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liglats
2002-Dec-19, 10:33 PM
I hears a few years ago that someone had worked out that it would be possible to continue the flight of the external tank of the shuttle so it actually reaches orbit. It was then suggested that these could be clustered together for use as space station modules.

Has anyone else heard of this, has NASA ever considered it, and how much extra kick would it need to get one into orbit? Could you do it with another SRB, or would it totally defeat the whole purpose by needing another external tank to get the first one up there?

John Kierein
2002-Dec-19, 11:43 PM
I did some work with "External Tank Corporation" which was a spinoff of the National Center for Atmospheric Research. They negotiated with NASA to try to get the rights to use of the ET. On some mission profiles the ET is carried almost to orbit and re-enters over Hawaii splashing down east of there. There are some superb spectacular videos of these re-entries taken from Maui by the Air Force. If the shuttle carried just a little smaller payload it could easily take an ET to orbit. There were many wild schemes to use the ET, but they conflicted with plans to build the ISS. I tried to do smaller steps first. ET Corp got a pattent on a concept I came up with to replace the door to the area between the hydrogen and oxygen tanks with a new door/pallet that could carry experiments to near orbit. We had a way to eject small spacecraft with a small kick stage to get payloads to orbit cheaply by piggybacking on the flight. Owen Gariott, a Skylab astronaut, who was working at Teledyne Brown in Huntsville, came up with an inexpensive scheme to fill the very large volume between the oxygen and hydrogen tanks with equipment such as living quarters, breathing O2, etc. Eventually they could inhabit the large tanks themselves in a scheme reminiscent of the "wet workshop" early Skylab designs. NASA in Huntsville wanted to use the ET as an unmanned gamma ray observatory and some of us wanted to put synthetic aperture radar panels on the ET and do a radarsat. There is a very strong truss between the LOX and Hydrogen tanks that carry the SRMs load. It's a natural place to attach solar panels. Lots of people wanted to do this, including the Martin Marietta folks at Michoud where they build the tanks. This was all about 10 to 12 years ago. But NASA Houston won out and NASA instead is spending all our money on the ISS; to my mind a terrible waste. Just think what wonderful science we could be doing with all those wasted billions.

Some people were still carrying the torch to make a farm of ETs as late as just a few months ago. But it's just not politically correct at NASA while they are doing the ISS.

(We almost got an ET on display at the Biosphere in Oracle AZ to show how we could use grow lights to grow food in orbit inside an ET, but ET Corp got cancelled before we could pull it off.)

<font size=-1>[ This Message was edited by: John Kierein on 2002-12-19 18:46 ]</font>

<font size=-1>[ This Message was edited by: John Kierein on 2002-12-19 18:51 ]</font>

daver
2002-Dec-19, 11:52 PM
On 2002-12-19 17:33, liglats wrote:
I hears a few years ago that someone had worked out that it would be possible to continue the flight of the external tank of the shuttle so it actually reaches orbit. It was then suggested that these could be clustered together for use as space station modules.

Has anyone else heard of this, has NASA ever considered it, and how much extra kick would it need to get one into orbit? Could you do it with another SRB, or would it totally defeat the whole purpose by needing another external tank to get the first one up there?

It was considered during the early days of the program. At that time the shuttle was deliberately taking a different route to orbit, in order to make sure that the external tank dropped somewhere where it wouldn't hurt anyone. That route was actually costing them some energy--it wouldn't have been that much more expensive to just take the tank all the way to orbit.

Now they've determined that the tank will burn up on reentry, and they're a bit more cavalier about where they drop it. So now it would cost them a fair amount of energy to take the tank into orbit (no more than it would have then, but they've gotten used to having the extra energy).

Anyway, the idea is feasible, but there are problems.

1. The tank is very light (low mass/surface area). It wouldn't be put in a very high orbit, and the orbit would decay fairly rapidly.

2. The external insulation on the tank isn't stable in vacuum. It'd bubble off, producing scads of (short-lived) junk in orbit.

3. It's hard to match orbits. Not impossible--the shuttle does it with the space station, and that's a much harder target. But it's reasonably difficult. And you don't want to do much (if any) maneuvering with the tank still attached.

4. It's not clear how useful the tanks would be. They don't have airlocks or docking ports and aren't all that well suited for a station. It might be possible to do something like the initial "wet" skylab proposal--build a special-purpose tank (one with special insulation, an airlock, some grid decking, windows, whatever), fill it with liquid H2 and launch it. But this introduces a big boatload of problems (different weight distribution, making all that extra equipment compatible with the liquid H2, what have you). I don't think it would be quick or easy or cheap.

Anyway, if what you want is a comparatively low-priced space station, Lawrence Livermore's inflatable space station looks a lot more feasible to me.

Oops, I just read the previous post. I'm an interested amateur, he's a professional. His ideas on what you can do and how much it would cost are much better informed than mine.

<font size=-1>[ This Message was edited by: daver on 2002-12-19 19:05 ]</font>

Colt
2002-Dec-20, 03:27 AM
Does anyone know where I might be able to find a video or images of the tank re-entry and splashdown near Maui? That would be very cool to see. /phpBB/images/smiles/icon_smile.gif

I personally think that a cheap spacestation could be constructed out of the spent ETs. I am certain that assembling them in orbit and refurbishing them from there, bringing up the extra pieces and all, would be far cheaper than the money-sucking monstrosity that the ISS has turned into ( /phpBB/images/smiles/icon_frown.gif ). And what has it accomplished? A few modules stuck together with some solar arrays, it looks more like Mir with a new coat of paint than anything better.

Whether the tanks would be stacked in a more average style or put into a spoked system for artificial gravity, it would still be cheaper.

Here is something on Astronautix with some concepts: http://www.astronautix.com/craft/stsation.htm

Not sure what else to say, perhaps someone who is more poetic could describe it. -Colt

Edit: Just pondered something. Instead of carrrying all of the deadweight of the shuttle on the back of tank, why don't they just build a station that launches like the shuttle does then cannabalizes (or carries extra parts to outfit) the ET? The main launch engines of the station could stay as the main engines. Think of it as a shuttle without wings and all of the other extra stuff it needs to land. -Colt
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<font size=-1>[ This Message was edited by: Colt on 2065-12-19 22:28 ]</font>


<font size=-1>[ This Message was edited by: Colt on 2002-12-19 22:39 ]</font>

John Kierein
2002-Dec-20, 02:24 PM
I had a copy for a while. It's quite spectacular because the the tanks heat up and overpressure and blow up one after the other. I'll look to see if I can find it. Maybe there's one on the web somewhere.

Glom
2002-Dec-20, 05:49 PM
I believe that for the STS 1 and 2, the ET was coated in a layer of latex insulation. It was junked because it was deemed unnecessary for the task, but with it, the ET might be able to survive in space.

The idea of using tanks and boosters as space stations is age old. Skylab was an S-IVB stage. The original plan called for a launch of a Saturn IB that would place its second stage (S-IVB) in orbit (wet). The tanks could be removed and subsequent flights could deck it out as a space station. However, with the extremely premature end of the lunar program, NASA had some Saturn V rockets left over. The S-IVB was the third of the Saturn V. With the much greater power of the S-IC and the S-II, the S-IVB could be launched into orbit, ready equipped (dry).

Von Braun's integrated space program called for many dry S-IVB stages to be launched to assemble a 100 man space station.

Colt
2002-Dec-21, 01:06 AM
I think I need a better description of the aboved mentioned idea.

It would be more like the first stage of a Saturn-IV built into a station with decks and everything, or an add-on module, strapped onto the back of the ET and the SRBs. -Colt

Kizarvexis
2002-Dec-22, 01:41 AM
Space Island Group may have what you are looking for with an External Tank space station.

http://www.spaceislandgroup.com/vehicles-systems.html

Their plans use a re-designed shuttle though.

Kizarvexis

ToSeek
2002-Dec-22, 02:59 PM
On 2002-12-20 12:49, Glom wrote:
The original plan called for a launch of a Saturn IB that would place its second stage (S-IVB) in orbit (wet). The tanks could be removed and subsequent flights could deck it out as a space station. However, with the extremely premature end of the lunar program, NASA had some Saturn V rockets left over. The S-IVB was the third of the Saturn V. With the much greater power of the S-IC and the S-II, the S-IVB could be launched into orbit, ready equipped (dry).


I could be wrong, but my recollection is that Apollo 20 was deliberately cancelled in order to provide for the "dry" option you describe.

Glom
2002-Dec-22, 05:51 PM
You may be right. But I thought that 18, 19 and 20 were cancelled before Apollo 11 together and SA-515 was assigned to Skylab 1 because of the cancellation rather than the other way round.

Colt
2002-Dec-23, 03:11 AM
Cool, they have a thing sort of like I was thinking of: http://www.spaceislandgroup.com/dual-launch.html The white thing riding on the ET. -Colt

calliarcale
2002-Dec-23, 04:39 PM
I think the *best* use of the ETs would be to make the flyback reusable tanks. /phpBB/images/smiles/icon_wink.gif It's the only major component of the Shuttle that does not get reused.

But I suspect it would be even harder to get an ET to survive reentry than it would be to get it to survive the conditions of low earth orbit. In the end, I don't think it'll be practical in the near future to transform spent ETs into space station components. Space Island Group has some cool ideas, but there are major technologies involved that are yet to be developed. Outfitting them on orbit will be difficult, and will mean shipping a great deal of equipment up. To turn one ET into a small spacestation might require three shuttle flights; in that case, is it really practical? It might be; recycling one of the three ETs isn't bad, considering we're currently not recycling any. But I'm still not convinced there's enough value to be gained by it to accept the various limitations imposed by such a design.

Besides, I'm hopeful that the next generation space shuttle will come into being within the next decade. That's about how long it would likely take to develop the neccesary equipment and techniques for building an ET station, in my opinion, so by the time we're ready to build and ET station (assuming we start the R&D today), we might not have anymore ETs to work with. And although an ET station would be cool, frankly I'd prefer a new, truly reusable shuttle.

ToSeek
2002-Dec-23, 05:06 PM
On 2002-12-22 12:51, Glom wrote:
You may be right. But I thought that 18, 19 and 20 were cancelled before Apollo 11 together and SA-515 was assigned to Skylab 1 because of the cancellation rather than the other way round.


Apollo 20 was cancelled by itself in January 1970, which made me think that it was deliberately cancelled to support Skylab. (Actually, after further research, my impression now is that the dry workshop decision was made early on, then Apollo 20 was cancelled when it was decided there wasn't the budget to build any more Saturn Vs.) Apollos 18 and 19 (actually 15 and 19 based on the mission plans) were cancelled in September 1970.

liglats
2002-Dec-23, 08:39 PM
Thanks folks - glad to hear for once that I'm not imagining things. But upset that i can't copyright my cunning plan to build a spacestation out of shuttle leftovers. Looks like I'll have to try another means of world domination... /phpBB/images/smiles/icon_wink.gif

calliarcale
2002-Dec-23, 08:55 PM
According to Encyclopedia Astronautica, the Skylab program was born way back in 1965. The idea of outfitting a spent second stage from a Saturn 1B (the "wet" OWS) was officially abandoned in July of 1969 -- while the Apollo 11 crew were on their way to the Moon. The idea was initially considerably more ambitious than what actually flew; I think the final design (based on S-IVB, launched "dry" and already modified) was becoming settled by early 1970. The OWS was actually delivered to KSC on Sept 23, 1972, and was launched on the last Saturn V ever to fly on May 14, 1973. A successor, Skylab B, was built and delivered (I don't have a date for Skylab B's delivery) but the program was cancelled before it could fly. NASA was ordered to mothball it and all unneeded Apollo and Saturn equipment in August of 1973 (leaving out only equipment already slated to fly). In December, 1976, most of the equipment was given to museums, including Skylab B. It now rests in the Smithsonian National Air & Space Museum, where visitors can stroll through it and see what it would be like to live on a space station. It will never fly.

Valiant Dancer
2002-Dec-23, 09:01 PM
On 2002-12-23 11:39, calliarcale wrote:
I think the *best* use of the ETs would be to make the flyback reusable tanks. /phpBB/images/smiles/icon_wink.gif It's the only major component of the Shuttle that does not get reused.

But I suspect it would be even harder to get an ET to survive reentry than it would be to get it to survive the conditions of low earth orbit. In the end, I don't think it'll be practical in the near future to transform spent ETs into space station components. Space Island Group has some cool ideas, but there are major technologies involved that are yet to be developed. Outfitting them on orbit will be difficult, and will mean shipping a great deal of equipment up. To turn one ET into a small spacestation might require three shuttle flights; in that case, is it really practical? It might be; recycling one of the three ETs isn't bad, considering we're currently not recycling any. But I'm still not convinced there's enough value to be gained by it to accept the various limitations imposed by such a design.

Besides, I'm hopeful that the next generation space shuttle will come into being within the next decade. That's about how long it would likely take to develop the neccesary equipment and techniques for building an ET station, in my opinion, so by the time we're ready to build and ET station (assuming we start the R&D today), we might not have anymore ETs to work with. And although an ET station would be cool, frankly I'd prefer a new, truly reusable shuttle.


My brother in 1982 or 1983 suggested the very same thin to NASA and included drawings and design diagrams. A very nice person (my brother was only 13 or 14 at the time) wrote him back and sent him a comprehensive package of materials about the space program and a letter thanking him for his suggestion but that the amount of weight added to the tank plus retreival equipment would seriously impact the amount of payload they would be able to put into orbit.

Kizarvexis
2002-Dec-25, 12:01 AM
On 2002-12-23 15:39, liglats wrote:
Thanks folks - glad to hear for once that I'm not imagining things. But upset that i can't copyright my cunning plan to build a spacestation out of shuttle leftovers. Looks like I'll have to try another means of world domination... /phpBB/images/smiles/icon_wink.gif


So, what are you going to do tomorrow night?

Kizarvexis
Obscure cartoon reference. /phpBB/images/smiles/icon_smile.gif

Kaptain K
2002-Dec-25, 10:24 AM
So, what are you going to do tomorrow night?
Same thing I do every night!

Not that obscure.