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Skylab vs the ISS

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#26 llanitedave

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Posted 17 December 2013 - 11:09 AM

The thing I fear the most about the space elevator is having to listen to space elevator music all the way up and down.

#27 dickbill

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Posted 17 December 2013 - 02:44 PM

smaller has been done. they will experiment with bigger. I would love to see a space elevator in my lifetime too. *fingers crossed*

Those half mile long skyscrapers in Asia almost qualify.

#28 groz

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Posted 17 December 2013 - 06:45 PM

smaller has been done. they will experiment with bigger. I would love to see a space elevator in my lifetime too. *fingers crossed*


to build your space elevator you need to

a) Reach into the closet, and pull out a thousand tons of unobtanium
B) Launch it all up into geostationary orbit
c) Build some sort of shield so that it's never hit by a micro-meteorite
d) Shield the bottom so it's not whipped around by atmospheric currents (wind) at any altitude.


Pretty much guaranteed it'll never happen in your lifetime, or any other lifetime for that matter. The basic premise is fundamentally flawed. It relies on sending energy from the ground to the climber, in such a manner, it doesn't impact the actual tether. If you can aim an energy beam that strong, that accurately, you dont need the tether anymore, just beam the energy into a traditional winged vehicle. If it doesn't have to carry enough energy (fuel) to accelerate to orbital velocity, most of the difficult issues of launch vehicle construction just vanish from the equation. With an essentially unlimited energy source available, air driven propulsion can get you 99% of the way, and just a tiny bit of reaction mass required to stabilize the final orbit. And if energy supply is unlimited, just carry a little bit of air up with you to be the final reaction mass.

As far as some of the other issues of the tether go, just consider this. Did you ever play 'crack the whip' on skates as a kid ? Now consider the tether as 16,000+ miles in length, and, it's being pushed around at the bottom by different winds, and different altitudes, for the small portion in the atmosphere. That'll translate into waves going up and down the tether itself. Have you ever watched the video of 'galloping gertie' ?

Space elevator is the stuff of science fiction, and works real good, as long as you work in the 'ignore reality' premise.

#29 llanitedave

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Posted 17 December 2013 - 09:08 PM

The fact that it's untenable is the least of its problems. Even if you could build one, it simply wouldn't be all that practical. An orbital space ship that can actually go up and down and side to side, avoid space debris, retrieve and release other satellites, among other things, seems to me far more useful. And the price of access to space has already started coming down. With mass production and reusability of engines and launch vehicles and commercial competition between space companies, that price will be coming down even more, fairly quickly. I would bet that a Dragon or CST-100 or Dream Chaser visit to a Bigelow space station will be quite a bit more pleasant than swaying on a giant shakey lightning rod thousands of miles up.

#30 dickbill

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Posted 18 December 2013 - 09:39 AM

I think that the next (I)ST will be smaller/simpler than the present one.
Recently, yahoo news reported 'another' cooling problem in the ISS...
Perhaps the only thing to add would be a shield, for the space debris. How thick should it be?

#31 dickbill

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Posted 18 December 2013 - 10:49 AM

Firstsight, no need to apologize here. We were attacked by a troll, no doubt, and I recognize I fed him a little bit.

#32 dickbill

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Posted 18 December 2013 - 01:57 PM

The cooling problem in the iss not resolved. Now imagine Murphy's law strikes and a meteorite punctures a compartment. I assume the modules have self-sealing capabilities, but there must a be size limit to the hole that can be self-sealed. So let's assume a module completely depressurizes, in addition to the cooling problem, could the ISS survive that?

#33 Cliff C

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Posted 18 December 2013 - 02:24 PM

As a side note to the "What Ifs", not only was Skylab much larger than what the shuttle could bring to orbit but the second stage of the Saturn V which hauled Sklab to orbit stayed in orbit itself for 2 years or so. Now if the first stage had been a bit lighter with uprated F-1s or some solid rockets had been used in the first stage we could in one launch had a Skylab connected to a huge Saturn Second stage "wet workshop" that could have been converted to a station with tremendous volume. Even three or four launches over the course of one or two years could have generated a 2001 Space Odyssey sized station many years ago for much less money. Oh well.

#34 dickbill

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Posted 18 December 2013 - 03:18 PM

what are made of these second stage, a thin skin of aluminium over a steel frame?
Could that be rigid/strong enough for a station?
I heard something similar for the shuttle 'tank'. But given the environment of space debris, I'd feel safer with a very thick external wall.

#35 llanitedave

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Posted 18 December 2013 - 03:49 PM

It could have worked, but the tanks would have required lots of refurbishing, including adding solar panels, wiring harnesses, plumbing, furnishings, storage lockers, hatches...

It would have been cheaper to just build another module on the ground, furnish it, and launch it separately. Although the experience of learning how to do actual construction in space would have been valuable itself.

#36 groz

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Posted 18 December 2013 - 04:00 PM

All the nostalgia about skylab, folks seem to forget some of the details. Skylab was an unbearbly hot place for astronauts initially, due to cooling system failures. The fixes made later, made it 'just hot', but not a comfortable workplace.

The first mission, was essentially a repair mission, where various items damaged in launch were fixed, or where fix wasn't possible, jury-rigged as best as possible.

I know it's pretty easy for folks to wax nostalgic about skylab and it's series of missions. But, reality is, today if designing a space station and it's missions, looking back to skylab is done, as an example of 'how not to do it', not as an example of 'how to do it'.

#37 llanitedave

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Posted 18 December 2013 - 04:23 PM

Good point, groz. And with that missing solar panel, it never could develop the power it was designed for.

#38 dickbill

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Posted 18 December 2013 - 04:53 PM

Nuclear reactor plus Peltier cooler?

#39 obin robinson

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Posted 01 January 2014 - 04:14 PM

Isn't there any research, or actually ANYTHING, done on the ISS that could not have been done on the Skylab?
Perhaps even on a much cheaper Salyut station and Chinese derivatives?
Why justify then the exorbitant cost of the ISS?

Is there anything less rational than to say that the ISS was designed for the space shuttle, and the space shuttle was designed for the ISS?


Skylab could do something which the ISS can not do. For what it's worth the ISS can not do what the Almaz could do either. You either know what I'm talking about or you need to do a bit more research into just what really was going on in space during the Cold War. The ISS is a cooperative mission with the goal of science. Skylab, the Space Shuttle, the MMU, Buran, Polyus, Almaz, and Salyut wasn't necessarily about science. The size and payload requirements for the Space Shuttle have nothing to do with science at all. There was plenty of other stuff going on which I find to be much more interesting.

obin ;)

#40 llanitedave

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Posted 01 January 2014 - 04:38 PM

There's an opening at the NSA with your name on it.

#41 obin robinson

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Posted 01 January 2014 - 05:18 PM

LOL! The information is all out there and it's UNCLASS. A trip to the book store or local library is all that is necessary. People just need to take the time to read it.

obin ;)

#42 Rick Woods

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Posted 01 January 2014 - 07:50 PM

What book would they be looking for?

#43 David Knisely

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Posted 01 January 2014 - 08:03 PM

The USAF did want a manned station for their own use (MOL) but the program was canceled due to increasing budget concerns and the fact that spy satellite technology had advanced enough to render manned observation unnecessary. As far as I have been able to determine, Skylab did not directly conduct military missions. In fact, in 1974, the astronauts of Skylab actually screwed up by inadvertently photographing Area 51, which NASA had been specifically told not to do years earlier (once back on the ground, those images were immediately classified). About the only thing that I can find that might be remotely linked to military applications was the experimental manned maneuvering unit prototype (ASMU) that was tested inside the Skylab workshop. However, that went on to be used by NASA in the final form of the MMU for civilian applications. Yes, the Space Shuttle had some purely military missions, as did several of the Soviet Almaz space outposts. However, I can find no evidence that Skylab itself was ever deliberately used that way. Clear skies to you.






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