A Better Space Station?

[Giulio]

Now I'm no engineer so don't laugh! But I always wondered why we couldn't build a more advanced spacestation than the skylab on steroids we got up there now. I mean, It couldn't be that much more difficult than what we already did. Just a different configuration. Along the lines of many science fiction stories I've read, why not build a wheel in space and spin it for false "gravity". The center hub can serve as a docking port, zero-g labs and work stations for zero-g experiments. etc.., while the rim could have multiple modules for living quarters, non-zero g labs, bathrooms, kitchens, excersize rooms, etc... All the money spent on reinventing zero g toilets and galleys and living quarters and workstations and all the rest, could have been used for the added complexity of a more advanced station. Instead we could have used nearly conventional toilets and other such stuff for modules that would have "gravity". It could have been built in sections just like the ISS, but upon completion, instead of just saying, "ok, we're done!" we celebrate it's completion by setting it spinning. You build the wheel's framework first, then the center hub with the solar arrays and then begin to add modules to the rim. When all is balanced and complete, turn on the thrusters and the gyros or what-have-you and you have something that looks like a spacestation, not something that looks like its been thrown together ad hoc.
Again - don't laugh - but I have an image below to try and illustrate what I mean. It's not to scale at alland I don't know how big it would have to be to be feasible. OK, go ahead, shoot me down and speculate away!! :roll:

Here is a great explanation of the concept: http://chapters.marssociety.org/usa/oh/aero2.htm

 

[MeteorWayne]

The quick answer is: $$$$$$$$$$$$$$$$$$$$$

As in who's going to pay for it.
Lot's of people have interesting ideas.

Very few have a means or plans to pay for it.

 

[wick07]

Now I'm no engineer so don't laugh! But I always wondered why we couldn't build a more advanced spacestation than the skylab on steroids we got up there now. I mean, It couldn't be that much more difficult than what we already did. Just a different configuration. Along the lines of many science fiction stories I've read, why not build a wheel in space and spin it for false "gravity". The center hub can serve as a docking port, zero-g labs and work stations for zero-g experiments. etc.., while the rim could have multiple modules for living quarters, non-zero g labs, bathrooms, kitchens, excersize rooms, etc... All the money spent on reinventing zero g toilets and galleys and living quarters and workstations and all the rest, could have been used for the added complexity of a more advanced station. Instead we could have used nearly conventional toilets and other such stuff for modules that would have "gravity". It could have been built in sections just like the ISS, but upon completion, instead of just saying, "ok, we're done!" we celebrate it's completion by setting it spinning. You build the wheel's framework first, then the center hub with the solar arrays and then begin to add modules to the rim. When all is balanced and complete, turn on the thrusters and the gyros or what-have-you and you have something that looks like a spacestation, not something that looks like its been thrown together ad hoc.
Again - don't laugh - but I have an image below to try and illustrate what I mean. It's not to scale at alland I don't know how big it would have to be to be feasible. OK, go ahead, shoot me down and speculate away!! :roll:

Here is a great explanation of the concept: http://chapters.marssociety.org/usa/oh/aero2.htm

This is a great idea that has been floating around for a while. However, scale is what makes this difficult. The amount of gravity produced will be based on radius and rotational speed. Two other effects you should consider are differential acceleration and coriolis effect.

The differential acceleration is the difference between the apparent gravity on the head and feet. This could disorient crewmembers and induce vertigo. The smaller the radius, the greater the effect.

Coriolis effect will cause an apparent force on any motion in the station. So as I reach out to push a button I will feel my hand pushed by the "coriolis force". This will affect a crewmembers ability to accomplish precision tasks. The faster the RPM the greater the coriolis force.

So as you can see, if we want to make this space station we want the RPM as slow as possible, and the radius as large as possible. If we want to make the station one continuous ring, you can image how large a project this could be.

I was unable to get a good source telling me how high an rpm is acceptable, but Wikipedia (please use with caution) recommends no more than 2 rpm in this entry (http://en.wikipedia.org/wiki/Artificial_gravity), they don't say where they get that number. I had always heard 1 rpm as the optimal target.

In either case, a station roughly the diameter of the ISS's length (~70m) will have a radius of 35m, a circumference of 220m, rotate at 5 rpm, and have a differential gravity of 5%.

 

[JeffreyNYA]

How many Bigalow Sundancer modules would it take for a station of that size? Could not find the length of the sundancer, but then again I only had time to look for a minute or so.

 

[tampaDreamer]

as has been mentioned before, you could switch to a two-bumps-on-a-lot configuration rather than a ring. Then only the size of the central strut is affected by the "radius".

O-------x-------O

 

[Giulio]

Yes Tampa dreamer, my thoughts exactly. We should have already started building this thing. It doesn't need a rotation yet. Just construct portions of it as money and neccessity allow until sometime in the future when the thing is complete. Then you could initiate the spin. I envision a stationary central hub to allow for easy docking and perfect zero-g labs. Look at it like a giant electric motor but instead of spinning the shaft/hub you spin the whole motor/ring around the shaft/hub. A circular transport ring around the hub can be used as a method of aligning the access portals to the radial access tubes to the outer ring. So the main hub and solar arrays could always stay put. But Like I said, the whole argument with not building this thing is cost, well, no one says the whole thing has to be built at once. The portions built could be used as a conventional station meanwhile, with the aim of one day spinning it for artificial g. The ISS could have been the start of it. We could have built a giant ring truss system. That couldn't be that expensive. Just a bunch of nuts bolts and tubular pipes. Then started adding modules to it. Better yet, just build as much of the truss system you need for the time being, but with the intention that someday you'll complete a large ring. Remember this is a zero-g environment, It wouldn't need to be balanced until the very end sometime in the future when we finally intended to spin it.

 

[tampaDreamer]

I just dont think it's needed at this time. Why do we need gravity in space?

 

[Giulio]

I just dont think it's needed at this time. Why do we need gravity in space?

Below is an excerpt from the link in my original post.

"WHY ARTIFICIAL GRAVITY?

Prolonged human exposure to microgravity has been seen to contribute to numerous physiological problems, including fluid redistribution (and subsequent loss), cardiac and skeletal muscle deconditioning, loss of bone mineral density and so on. This deconditioning is currently fought (with variable success) only by 1-2 hours per day of aerobic and resistance exercises, with resultant hull vibrational stress and contamination of the cabin environment by sweat droplets.

Physiologic adaptation to microgravity necessitates readaptation to Earth-normal gravity, with consequent temporary incapacitation of varying severity. Additionally, microgravity complicates materials handling, waste management, cabin environment hygiene and the like.

Artificial Gravity holds the potential to resolve or ameliorate all of these problems. On-board centrifugation on Kosmos-782 in 1975 showed that 1.0 g for 24 hours a day is sufficient to stop physiological deconditioning (1). Eliminating the need to readapt to Earth’s gravity would do away with the temporary incapacitation that complicates emergency landing planning. AG would settle airborne contaminants and cancel the danger imposed by floating material, as well as freeing hours per day of valuable astronaut working time."

We are gravity creatures.

 

[tampaDreamer]

Some good reasons there, starts to make more sense the more people you have working up there.

 

[emudude]

I like your idea...the cheapest way I could see this happening is by making the ring section an attachment module to the ISS...it's already up there, it's internationally owned and operated, and it's the perfect place for it to go...no need to "reinvent the wheel" and get an entirely new structure up there when we've got a great one started. The cheapest way to do this would probably be to use the inflatable module concept, we could make a massive torus-shaped structure and could construct significant portions of it at a time, as the material would be lightweight and also able to be stowed in a lifter rocket in a folded up configuration. The structure would be kept rigid by air pressure. I believe there was going to be a smaller scale artificial gravity module added to the ISS but it was scrapped due to funding.

 

[Boris_Badenov]

Inflatable Torus Space Station planned by NASA in the 1960's.

 

[Jazman1985]

Fantastic idea, I think a deciding factor is the complexity of having part of the station spinning and the hub to not spin. The added thrusters to keep it spinning correctly and the weight of the gears to seperate sections are probably going to be expensive. I could see the Bigelow inflatables using this for sleeping quarters, although if I was a space tourist I would be pretty mad if there was gravity... Also, no need to have 1.0 g, I think 0.25 g would be sufficient to make it more comfortable and "homey", this would probably be sufficient to counter the physiological effects of microgravity. Afterall, we seem to do fine for 6 months at 0 g, 1 year at 0.25 g can't be anyworse.

 

[Giulio]

I was thinking more along the lines of a "mag-lev" type system for seperating the hub from the rest of the station instead of "gears". I'm sure some engineer could design an electromagnetic system to spin the station like a mag-lev train rides a circular track. I think this would reduce weight and help spin the station, and also avoid very costly maintnance since there would be no contact between the two seperate structures. You could have four mag-lev "cars" attached to the rotating section, equally spaced to do most of the work in spinning the outer "wheel". Thereby, saving feul for any back-up thrusters that would be needed. My only concern is an adequate gyro to keep the hub stationary. But then again this is space we're talking about, so once we get it going, it won't need that much effort to sustain it, beside occaissional corrections.

 

[Jazman1985]

I guess by gears I was assuming something more like maglev or a low friction system of some kind, probably easier than we would think in a zero g environment. Yes, the stabilizers and gyros would be the most complicated, although I can't imagine any of this equipment weighing more than the specialized workout equipment NASA has to have now. In order to maintain spin appropriately a small VASIMR propulsion system could maintain it. As I understand it the efficiency increases enormously when at a low thrust setting.

 

[tampaDreamer]

If you check out the movie 2001, i believe that's the one, there's a version of this for a ship rather than a space station. However they let the middle spin too, and docking ships just had to replicate the spin before connecting.

 

[Giulio]

If you check out the movie 2001, i believe that's the one, there's a version of this for a ship rather than a space station. However they let the middle spin too, and docking ships just had to replicate the spin before connecting.

Yes, one of my favorite movies! I know it could be done. They have to do it now to a certain extent, but it is a much more complicated/high-risk maneuver. But zero-g labs and zero-g tourist areas would almost still be a neccessity. Also the solar array would need to be relatively stationary in an orientation to the sun that would optimize energy absorption. A stationary hub would accomplish all of these functions and more...

 

[pmn1]

If you check out the movie 2001, i believe that's the one, there's a version of this for a ship rather than a space station. However they let the middle spin too, and docking ships just had to replicate the spin before connecting.

There was a paper in the December 1991 issue of the Journal of the British Interplanetary Society by Michael A Minovitch of Phaser Telepropulsion Inc proposing the building of rotating 2001 type stations 100 metres diameter for at least 150 crew by using automatic wrapping machines rotating round inflated Kevlar torus’ to wind thin layers of aluminium until the required thickness had been made.

The rotating toroidal living section would have a major and minor radii of 100m and 2m while the two central column cylinders with labs etc and constructed in the same way would each be 100m long x 10m diameter. The two column cylinders would connect into a pre-fabricated central hub into which three spokes 100m long x 4m diameter also constructed in the same way would be fitted to join the hub to the toroidal living section.

The station also served as the basis for a 'cycling' ship and would take about 10 HLLV (assuming 100 tons/launch) or 14 Shuttle-C launches and 1 STS flight with minimal EVA.

Costs were about $400 billion for an Earth orbit station, a Mars orbit station and a cycling ship

 

[Jazman1985]

I wonder how economical it would be to forego keeping two parts of the station separate and simply start it spinning for about 12 hours a day, time for a sleep cycle and other necessary human activities(eating, exersizing). This way it would not interfere with experiments and such. A low velocity is all that is needed for artificial gravity. What size station and what scale of g forces are necessary?

 

[Giulio]

I wonder how economical it would be to forego keeping two parts of the station separate and simply start it spinning for about 12 hours a day, time for a sleep cycle and other necessary human activities(eating, exersizing). This way it would not interfere with experiments and such. A low velocity is all that is needed for artificial gravity. What size station and what scale of g forces are necessary?

But zero-g experiments would need more than 12 hours I would think. How do you isolate them from experiencing any artificial gravity when the station is spinning? And it takes just as much feul or power to stop the station as it does to start it spinning again. It is not economical to continuously start and stop it.

See the link in my original post for size and other requirement info.

 

[elroy_jetson]

A better space station would be great. Perhaps a central docking hub tethered to two or three habitat/experimentation pods, with tethered elevator capsules running from the docking hub out to the pods for moving people and supplies. The slowly spinning hub would put tension on the tethers, inducing artificial gravity in the distant pods. It might be cheaper and easier than building a rigid ring structure in space.

 

[WillCarney]

I just dont think it's needed at this time. Why do we need gravity in space?

It was a Russian astronaut that got off MIR after 18 month's that could not walk. He had to be carried off.
He had trouble walking for at least a month and he did exercise in space. Send people to Mars without some
type of induced gravity would be stupid. It would take more than 18 month's just to get there and they could
not walk when they do, maybe for a month or more.

The travel time to Mars would have to be 30 days or less if you are not inducing gravity in some form. Only
a NERVA type engine with plenty of fuel could do this. With the present anti-nuclear crowd that ain't going
to happen. No other propulsion tested to date could get us there faster. Any time longer than 30 days you
start to loose muscle and bone. That is also why the ISS is needed for such long space flight tests.

William

 

[aremisasling]

What size station and what scale of g forces are necessary?

Judging by this, not very large at all.

http://en.wikipedia.org/wiki/Centrifuge ... ons_Module

Granted this experimental module was not meant to provide gravity for crew, but it was a standard tin-can module like the one's we're used to. It would need to be bigger, I'm sure, to be effective for human occupation and operations, but we can create centrifuges capable of several g's that are very small for purposes here on earth.

 

[b0bhill]

I disagree that the ISS is in the proper position. Proper position for what? So that it could be built with the space shuttle? IMHO it should be located at a point where it is not constantly being pulled back toward the earth. A space station needs to be designed to last indefinitely with proper maintenance. It should be large enough to house at least 50 people possibly more with an engineering crew to make repairs, a medical team for everyday needs and emergencies. Everything we have put in orbit is temporary so far and we need to think permanent. It might take a lifetime to build but would serve mankind for centuries.

 

[Rootieboy]

NASA's original concept of the external fuel tank was to use them as nodes for a space station. There is a group who is still very interested in the idea but I doubt it will ever get done. Check out this site for more details. They are called space island group.

http://www.spaceislandgroup.com/wheel-stations.html

 

[holmec]

Very nice design for a wheel.

But, it might be cheaper to make a space station with artificial gravity to be in an in-line configuration.

That way you have the hab modules on one end and power modules or something else at the other.

With this configuration you can expirment with different mass at different ends and allow the "center" to vary. You could have a central docking port or you could just stop the lab from rotating all together to dock.

In-line configuration allows for freedom of operations while the wheel may require the center of gravity to remain in the center of the wheel. But as mass moves around so does the center of gravity (really center of centrifugal force).

Things I think that need to be experimented with are:

-Various docking configurations.
-Various G forces on humans - <1G and >1G.
-rotation control-traditional thruster, ion thrusters, mechanical gyroscopic type control.
-space station configuration to provide more than one level of artificial gravity for various experiments.
-design configuration research for an interplanetary crewed craft with artificial gravity - ie like taking crew to Mars and back.

To me a wheel would not allow for variations like these. And the primary goal of space stations so far has been for research.