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See http://www.paulbirch.net]www.paulbirch.net for his articles I,II and III about the orbital ring systems and other 'dinamic compression members'.
Paul Birch there states that using conventional materials we could built very cheap and convenient access to space, also rapid interplanetary transfers. The concept for the kinethic structures contains promises for unexpected and quite usefull applications. Within its vast 'progeny' are: Forward`s statites, The "space fountain', Lofstrom loop, the ideas of Forrest Bishop ( see http://www.iase.cc]www.iase.cc )
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Stability and catastrophic failure modes come to mind.
But then, we need other than rockets to access space.
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Nah, rockets and airplanes can do the job, we just have to learn to take advantage of the free oxygen, reaction mass, and aerobraking that our atmosphere provides.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Nah, rockets and airplanes can do the job...
Airplanes? By definition, these are creatures of the air, not space. If airplanes, why not submarines?
But rockets can do the job for a long time to come. Think Sea Dragon or bigger, lifting 500 tons or more per launch.
Think Sea Dragon or bigger, launching Orion-class nuclear-powered space cruisers.
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Stability and catastrophic failure modes come to mind.
But then, we need other than rockets to access space.
The kinethic structures has to be pumped with and contain so much energy to be operational, that theey possess intrinsically indeed quite big stability and sudded type of cathastrophic failure is not an issue in their case. The same way ( a little bit contraintuitive, yeah ) a helicopter would not fall as a stone if his engine fails and will glide to the surface only on the spin momentum of its blades, literaly parachuting on its rotors -- a, say, 'space fountain' tower lifted and held by constant supply of accelerated-and-returned in railgun tube stream of particles, would not immediatelly fall down in case of lectric blackout. The kinethic energy 'perpetual' recovering put in these concepts and the comperativelly slow transformation of the particles` (or cable) velocity in heat should land very in very slow and controled manner the construction on ground.
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Nah, rockets and airplanes can do the job, we just have to learn to take advantage of the free oxygen, reaction mass, and aerobraking that our atmosphere provides.
I agree -- we didn`t took all that aeroplane/rocket techology offers, yet. There is quite big field for development and refinement of these technologies.
On smaller bodies (Titan?) accelerating within the atmosphere with scramjet for example could give us orbital or escape velocity.
The same way as the invention of aeronautics didn`t pass into oblivion the ground means of transport - cars and trains, I think that in future we`ll have comparably or with bigger diversity system for space transportation. Different task, natural conditions and economical frames give us wide range of possible logistics.
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Think Sea Dragon or bigger, launching Orion-class nuclear-powered space cruisers.
I think Orion NPR is usefull more as off-ground heavy lift system -- if non-fallout pulse units are created or if we consider a single, 'dirty' launch puting in LEO several dozens of thousands metric tones for bootstraping the industrialisation of the System off-earth. Puting an Orion on top a Sea Dragon criples the total efficiency of the nuiclear pulse rocketry.
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Nah, SeaDragon et al. are not suited to people or other "granular" payloads, and BDB will never be able to take advantage of the economies of scale that a SSTO/TSTO spaceplane could offer, if for no other reason than its extreme size... Which beyond a point, is a liability, not an advantage. That isn't to say that a rocket larger than what we have now isn't useful, and it will certainly be the preferred method for launching spacecraft until on-orbit construction DOES become routine and even will probobly be useful for large items.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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If you are looking for an example... giant oceangoing freighters are good for carrying things, but they aren't much good without trucks and busses.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Nah, SeaDragon et al. are not suited to people or other "granular" payloads, and BDB will never be able to take advantage of the economies of scale that a SSTO/TSTO spaceplane could offer, if for no other reason than its extreme size... Which beyond a point, is a liability, not an advantage.
Oh come on GCN, are you just trying to pick an argument with me here? We've been through all this before.
To say SSTO/TSTO spaceplanes have the economies of scale advantage over BDB, you are kidding, aren't you?
You know as well as I that unless you can guarantee a huge demand for traffic, all day, every day, year in, year out, any SSTO/TSTO spaceplane system is a sure-fire way to throw away a very large fortune. When you can convincingly guarantee that sort of demand, I'll be the first to support the spaceplane concept. But until that wonderful day dawns, what you'll need are BDBs with the throw weight to deliver huge chunks to LEO. These chunks can be space stations, Mars expedition vehicles, SSPSs, or even Orion-style, nuclear-powered, real spaceships.
Now on these Orions, what I'm thinking of is, (a) it goes up to orbit uncrewed and unfuelled, and (b) I'd want a fusion pulse (more like Daedelus) propulsion system instead of throwing a-bombs out the back.
But generally, the way to create a demand that justifies your spaceplane or whatever is to build the infrastructure in space that will need it. And you do that with BDBs like Sea Dragon that can deliver the components that make up that infrastructure in suitably big chunks.
Sure, BDBs are unmanned, but what's needed to answer that need in the immediate future is not a spaceplane, but more like a revived Apollo capsule.
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That isn't to say that a rocket larger than what we have now isn't useful, and it will certainly be the preferred method for launching spacecraft until on-orbit construction DOES become routine
Maybe I oughtta emphasize a lil' line in my last post... Note the qualifier concerned with time involved ("when).
I agree with you entirely that building a space plane right now doesn't make alot of sense without payloads to launch or better skills/tech for orbital construction. Additionally, we ought to build rockets that are larger than the current ones available today. In the long run though, particularly with better orbital construction capacity, spaceplanes will replace nonreuseable BDBs for the vast majority of payloads.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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In the long run though, particularly with better orbital construction capacity, spaceplanes will replace nonreuseable BDBs for the vast majority of payloads.
I assume by "better orbital construction capacity" you don't mean taking the orbital equivalent of bricks and mortar from earth to LEO by spaceplane (a sort of Berlin airlift to LEO), but the evolution of space-based, or moon-based, or Mars-based, etc. mining and industries that can create the orbital equivalent of bricks and mortar up there?
Anyway, 1st stage BDBs like Sea Lions canbe made reuseable.
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Nooo, they can be made refurbishable... there is no way you can get them back to the launch site in fill & fly condition following the mission, which at the very least entails the mess of reintegrating two very large pieces of metal and the whole floating/towing/etc mess.
When i'm thinking orbital construction, i'm thinking like launching kit pieces, not like sending up aluminum ingots and milling them into useful shapes.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Nooo, they can be made refurbishable..
Well, the difference between reusable and refurbishable is, in the end, one of degree.
Refurbishable like the SSMEs is, is so expensive it's not worth doing. Same for the SRBs. If (as I suspect) the shipyard-built and very rugged first stage of Sea Dragon can survive launch and recovery with very little damage, that might well be considered reusable. (But this is a side issue.)
Y'know, what matters is not reusability, refurbishability or not, but cost. All other considerations are secondary.
i'm thinking like launching kit pieces,
You mean, just like Lego? (....after all!)
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As more expensive is the infrastructure of any transportation system as lower is the cost per transported unit. On Earth now - the lowest prices per metric tonne are offered by the most massive infrastructures - pipelines, railway, watergoing vessels ( the ocean as natural road infrastructure) ... If you want to transport a thing with, say helocopter or offroad ground vehicle -- than you hit thee upper cost boundary. The matter is not in the reusabilty , so much.
The same way - space elevators of beanstalk synchronous or orbital ring active one type would need massive investmentss of money in massive in tonnes infrastructure, but the unit prices will be significantly lower than these of the rockets, no matter how much they are refurbishable or reusable. The rockets and planes need huge onground infrastructure, too.
Rockets would be used to bring cargo there where the "railway" doesn`t reaches. Or solar sails...
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But still, reassembling such a huge vehicle is still not ever going to be simple/quick/easy. See the operation where they "stretch" ocean liners, and this would be a much much more exacting procedure... and then you have to worry about corrosion and it being water tight and so on. It is practical for launching the occasional big payload, but not for everyday launches.
When I say "kit pieces" i'm not talking about prebuilt ISS modules or other nonsense, but more along the lines of structural componets, doing the milling and some of the welding on Earth and thats about it.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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maybe an old topic worth looking at considering people are talking about space elevators again
if we had a base on the Moon, it would seem to be a place to build a 'Space Elevator' or an Orbital Ring or maybe from Mars to start a Space Elevator or Orbital ring before it happens on Earth.
Paul Birch articles
https://web.archive.org/web/20130721061 … gs-III.pdf
Scifi and real world speculation 'Mega Structures'
Orbital Rings & Space Elevators
https://www.youtube.com/watch?v=MQLDwY-LT_o
'Kilometer-Scale Space Structures from a Single Launch'
https://www.nasa.gov/general/kilometer- … le-launch/
To produce artificial gravity near 1g at rotation rates of 1-2 RPM, a kilometer-scale structure is needed. The core of our solution is a high-expansion-ratio deployable structure (HERDS) build from mechanical metamaterials. Specifically, we exploit two kinematic discoveries made in the last 5 years: shearing auxetics and branched scissor mechanisms. We intend to produce tube structures with an unprecedented 150x expansion ratio. Our Phase I NIAC study has demonstrated the viability of this approach and pointed us to several technical problems that must be addressed in Phase II. The key technical work in Phase II will be focused on four specific thrusts: 1) modeling and understanding the complex deployment dynamics of our expanding hierarchical structure in detail; 2) mitigating jamming during deployment in the presence of manufacturing errors and external disturbances using simulation and design optimization; 3) rapid prototyping and hardware-based design iteration to calibrate models and evaluate sub-system components; and 4) experimental validation of meter-scale prototypes with thousands of links to demonstrate deployment without jamming and high expansion ratios. This work will have immediate and long term impact for NASAs objectives. In the near term, such a structure would make sustained human habitation in cislunar space, for example, as part of the Lunar gateway, possible. In the medium-to-longer term, such structures will be critical to sustaining humans in deep space. Finally, large structures will also advance astronomy by supporting large-scale telescope arrays.
Last edited by Mars_B4_Moon (2023-12-12 19:14:11)
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