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Rockets vs. Airbreathers

Posted by: spacecowboy - Thu May 26, 2005 12:44 pm
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Rockets vs. Airbreathers 
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Space Station Commander
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Post    Posted on: Fri Jul 01, 2005 2:50 pm
"Sure, I think we need to put our resources into what works, but we need innovation, too. I hope like hell that my grandkids won't live in a world where the only way to orbit is in a pressure-fed iron-hulled behemoth. And the notion of "growing crystalline airframes in zero-G orbital factories" seems a lot more far-fetched to this engineer than does the notion of conformal composite LH2 tanks."

So much for innovation. Zero-g factories are going to be your biggest reason to industrialize space--not just a handfull of trips for a handfull of tourists richer than Croesus. Pressure-feds do seem to be the standard. When scaled up big enough--maranging steel works just fine. It beats $200 billion JSF programs, and this new super-carrier they want to replacle CVAN-65 Enterprise with.

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The Soviets got ahead


Ahead by what measure? They offer the most affordable launch options on this dirt clod, they build thier rockets for peanuts, they should have put everybody else out of the business by now. But even in the most prohibitive regulatory environment (i.e. the US), we have multiple startups (one about to fly now) whom are saying they can do it cheaper... with smaller birds?

Yes we have multiple start-ups. Let me know when we have multiple finishers.

"Musk is building his bird for the MARKET, which is the only force which can drive space travel over the long haul. When the market wants a 500-ton payload launcher, it will get one. Your containerships vs. clippers is a good example. The clippers disappeared because the containerships made more economic sense, not because some 'visionary' shipwright built them ahead of the shipping market's demand for capacity. "

You mean like Brunel--right?--he didn't exist?--sure :roll:

...the pharmaceutical researcher calls his patron one day and says, "Hey, I have a formula that can grow hair on a billiard ball!"

...to which the reply is "Who wants hair on a billiard ball?"


That's good--but just remember--the military didn't want R-7 any more than they wanted hair on a billiard ball--but Korolov--who was a visionary--got his way--and Tito got his ride.

If it had been up to the brass--the Minuteman and the Topol-M would have been this planets largest rockets.


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Post    Posted on: Fri Jul 01, 2005 4:04 pm
You know, you have talked a great deal about on-orbit fabrication, and in light of the numerous experiments which have flown on Mir, ISS and SpaceLab, I would think that some clear vision would be forthcoming by now. But it isn't. Your drug company money hasn't materialized yet, because there hasn't yet been shown a viable economic benefit to making things in zero-g. I am sure that a number of things that have been learned in these experiments will have applications in terrestrial manufacturing processes, but I expect that it will be a considerable length of time before some manufacturing concern decides that the most cost-effective way to make things is in space. Why spend so much money to build your factories in the sky if you can trick molecules into doing what you want right here on earth?

As far as your buddy Isambard goes, I wonder if you are considering the 13% increase in size provided by the Western ( http://www.spartacus.schoolnet.co.uk/RAbrunel.htm ) as "visionary":
Quote:
Brunel persuaded the Great Western Railway Company to let him build a steam boat to travel from Bristol to New York. The Great Western made its first voyage to New York in 1838. At that time the largest steamship in existence was 208 feet long, whereas the Great Western was 236 feet long.

...because I hardly think that qualifies. You must be talking about the Eastern ( http://www.portcities.org.uk/london/ser ... liner.html )
Quote:
Although the design of the Great Eastern was brilliant, in some ways the story of the ship is a sad one. Brunel's mighty vessel was considered a commercial failure as a passenger ship. After a brief period as a cable-laying ship she ended her career as a floating billboard before being scrapped in 1888.

Somebody said that if you build something bigger just because you think "bigger is best" then it won't survive... do you suppose that's the sort of thing he had in mind?

R-7 IS a good rocket. You are correct in asserting that a lot of the Soviet space program was done right. You are correct in saying that the military's percieved needs alone are a poor driver for space technology. You once said that the government should lead, and industry should follow; that is exactly right and that is what Griffin is all about, wouldn't you agree? And Griffin probably isn't going to build an all-new HLLV because in his own words, LEO is not the frontier. If he has enough payload demand to drive the market in that direction, then he'll get a new BFR. But what he (and most everyone on this board) want to see is for the market to outgrow NASA's demand, because then his spending power is increased without having to bribe any congress members.

BTW SuperCarrier isn't really new. Enterprise was actually a scaled-down rendition of that concept. And are you saying that we SHOULDN'T build the biggest f'ing bucket we possibly can? Who are you and what have you done with our pal publi?


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Post    Posted on: Fri Jul 01, 2005 7:11 pm
You know, you have talked a great deal about on-orbit fabrication, and in light of the numerous experiments which have flown on Mir, ISS and SpaceLab, I would think that some clear vision would be forthcoming by now. But it isn't.

You can't run a auto manufacturing plant out of a doghouse either. And that is what our spaceplatforms have been--doghouses That is the hold up.

Why spend so much money to build your factories in the sky if you can trick molecules into doing what you want right here on earth?

Why go to the moon when you can go to Paris. Because there are things there that are nowhere else.

Although the design of the Great Eastern was brilliant, in some ways the story of the ship is a sad one. Brunel's mighty vessel was considered a commercial failure as a passenger ship. After a brief period as a cable-laying ship she ended her career as a floating billboard before being scrapped in 1888.[/quote]
Somebody said that if you build something bigger just because you think "bigger is best" then it won't survive... do you suppose that's the sort of thing he had in mind?


It was better because it was bigger--but also overcomplicated. STS is like Great Eastern--paddlewheels and sails--leave the orbiter off--and leave off the sails and the paddlewheel--and you have a nice, big simple rocket.

Sea Dragon is bigger--and simpler than even SDV HLLV--a good next step--and gets you $200 per pound to LEO or less.

"You once said that the government should lead, and industry should follow; that is exactly right and that is what Griffin is all about, wouldn't you agree? "

Yes.

And Griffin probably isn't going to build an all-new HLLV because in his own words, LEO is not the frontier. If he has enough payload demand to drive the market in that direction, then he'll get a new BFR. But what he (and most everyone on this board) want to see is for the market to outgrow NASA's demand, because then his spending power is increased without having to bribe any congress members.

I think it would also help his cause if people were to invest in private payloads for it--instead of dismissing it out of hand or poo-pooing it. You don't have the space factory if you don't have the structure. To build a profitable space factory--you first have to build the HLLV to put it there. That is why no one has done anything but tests aboard doghouses--because they cannot afford the HLLV. Let NASA do this--and then you just need the payload. That should be obvious.

Look, we only flew the Saturn V a handful of times--where we flew Shuttle over 100 times. Imagine if only half of those flights had been HLLVs--imagine the infrastructure--and the interest.

"BTW SuperCarrier isn't really new. Enterprise was actually a scaled-down rendition of that concept. And are you saying that we SHOULDN'T build the biggest f'ing bucket we possibly can? Who are you and what have you done with our pal publi?"

The NAVY and the Air Force have had their megaprojects. Isn't it time for ours?


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Post    Posted on: Fri Jul 01, 2005 7:35 pm
publiusr wrote:
The NAVY and the Air Force have had their megaprojects. Isn't it time for ours?


I hear you on that one. I'm just worried what would happen if the space industry becomes even MORE like the defense industry. Is there a way to funnel huge amounts of tax money into it without turning it into a circus? I simply don't have faith in the government's methods for handling the selection of projects and vendors. If Griffin was going to have personal control over every nickel, I'd be happy to have him get $100 billion bucks. But he can't do it all, he's just one guy; and the extant mechanism can't be trusted with that kind of cash. It's the fox minding the henhouse. There's nothing to stop LockMart or Boeing from raiding the coffers for minimal return.

A market-driven space economy is self-policed. It will force the big concerns to be better businesses and let their engineers do better work. If Falcon I doesn't auger, look for the Big Two to announce "new innovations in cost-saving technologies" for Delta/Atlas right about the time Musk is erecting Falcon V on the pad. A legion of special congessional budget investigators couldn't accomplish that in a lifetime of auditing.

You're right about STS being a waste of lift. As Griffin pointed out, it is a 20-ton payload in an 80-ton shroud. We WOULD have been better off with >100 Saturn Vs. But the payloads you want won't just follow because the vehicle is there. The Soviets flew WAY more total lift than we did, and the results you have so often forecast did not materialize. Why is that?


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Post    Posted on: Sat Jul 02, 2005 7:34 am
Please avoid discussions about the economic aspects of government and private industry here - it's the fate of governments and their agencies not to have personal control over pennies as well as over billions of dollars because each democratic constitution says that the parliaments as the representation of the taxpayers has the control.

This is a constraint for this section. If the constraint should be discussed it would be advantagous to do that in the Regulations section, the Spaceflight Cafe or the Off-Topic section.

Here it is a constraint which only can - and should - be used as a criterion to answer the question who of the both will accomplish more or better.

Originally spacecowboy wanted to discuss rocket vs. airbreathers here regarding the technologies, publiusr - please concentrate on that.



Hello, SawSS1Jun21,

most of your economic arguments are reasonable and valid - they are good reasons to try to work out the both technologies in more details here.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


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Post    Posted on: Tue Jul 05, 2005 1:17 pm
Heh. I'm not worried. Besides, they're not really discussing economics: more like the politics involved with large sums of money.

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Post    Posted on: Tue Jul 05, 2005 7:56 pm
Don't sweat it, Ekke, I'm thinking I'm finished on this thread now anyway.

Now that my engineering position has been validated by the professional rocket designer (rp) and my socio-economic position has been validated by the professional politcal economist (Ekke), I don't imagine there is much more convincing that I ought to be doing.

I think I might start a really esoteric thread on propulsion. I have to dig around a bit first.

Cowboy, I agree with you that scooping your oxidizing agent from the atmosphere is the optimal answer for chemical energy launch from earth. The key is going to be materials and integrated system design. You're probably on the right track with some kind of hybrid engine which can use either external or internal oxidizer supply. I expect to hear about your achievements in the field starting about 5 or six years from now.


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Post    Posted on: Wed Jul 06, 2005 8:40 am
Hello, SawSS1Jun21,

I never had real problems with your posts but find them interesting and positive mostly. Please go on.



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Post    Posted on: Wed Jul 06, 2005 3:51 pm
SawSS1Jun21 wrote:
I expect to hear about your achievements in the field starting about 5 or six years from now.


That's a pretty tall order: at absolute best, I'll be getting out of graduate school about then. I guess I gotta get my six in gear and start coming up with some reasonably brilliant ideas if you want results before my loans even come due.

Hey, now that I mention it, that's not such a bad idea.... Make a few million, pay off the loans, finance my own personal spaceship (with all of Marshall's connotations attached: see the Terminology thread in the Cafe).... Yeah, I could handle that.

Now all I need is a couple of those reasonably brilliant ideas...... :roll:

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Post    Posted on: Wed Jul 06, 2005 6:15 pm
The biggest hold up with scram-jets--which (unlike rockets) have to linger in atmo and also build up a lot of heat leaving Earth as well as returning--is the lack of large scale testing.
That is why I harp on HLLV. I want to see a large airframe tested at speed. It may be that some type of hypersonics tests of a large scale craft is in order.

t/Space might also play a role. The AN-225 could carry a hypersonic boilerplate much larger than the X-43. Since Griffin will focus on the big rocket (SDV HLLV) and the simple rocket (the Stick)--then the burden must be upon the Alt.Space groups to actually prove they can produce the cheap rocket--or go back inside the closet.

Even here--there is no way to be free of Government. t/Spaces capsule is an ISS servicecraft--like Soyuz, but with a bit less reboost capacity--less than Progress anyway. ISS is a govt' facility. You will likely need some funding from Gov't to get AN-225--or any large plane--plus buy some loyalty from the aeronautics folks who fear Langley becoming less and less relavent.

There is a place for both public and private ventures. NASA provides BIG acess to space and launches stations--and the job of folks here is to try to get rapid access.

Air launch may offer that--but if you take a purist approach and eschew any gov't help--you could very well be doomed to fail.

Sadly, most of the public (and that includes investors) don't care for space.

Many in the aeronautical community don't like Griffin because they feel he is robbing them of actual spaceflight--going with HLLVs, capsule and the like.

My point is that this situation is actually what we need. If some of the flyboys are getting a little desperate--they may be a little more co-operative with private concerns they would otherwise have ignored if they were getting make work money from Goldin--who was big on giving everyone a piece of the pie--but had no hardware to show for his efforts.

SLI/OSP are examples of how (sometimes) gov't doesn't work--except to preclude some private initiative. Griffin wants the Apollo method: i.e. put your money in hardware--build in house as much as you can--distrust contractors--and don't try to baby everyone. (good Gov't).

With the hypersonicists and others needing support--the private spaceflight community can have a foot in the door--also thanks to Griffin and his sense of discipline.

Had Goldin or O'Keefe remained--they would probably have renewed the OSP concept with LockMarts OSP entrant (which seems extravagant to me) just to keep the spaceplane people happy. They get fat and feel no need to talk to you.

Starve them a bit--and they innovate, and become more tractable.

Divide and conquer.


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Post    Posted on: Thu Jul 07, 2005 12:33 pm
I'm going to point out here that in several places (either Aerospace America or AW&ST or both), Griffin has been quoted as saying that he wants to revive NASA's hypersonics research. How committed he is to this, I don't know. But, personally, I think it at least deserves more than just the casual glance that the X-43 was able to give it. Don't get me wrong: it was an outstanding program, and the engineers pulled off some pretty amazing stuff. But two successful flights by two copies of one design does not give us the amount of data that we need to design a successful spaceplane.

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Post    Posted on: Thu Jul 07, 2005 5:11 pm
True enough. But he can't fund everyone. He isn't Goldin. He isn't about make-work--and knows that launch vehicle independance has to come first. Delta IV is almost as bad a pad-sitter as the extinct Titans--Atlas V has no 'heavy' variant--and both it and Boeings's Sea Launch Zenit must use Ukrainian motors.

Griff finds this state of launcher affairs intolerable and will have none of it, so far as I can tell.

I would cut the funding to the Gore-Greens that infest Goddard. Their Earth Science program needs to be absorbed by NOAA.


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Post    Posted on: Sun Jul 10, 2005 2:04 pm
publiusr wrote:
I would cut the funding to the Gore-Greens that infest Goddard. Their Earth Science program needs to be absorbed by NOAA.


This is an interesting point, should NASA be doing the range of work it does or should it concentrate on its exploration program and leave other organisations to deal with the life sciences part of its operations. Perhaps NASA is spread to thin anyway and needs to focus on a few core subjects rather than everything that has even a remote connection to space exploration.

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Post    Posted on: Wed Jul 13, 2005 1:23 pm
Hrm... That's a thought, I never even considered the redundancy in NASA programs. Of course, why is that latest Titan owned by the NRO (whoever the hell they are), instead of the NSA/CIA/DIA/USAF Space Command/<insert your favorite intelligence/space agency here>? What does the NRO do, who do they answer to, who do they work with, and why haven't I heard about 'em before? And why are they launching a sattelite?

Yet another facet of bureaucracy: insane amounts of redundancy.

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Post    Posted on: Wed Jul 13, 2005 5:41 pm
SIGINT (signal intercepts/intel most likely) the other Titan IV launched a school bus sized Lacross spysat. If I told you any more, I'd have to....nah--its just spysat tech.

Last Titan launch--ever IIRC.


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