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#176 2005-07-29 14:39:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,330

Re: STS-114 Mission Coverage and Discussion

They remove the painted white color from the tanks to increase the payload capability at launch, thou I do not recall how much the weigh difference was.

Saw simular reports of strikes to orbiter of softball size in addition to the near miss of the much large piece.

How did the Russians deal with this problem on the Burran systems ET. Did they have the same problem or was there design better?

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#177 2005-07-29 14:49:13

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

Carbon fiber laminate would be difficult to do in a short timeframe properly I bet and kind of overkill... it doesn't need to be anything that complex, probobly some Kevlar netting with holes 2-3in square would probobly do the job, or a thick layer of rubber paint that could resist some deformation from internal pressure. When carbon composites break, they also tend to break in a big way.

As far as I know the Energia tank had foam insulation too (same white color as Shuttle, no obvious ice) but we really might not ever know, since Russia only launched Bruan once or twice and Energia a few times, probobly none of them with high-resolution cameras ringing the tank.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#178 2005-07-29 16:08:04

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,863
Website

Re: STS-114 Mission Coverage and Discussion

http://www.energia.ru/english/energia/l … .html]This web page states one of the problems resolved was "non-destructive quality control of adhering thermal insulation and heat protective coatings." That implies that had some sort of thermal insulation, but it doesn't say what.

Energia was launched twice, both successful. The first launched Skif-DM, a full-size mock-up of the Polyus combat satellite. Launch was successful but the satellite's on-board thrusters failed to circularize orbit. The second launch was the Buran orbiter, unmanned on autopilot. It was fully successful and landed perfectly.

I discovered the tanks for Energia are made in the "Progress" factory in the city now called Samara. I found the factory's web site, but it doesn't have any information about Energia.

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#179 2005-07-29 16:30:40

srmeaney
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Registered: 2005-03-18
Posts: 976

Re: STS-114 Mission Coverage and Discussion

surely a large constricting "sock' over the fueltank was all they realy needed. There was little need for some great laminating carbonfibre. Such a thing only needs to survive exiting the atmosphere once it it does its job.

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#180 2005-07-29 16:32:27

BWhite
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From: Chicago, Illinois
Registered: 2004-06-16
Posts: 2,635

Re: STS-114 Mission Coverage and Discussion

Michael Griffin to appear on "Meet the Press" on Sunday.

Pablum or candor?

It might be interesting, or not.   wink


Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]

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#181 2005-07-29 16:47:41

srmeaney
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Re: STS-114 Mission Coverage and Discussion

Torch & Pitchfork time.

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#182 2005-07-29 19:24:52

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

Could we contain foam using the same spray-on film as Audi now uses for car bodies? GCNRevenger, you're a polymer scientist; what's your professional opinion?
Link: http://www.audiworld.com/news/02/spray/ … l]Spray-on Protection for Vehicles in Transit

This is probobly on track to the right idea, but using this particular material won't likly do the job, and definatly wouldn't be ideal.

The material I am thinking about would aim to maximize break strength, not flexibility nor sheer tensile strength, but rather be something that would give a little bit if the foam under it were to crack or "blow" out from underlying boiling gasses.

I do have something in mind though... I remember reading from some time back about a thick elastomer paint developed for airliners or gov't buildings which was - get this - explosive resistant. Test walls were built (from concrete I think, I forget) and the USAF "donated" 400lbs of explosives (and demo experts) to test it, and the wall survived being 12ft from the bomb or so.

Something like that, except perhaps a little bit "stretchier" and a thinner coat, over the orbiter side of the tank. Punch holes in it at regular intervals to vent off gasses... That would be the first thing I would investigate.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#183 2005-07-29 19:46:26

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

If you are in the mood to call somebody Robert...

http://www.specialty-products.com]www.specialty-products.com

They have a material nicknamed "Dragonshield" tested in conjunction with the USMC for use as (somewhat) light-weight secondary armor for Humvees/trucks to counter explosives and self-sealing tanker trucks.

They also sell a number of other products with a variety of properties... they could probobly come up with something that would do the job by itself or in conjunction as a composite/laminate.

Edit: http://www.specialty-products.com/pdf%2 … agonshield itself

As far as WHICH material would be ideal, you'd have to ask NASA what it has to stand up against, and a chemical engineer rather then a chemist which material would be best. The stuff looks easy to apply too.

Edit edit: For their reactive hardening products, keep in mind that the temperature that the feedstock material melts at will be much lower then that for the applied, set coating. Density is about 1.02g/cc before hardening, probobly similar or a little less afterwards.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#184 2005-07-30 02:08:23

Yang Liwei Rocket
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Registered: 2004-03-03
Posts: 993

Re: STS-114 Mission Coverage and Discussion

GCNRevenger I've heard problems before with that stuff, I'm not to sure about the exact product, Chinese and Russians had plans for stuff like it but I read that some of those explosive resistant materials start to lose their inegrity once they are in deep freeze, they crumble from the low temp. Maybe that's not the case here, but there will always be the question of how that stuff handles the temperatures of cold space.


'first steps are not for cheap, think about it...
did China build a great Wall in a day ?' ( Y L R newmars forum member )

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#185 2005-07-30 09:08:47

GCNRevenger
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Re: STS-114 Mission Coverage and Discussion

Of course it would lose properties when it gets too cold, but would that be a problem here? The insulation holds in the cold so well from the fuel that little/no condensation forms on the exterior of the tank, and acent only lasts a few minutes, and infact may get hot from the supersonic air friction.

If it is a problem, then the "plan B" would be to wrap the pertinant portions of the tank with a mesh or netting made from a material that can withstand the temperatures applied while the tank's outtermost foam is setting such that it is flush with the surface. Kevlar or titanium wire or something.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#186 2005-07-30 10:39:46

Commodore
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From: Upstate NY, USA
Registered: 2004-07-25
Posts: 1,021

Re: STS-114 Mission Coverage and Discussion

Of course it would lose properties when it gets too cold, but would that be a problem here? The insulation holds in the cold so well from the fuel that little/no condensation forms on the exterior of the tank, and accent only lasts a few minutes, and in fact may get hot from the supersonic air friction.

I could be wrong, but weren't we dropping Ice from Shuttles as well? Granted that might not be from the surface of the tank, but you've still got very cold surfaces in close vicinity that will need to be considered.

If it is a problem, then the "plan B" would be to wrap the pertinent portions of the tank with a mesh or netting made from a material that can withstand the temperatures applied while the tank's outermost foam is setting such that it is flush with the surface. Kevlar or titanium wire or something.

With the stress of launch that might just break the foam into pieces small enough to fit through the mesh, which depending on the size of the holes in the mesh, might mean just fine particulate, or pieces otherwise too small to cause any damage. But you got to be careful in how much weight you add to the tank, lest you some how alter the dynamics of the STS. This mesh after all, is payload.

I think the solution is not to spend another dime on the ET. After all, the Shuttle is going to be retired, and this won't be an issue with inline SDV, and even with a Shuttle-C, there a lot of things you can to the payload faring that you can't do with the Shuttle.

The solution is to look at the Shuttle itself, along with alternative launch methods, to limit the number of orbiter launches as much as possible. If we do it right, we can do it with 1, and even then not be concerned with reentry.


"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane

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#187 2005-07-30 13:06:39

GCNRevenger
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From: Earth
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Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

I think you are wrong, there isn't anything in the way of ice that I know of, and probobly not much/any condensation either.

The idea is to protect the orbiter from foam debries big enough to hurt it, right? If a dangerously large piece of foam cracks or is blown off by underlying pressure, then the mesh would keep it on the tank or break it into smaller peices. Either way, the objective would be accomplished.

Frankly, the payload problem is something that KSC will just have to deal with. Fixing the external tank right is a low-cost solution: rip off the manually applied foam, add more heaters like the bipod ones, and apply a coating/net to the Orbiter side of the tank. Problem solved.

"Fixing" the Space Shuttle cannot be the solution, it is too complex and too fragile, the RCC pannels cannot be improved because no superior material exsists, and replacing the pannels would be extremely expensive. The glass tiles too, they should be stronger as well, but no superior tile materials are available. And what if a large piece of foam falls off and hits the cockpit windows? You get the idea. The Shuttle cannot be improved without great difficulty if at all, and fixing the tank should be a much easier task.

I would like to reiterate though this point: when I said earlier that flying Shuttle with the foam problem was an unacceptable risk, I meant that quite literally. NASA should never, ever fly Shuttle again, not even a single time for any reason reguardless of petty political consequence, until this problem is remedied. Period.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#188 2005-07-30 15:35:22

idiom
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From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: STS-114 Mission Coverage and Discussion

Well now is the time to open the whole can of worms to find out what other technical issues have been swept under the rug. If we can't five them in the next five years then we need to have them clearly identified so the don't plauge the CEV, or even the SDV.

And how come none of the SSME's have ever exploded? I thought they were supposed to be time bombs?!?


Come on to the Future

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#189 2005-07-30 16:58:37

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

The CEV is going to be about as far from the Space Shuttle as you can get, basically a brand new vehicle, there will be no commonality between them other then the SRB, which works okay.

The big SDV will also only share major componets, unless we make the mistake of going the Shuttle-C route. Modified inline main tank, heavier boosters, upper stage with off-the-shelf control hardware, circulization engine (maybe Delta-II/III/IVS derived), and the biggie: a modified low-cost one-shot expendable version of SSME. No hydraulics, RD-0120 style nozzle, etc.

SSMEs have reached an acceptable level of reliability, they have come a long way.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#190 2005-07-30 17:57:46

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,863
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Re: STS-114 Mission Coverage and Discussion

Idiom: SSME a time bomb? Where did you get that? They are reliable engines with the highest specific impulse of any ground launched chemical engine. The only engine with higher Isp is purpose built for the vacuum of space. SSME was the first cryogenic liquid fuel engine to be reusable. The Russians tried to copy it but didn't succeed in getting RD-0120 reusable. They continued at it and the RD-0750 is now reusable, but it's new and never flown. It has been fired in a static test stand, but never flown in space. The OME and RCS engines are also reusable, but they're small and use storable propellant: MMH/N2O4. The SSME is a marvel of engineering.

GCNRevenger: SSME is an integrated engine. If you simplified it to make it cheaper, it probably would loose performance. The RS-68 was designed to be simpler and less expensive; it has a lower specific impluse. An attempt to make SSME cheaper would result in either RS-68 or RD-0120. Hmm, the RD-0120 is expendable. Since it's Russian made I assume it's cheaper; never did get a price.

"mistake of going the Shuttle-C route"? You just had to throw that in. Shuttle-C wouldn't have any tiles so would be immune to foam. All the foam on the tank could fall off and no damage done. I have issues with a segmented solid rocket beside a liquid hydrogen tank, but NASA appears to have that problem licked and SDV does not have to be man rated.

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#191 2005-07-30 19:16:18

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,330

Re: STS-114 Mission Coverage and Discussion

Well this is really ticking me off with regards to incompetance.
NASA Glenn tests didn’t cover Discovery’s problems

Engineers at NASA Glenn Research Center say they did tests on space shuttle Discovery’s external fuel tanks, but could not have predicted the problems that occurred during Tuesday’s launch.

Glenn engineers scrutinized two troublesome areas on the external fuel tank in the months before the launch, one of which would turn out to be the source of Discovery’s foam loss.

However, they examined only airflow patterns and did not judge foam durability on the tank.

We did what we could within the guidelines we were given

Like dah, what did they think they were testing...
Talk about your half done engineering.

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#192 2005-07-30 20:28:01

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,330

Re: STS-114 Mission Coverage and Discussion

For NASA, Misjudgments Led to Latest Shuttle Woes

After the Columbia accident, NASA examined all possible sources of liftoff debris, eventually identifying more than 170. Engineers recognized that they could not eliminate all risk from debris, but they could do a much better job of reducing it.

But this bugs me, same olde Nasa :

Potentially useful tests were not performed. Innovative solutions were not seriously pursued. Tantalizing clues were missed. In the end, the old engineering maxim "If it ain't broke, don't fix it" trumped vague misgivings about a part that had not shed any foam, as far as anyone knew, since 1983.

There was no evidence that the ramp had shed foam since the early 1980's, he said, adding, "We had had very few problems with the PAL ramp and we decided it was safe to fly as is."

Tank process for manual spraying only gets better:

Among other things, it improved the training processes for applying foam by hand. At the Michoud tank assembly plant in Louisiana, an observer monitors every worker spraying foam - "for every sprayer there's a watcher, a second pair of eyes," said June Malone, a NASA spokeswoman.

But the tank that flew with the Discovery last week was made before the new procedures went into effect, and NASA stopped short of requiring that the ramps be redone, said a spokesman, Martin J. Jensen.

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#193 2005-07-30 20:50:26

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,669

Re: STS-114 Mission Coverage and Discussion

No evidence since the early 80's

Double-speak?

either it's "never" or it is since day XYZ... Early 80's ?? First shuttles were launched early 80's.

My guess: they SAW shedding, the first few launches... But fairly early into the STS history they stopped filming launches with multiple cameras (was quite expensive, have an article about it lying somewhere)


BTW... Don't laugh, but can't they launch the shuttle, 'wrapped' with some kind of protective blankets around the leading edges and belly? and shed those blankets once in orbit or near orbit?

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#194 2005-07-30 21:38:30

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

Idiom: SSME a time bomb? Where did you get that? They are reliable engines with the highest specific impulse of any ground launched chemical engine. The only engine with higher Isp is purpose built for the vacuum of space. SSME was the first cryogenic liquid fuel engine to be reusable. The Russians tried to copy it but didn't succeed in getting RD-0120 reusable. They continued at it and the RD-0750 is now reusable, but it's new and never flown. It has been fired in a static test stand, but never flown in space. The OME and RCS engines are also reusable, but they're small and use storable propellant: MMH/N2O4. The SSME is a marvel of engineering.

GCNRevenger: SSME is an integrated engine. If you simplified it to make it cheaper, it probably would loose performance. The RS-68 was designed to be simpler and less expensive; it has a lower specific impluse. An attempt to make SSME cheaper would result in either RS-68 or RD-0120. Hmm, the RD-0120 is expendable. Since it's Russian made I assume it's cheaper; never did get a price.

"mistake of going the Shuttle-C route"? You just had to throw that in. Shuttle-C wouldn't have any tiles so would be immune to foam. All the foam on the tank could fall off and no damage done. I have issues with a segmented solid rocket beside a liquid hydrogen tank, but NASA appears to have that problem licked and SDV does not have to be man rated.

The SSME engine itself has acceptable reliability, but I have misgivings about its antiquated control hardware and the mass/complexity of ancillary systems (eg hydraulics). The big problem with it though is cost, that the thing costs alot to build since it operates under much rougher conditions then any other Hydrogen engine and since its design favors performance over simplicity.

A redesign (edit: or renegotiation to buy in bulk?) to reduce its cost is nessesarry, and with newer technology, manufacturing techniques, and nonreuseable design changes. NASA seems to have passed on the far cheaper per-thrust RS-68 since its performance is markedly lower, and because they get to have an excuse to retain Shuttle Army personell associated with the engine. The Russian RD-0120 does not provide this excuse, nor is in production, and  building it in Russia is unacceptable for political reasons (i.e. Iran nuclear issue and Russia having veto power over NASA like ISS). I wish that NASA would consider using an upgraded version of RS-68, but that doesn't appear to be in the cards.

I mentioned that Shuttle-C would be a mistake in my last post in the context that it would carry over more of the antique ultra-high cost hardware and the multiple design inefficencies from Shuttle, which it would... and for what? To save a dime today? The thing wouldn't be ready until 2009 anyway probobly, and is too small for efficent Moon/Mars missions.
------------------------------------------------------------

NASA has really, really got to fix this problem and soon, the embarrasment over the Michoud/Glenn incompetance is really costing NASA with the public.

http://www.comics.com/editoons/cohen/ar … 8.gif]This cartoon depresses me. Don't look, Cindy.

Some heads need to roll over this... NASA can't afford to leave people like this in charge. The problem that doomed Columbia was not "manually applied foam falling from the ET bipod," the problem that killed those astronauts was that a big chunk of foam fell off the tank. They have really, really got to do the job right, and do it right right now.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#195 2005-07-31 01:05:16

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,863
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Re: STS-114 Mission Coverage and Discussion

The Russian RD-0120 engine not in production? We went over this several times. I'm the one who wrote KBKhA to ask about it. They have 9 engines sitting in inventory, and parts for a few more. Jigs and plans have been retained, although they would need a new CNC machine and probably some more stuff. Most importantly, they're willing to swallow the cost of re-tooling on condition they get a solid order for engines. That means RD-0120 is more "in production" than Lockheed-Martin's triple CCB Atlas V Heavy. Remember Lockheed-Martin never finished development, but claim they could roll one out just 30 months after receiving an order. However, politics of the Iran nuclear reactor prevent buying one. Considering the Atlas V uses an RD-180 engine, what's stopping RD-0120?

As for Shuttle-C, it is optimum to deliver heavy cargo to LEO; more so than Magnum. A pure axial configuration does not have a recoverable engine pod. Placing cargo on top with main engines on the bottom of the tank means you can't put OMS and RCS engines with the main engines, so no recoverable pod. Magnum is dedicated to all expendable operation. That means you can't rendezvous with ISS, can't stabilize cargo while plucking off modules. It also means you can't rendezvous a rocket stage with a pre-launched Mars spacecraft. How do you assemble the big ship for NASA DRM3 without the OMS and RCS engines of a Shuttle-C engine pod?

Lastly, you claim Shuttle-C has a narrow payload fairing. That's true of most artwork for Shuttle-C because it replaces the orbiter with a fairing of the same diameter: 15 feet or about 5 metres. However, this is http://www.astronautix.com/lvs/shuttlez.htm]Shuttle-Z, the bulked-up version. It was designed with an expendable engine pod with 4 SSMEs and no OMS or RCS, but it also has an upper stage. The upper stage has a single SSME and a greater diameter. Robert Zubrin's art work in his book "The Case for Mars" shows a cylindrical side-mount upper stage instead of tapered to the engine pod, but both show 10 metre payload fairing. This version of Shuttle-Z would use a standard ET and Advanced Solid Rocket Motors (ASRMs) instead of the current 4-segment SRBs. The ASRM was cancelled before development was completed, but 5-segment SRBs should provide more thrust. The upper stage and payload fairing could easily be used by Shuttle-C for heavy cargo to LEO.

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#196 2005-07-31 01:28:26

idiom
Member
From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: STS-114 Mission Coverage and Discussion

My bad. I was under the impression that the SSME's were the items that were thought to be highest risk, before Challenger and Columbia.

Placing cargo on top with main engines on the bottom of the tank means you can't put OMS and RCS engines with the main engines, so no recoverable pod.

They have to come down sometime don't they? What would it take to recover the engines under the tank? Something to move the centre of drag to the rear, a shield to fend of melting chunks of tank, chutes and ....?


Come on to the Future

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#197 2005-07-31 02:18:49

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,863
Website

Re: STS-114 Mission Coverage and Discussion

They have to come down sometime don't they? What would it take to recover the engines under the tank? Something to move the centre of drag to the rear, a shield to fend of melting chunks of tank, chutes and ....?

But if you separate OMS and RCS from main engines, they can't come down together. If you want to assemble a large structure like a Mars vehicle that will also require guidance. You don't want two separate atmospheric entry pods: main engines and on-orbit tug. You could just launch cargo into LEO with no attempt to rendezvous, then send a reusable tug from ISS or some other storage location to the cargo, then lift cargo to the correct orbit and dock. That would require not only developing a tug, but refuelling it. The only fuel tanker we have now is a Russian Progress.

So options:
- make everything expendable
- recoverable main engine pod with expendable OMS/RCS tug
- recoverable main engine pod with refuellable on-orbit tug
- integrate main engines with OMS/RCS, which requires attaching cargo to main engines in such a way that main tanks can be jettisoned. That's Shuttle-C.

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#198 2005-07-31 02:59:48

srmeaney
Member
From: 18 tiwi gdns rd, TIWI NT 0810
Registered: 2005-03-18
Posts: 976

Re: STS-114 Mission Coverage and Discussion

I would like to reiterate though this point: when I said earlier that flying Shuttle with the foam problem was an unacceptable risk, I meant that quite literally. NASA should never, ever fly Shuttle again, not even a single time for any reason reguardless of petty political consequence, until this problem is remedied. Period.

Considering the unwillingness of NASA to leave a shuttle in orbit (and re-task it for a space-only mission) if a vehicle is ever unreturnable, I would have to recommend retiring them before they become a problem.

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#199 2005-07-31 07:14:23

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

I would like to reiterate though this point: when I said earlier that flying Shuttle with the foam problem was an unacceptable risk, I meant that quite literally. NASA should never, ever fly Shuttle again, not even a single time for any reason reguardless of petty political consequence, until this problem is remedied. Period.

Considering the unwillingness of NASA to leave a shuttle in orbit (and re-task it for a space-only mission) if a vehicle is ever unreturnable, I would have to recommend retiring them before they become a problem.

It doesn't work that way. Shuttle's power and life support systems are only good for about one month, and neither they nor the maneuvering engines can be refueled on orbit.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#200 2005-07-31 08:20:43

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: STS-114 Mission Coverage and Discussion

The Russian RD-0120 engine not in production? We went over this several times. I'm the one who wrote KBKhA to ask about it. They have 9 engines sitting in inventory, and parts for a few more. Jigs and plans have been retained, although they would need a new CNC machine and probably some more stuff. Most importantly, they're willing to swallow the cost of re-tooling on condition they get a solid order for engines. That means RD-0120 is more "in production" than Lockheed-Martin's triple CCB Atlas V Heavy. Remember Lockheed-Martin never finished development, but claim they could roll one out just 30 months after receiving an order. However, politics of the Iran nuclear reactor prevent buying one. Considering the Atlas V uses an RD-180 engine, what's stopping RD-0120?

As for Shuttle-C, it is optimum to deliver heavy cargo to LEO; more so than Magnum. A pure axial configuration does not have a recoverable engine pod. Placing cargo on top with main engines on the bottom of the tank means you can't put OMS and RCS engines with the main engines, so no recoverable pod. Magnum is dedicated to all expendable operation. That means you can't rendezvous with ISS, can't stabilize cargo while plucking off modules. It also means you can't rendezvous a rocket stage with a pre-launched Mars spacecraft. How do you assemble the big ship for NASA DRM3 without the OMS and RCS engines of a Shuttle-C engine pod?

Lastly, you claim Shuttle-C has a narrow payload fairing. That's true of most artwork for Shuttle-C because it replaces the orbiter with a fairing of the same diameter: 15 feet or about 5 metres. However, this is http://www.astronautix.com/lvs/shuttlez.htm]Shuttle-Z, the bulked-up version. It was designed with an expendable engine pod with 4 SSMEs and no OMS or RCS, but it also has an upper stage. The upper stage has a single SSME and a greater diameter. Robert Zubrin's art work in his book "The Case for Mars" shows a cylindrical side-mount upper stage instead of tapered to the engine pod, but both show 10 metre payload fairing. This version of Shuttle-Z would use a standard ET and Advanced Solid Rocket Motors (ASRMs) instead of the current 4-segment SRBs. The ASRM was cancelled before development was completed, but 5-segment SRBs should provide more thrust. The upper stage and payload fairing could easily be used by Shuttle-C for heavy cargo to LEO.

I am unimpressed and unconvinced by the assertions of this Russian fellow you have contacted, that they could "easily" restore engine production after all these years. I don't buy it... the bennefit to Russia would be a major PR coup that the anti-American media would wet themselves to parade in this, in the most patriotic of non-military activities. Just like Russia announcing last week of all times that they could put Soyuz around the Moon for $100M in the time of NASA's greatest weakness, and their grandstanding demanding that the US pay for Soyuz rides despite Russia defraduing us over ISS modules. And yes, then you have the Iran crisis which - by any measure of their new "president" - is only going to get worse.

Oh yes, and before I forget to mention, that RD-180 is acceptable to the USAF because it could be produced here if we had to, a capability which I am certain took alot of money, and each domestic engine would be far more expensive. Hence a similar setup with the RD-0120 would not save much money anyway, because of the expense of gaining and maintaining the ability to copy the engine. Oh and plus the modifications to it to make it compatible with American hardware. Just how reliable is the 0120 versus SSME anyway?

RS-68R would be ideal, but barring that a simplified SSME is a known and much better solution overall then buying the dead phantom RD-0120 from political rivals. Period.
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"Shuttle-C, it is optimum to deliver heavy cargo to LEO; more so than Magnum"

Please, nonsense... Do I have to enumerate everything over again?

Shuttle-C pod cons:
-Reduces total payload by 10-15MT+
-Engine pod likly to cost >$1Bn to develop
-Engine pod saves little money vs. development
-Engine pod reliability much less per flight
-Engine pod loss risks subsequent flights
-Engine pod must have multiple backups & spares ($$$)
-Engine pod reprocessing prevents surge launch (Mars missions)
-Engine pod retains Shuttle Army personell (bad!)
-Engine pod increases overall mission complexity
-Engine pod uses outdated Shuttle harware

Are you kidding about Shuttle-Z? I mean, come on, just look at it! The thing even looks crazy, and thats because it is... There isn't even any information about it on Astronautix of all places! One mention it does have however...: Shuttle-Z was concieved as part of NASA's 90-day study, which nobody can honestly conclude was a serious plan. In fact, I think that history shows with fair clarity that NASA intentionally came up with a bogus plan to scuttle any talk of Mars missions, because that would disrupt the Shuttle/SS Freedom status quo. I don't believe that Shuttle-Z is a credible concept, its a red herring intended to look like a bad idea on purpose.

I shudder to think about the payload losses due to drag and even more thrust wasted to keep from tipping over sideways... No tug is going to happen either, you can bet on that. If the robot plan to fix Hubble cost $2-3Bn, then such a tug would cost $1-2Bn at least... and we have no means of refueling.

"Magnum is dedicated to all expendable operation. That means you can't rendezvous with ISS, can't stabilize cargo while plucking off modules."

Thats correct, yes. This is actually a positive, favorable, dare I say a GOOD thing: nobody thinks that any SDV heavy lifter can be built rapidly, with development times generally quoted as 3-4, perhaps five years. As this will not be soon enough to employ Shuttle as a tug to ferry ISS payloads to the station. DO NOT compromise SDV for the ISS.

This is a big deal, because without Shuttle then the Shuttle-C cargo pod must now be "smart" enough, maneuverable enough, and have power supplies to act as its own tug vehicle. This means radar/lidar systems, fuel cells for two weeks, autonomous control systems (for dock abort), and nose-mounted RCS thrusters. All these things will radically increase Shuttle-C's development cost, decrease its payload by still more tonnes and tonnes, plus delay its development even longer such that the ISS gets even older before it is useful.

Just how far do we have to bend over backwards and kick the legs out from under VSE to appease the ISS cheerleaders? The station, which even when it is "finished," will produce little useful science and have a quite short remaining lifespan. What will seperate VSE from becomming an Apollo-style flags/footprints affair, or Mars missions between making a real base or just piddling around is payload. That extra 20-30MT and 2-3m diameter to orbit for a rocket that costs about the same makes all the difference!

"It also means you can't rendezvous a rocket stage with a pre-launched Mars spacecraft. How do you assemble the big ship for NASA DRM3 without the OMS and RCS engines of a Shuttle-C engine pod?"

Now Robert, if you had actually botherd to read the DRM-III plan carefully, you would have noted that the TMI rocket stage performs a disposal maneuver after firing, and that the stage itself has RCS thrusters. Throw in Boeing's integrated fuel cell power bus and a little bottle of LOX, and it could stabilize its attitude just fine by itself. And the manned vehicles will all have maneuvering ability themselves... SO, your statement is nonsense.

...Expendability, expendability has proven itself to be the correct course of action, reuseability - especially with using actual Shuttle hardware - has been shown time and time again to be a miserable failure at saving money or time, key to the continued exsistance of NASA. In fact, thanks to expendability being the standard and not reuseability, Magnum will cost even less to develop since affordable proven hardware can be readily adapted from other rockets (Delta-III/IVS etc).

The engine pod on the other hand uses hardware that has been proven to be too expensive to maintain, forces NASA to retain Shuttle Army personell that it must cast off to survive, and the extra cost must be paid up front now when NASA needs the money the most. And as a second fatal blow to this terrible idea, guts the performance from SDV by seriously hurting its payload mass and limiting diameter thanks to its Shuttle heritige.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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