Conference 7.286::space

You'll have to add in another billion to modify the shuttle to do all
the things you want.   As it exists, it won't have the fuel or stores to
stay up there very long - without a *lot* of changes (structural and
system-wide).

I doubt very much you could retrofit an existing shuttle to do this, and
I'm not all to sure the required changes would fit inside the existing
ship without violating structural limits required for takeoff and landing.

- dave

This is actually a pretty interesting idea.  The shuttle-station when it goes
up would not have to carry any "additional" cargo.  That means that they could
afford 65,000 pounds of infrastructure changes.

I suspect that the big issue would be lifetime issues for various components.
For example, even if you have lots of fuel for the fuel cells, are the fuel
cells designed to run for longer than 30 days?  I bet not.  Ditto the
air supply, fridge, etc etc.

Burns

  One problem is that the Shuttle's seem to need a fair amount more maintenance
then was originaly planed. Much of the work can only be done in the OPF. Doing
it with space walks might be tough, especially if it's to be kept in a
condition ready for quick reentry. For example, how often would they have to
check the air pressure in the tires and would they have to go outside to
perform maintenance on the landing gear? How would they replace tiles when
the glue got brittle, etc?

  Also, the Shuttle is pretty heavy. The station will have to burn fuel to
trim it's orbit and the shuttle weight is all that much more to push around.

  A compromise might be to work on extending the time in orbit for a shuttle
to something like a month or two and flying more spacelab types of flights.
Spacelab is something it was designed to do and using something the way it's
designed is usually better than using it in a way it was not designed. 

  George

    Actually, this is not a very good idea.  Livingspace on the shuttle,
    while adequate for 7-14 days (heck, they stayed up in Gemini's for 14
    days) is probably inadequate for prolonged periods.
    
    A much better idea would be the SSI idea.  This was to build a
    compartment, similar to a spacelab of today, but equip it for free
    flying, with some solar pannels, etc.  This would never be able to
    support continuous inhabitation, but would provide a shirt-sleve
    environment for specialists visiting with the shuttle, to restore
    supplies, remove product, etc.  Estimates from SSI in the mid-1980's
    were that this type of station would cost something around $700M and be
    ready within 5 years.  Naturally NASA fought it tooth and nail because
    they were afraid that it would remove the urgency of space station.
    
    Tony

How about this:

	1. Use one (or more) ETs for habitation areas.
	2. Build an access section component (ala Mir) (see below)
	3. Keep launching Spacelabs and connect them up.

	Voila.  Station on the cheap.

The access section is a small area with hatches.  You hook one side up to
an ET, one side up to a Spacelab, and the two other sides to other access
sections.  Looking from the top:

				shuttle
				 |			
		ET ---><-- Access Section --><--- Spacelab
				 |
		ET ---><-- Access Station --><--- Spacelab
				 |
				 .
				 .
				and so on...

Of course, since you have all three dimensions to work with, you could build
that way, but this is simpler.  If the hatch areas are universal, then you
could hook up other things, as their designed - such as an SSI section,
Spacelab Mk II, Hermes, visiting Soviet ship, etc.

    
    I think if you really wanted/needed a fast and cheap space station then
    you should  'rent' the MIR space station. NASA could modify their shuttles
    to dock with the 'xtal' module.  The Soviets need grain, etc.  We could in
    return get the use of MIR, plus we could even charge the Soviets to return
    their space built material to earth.  
    
    The Soviets have a space station and are trying to find money/payload 
    to justify their building of a shuttle.  THe US on the other hand has 
    a shuttle and no space station.  Only one small problem,, yup politics.
    
    
    john
    

I think the problem with using an ET as a space station or anything else is
going to be the fact that it was designed as a tank, not a space station.  There
will be major work involved, either on the ground in redesigning it to work
both as a tank and a station, or in space in constructing a station inside
it.  It's only advantage is that it goes into orbit for almost-free as a
byproduct of any shuttle launch.

That was what I liked about .0's idea:  it uses the ET as a tank, and uses
something that was designed for astronauts to live in as a habitation module.

Burns

    There are other uses too. Storage, Hydroponics (make it into a big
    "salad machine"), raw material... The big step is getting them up there
    and then herding them into orbit together so they can be used. The
    drawback is that they're designed to reenter and burn up so the vacuum
    integrity and lifetime probably isn't what you're hoping for. I'm not
    convinced there is any value in this type of space "fix it upper"
    habitat.
    
    As to parking Spacelab semi-permanently, that's one of the proposals
    for Freedom. A collection of modules delivered by shuttle. Trouble is
    we only have one Spacelab currently. Funding for Freedom would build
    other modules that would link together very similarly to Mir with a
    central backbone and power "grid" (panels). The current design is
    trying to make it an integrated "station" more than a space based
    trailer park.

    Acording to note 282.119, Space Station Freedom costs about 18.5 Billion
    to develop and build. The rest of the cost  (128.9) is for launching it,
    operating it, and resuplying it by shuttle for the next 40 years, that
    is 3.2 Billion a year. (Included are 4 shuttles a year or 1.36 Billion)
    
    The Space Station Freedom total life cycle cost is 147.4 Billion
    
    				...
    
    Now my proposed Shuttle Station, costs at most 4 Billion to develop, 
    build, and launch. Operating it and resuplying it for the next 40 years
    to cost around 62 Billion, or 1.55 Billion a year. (Including 2 shuttles
    a year or .68 Billion)
    
    For a grand total of 66 Billion (45% of Freedom)
    
    With the Great bonus that the Shuttle Station would expand by 80 tanks
    transformed in living/working quarters  and  about 12 retired shuttles
    at the end of 40 years.
    
    Gil
    
    
    
    This is how I see the configuration:
    
    
    		      |||||||||
    			  \	    __    --    --
    		        |||||||||  /  \  /  \  /  \
    			    \	   |  |  |  |  |  |
    		    |\	     \	   |T |++|T |++|T |++
    	           -| \-------\-_ /|A |  |A |  |A |
    		   SHUTTLE|)>  o )-|N |  |N |  |N |
    		   -| /--+------~ \|K |  |K |  |K |
    		    |/   +	   |  |  |  |  |  |
    		         ++++++++++|  |++|  |++|  |++
    			 +         |  |  |  |  |  |
    		   ______+_        ----  ----  ----
    		   | SL	  |
    		   ~~~~~~~~
    
    The tunnels (++), in addition to providing air locks and windows, are
    connected to the power, air, water, etc systems so that they can provide
    life support to the tanks they are connected to. 
    
    Spacelab (SL) 
    Solar Arrays (||||)
    

  I think you will find that the shell of the station is not really a large
percentage of the cost. It starts getting expensive when you start to add
the life support, electronics, power supply, support equipment for experiments,
etc. True some of this would come with the shuttle, but none would come with
the tank. In fact, the tank might be more expensive since it would have to
be completely rebuilt in space where as under the current configuration the
modules can be assembled on the ground.

  And that's only the initial cost. As it was pointed out, maintenance of
all these things adds even more to the cost.

  With the Shuttle/Station system you get a small life support area and power
supply but that's about it. For maintenance, it's probably more expensive than
the new design. The Tank gives you a shell that would require a lot of orbital
man hours to convert into a space station. 

  I doubt that you would save much. I think the best method would be to
use the Sky_Lab/Soviet system of building systems designed to be launched
and deployed with the only outside work being to fix problems. Maximize
the work done on the ground and minimize the work required in space.

  George

    Well, maybe we could design an access tunnel module that is built to
    fit the curvature of the tank. Pre-built, on earth, with a flange that
    has holes predrilled. It has a premade gasket to make a good seal with
    the tank wall. In space, you have to:
    
    1) cut a hole of prescribed diaeter in the tank (with a torch), and
    
    2) site the access module, drill holes, run a mess of bolts through it.
    
    
    	As to tank integrity, if it can hold tons of cryogenic fuel without
    leaking through the walls, I imagine it could hold an atmosphere of
    air. Aren't the insides of the tank a series of ring ribs, and a
    dividing bulkhead? I think of the tanks as merely places to strap
    things on the interior.
    
     But, whether we build a tank farm or FREEDOM, no one has described to
    me just what this thing will do, why we should build it, and how it is
    a step in the process - or what that process might be.
    
     I'm all for a manned space program. But only if there is a goal. I see
    it without a goal other than "build something".
    
    Gregg

    
    	This whole idea reminds me too much of the original Skylab
    proposal. Originally a Saturn V would launch into orbit its third stage
    along with a whole mess of equipment to outfit the empty stage to turn
    it into a space station. It was thought that since it was meant to hold
    cryogenic propellants that it would make a nice neat pressurised space
    station. It turned out to be FAR too complicated and expensive to
    outfit the empty third stage in orbit and it was a real bitch trying to
    set it up on the ground. The lesson here is just because a structure
    makes a good propellant tank, it won't necessarily be easy to convert
    into a space station.
    	What I've advocated for a LOOOOOOOOOOOOOOONG time is build a
    simple, modularized Skylab-class space station on the ground and launch it
    as one piece on a Shuttle derived HLV. And when I say "modularized", I 
    mean a modualrized interior where various subsystems, equipment, and
    experiments can be easily changed out with new and/or improved modules
    (basicly so that the station can be gradually upgraded in a way that
    makes use of experience with previous syubsystems). There should also
    be provisions to dock Spacelab-like modules to this station to provide
    specialized laboratory space. Now that would be a useful space station
    that could grow (and if only simple proven systems are used to begin
    with, it would cut down on development costs also).
    	Well, that's just my two cents worth.
    
    				Drew
    

    Re .12
    
    The idea of a tank farm station, its not of launching normal tanks
    and then converting them in orbit with lots of labor and add-ons.
    
    Its to design and build tanks with a double design, the primary
    function to be the current one, and the secondary function to be a
    living/working station module. They would be a bit heavier then normal 
    tanks (say 500 Kgs), but that would still mean a net gain of 33.5 tons,
    since otherwise the hole 34 ton tank will be wasted.
    
    Since the tanks compete one to one with suttle payload, they are 
    designed to be as light as possible. But if you don't mind making them 
    a bit heavier, you could build in some extra plumbing and access doors, 
    without sacreficing safety. The inter-tank modules would be launched
    as regular cargo. 
    
    The only orbit work, would be to connect the inter-tank modules and the
    tanks to each other and to the core station. As a matter fact this usage 
    of the tanks could be done no matter what king of core station is 
    implemented.
    
    Gil

    Gil is right. No sweat to sacrifice a bit of payload a few flights, to
    get a ready-to-go tank up in orbit.
    
    Gregg

I don't think that the problem is sacrificing payload weight.  It is designing
a habitable space which can still work as a tank for cryogenic liquids.

For example:  You put in bunks and lab benches and stuff.  Is there still enough
volume to hold the required propellents?  You cut a hatch.  Will it leak H2 even
if it won't leak "air"?  What about all the slosh baffles and stuff that are in
the tank now?  If you make the tank skin strong enough to hold all the extra
stuff attached to it, have you exceeded the 65k pounds that the shuttle has
available.

I'm not saying it is impossible.  I'm saying that you can't dismiss this part
as being easy and cheap.

Burns

  Once again, this idea would be great if the major cost were the shell
of the space station. I doubt, however, that the shell is the major cost.
The thing that makes this expensive is what goes inside and the work required
to get it all designed, built, and running.

  I really don't see where tanks address much more than a couple percent of
the cost of getting the station up and running.

  George

    Burns,
    
     I don't know what other people are advocating, but I never suggested
    mounting anything inside the tank before liftoff. Some attachpoints
    on the internal structure might not be too bad, though. 
    
    Gregg

    There still seems to be a problem with the physical effects of long
    term weightlessness.....
    
     I guess we have given up on the notion of a spinning space
    station (i.e. the wheel in space)...Do any of you think it ought to be
    resurrected.
    
    Gregg

    Re .-1
    
    Space Stations with (Spinning Gravity) will come later on, right now
    the hole point is to study the effects of zero-G. Both in biology and
    materials processing.
    
    Gil