Rotating Spaceships

[spacester]

Dumbbell configuration seems to be the AG implementation with "nothing left to take away."

Or variations like the simple baton.

For example, taking Spacester's proposal: Using the rectangular panels in his eight, square-cross-section, "apartment tubes" you can build a hexadecagonal-cross-section baton with the same overall length. Same surface area (for radiation/MMOD shielding) but you now get 180 square metres of space on each floor, instead of 72 sq_metres (in 9 sq_metre sections). Same 2.5x increase in volume. And IMO, vastly more usable volume. (Or reduce the mass/surface area by 40% if you only want the same volume. Although still in a much more usable, open form.)

The "chutes" are eliminated entirely. As are most of the tensile cables and support structure. As are the weird telescoping rings. That mass can either be skipped entirely, or substituted for more construction material to make the main baton larger/wider. [Also, the hub can now be in the plane of rotation, as can the "process" modules, improving the mass distribution.]

Cover the sun-facing side with thin-film solar panels, offset from the baton to serve as a sun-shade, cover the back-side with radiators. (Given that it's an AG structure, might be able to get away with spiral droplet-radiators for greater mass-efficiency.)

The baton also makes your infrastructure easier. Running ECLSS and utilities through Spacester's design would be a nightmare.


I've included an artist's render of the station, below. Along with an earlier, hexagonal octagonal pathfinder station.

I like it. These are the kind of reconfiguration options we can play with. I do not like the 3 m by 3m cubicles either, actually. Your octagons look nice.

I am not clear where the spin axis is and what is the value of the spin radius, will comment more with that info.

So the design basis for Aquarius is a ring station. What I am showing is not a Hollywood design, it is a bridge-like structural system spinning in space. It is firstly a ring of modules connected around the circumference of a 200 m diameter circle. That is its essence. The Nodes are part of that system but the Tubes and Chutes are not. They are added for circulation of people, air, water and everything else. The main reason for the chutes is they will nominally have an updraft. I haven't shown the 44 pipes yet, see attached.

The hab modules forming the ring are total placeholders in this design. Their design is not dumb, but I have no doubt it will get its ass kicked right off the bat. Still for the moment they are locked in as placeholders. Notably, no where on Aquarius have I used expandable structures. Except that these hab modules are designed to squeeze into the Starship payload envelope, and launch as three nested circular cylinders with half-meter walls of PE and water. After delivery they are expanded axially - the long axis - and you get what I show. 16 of them wrap that circle nicely; the connecting nodes are not too big to launch on Starship.

I show some strongbacks on the habs because I am really paranoid when it comes to structure. The strongbacks and the tension pipe add to the visual clutter on those pdfs, but this is a bridgework structure designed to last 200 years, not a Hollywood concept.

So yeah the 44 pipes per tube is a big part of the deal. Circulation galore, in any given location, you can access hot and cold water, warm dry air or warm moist air or a cool breeze. The central hub makes that all available in plenums attached to the 44 pipes. Each pipe is about 10 inch diameter, so lots of capabaility for smaller conduits for other things.

The 44 pipes house the CO2 scrubbers. Aquarius will have enormous CO2 capture capability.

The solar arrays will be cooled by ammonia based radiators. That's fine, but ammonia is totally banned inside the pressurized volume.

The central hub is the crown jewel, the luxury liner's grand ballroom. A huge shirtsleeve mini gravity playground for sports, movie making and what not. It exists to house the mechanical rooms, and is designed to be huge because we can. Because Starship.

[Coastal Ron]

So the design basis for Aquarius is a ring station.

Ring designs are very popular, though until we actually build such stations we have no idea if they are practical.

One of the things that catches my attention with them is how much mass they require per volume of usable space. In contrast, O'Neill cylinders are much more mass efficient - though I personally don't think O'Neill cylinders are buildable.

But hey, as long as we are debating theoretical designs here, we might as well have some way to measure them, and volume of usable space per mass of structure is one way. Other measurements to consider is the ability to survive collisions with space debris, or how many unique components need to be designed, since the more complexity you have the more costly the design likely is, and the more costly to maintain it once operational.

Notably, no where on Aquarius have I used expandable structures. Except that these hab modules are designed to squeeze into the Starship payload envelope, and launch as three nested circular cylinders with half-meter walls of PE and water. After delivery they are expanded axially...

Yeah, I think you contradicted yourself there. 

And when I saw your design the first thing I thought was that you were using nested cylinders that expand out. Which is a novel idea, but has the same limitations as other expandable structures, in that now you have to have outfit the insides, and outfitting in space is harder and more costly than outfitting on Earth. An alternative would be to build all the modules on Earth and then ship them to orbit - it would likely use less launches than having to launch the parts and workers to outfit them in space. Something to consider...

...but this is a bridgework structure designed to last 200 years, not a Hollywood concept.

You keep trying to distinguish your concepts from the concepts of "Hollywood". Until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts. Same with my designs too.

As to service life, what we are all proposing are 1st generation rotating space stations, and none of them are truly big enough for colonies, so it would be unlikely that any 1st generation rotating space station would need to stay operational very long before it was superseded by a 2nd generation design that is a major improvement. Just a thought...

[spacester]

I drew up plans for a rotating space station or it could easily be a space ship, just add appropriate thrusters to the non-rotating hub. Download complete description SpaceStation.pdf attached.

Ooops, I almost missed this post, sorry. I am reading it now, might take a bit to react.

[spacester]

So the design basis for Aquarius is a ring station.

Ring designs are very popular, though until we actually build such stations we have no idea if they are practical.

One of the things that catches my attention with them is how much mass they require per volume of usable space. In contrast, O'Neill cylinders are much more mass efficient - though I personally don't think O'Neill cylinders are buildable.

But hey, as long as we are debating theoretical designs here, we might as well have some way to measure them, and volume of usable space per mass of structure is one way. Other measurements to consider is the ability to survive collisions with space debris, or how many unique components need to be designed, since the more complexity you have the more costly the design likely is, and the more costly to maintain it once operational.

Notably, no where on Aquarius have I used expandable structures. Except that these hab modules are designed to squeeze into the Starship payload envelope, and launch as three nested circular cylinders with half-meter walls of PE and water. After delivery they are expanded axially...

Yeah, I think you contradicted yourself there. 

And when I saw your design the first thing I thought was that you were using nested cylinders that expand out. Which is a novel idea, but has the same limitations as other expandable structures, in that now you have to have outfit the insides, and outfitting in space is harder and more costly than outfitting on Earth. An alternative would be to build all the modules on Earth and then ship them to orbit - it would likely use less launches than having to launch the parts and workers to outfit them in space. Something to consider...

...but this is a bridgework structure designed to last 200 years, not a Hollywood concept.

You keep trying to distinguish your concepts from the concepts of "Hollywood". Until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts. Same with my designs too.

As to service life, what we are all proposing are 1st generation rotating space stations, and none of them are truly big enough for colonies, so it would be unlikely that any 1st generation rotating space station would need to stay operational very long before it was superseded by a 2nd generation design that is a major improvement. Just a thought...

Usable pressurized volume per mass of structure is a perfectly good metric. Aquarius in current form will not rank well on that metric, I am fine with that at this stage.

I am purposely leaving things wide open for Aquarius to be shown up on certain criteria. There is method to the madness.

You missed the word except. No expandability EXCEPT the stretching out of the hab payloads. I am trying to hint at a change a person could propose to my baseline reference design, and you are trying to find contradictions. Hint: Bigelow or BEAM or derivatives.

On complexity of parts, Aquarius will score very well indeed. This is not a science lab like ISS and EVAs are going to be very rare. KISS applies.

Structural design is not rocket surgery. I have experience in heavy steel fab and I have run some numbers and what I have is almost certainly over-designed. Certainly a professional analysis would be great but in the meantime we can proceed from conceptual design with no numbers to preliminary design with numbers. Structural revisions should be only favorable.

The distinction with Hollywood is about looking at their hardware and seeing a need for unobtanium while I am an engineer working with good old stainless steel and used to "when in doubt, build it stout." It is not about probability of actually getting built. Too soon for that discussion.

[Coastal Ron]

No expandability EXCEPT the stretching out of the hab payloads.

I was just pointing out that expanding by stretching is still expanding. No need to split hairs... 

On complexity of parts, Aquarius will score very well indeed. This is not a science lab like ISS and EVAs are going to be very rare. KISS applies.

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station? The space equivalent of mountain climbing, but with far more equipment. Which is why I foresee the need for robotic systems for doing "outside" maintenance on rotating space stations - which requires some technological improvements, but not a lot.

Structural design is not rocket surgery.

Right. Structural design is not truck driving either. Luckily we don't need to find imperfect analogies when the original thing works fine. Structural design is like structural design. Next!

I have experience in heavy steel fab and I have run some numbers and what I have is almost certainly over-designed. Certainly a professional analysis would be great but in the meantime we can proceed from conceptual design with no numbers to preliminary design with numbers. Structural revisions should be only favorable.

Since we're all working on concepts, there is no need to sweat design optimization, because that does come later.

The distinction with Hollywood is about looking at their hardware and seeing a need for unobtanium while I am an engineer working with good old stainless steel and used to "when in doubt, build it stout." It is not about probability of actually getting built. Too soon for that discussion.

The reason I mention it is that I think you are focused on something that doesn't matter, which makes it seem like you are trying to shift focus from your own design. Everyone should know that science FICTION is FICTION, and that entertainment shows are NOT sources of information about potential space hardware, but just sources of entertainment.

Rotating space stations will require engineering that has never been done before, but luckily a lot of the physics are known. I think the hardest part will be in keeping the rotating structure in a stable rotation, because I have yet to find a way for free-floating rotating structures to stop wobbling on their own.

And rotating structures will wobble, for many reasons, so I've been spending time working on what I hope are simple active control systems that don't use a lot of consumables.

[Paul451]

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station?

Same as you do on any tall industrial structure, walkways. Or do you leave it off and just hope that you never need it?

[spacester]

No expandability EXCEPT the stretching out of the hab payloads.

I was just pointing out that expanding by stretching is still expanding. No need to split hairs... 

On complexity of parts, Aquarius will score very well indeed. This is not a science lab like ISS and EVAs are going to be very rare. KISS applies.

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station? The space equivalent of mountain climbing, but with far more equipment. Which is why I foresee the need for robotic systems for doing "outside" maintenance on rotating space stations - which requires some technological improvements, but not a lot.

Structural design is not rocket surgery.

Right. Structural design is not truck driving either. Luckily we don't need to find imperfect analogies when the original thing works fine. Structural design is like structural design. Next!

I have experience in heavy steel fab and I have run some numbers and what I have is almost certainly over-designed. Certainly a professional analysis would be great but in the meantime we can proceed from conceptual design with no numbers to preliminary design with numbers. Structural revisions should be only favorable.

Since we're all working on concepts, there is no need to sweat design optimization, because that does come later.

The distinction with Hollywood is about looking at their hardware and seeing a need for unobtanium while I am an engineer working with good old stainless steel and used to "when in doubt, build it stout." It is not about probability of actually getting built. Too soon for that discussion.

The reason I mention it is that I think you are focused on something that doesn't matter, which makes it seem like you are trying to shift focus from your own design. Everyone should know that science FICTION is FICTION, and that entertainment shows are NOT sources of information about potential space hardware, but just sources of entertainment.

Rotating space stations will require engineering that has never been done before, but luckily a lot of the physics are known. I think the hardest part will be in keeping the rotating structure in a stable rotation, because I have yet to find a way for free-floating rotating structures to stop wobbling on their own.

And rotating structures will wobble, for many reasons, so I've been spending time working on what I hope are simple active control systems that don't use a lot of consumables.

My point on structural design was in response to you seeming to say that until a professional design review is done we don't know anything.

"Until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts"

I reject that. We know what we know, I know what I know, you know what you know, math is math and steel is steel. Do the math, apply a factor of safety, use that result until the design is more mature.

I did the math so I am working with an engineering model. You want to restrict me to conceptual models only. Homie don't play that.

Hollywood does not worry about structural margins and failure theory. I am showing an engineering model to people who are used to seeing Hollywood models. It looks clunky, and I was explaining why. Also, I am not happy with the pdf drawings I can easily whip out from my CAD model.

Not every word I write in response to you is completely addressed only to you. I write to the entire audience.

We are on the same page with the wobbling question. I have taken great care in the construction design to allow for a very precisely balanced structure, and am going to get the moments of inertia fixed, but yeah, from what I understand there will be wobble no matter what. How hard it is to correct is very much guesswork for me at this time.

I do not see it as a showstopper by any means, whatever wobble we get will simply be included in the package of things people are going to need to get used to, along with the Coriolis. It's not like anyone is going to forget they are on a spinning ship.

As you say, how much active control is needed and the propellant cost is a big unknown. I can tell you that when I went to calculate the spin-up propellant needed for a fully equipped Aquarius, I did not like or believe the result. It's a lot. It will likely be desired to spin it up once and never stop spinning after that.

I will doff my cap to anyone who tackles the math of wobble correction control theory. I could possibly do it myself but it would take way too much time.

[spacester]

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station?

Same as you do on any tall industrial structure, walkways. Or do you leave it off and just hope that you never need it?

Well if you had to do an EVA on an operational (spinning) Aquarius, you would be using winches to lower the person down to the work site. Messy and expensive and not part of the program.

Aquarius is going to need a small army of robots to construct and maintain.

[Coastal Ron]

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station?

Same as you do on any tall industrial structure, walkways. Or do you leave it off and just hope that you never need it?

Come on Paul, you've seen spacesuits, yes? They weigh about 280 pounds (127 kg), and they are not balanced for standing in gravity.

Add to that the immobility of the suit due to the nature of inflated suits, and it should be clear that current generation spacesuits can't be used for EVA on rotating space stations. Something else will be needed, and it will likely be robotic in nature.

[Coastal Ron]

My point on structural design was in response to you seeming to say that until a professional design review is done we don't know anything.

Until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts"

I reject that. We know what we know, I know what I know, you know what you know, math is math and steel is steel. Do the math, apply a factor of safety, use that result until the design is more mature.

First of all please learn to use HTML quotes, that way you don't have such a long post. Notice how most other people are able to cut out sections of text that aren't needed?

As to what you quoted from me, as far as interactions here on NSF my comment stands. You might be an engineering genius in real life, but here on NSF you are just poster "spacester", and no one knows if you know what you are talking about. Sorry.

I did the math so I am working with an engineering model. You want to restrict me to conceptual models only. Homie don't play that.

Well Homie, you can do whatever you want on NSF, but that doesn't mean anyone has to believe you. That is my point. And I don't expect everyone to believe me - just ask Paul451, who is someone I have come to know over many years, and although I don't always agree with him, I've come to value his input and ideas. But he certainly doesn't agree with everything I write (see above).

Hollywood does not...

You have a thing about comparing yourself to Hollywood. Just an observation, since I don't recall anyone else on NSF so concerned about how they are perceived against the entertainment industry in Southern California.

My assumption is that the first successful 1st generation rotating space stations won't look like anything we see in movies. Which shouldn't bother anyone building rotating space stations, since they were never competing with the graphic artists trying to make entertainment.

We are on the same page with the wobbling question. I have taken great care in the construction design to allow for a very precisely balanced structure, and am going to get the moments of inertia fixed, but yeah, from what I understand there will be wobble no matter what. How hard it is to correct is very much guesswork for me at this time.

You can design to the nth degree for balance, but once you put in humans and supplies, and people are walking around, and liquids are moving around the station, and hundreds of various inputs, the station won't be perfectly balanced. Some (not all) of that can probably be counteracted with moveable masses on the station itself, and propellant could be used too, but I'm hoping to find solutions that can take into account worst case scenarios. Too early to know if I've found them, so not talking about them yet.

I do not see it as a showstopper by any means, whatever wobble we get will simply be included in the package of things people are going to need to get used to, along with the Coriolis. It's not like anyone is going to forget they are on a spinning ship.

The studies I've seen (probably from Paul451) suggest that Coriolis force should not be a factor for humans, in that they should adapt fairly quickly, even on short diameter stations. Not sure I've seen any studies on wobble, so I can only guess that it would be kind of like being on a ship in heavy swells.

As you say, how much active control is needed and the propellant cost is a big unknown. I can tell you that when I went to calculate the spin-up propellant needed for a fully equipped Aquarius, I did not like or believe the result. It's a lot. It will likely be desired to spin it up once and never stop spinning after that.

Not surprised at your result. I suggest a quote from Archimedes that I think is valuable for solving this particular problem?

Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.

In other words, mount your engines out beyond the diameter of the station. For instance, instead of chemical engines you can use Solar electric propulsion (SEP) on cables mounted around the perimeter of your station (hung off the "bottom" of the station). You'll only need 10% of the propellant, and time-wise it may not take that much longer considering the supply chain for refilling your chemical rocket engines.

I will doff my cap to anyone who tackles the math of wobble correction control theory. I could possibly do it myself but it would take way too much time.

I think the control system will be easy. The hard part is generating the physical inputs to counteract the wobble.

[jdon759]

As you say, how much active control is needed and the propellant cost is a big unknown. I can tell you that when I went to calculate the spin-up propellant needed for a fully equipped Aquarius, I did not like or believe the result. It's a lot. It will likely be desired to spin it up once and never stop spinning after that.

Not surprised at your result. I suggest a quote from Archimedes that I think is valuable for solving this particular problem?

Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.

In other words, mount your engines out beyond the diameter of the station. For instance, instead of chemical engines you can use Solar electric propulsion (SEP) on cables mounted around the perimeter of your station (hung off the "bottom" of the station). You'll only need 10% of the propellant, and time-wise it may not take that much longer considering the supply chain for refilling your chemical rocket engines.

I will doff my cap to anyone who tackles the math of wobble correction control theory. I could possibly do it myself but it would take way too much time.

I think the control system will be easy. The hard part is generating the physical inputs to counteract the wobble.

I like this idea for the position of the engines.  It seems like it would be suitable for propulsion engines as well as spin-up engines.
However, for spin-up, why not have another ring - a counterweight or a living space - rotating in the other direction?  Use the power of electric motors instead of a consumable.
Perhaps a counterweight spinning ring could be used to tackle the problem of wobble too, if it had enough degrees of freedom?

[Paul451]

[...] and it should be clear that current generation spacesuits [...]

"Doctor, it hurts when I do this..."

We are either building better suits, or we aren't building much anywhere in space beyond a few pre-built modules berthed together.

[spacester]

My point on structural design was in response to you seeming to say that until a professional design review is done we don't know anything.

Until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts"

I reject that. We know what we know, I know what I know, you know what you know, math is math and steel is steel. Do the math, apply a factor of safety, use that result until the design is more mature.

First of all please learn to use HTML quotes, that way you don't have such a long post. Notice how most other people are able to cut out sections of text that aren't needed?

As to what you quoted from me, as far as interactions here on NSF my comment stands. You might be an engineering genius in real life, but here on NSF you are just poster "spacester", and no one knows if you know what you are talking about. Sorry.

I did the math so I am working with an engineering model. You want to restrict me to conceptual models only. Homie don't play that.

Well Homie, you can do whatever you want on NSF, but that doesn't mean anyone has to believe you. That is my point. And I don't expect everyone to believe me - just ask Paul451, who is someone I have come to know over many years, and although I don't always agree with him, I've come to value his input and ideas. But he certainly doesn't agree with everything I write (see above).

Hollywood does not...

You have a thing about comparing yourself to Hollywood. Just an observation, since I don't recall anyone else on NSF so concerned about how they are perceived against the entertainment industry in Southern California.

My assumption is that the first successful 1st generation rotating space stations won't look like anything we see in movies. Which shouldn't bother anyone building rotating space stations, since they were never competing with the graphic artists trying to make entertainment.

We are on the same page with the wobbling question. I have taken great care in the construction design to allow for a very precisely balanced structure, and am going to get the moments of inertia fixed, but yeah, from what I understand there will be wobble no matter what. How hard it is to correct is very much guesswork for me at this time.

You can design to the nth degree for balance, but once you put in humans and supplies, and people are walking around, and liquids are moving around the station, and hundreds of various inputs, the station won't be perfectly balanced. Some (not all) of that can probably be counteracted with moveable masses on the station itself, and propellant could be used too, but I'm hoping to find solutions that can take into account worst case scenarios. Too early to know if I've found them, so not talking about them yet.

I do not see it as a showstopper by any means, whatever wobble we get will simply be included in the package of things people are going to need to get used to, along with the Coriolis. It's not like anyone is going to forget they are on a spinning ship.

The studies I've seen (probably from Paul451) suggest that Coriolis force should not be a factor for humans, in that they should adapt fairly quickly, even on short diameter stations. Not sure I've seen any studies on wobble, so I can only guess that it would be kind of like being on a ship in heavy swells.

As you say, how much active control is needed and the propellant cost is a big unknown. I can tell you that when I went to calculate the spin-up propellant needed for a fully equipped Aquarius, I did not like or believe the result. It's a lot. It will likely be desired to spin it up once and never stop spinning after that.

Not surprised at your result. I suggest a quote from Archimedes that I think is valuable for solving this particular problem?

Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.

In other words, mount your engines out beyond the diameter of the station. For instance, instead of chemical engines you can use Solar electric propulsion (SEP) on cables mounted around the perimeter of your station (hung off the "bottom" of the station). You'll only need 10% of the propellant, and time-wise it may not take that much longer considering the supply chain for refilling your chemical rocket engines.

I will doff my cap to anyone who tackles the math of wobble correction control theory. I could possibly do it myself but it would take way too much time.

I think the control system will be easy. The hard part is generating the physical inputs to counteract the wobble.

I know how to do the html thing with the quotes but I do not do it because I am not like you in focusing on refutation. I am not here to refute everybody else. I am not interested in tearing apart your posts one point at a time. I find it childish. I put up the quote in full because I do not cherry pick. I do not break it apart because I am not obligated to organize my thoughts based on your presentation. We can all see what you said, and I trust the audience can see the relationship between your words and mine.

If you show me you are capable of reading my entire sentence before knee-jerking and cherry picking and firing off your rebuttal and refutation, I will do you the honor of breaking out the quotes.

I have explained the reference to Hollywood several times and in no case have you reflected back any level of comprehension. Apparently you see that word and don't even finish the sentence. Grow up.

When you ignore the answers, you are being intellectually dishonest.

When you pretend that math is only opinion, I just have to laugh.

As to the moment arm thing, are you telling me that we can produce more angular momentum from the same amount of propellant by increasing the distance of the thruster from the spin axis? Are you sure about that?

[spacester]

[...] and it should be clear that current generation spacesuits [...]

"Doctor, it hurts when I do this..."

We are either building better suits, or we aren't building much anywhere in space beyond a few pre-built modules berthed together.

I have designed the assembly and welding of Aquarius to be done with robotic arms operated by humans with direct line of sight supervision, in shirtsleeves. Payload zero provides that capability.

[Coastal Ron]

If you show me you are capable of reading my entire sentence before knee-jerking and cherry picking and firing off your rebuttal and refutation, I will do you the honor of breaking out the quotes.

Great, start now. I read your whole post on a 27" monitor, but many NSF members read posts on their mobile devices, so you are disrespecting THEM, not me, by loading your posts up with non-value added text. Because they know where to read the original post, which is why you don't have to completely copy it. Time to stop being a newbie Homie... 

When you ignore the answers, you are being intellectually dishonest.

We all have OPINIONS, and we can also have facts. But "answers" are not necessarily facts. And your opinions about your designs are just that, opinions. Same as my opinions about my designs are just opinions. You may think they are facts, but since we can't judge your work we have to treat them like opinions. That is just how the internet works.

When you pretend that math is only opinion, I just have to laugh.

You are laughing at your own joke, since I never said "math is only opinion". Don't make things up.

As to the moment arm thing, are you telling me that we can produce more angular momentum from the same amount of propellant by increasing the distance of the thruster from the spin axis? Are you sure about that?

Don't believe me, believe Archimedes - and math. Heck, you can prove this to yourself at home by doing a simple experiment with two levers of different lengths.

I have designed the assembly and welding of Aquarius to be done with robotic arms operated by humans with direct line of sight supervision, in shirtsleeves. Payload zero provides that capability.

My post wasn't about how to build a rotating station before it starts rotating, but how to MAINTAIN one that is already rotating. Unless you are assuming you are going to de-spin the rotating space station every time you need to do exterior inspection and maintenance.

My OPINION is that we won't use humans for such operations, but robotic systems. And for my rotating space station designs my assumption is that if humans have to go "outside", then they will need a lot of assistance (and I'm designing such systems). But I'm really hoping to eliminate the need for humans to need to go "outside" for normal maintenance needs.

[Twark_Main]

On complexity of parts, Aquarius will score very well indeed. This is not a science lab like ISS and EVAs are going to be very rare. KISS applies.

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station? The space equivalent of mountain climbing, but with far more equipment. Which is why I foresee the need for robotic systems...

...or a window-washing platform.

[Coastal Ron]

On complexity of parts, Aquarius will score very well indeed. This is not a science lab like ISS and EVAs are going to be very rare. KISS applies.

Of course EVA's are going to rare, since how do you do an EVA on the exterior of a rotating space station? The space equivalent of mountain climbing, but with far more equipment. Which is why I foresee the need for robotic systems...

...or a window-washing platform.

Sure, you can dangle someone down the outside of the station. But there is still the challenge of them being in a spacesuit that is likely as heavy as they are, or heavier, and the inflatable nature of those suits makes work difficult.

Not sure why there is so much resistance to the idea that we'll use robotic systems. In fact they would use teleoperation since humans can be nearby.

[spacester]

If you show me you are capable of reading my entire sentence before knee-jerking and cherry picking and firing off your rebuttal and refutation, I will do you the honor of breaking out the quotes.

Great, start now. I read your whole post on a 27" monitor, but many NSF members read posts on their mobile devices, so you are disrespecting THEM, not me, by loading your posts up with non-value added text. Because they know where to read the original post, which is why you don't have to completely copy it. Time to stop being a newbie Homie... 

I was trying to fit in with that procedure. I see it done a LOT here, they quote the whole nested stack and post just two sentences. I think it wastes space too, but I see it done a lot. The exceptions are guys like you who break it apart in order to tear it down. That was my observation, anyway.

We all have OPINIONS, and we can also have facts. But "answers" are not necessarily facts. And your opinions about your designs are just that, opinions. Same as my opinions about my designs are just opinions. You may think they are facts, but since we can't judge your work we have to treat them like opinions. That is just how the internet works.

One fact is that I presented a comprehensive design with specifications resulting from doing basic math. There is a CAD model and text descriptions of the design concept and execution. Another fact is that after all those years of arguing with each other here you have produced no comparable work product, even on a solo basis. If that is not a fact, just show me where to find it.

And maybe explain why you are incapable of judging my work. Unwilling, I get, but incapable? I take it that means you are incapable of judging anyone else's work? Maybe that's how the internet doesn't work.

Your statement

"until your design goes through an engineering review it is just a concept, no more or no less probable than "Hollywood" concepts"

is bogus. You are trying to dismiss my work.

You also continue to misconstrue my reason for referring to Hollywood, imposing your imagination on the subject of my thought process and failing to accept my answer, or react to it in any way that indicates you are listening to me. You are telling me what I think and why and I object. Who wouldn't?

Maybe even if no one at NSF worries about comparisons to Hollywood imagery and mythology, they should. Maybe explaining that to you is hopeless. Moving on then.

No one has built anything but that does not mean we know nothing. You might not be able to admit to knowing anything, which is weird, but we know that a guy named Ted Hall does know a lot. Also, at least one guy has presented some work on this thread that rises above mere opinion. We know that the object I depict and describe has been analyzed to the point where mass estimates and launch numbers have been produced. We know of the existence of one comprehensive design put forward by a person here ready to talk about it. We know that other designs have been discussed, and opinions offered, but we are not aware of any additional comprehensive designs being presented on this thread.

(snip)

Ron, you have blundered with this moment arm thing. You are making it look like you never took a physics class. It's called conservation of angular momentum. There is no such thing as a free lunch.

Rocket impulse transfers energy and momentum to the station. A given thrust will apply more torque at a greater moment arm, but work equals force times distance and since the work being done on the station by the rocket has to travel a longer distance over the same elapsed time the net effect is no change. The amount of impulse coming out the back of that rocket, ignoring losses, is the amount of impulse added to the rotational inertia (angular momentum) of the station, no matter where you mount it.

You go ahead and stick with Archimedes, I will go with Newton.

[Coastal Ron]

One fact is that I presented a comprehensive design with specifications resulting from doing basic math. There is a CAD model and text descriptions of the design concept and execution.

Gee, text descriptions too? Well, that must be proof that you have thought everything through then, right? 

Look, you aren't the only person that can use CAD, and just because someone uses CAD doesn't mean that what they designed is doable. And your design may in fact turn out to be viable, but what I have stated is still valid, in that none of our concepts can truly be assumed to be anything other than concepts until an engineering assessment is done. I can't tell you how many times in my manufacturing career that CAD drawings have led to parts that didn't work.

Another fact is that after all those years of arguing with each other here you have produced no comparable work product, even on a solo basis. If that is not a fact, just show me where to find it.

1. You are a newbie here, so are you stating that you have gone back over all the years of my posts to see if I have (or have not) released detailed drawings for my rotating space station designs? I think not.

2. Why would anyone feel they have to prove anything to you? Me personally I've defined two families of rotating space stations designs, but my preference is not to publish them until they have been validated enough to merit being shown to the public. Maybe others feel the same way too? Absence of proof is not proof of absence.

And maybe explain why you are incapable of judging my work. Unwilling, I get, but incapable?

At this point in time on NSF I don't critique rotating space station or rotating spaceship designs. I have previously, but I don't anymore.

And again, I haven't critiqued your design. Maybe it is workable, maybe not. However just because there is a design that holds together physically, that doesn't mean that it is affordable or practical.

There are LOTS of proposed designs for LOTS of things. At the end of the day though, if they can't get built then it doesn't matter. Hence my shift in focus to things that have a chance in getting built.

[spacester]

(snip)
There are LOTS of proposed designs for LOTS of things. At the end of the day though, if they can't get built then it doesn't matter. Hence my shift in focus to things that have a chance in getting built.

Newbie? I registered here in 2005. IIRC it was before there was even an L2 section. I posted for several years, but as it became increasingly clear that big ideas were not welcome, that amateurs were not welcome, and that this wonderful website was doing great things for lots of people besides me, I faded away. I checked in from time to time, and all I would see is the same old attack and refute and cherry picking.

I stayed away for years, lurking and waiting. Even with the rise of SpaceX my ideas were too big and too speculative.

Almost all eyes were on the past and almost none on the future. ISS was going to develop a magic pill to counteract the some 17 deleterious effects of micro-gravity. I was kinda being blasphemous with the whole AG thing.

I kept my eye open for AG threads, I may have missed one. And maybe there was one where people got along and worked together but I missed it. I doubt it though, culture is culture. I was sick and tired of that stuff 12 years ago. I have enormous respect for Chris B and everyone else here, but most people on the forums are not interested in the future like I am.

I am back because Starship is on the pad so they cannot tell me that my big projects are impossible any more. I am here to get stuff done. This threatens you. It shouldn't. I want to start really comparing the design choices. With numbers. That's what they told me here, without numbers they could not be bothered. So I am back with numbers and yeah, same old crap.

No one needs to prove anything to me, duh. As if, lol. I just want to not be dismissed again some more. You are trying to dismiss me by refusing to admit that conceptualization is not the end state of discussion.

If nothing matters until something gets built, why are you even here? It doesn't matter, right?

I want my efforts to matter. I want Paul's efforts to matter, I want to attract new voices. I want to talk to the other people on this thread besides you two. I want to demonstrate collective competency on the subject at NSF and start getting the public excited about AG. Which seems to threaten you. Whatever, I only have so much bandwidth for you.

The sooner you accept this the sooner you can start sharing all that knowledge you've got.

But that thing you just did there with the quotes? I call that cherry picking. The things you snip out matter too. Your physics blunder for example.

I applaud your wanting to work on things that get built. We do too, I have to suppose. But I want to collaborate.