may be akin to playing a musical instrument.


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## Vertigo (Sep 12, 2011)

I had thought about using some sort of self replicating nanotech to actually do the digging out of the asteroids to start with. Maybe some kind of electrical fields might be used define the limits of where they should "dig". They might even be able to separate useful material from the rock before the slag is ejected.

I think I would go with your idea that medical nanites can do just so much on their own. But essentially they would be quite dumb and need direction from a proper medical centre to do anything serious. Maybe a limited amount of control could be applied through the same link used for commuication.

Whilst I think I would allow a link that permits a computer to speak to me and show me images, I'm not sure I would want it able to take control of parts of my body such as speech. My gut feel is that would be orders of magnitude more complicated to achieve. Raw sound and vision are relatively simple things, all the complex stuff goes on in the brain interpreting it but actually controlling all the fine musclature involved in speech would I think be massively difficult. Maybe not impossible but I'm not sure I would want it except possibly for some medical application eg if someone has suffered a stroke, though I suppose with all thos medical nanites whizzing around that shouldn't happen but you get my drift.

I've not read anything by James P Hogan but I'm beginning to think I might need to try some . So much still to read...


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