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Damburger
2007-May-09, 07:42 PM
The ISS is fairly limited in terms of what it can do.

You could extend it with extra modules, but it looks like something that can't be accelerated to a significant speed without falling apart, so therefore can't even operate anywhere other than low-earth orbit.

Wouldn't it be better to build space stations in such a way as they can either do science where they are, but also could be attached to a large booster, and used as a habitation module/science module for an interplanetary mission?

Given the huge amount of time and money a space station involves, wouldn't it make sense to produce something more versatile?

Warren Platts
2007-May-10, 04:31 AM
One of the bigger limitations is the high-inclination orbit that the ISS resides in. Low-inclination orbits are much easier to launch to (unless you launch from a high latitude), and this is especially true of missions to the Moon. (That's why the Columbia space shuttle did not have the option of moving to the ISS, even if they had known about the heat shield damage.)

The ISS can be moved. Indeed, it requires periodic boosting to keep it from falling out of the sky. However, we once calculated somewhere on this forum that the cost of missions and fuel to move the ISS to a low-inclination orbit would be as much as building a new station from scratch.

So, that's the thing about space stations; they're big and heavy and expensive to move around. That's why they're called "stations", because they're intended to be stationary. What you want is a true space ship. Something shuttle-sized on the inside, but without unnecessary wings; i.e., something roomy and comfortable, unlike these CEV's now being contemplated.

If it were up to me, I'd build a new space station in a low-inclination orbit. I'd scrap the Orion project, and dig Blackstar out of the mothballs. Then build a true space ship in orbit, whose only job would be going back and forth to the Moon. The Blackstar spaceplane would send astronauts to the new space station where they would transfer to the lunar space shuttle. Once in lunar orbit, they would transfer to a single-stage to orbit lunar lander. So, going to the Moon would involve three completely reusable spacecraft, each one specifically tailored for only one task each: (1) Earth to LEO; (2) transfer from LEO to lunar orbit; (3) lunar orbit to the lunar surface.

cbacba
2007-May-10, 06:28 PM
Probably some of the problem originally was that the soviets needed a low orbit in order to get to it. The higher the orbit, the harder it is to get to it AND, the further away from earth's protective magnetic field one winds up at and the closer to the Van Allen Belts.

Having larger, space only based craft which merely need refueling and occaisional maintenance make things much better.

Part of the justification process for the shuttle basically tried to dump unmanned launches into shuttle cargo making things far more expensive to get into orbit - and consequently dangerous for astronauts turned truck drivers. Hence, all future space efforts were made far more expensive and limited.

If there was a cost effective heavy lift vehicle (preferrably somewhat cheaper than paying the russians to do it), even if it was into low orbit only, things would be tremendously better. While the shuttle needs replacing for well known reasons as a human carrier - putting in a personnel carrier in the cargo bay (seems like there was once an ESA lab that fit into the cargo bay) then somewhat more serious efforts could be done on a fairly cost effective basis. Once fuel (and supplies) can be launched (unmanned carriers) in quantity, then the ability to have multiple stations and multiple space only vehicles should be quite plausible.

Warren Platts
2007-May-10, 08:21 PM
Probably some of the problem originally was that the soviets needed a low orbit in order to get to it. The higher the orbit, the harder it is to get to it AND, the further away from earth's protective magnetic field one winds up at and the closer to the Van Allen Belts.
Dude, a high inclination orbit is not necessarily a high altitude orbit. The inclination is just the highest latitude of the ground track that a satellite traces out as it circles the Earth. The Russians used to do most of their launching from Baikonur (http://en.wikipedia.org/wiki/Baikonur_Cosmodrome) which is at latitude of about 46o North, so it's easier to get to a high inclination orbit from a high latitude launch site.

(But why 51o instead of 46o? I don't know.)

One interesting thing I just ran across that I hadn't thought of before, however, is that the ISS orbit could be changed using an electrodynamic tether (http://www.nasaspaceflight.com/content/?cid=4370). This would require zero propellant (beyond that required to loft a tether module). Then there would be no need to continually reboost the ISS, and its orbit could be modified to any desirable configuration. Hence the ISS could in fact serve as a suitable way station/dry dock for missions to the Moon and beyond.
:D

ToSeek
2007-May-11, 02:17 AM
(But why 51o instead of 46o? I don't know.)


46o goes right over China in short order, probably not something that would go over well.

danscope
2007-May-11, 03:37 AM
Quite often, I have reconsidered Arthur C. Clarke's excellent design for a space station. Consider having one wheel in slow rotation for a partial gravity....say
.15 G , which would serve everyone living aboard, and facilitate the mundane chores of everyday life. It is kept balanced by a simple trim and drain system such as you would find on ANY submarine. Perfect balance , as programed by computer. Since it is in rotation, there is, in effect, a "Bottom" to each section, and tank, from which water may be stored, withdrawn or pumped to. The tanks can be plastic or silicone rtv lined , like a bladder, to conveniently isolate and facilitate the trim system. The system "knows" where all the water is, at any one time, and as people move about, they simply instruct "Hal", the central computer, to co-ordinate their movements. Now, you can have a running deck , and enough gravity to maintain health and conduct life's functions in a more pleasant fashion. Luxury beyond the wildest dreams of avarice .
And from the central axle, the second wheel , stationary; zero G, observation
platform, experimental, industrial etc. etc. as suits and requires zero G.
Storage, ship components, fuel, water etc. Static weight. The solar array
would probably be on this end as well.
This might,perhaps, be a method for life in space. Several years at .15
would be preferable in many ways to zero G 24/7 . There are advantages.
Best regards, Dan

danscope
2007-May-14, 06:22 AM
Hi, Simply academic question: Can a wheel comprised space station design be balanced in mass, one to another and then be dynamically balanced such that acceleration is precisly distributed, encouraging smooth linear acceleration on it's intended vector for orbit correction and re-position , and even perhaps maintain local gravity close to acceleration durring change of orbit?
--------- A possible advantage is that a basic arbor, even under partial component assembly can still have a fluid tank system, and, by degrees remain in a working state of construction over time, yet generating live abord conditions
for more people than the standard profile....re non- astronauts, science staff,
other specialists. A little like building the Hindenburg in space or a very large
Ferris wheel. And...can any main fuel tank ( a la Shuttle _ be re-employed
in orbit as a major pressure vessle component of such a structure. Is it.....
Impossible? Has it been considered? Just curious.
In theory......
Best regards, Dan

Romanus
2007-May-14, 01:38 PM
I think a single massive module would work, a la Salyut or Skylab. However, as WP already wrote, once you do all this you're not really talking about a space station any more. In my op, their mass and spaciousness can't quite compensate for the much greater amount of fuel necessary to get them from points A to B, unless it's a one-time feat. That is, unless we wanted to build a station in Earth orbit, shift it to Mars, and keep it there as an orbiting platform to serviced by future missions from Earth or the Martian surface.

danscope
2007-May-14, 06:23 PM
Hi, My thoughts pertained only to Earth orbit, hopefully an earth orbit that would be in proximity to a space telescope ( a new Hubble or move Hubble to
this new and more convenient orbit ?) such that we had a usefull space station
more easily serviced and in position to service those devices which require such. We need to get even better accomplished in NEO before we think about mars, in my opinion.
Best regards, Dan

Larry Jacks
2007-May-14, 06:53 PM
The ISS is in a 51 degree inclination orbit because when we decided to partner with the Russians, that was the lowest inclination they could launch into. Earlier versions of the station design called for a 28 degree inclination (the lowest you can launch into from the Cape). Had we gone with one of those designs, we could've launched more massive modules using the Shuttle and would've been in a better position to develop an on-orbit assembly facility for missions to the Moon and Mars. However, we would've had to abandon that station for long periods following an accident like Columbia. Having the ISS in a 51 degree inclination means it was manned continuously while the Shuttle was grounded. The Soyuz and Progress missions kept the ISS alive.

Damburger
2007-May-14, 07:52 PM
In my op, their mass and spaciousness can't quite compensate for the much greater amount of fuel necessary to get them from points A to B, unless it's a one-time feat. That is, unless we wanted to build a station in Earth orbit, shift it to Mars, and keep it there as an orbiting platform to serviced by future missions from Earth or the Martian surface.

What would a space station need that an interplanetary manned mission would not? Where would the wasted mass be?

Ilya
2007-May-14, 07:54 PM
The ISS is in a 51 degree inclination orbit because when we decided to partner with the Russians, that was the lowest inclination they could launch into.
Politically "could", not technically. As someone else pointed out, Baykonur is located at 46 deg North, so theoretically you can launch from it into 46 degree orbit -- in fact this uses very slightly less fuel than 51 degree orbit. But it means dropping spent stages on China (also on Mongolia).

NEOWatcher
2007-May-14, 07:56 PM
What would a space station need that an interplanetary manned mission would not?
Media interest. :D

Ilya
2007-May-14, 08:05 PM
Hi, Simply academic question: Can a wheel comprised space station design be balanced in mass, one to another and then be dynamically balanced such that acceleration is precisly distributed, encouraging smooth linear acceleration on it's intended vector for orbit correction and re-position , and even perhaps maintain local gravity close to acceleration durring change of orbit?

I seriously doubt it.

Also not necessary.

Keep in mind, the spoked-wheel space station design dates from the 1950s, when nobody knew how well humans would handle zero-gravity. Medicine being a conservative profession that it is, before first manned launches no respectable doctor was optimistic about that at least, not in public. Conventional wisdom was that weightlessness is completely debilitating; I read serious claims that eyes would not focus in zero-gravity due to distortion of the eyeball, or that more than a few minutes of no-weight would make a person go insane from fear because what could be more frightening than perpetually falling?

From those fears the wheeled space station design was born. In reality zero-gravity turned out to be not nearly as bad as expected, and extremely added mass and cost of the wheeled station simply unnecessary.

Larry Jacks
2007-May-14, 08:29 PM
Politically "could", not technically. As someone else pointed out, Baykonur is located at 46 deg North, so theoretically you can launch from it into 46 degree orbit -- in fact this uses very slightly less fuel than 51 degree orbit. But it means dropping spent stages on China (also on Mongolia).

The Russians (then Soviets) accepted the 51 degree orbit as both a range safety issue and a political constraint. Back then, the Soviet Union and China were on very bad terms and dropping rocket parts would not only be a provocation, it might have given the Chinese access to technology that the Soviets didn't want them to have. Even today, dropping large hypergolically fueled rocket stages on someone isn't exactly considered neighborly. Under the Outer Space Treaty of 1967, the Russians would be liable for any damages they inflicted on the Chinese. They didn't have to worry about anyone filing damages for debris dropped on their own people.

danscope
2007-May-15, 04:24 AM
I seriously doubt it.

Also not necessary.

Keep in mind, the spoked-wheel space station design dates from the 1950s, when nobody knew how well humans would handle zero-gravity. Medicine being a conservative profession that it is, before first manned launches no respectable doctor was optimistic about that at least, not in public. Conventional wisdom was that weightlessness is completely debilitating; I read serious claims that eyes would not focus in zero-gravity due to distortion of the eyeball, or that more than a few minutes of no-weight would make a person go insane from fear because what could be more frightening than perpetually falling?

From those fears the wheeled space station design was born. In reality zero-gravity turned out to be not nearly as bad as expected, and extremely added mass and cost of the wheeled station simply unnecessary.

And you see no advantage? Well, perhaps radiation is the worst aspect of space. And zero G is only partly debilitating.
I was thinking that the dual wheel was stronger, better suited to future acceleration to preserve or change orbit and offered some day to day advantages. If you are going to live there for an extended period of time.
Best regards, Dan

NEOWatcher
2007-May-15, 12:24 PM
And you see no advantage?
Yes; there are advantages to artificial gravity, but consider what the goals of current experimentation is.
We are at the point where we are studying microgravity, on various materials and on the human body. Without the sustained weightlessness, the experiments would be useless.
We are also using the space station as an observation platform. It makes it very diffucult to view the surface of the earth if it keeps disappearing from the porthole.
We also have crude docking technology. A spinning station would be extremely dangerous.
For a station to have artificial gravity, I think the goal of the station would have to be considerably different. So; let's get a problem before we try to find a solution. These uses might be around the corner.
Space Hotel.
Staging port.
I'm not sure what else...

danscope
2007-May-15, 05:15 PM
Hi, If you read my original post, there is one wheel for zero G..(non-spin) and one which generates a modest gravity...say .15 G . You can have your cake and eat it too.
Dan

NEOWatcher
2007-May-15, 05:49 PM
Hi, If you read my original post, there is one wheel for zero G..(non-spin) and one which generates a modest gravity...say .15 G . You can have your cake and eat it too.
Dan
Yes, I do remember that, but, when you add the complexity, is it worth the effort for the experiments that are being performed?
Plus; as I mentioned about zero-G physiology research, the subject astronaut would need to stay in the zero-G section anyway.
Again; what are we doing now, or hope to do in the near future (funding possibilities) where this is helpful?

Romanus
2007-May-15, 08:44 PM
<<What would a space station need that an interplanetary manned mission would not? Where would the wasted mass be?>>

The comparisons between space stations and interplanetary transfer vehicles is, IMO, one between a car and an RV. ITVs will probably not be designed for long-term habitation, but for a singular purpose: to get there and back in one piece. It places a premium on a balance between fuel and speed. A space station is designed for long-term habitation, and presumably for *more* use as well--experiments, expansion, backup and supplies (for planetary missions), etc.--making it heavier than it needs to be.

If we really insist on interplanetary space stations, what we should do--again, IMO--is simply use regular ITVs to get there, then link them up and increase the nascent station's size with each successive mission (with a return vehicle, of course).

Warren Platts
2007-May-16, 12:07 AM
Interplanetary Transfer Vehicles would have to be mini space stations unto themselves because they necessarily involve long-term habitation. I mean could you imagine spending several months cooped-up in one of those CEV's with three other guys that you might not even like? You'd go crazy. You need to think nuclear submarines; so you need something at least about skylab-sized and hooked up to about 5 refuelable J-2's.

Even so, a skylab sized craft is only big enough for voyages lasting several months at most. Something more along the lines of the ISS is needed for missions that might last a year or more. Hence, the first permanent manned presence around Mars will be an ISS-style modular spacestation in a low altitude Martian orbit. We have to prove that we can master the logistics of just going and surviving in a Martian orbit before we can be sure that we can reliably resupply the Martian surface.

The space station would at first consist of several, separately launched modules docked together robotically before the first manned mission. Thus, astronauts could jet to Mars in a fast, spartan, yet endurable, ITV and then have a decent space station waiting for them where they could live indefinitely.

Special SSTO landing craft for going back and forth to the Martian surface would be docked to the MSS. I would suggest a fleet of about 4 landers. You want to maintain triple reduncancy on such a mission-critical capability--so with four, if you lose one, you still have 3 left.

On Mars, there is no Kennedy Space Center to do the maintenance on your reusable craft. So the MSS will be equipped with an inflatable "dry-dock" large enough to surround an ITV or lander with a pressurized, shirt-sleeve environment where human technicians could do whatever maintentance that's required.

mugaliens
2007-May-16, 07:08 PM
The Blackstar spaceplane would send astronauts to the new space station where they would transfer to the lunar space shuttle. Once in lunar orbit, they would transfer to a single-stage to orbit lunar lander. So, going to the Moon would involve three completely reusable spacecraft, each one specifically tailored for only one task each: (1) Earth to LEO; (2) transfer from LEO to lunar orbit; (3) lunar orbit to the lunar surface.

Come to think of it, a rotovator concept would work exceptionally well on the Moon - far lower velocities and accelerations due to it's much smaller gravity well and no atmospheric friction to worry about!

Noclevername
2007-May-19, 06:50 PM
Bulding a moderately sized rotating station would --from a purely engineering standpoint-- not be much more difficult than building a good-sized suspension bridge. And once it's done, and there's proof of concept, more will be built, including mobile wheels for spacecraft, and all this messing around with microgravity will be downgraded to a boondoggle. The best part is, it can be used for testing long-term habitation in all sorts of gravity.

Do I think it's likely to happen soon? No. That would be asking too much. The way things work, we have to wait until the Soviets beat us to it and then rush to surpass them... oh, wait...

NEOWatcher
2007-May-21, 02:44 PM
Bulding a moderately sized rotating station would --from a purely engineering standpoint-- not be much more difficult than building a good-sized suspension bridge.
And from a non-engineering standpoint?

The best part is, it can be used for testing long-term habitation in all sorts of gravity.
Right now, we have Earth gravity, micro-gravity, and are striving to be able to study at moon's gravity. What other kinds of granularity would be useful and why?

Do I think it's likely to happen soon? No. That would be asking too much. The way things work, we have to wait until the Soviets beat us to it and then rush to surpass them... oh, wait...
What current need is there for an artificial gravity? Yes; it would be an interesting study, but there is no current problem that we have that would require that particular solution.

Drbuzz0
2007-May-21, 05:28 PM
My biggest frustration with the space station is simply that it never was completed to what it was supposed to be and currently is operating in a capacity which makes it's usefulness limited.

It's not in the most desirable orbit, but that's not something we can do all that much about...

Perhaps this is an overly-simplistic view (and I know it is).

But I'd really like to see a commitment to what we are going to do with it.

I'd like to see the station get some big, capable and well built modules get attached so that it can start functioning well and have all the capabilities it was supposed to.

Launch a couple of large habitats with equipment pre-installed on the heavies life platform avaliable, like was done with Skylab. Give it the size, capacity and power to do what it was supposed to.

Yes, that would be expensive, as heavy lift rockets tend to be. And yes, if you worked enough you could possibly shave off a few pounds by using small upgrades.

My point is GET IT DONE AND DO IT NOW! One shot (or a couple) Boom! Done! Then it can actually start to be really useful. Don't leave it to the next administration or it won't happen. Put the money aside and do it!


or...

Just give up on the damn space station and say "Well, we launched it and then changed out minds."

Either do it right or don't do it!

Noclevername
2007-May-21, 06:24 PM
I feel your pain, Drbuzz. The ISS, like the Shuttle before it, is Frankensteinish political compromise. It's so frustrating to watch.

NEOWatcher
2007-May-21, 06:29 PM
My biggest frustration with the space station is simply that it never was completed to what it was supposed to be and currently is operating in a capacity which makes it's usefulness limited.
A whole lot of people share that frustration...

But I'd really like to see a commitment to what we are going to do with it.
The very reason that the shuttles are still flying is a sign of the commitment to the station. Possibly a losing proposition, but it is a commitment.

I'd like to see the station get some big, capable and well built modules get attached so that it can start functioning well and have all the capabilities it was supposed to.
And that would require many years of design to be able to fit them to a launch platform. Even though STS is a slow, lumbering, seemingly endless way to get the job done, it still has advantages over starting over.



My point is GET IT DONE AND DO IT NOW! One shot (or a couple) Boom! Done!
That's the problem, get it done now, and one little mishap may cause it to go boom, and then we are really done.

It took decades to design this behemoth, and at the time, STS was a promising upcomming platform.

To name a few factors...
1) all the cooperating countries need to agree to any changes because they are bound to the current direction.
2) It was designed with the shuttle being an integeral part of the entire program. A lot needs to be changed to adapt, and that will take time.
3) Pulling out of the agreement (by NASA) would be an internationally political nightmare.
4) It's all we got at the moment.

Grey
2007-May-21, 07:03 PM
Here (http://www.davidbrin.com/tankfarm1.html)'s my favorite idea for a realistic space station. Obviously, this is fiction, but the basic idea is one that would work more or less as described.

Noclevername
2007-May-21, 07:39 PM
What current need is there for an artificial gravity? Yes; it would be an interesting study, but there is no current problem that we have that would require that particular solution.

Who said anything about "current"? I'm looking at our future needs here.

How about the problem of long-term and eventually permanent habitation? The sooner we start working on the problem, the sooner it'll become a reality. And differing gravities would be useful because different celestial bodies have different gravities. The ability to simulate anything we might encounter will leave us better prepared for what we will encounter.

As for non-engineering problems, the only major one is getting enough structural material into orbit; using asteroidal material would do for most of it. Lunar, if need be, but why waste delta-v we don't have to?

There are already several groups starting to work on the engineering of potential asteroid mining/processing methods. It's just starting its first baby steps, don't dismiss the concept just cause it can't run marathons yet...

NEOWatcher
2007-May-21, 07:47 PM
Who said anything about "current"? I'm looking at our future needs here.
That's my point... We know the science, so now the need will be up to private companies.

How about the problem of long-term and eventually permanent habitation?
We learn about those now.

The sooner we start working on the problem, the sooner it'll become a reality.
What problem?

And differing gravities would be useful because different celestial bodies have different gravities. The ability to simulate anything we might encounter will leave us better prepared for what we will encounter.
So, why not just go encounter it and study it? Why do we need to simulate different gravities when we know the effects and can extrapolate the different levels of gravity?

As for non-engineering problems, the only major one is getting enough structural material into orbit;
That is an engineering problem because we already have the technology to do it. We just don't have the money.

using asteroidal material would do for most of it. Lunar, if need be, but why waste delta-v we don't have to?

There are already several groups starting to work on the engineering of potential asteroid mining/processing methods. It's just starting its first baby steps, don't dismiss the concept just cause it can't run marathons yet...
Yes; but we don't need gravity for that.

Noclevername
2007-May-21, 08:44 PM
I'm not sure I understand your replies.


That's my point... We know the science, so now the need will be up to private companies.

Never said public or private. Whoever gets it done is fine with me; at this point it looks like private will get to it first. And we only know a tiny fraction of the science needed for permanent colonization.


We learn about those now.

Where the heck did you get that idea? The longest anyone has spent in space was a little over a year (IIRC), in zero-gee, with all the long-term medical effects that implies. And those were cosmonauts carefully selected for their superior health and ability to withstand space conditions.


What problem?

"How about the problem of long-term and eventually permanent habitation?"

That one. It was the sentence I started the paragraph with.


So, why not just go encounter it and study it? Why do we need to simulate different gravities when we know the effects and can extrapolate the different levels of gravity?

You think travelling to every body in the Solar system would be easier or cheaper than buiding a variable-rotation space station?? Explain your reasoning, please!


That is an engineering problem because we already have the technology to do it. We just don't have the money.

Which is exactly what I said. We're in the process of developing the engineering to get the needed materials as cheaply as possible.

Getting money is not, however, an engineering problem.



Yes; but we don't need gravity for that.

Never said we did. I said (or implied) that having such mining/processing tech would make building space stations (rotating or not) and spacecraft, and eventually a whole space infrastructure, a lot more viable. We need the gravity to live in space. Sorry if that was unclear.

danscope
2007-May-22, 01:50 AM
Hi, This may have been suggested before, but the concept of employing the
main shuttle fuel tank as a reincarnated pressure vessel module of a wheel assembly would make excellent sense economiclly, and would surely be strong enough to do the job. Instead of throwing away a perfectly good pressure vessel, why not incorporate that which you have already paid so dearly to boost up in the first place. Put 20 of these things together in a circle and you have
one good sized station, storage, tankage, fuel storage etc.
RECYCLE is not a dirty word.
Best regards, Dan

Drbuzz0
2007-May-22, 03:46 AM
A whole lot of people share that frustration...

The very reason that the shuttles are still flying is a sign of the commitment to the station. Possibly a losing proposition, but it is a commitment.


*sigh* have you noticed that all the shuttle missions are now dominated by checking the shuttle to make sure they won't die? They get to space and then most of the concern seems to be making sure they get back...

I'm begining to think it's only flying at all because they don't want to have zero American manned space systems.




And that would require many years of design to be able to fit them to a launch platform. Even though STS is a slow, lumbering, seemingly endless way to get the job done, it still has advantages over starting over.


It will take even longer if they never start. Are the shuttle missions actually carrying anything major up anyway? Or just a few replacement parts and whatnot?


How long did it take to get Skylab put together? At this point I'd be willing to accept adding the capacity to the space station that it needs even if its less then elegant. I'd rather send up a 20 ton module then spend ten years and a billion dollars developing new composit materials that would reduce the total weight to 19.3 tons and thus save a few million dollars in launch costs.

NEOWatcher
2007-May-22, 01:18 PM
I'm not sure I understand your replies.
Quite possibly true...

Never said public or private. Whoever gets it done is fine with me; at this point it looks like private will get to it first.
I think this is where we part ways. When I speak of the "we" in we should, I am speaking of the governmental research agency known as NASA.
I just don't see the current scientific research benefits of an artificial gravity.

Let me try to sum it up this way:
Reduced gravity is a problem in space travel; but, It is only a minor problem when compared to radiation, supplies, phsychology, and others.
Current zero-G research may provide an alternate solution to the problems. We know artifical-G is one solution, so let's see if there is another.
Zero-G is a factor but is not impeding space research.

NEOWatcher
2007-May-22, 01:25 PM
Hi, This may have been suggested before, but the concept of employing the main shuttle fuel tank as a reincarnated pressure vessel module of a wheel assembly would make excellent sense economiclly
Yes it has been. But; as far as the economic sense, I would like to know the following:
How much (with that theoretical HLV) would it cost to put the equivalent weight into orbit?
How much of the cost of a space station is the pressure vessel by itself?
How do you purge residual fuel from the vessel?
How do you equip the inside of the vessel with all the equipment, electrical, connectors, hatches, or whatever would be needed in a station module without interfering with the fuel supply?

NEOWatcher
2007-May-22, 01:45 PM
*sigh* have you noticed that all the shuttle missions are now dominated by checking the shuttle to make sure they won't die? They get to space and then most of the concern seems to be making sure they get back.
Why not, as long as the primary mission is not compromised?

I'm begining to think it's only flying at all because they don't want to have zero American manned space systems.
We've had gaps in capabilities before, so, I don't think that is a major concern. Although; that impression is there.


Are the shuttle missions actually carrying anything major up anyway? Or just a few replacement parts and whatnot?
Whatever whatnots there are, are primarily handled by progress. Yes; major components are sent by shuttle, with whatever spare space leftover filled with whatnots.
The station is about half finished, we still have about a half a million pounds of station to get up there. Some of the components are vital for the operation of ISS. For instance, the solar arrays. Without some of these components, the ISS will remain in a "maintenance" mode and will not be of any use. These components are already designed for shuttle.


How long did it take to get Skylab put together?
The comparison is very difficult:
First, each module is designed by different agencies for different goals (including international politics, but we wont go there)
Another is the available lift vehicles at the time of design.
Plus; even if they were Skylab type modules, we are still talking about 6 major components, and we still need a way to construct and maintain them.

Grey
2007-May-22, 02:32 PM
Hi, This may have been suggested before, but the concept of employing the
main shuttle fuel tank as a reincarnated pressure vessel module of a wheel assembly would make excellent sense economiclly, and would surely be strong enough to do the job. Instead of throwing away a perfectly good pressure vessel, why not incorporate that which you have already paid so dearly to boost up in the first place. Put 20 of these things together in a circle and you have
one good sized station, storage, tankage, fuel storage etc.
RECYCLE is not a dirty word.
Best regards, DanYup. The link to the short story by David Brin I posted suggests exactly that.

Noclevername
2007-May-22, 05:23 PM
When I speak of the "we" in we should, I am speaking of the governmental research agency known as NASA.
I just don't see the current scientific research benefits of an artificial gravity.

I mean "we" in the sense of everyone her on Earth. And as I said before, I'm not talking about our current sad state of affairs, but our future needs.

...

If you can't see the benefits of being able to colonize space, there's really nothing I can say to that...

NEOWatcher
2007-May-22, 07:09 PM
I mean "we" in the sense of everyone her on Earth. And as I said before, I'm not talking about our current sad state of affairs, but our future needs.
Yep; I kind of suspected the "we" is where we parted.

If you can't see the benefits of being able to colonize space, there's really nothing I can say to that...
Absolutely, I do see the benefits. But; as far as who is responsible for getting it going, I'm not yet sure whether it should be government controlled, or will occur naturally as space opportunities arise.
For me, the important governmental goal at this point is to discover...

Noclevername
2007-May-22, 09:15 PM
Hmmm. The problem, as I see it, is that we're not talking about something that naturally occurs. It takes directed effort and specific knowledge and skills, which seem to be slow in coming. This is all stuff which was technically feasible in my childhood, and yet we're still putzing around our own backyard!

danscope
2007-May-23, 03:19 AM
Many of the advantages of space and zero G, and pure optical considerations
are, in fact, right in our own back yard. Nothing wrong with that.
There are those who yearn for the esoteric and wish that to be "The" goal.
But our benefits have come from NEO. This has been the best and biggest payoff. This has been expensive and dangerous enough as it is.
The " other things" get exponentially more dangerous and more expensive.
Millions vs billions.
We may be better off employing robots to do "The other things" .
Dan

Noclevername
2007-May-23, 03:14 PM
Robots can't colonize.

Damburger
2007-May-23, 05:25 PM
RECYCLE is not a dirty word.

It is when you really mean REUSE ;)

Drbuzz0
2007-May-23, 05:30 PM
The comparison is very difficult:
First, each module is designed by different agencies for different goals (including international politics, but we wont go there)
Another is the available lift vehicles at the time of design.
Plus; even if they were Skylab type modules, we are still talking about 6 major components, and we still need a way to construct and maintain them.

The thing about a skylab-like approach is that it would allow major capabilities to actually be added.

As much as I appreciate the fact that a one-shot big-module approach is not the most weight frugal or necessilary elegant approach. Incase you have not noticed: When government agencies take on long-term projects of many small components with long development times and studies to determine what type of materials to use: They have a tendency to never actually happen or spend decades in the planning stages and we end up with a bunch of really nice artists' renderings of what it might have looked like.

Skylab was a rather quick-and-dirty aproach which converted the upper stage of a staurn-5 to a work modal. It was not exactly geared to being light weight or especially elegant in design. Just the same: it worked and it was actually a rather roomy and very durable design. (Which unfortionately was allowed to fall from orbit despite being a very robust basic platform)


Skylab weighed about 75 metric tons. That would be beyond the capabilities of any active launch systems I am aware of. However, with some slight scaling down and and the use of some newer materials and construction techniques, I don't think it's unreasonable to think 50 metric tons would be possible for a module of size and capability on par with Skylab.

IIRC, that should be just within the limits of the (as yet unflown) Delta IV Super-Heavy, which is basically the same as the Delta-IV heavy but with four side boosters instead of two.

Of course, if you could get an Energia-Vulcan mission, then you could carry a lot more.

But my point is based more than anything on frustration! As much as I understand that weight is expensive to launch and it's better to save as much mass as possible, I'm not looking forward to spending 20 billion dollars and 10 years for a program to develop a new type of composite construction technique which will reduce the weight by 500 lbs.

Can we please.. just... you know... do this? A few delta IV super heavies... bite the bullet on the cost as opposed to spending less money in the shortterm and having... Nothing.....ever......happen

Larry Jacks
2007-May-23, 06:23 PM
Inflatable modules like what Bigelow is testing have a lot of volume for their mass, much more than rigid modules. Depending on the station's mission, it should be possible to build a good station that could be launched with today's boosters. Bigelow sure thinks so and he's putting up his own money to prove it.

Noclevername
2007-May-23, 07:11 PM
Skylab was a rather quick-and-dirty aproach which converted the upper stage of a staurn-5 to a work modal. It was not exactly geared to being light weight or especially elegant in design. Just the same: it worked and it was actually a rather roomy and very durable design.


The trouble is, "quick and dirty" have now become dirty words to NASA. The politicians who hold the purse strings want the latest, shiniest, most advanced tech that the US can show off, not the proven, sturdy, but non-spectacular workhorse tech. Hence no HLV.

satori
2007-May-24, 05:47 PM
Skylab was very inspiring after the the largely nonsensical apollo adventure
now it's ISS that sucks.................(funds!)
((but everybody knows that, so......................sorry))

R.A.F.
2007-May-24, 06:03 PM
...largely nonsensical apollo adventure...

You're posting to the space exploration forum of a science board. The only reason I can think of for you to say something as dopey as what you just said is to PROVOKE A REACTION.

So the question becomes, why do you think it a good idea to purposefully "jerk our chains"??

...and just to be "fair", please post just why you consider the Apollo missions to be "nonsensical".

Noclevername
2007-May-24, 06:07 PM
Satori, have you been hitting that smoked-bee honey again?

satori
2007-May-24, 07:01 PM
never even smelled this stuff, Noc!
when i learned my moderation lessons this plant was out of the game

to you R.A.F.
why are you not seeing the positive part of my little utterance
i mentioned Apollo only to contrast it with the marvelous Skylab mission
if this was a board about patriotism and engineering i could fully understand your temper
in those fields Apollo would seem to be a bright and shiny light
i thought it a common place notion by now (40 or so years after!) that the Scientific gain of this Great Patriotic Undertaking was fairly limited (to say it in a way that might be acceptable to your ears)

and now listen: if all the sentiment you are projecting should in fact be heart felt and not just a mere Ado About Nothing to get me exposed to the wrath of the community...
i retract my original statement and apologize.....as it was done in a light hearted vein (such as exists in absentia of cannabinoids also!)

satori
2007-May-24, 07:10 PM
You're posting to the space exploration forum of a science board.
o.k. R.A.F.
point for you!
i think i was a little negligent!!
so, sorry ones again

R.A.F.
2007-May-24, 07:36 PM
i thought it a common place notion by now (40 or so years after!) that the Scientific gain of this Great Patriotic Undertaking was fairly limited.

So is that your answer to my question? Apollo was nonsensical because the scientific "gain" was limited?


...to get me exposed to the wrath of the community...

Why am I at "fault" for something you posted??

Ever heard of being personally responsible for one's own actions??

satori
2007-May-24, 07:57 PM
we all are entiteled to our own opinions (aren't we) even if they may be false, ill informed or outright foolish
should i have just managed to show my utter stupidity to the Whole Wide World so is it my burden to carry the heap of shame
i have apologized to you in a mannered way
i owe you no further

R.A.F.
2007-May-24, 08:01 PM
i have apologized to you in a mannered way i owe you no further

Well, it would be nice if you answered my Apollo question...but given the "style" of your posts, I'm not expecting you to...

satori
2007-May-24, 08:30 PM
well R.A.F. you have been coming at the sharp end of my tongue on occasion.....and i may have been not entirely fair to you
i see that well......allas
i beg you take my apology at face value
i am really not overly well informed on Apollo
take my whole damn post as a void exercise in vanity
it was really less than the usual two cent.....lack of self discipline if you will

so have a good night (or good afternoon or what ever) and.................................good bey

Drbuzz0
2007-May-25, 06:07 AM
Skylab was very inspiring after the the largely nonsensical apollo adventure
now it's ISS that sucks.................(funds!)
((but everybody knows that, so......................sorry))


I disagree on Apollo. Okay, I suppose my judgment is a bit non-objective by the fact that I find the whole program not just inspiring but freakin cool!

Apollo was basically driven by a patriotic and political agenda, however it also focused attention in a way that would be difficult to without such a high goal. It definitely resulted in a huge technological leap beyond the previous rather crude systems.

But even if science was not really as much of a driving force as it's sometimes claimed to be, it did result in some astoundingly important discoveries. Simply the fact that the age of the moon could be established as well as it's basic composition pretty much wrote the book on how the moon formed (from an impact). That really changed a lot about how we view the earth and the early solar system and just the laser refelecters left behind have allowed us to determine the moon's orbital nature much more precisely.

The information gained has really had a great effect on views of planet formation and the solar system. One could argue that it could have been done with simpler unmanned missions, but it was still Apollo that did it.


Ok... now I've gone off topic for the thread haven't I?

satori
2007-May-25, 06:46 AM
Ok... now I've gone off topic for the thread haven't I?

that's not for me to judge
non-objectivity is fine with me
who would be so audacious as to claim beeing able
to judge Apollo from a position of objectivity?
so i read your stance on things with interest
your pitch (as opposed to mine) has the merrit
of beeing explicative to some degree.....
i see that you have raised some valuable points