Author Topic: Sea Dragon class LV thread  (Read 187473 times)

Offline Jim

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Re: Sea Dragon class LV thead
« Reply #40 on: 11/14/2007 05:12 am »
Quote
Michael Bloxham - 13/11/2007  8:07 PM


What about clustering smaller rockets in parallel to allow for the occasional oversized payload?

Boeing envisions this for the Delta IV: A first stage consisting of 7 CBC's clustered together is their ultimate configuration. A configuration like this might be capable of lifting more than 7-times as much as a Delta IV Medium with just one CBC ("more than" due to the advantages of parallel staging).

I used this as inspiration for my PARIS VII rocket, which envisions a cluster of 7 Ares V-derived tanks to allow for payloads of over 500 tonnes:

http://cleanslate.editboard.com/free-chat-f1/paris-launch-system-t11.htm
b

because it is inefficient and there are most disadvantages than advantages.  The 7 core D-IV was a quick and dirty study and not a really viable vehicle

Offline publiusr

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Re: Sea Dragon class LV thead
« Reply #41 on: 11/16/2007 04:17 pm »
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meiza - 2/11/2007  1:38 PM

Just mentioning that bigger is not always the most cost effective approach. It depends on a lot of details.

And smaller is certainly not always the most cost effective approach--otherwise we'd ship oil on thousands of bass boats than in supertankers--that may very well be a harder build than Sea dragon--a simple tube. We just have to get rid of this bias that LVs cannot grow in size--while airplanes and ships continue to grow. They're not cheap either. It took Brunel, the Mike Griffin of another age, to show the virtue of not being limited to clipper ships.

Offline kkattula

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Re: Sea Dragon class LV thead
« Reply #42 on: 11/17/2007 04:13 am »
Quote
Michael Bloxham - 14/11/2007  11:07 AM

Boeing envisions this for the Delta IV: A first stage consisting of 7 CBC's clustered together is their ultimate configuration. A configuration like this might be capable of lifting more than 7-times as much as a Delta IV Medium with just one CBC ("more than" due to the advantages of parallel staging).

Did you see the launch transient fireball of the recnt D-IVH?
Imagine one from 7 CBC's!

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #43 on: 12/14/2007 02:43 am »
Sea Dragon with a third stage is 970mt to LEO.

That is more than double the payload without the third stage.

Offline gospacex

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Re: Sea Dragon class LV thead
« Reply #44 on: 12/14/2007 06:01 am »
Quote
publiusr - 16/11/2007  11:17 AM
Quote
meiza - 2/11/2007  1:38 PM
Just mentioning that bigger is not always the most cost effective approach. It depends on a lot of details.
And smaller is certainly not always the most cost effective approach--otherwise we'd ship oil on thousands of bass boats than in supertankers--that may very well be a harder build than Sea dragon--a simple tube. We just have to get rid of this bias that LVs cannot grow in size--while airplanes and ships continue to grow.

They grow - and viability of this is tested by the market. "Big" LVs were also used. Let's look at the results?

Saturn V (~100 mt class) is abandoned
Shuttle (120 mt gross) is going to be abandoned
Altas and Delta (10 - 20 mt) are flying
Pegasus (less than 1 mt) - flying
Energiya (~100 mt) - abandoned
Soyuz (~10 mt class) - flying
Zenit, Proton (10-20mt class) - flying

See the trend? Market does not (yet?) require 100 mt vehicles. What's the point in trying to build 100 mt LV again? We need smaller steps. Build 40-80 mt (DIRECT) ans see how well that will work, economically.

Offline grakenverb

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Re: Sea Dragon class LV thead
« Reply #45 on: 12/15/2007 12:38 pm »
[
Quote
tnphysics - 9/9/2007  1:34 AM



 Higher frequency gammas are much more damaging than lower.


Just look at what happened to Dr. Bruce Banner.  I'd hate to have the astronauts travel all the way to Mars, only to have them turn green and smash everything.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #46 on: 12/19/2007 03:11 am »
Has anyone thought of the problems involved in designing an LAS for a spacecraft to go on top of Sea Dragon?

I don't think that you can pull someone from on top of a medium-sized nuclear weapon to safety in about two seconds.

Offline ChrisInAStrangeLand

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Re: Sea Dragon class LV thead
« Reply #47 on: 12/19/2007 04:30 am »
Someone who's name is 'tnphysics' ought to know the difference between detonation and combustion.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #48 on: 12/19/2007 04:41 am »
I was referring to a worst-case LV detonation. If events that would cause this were detected it would then be necessary to get the crew to a safe distance from a detonation that has the energy of a nuclear weapon with only two seconds warning time. This may not be practical.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #49 on: 01/28/2008 01:42 am »
Similar to last year's Sea Launch failure.

Offline MKremer

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Re: Sea Dragon class LV thead
« Reply #50 on: 01/28/2008 02:28 pm »
If the Sea Launch failure would have been a true detonation/explosive event, it would have taken out (ie- destroyed/shattered/mangled) most of the *entire* rear section of the launch platform vessel.
Obviously that didn't happen.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #51 on: 01/28/2008 09:30 pm »
Or like one of the N1 falures.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #52 on: 02/04/2008 11:50 pm »
Or a thrust chamber disintigration.

Offline guru

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Re: Sea Dragon class LV thead
« Reply #53 on: 07/10/2008 08:35 pm »
It will be cool if someone would build something like the Sea Dragon.  I don't think it's fair to say that it is too big just because the Saturn V and Space Shuttle have no market.  Obviously, those are both really complex and thus expensive launch vehicles which are made even more so because they are intended to carry human cargo.

I would suggest, though, that those two vehicles didn't last because they are in the wrong payload lift range.  They are too big for all current applications, yes, but they are too small and too expensive to make a first generation space based industry feasible.  If you could put 2 million pounds into LEO with one of these things at a cost of 200 million dollars, and launch twelve of them per year, then space based solar power would suddenly be a lot more reasonable.   This is an option that is every bit as cheap as using propellant depots if your goal is eventually to mine gold and vanadium out of asteroids.

On another note, for as many formal analyses as were done on this, and for as much enthusiasm as some people have for this rocket, I can find precious little documentation regarding it.  I have seen the Wikipedia entry, the Encyclopedia Astronautica entry, the Truax website, and some page that says "Lots of pictures.  Loads slowly, but worth it."  But none of these sites seem to include any information on the method of guidance and control, for example.  Was this vehicle supposed to use liquid injection for thrust vectoring?  I doubt an engine that big was supposed to gimbal.

How were the engines to be cooled, if at all?

What type of propellant injector was assumed?

I've known about this concept for over a decade, but these are things (mostly about the engines) I have just never been able to find with a casual internet search.

Offline guru

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Re: Sea Dragon class LV thead
« Reply #54 on: 07/10/2008 08:42 pm »
Has anyone thought of the problems involved in designing an LAS for a spacecraft to go on top of Sea Dragon?

I don't think that you can pull someone from on top of a medium-sized nuclear weapon to safety in about two seconds.

Most people don't drive their oil tanker to work for the same reason.  They drive smaller, safer cars, or atleast ride safer buses.  Likewise, one would fly human cargo on a smaller rocket.

Offline tnphysics

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Re: Sea Dragon class LV thead
« Reply #55 on: 07/10/2008 11:30 pm »
It will be cool if someone would build something like the Sea Dragon.  I don't think it's fair to say that it is too big just because the Saturn V and Space Shuttle have no market.  Obviously, those are both really complex and thus expensive launch vehicles which are made even more so because they are intended to carry human cargo.

I would suggest, though, that those two vehicles didn't last because they are in the wrong payload lift range.  They are too big for all current applications, yes, but they are too small and too expensive to make a first generation space based industry feasible.  If you could put 2 million pounds into LEO with one of these things at a cost of 200 million dollars, and launch twelve of them per year, then space based solar power would suddenly be a lot more reasonable.   This is an option that is every bit as cheap as using propellant depots if your goal is eventually to mine gold and vanadium out of asteroids.

On another note, for as many formal analyses as were done on this, and for as much enthusiasm as some people have for this rocket, I can find precious little documentation regarding it.  I have seen the Wikipedia entry, the Encyclopedia Astronautica entry, the Truax website, and some page that says "Lots of pictures.  Loads slowly, but worth it."  But none of these sites seem to include any information on the method of guidance and control, for example.  Was this vehicle supposed to use liquid injection for thrust vectoring?  I doubt an engine that big was supposed to gimbal.

How were the engines to be cooled, if at all?

What type of propellant injector was assumed?

I've known about this concept for over a decade, but these are things (mostly about the engines) I have just never been able to find with a casual internet search.
I believe that a pintle injector was to be used, but that's just based on similar (but much, much smaller) rocket designs such as the Apollo LM DPS.

Offline Ronsmytheiii

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Re: Sea Dragon class LV thead
« Reply #56 on: 08/18/2008 07:24 pm »
This concept was tested on a smaller scale on the sea bee program which used an aerobee rocket fired from underwater.  It was shown that reusing the rocket cost 7% that of building a new one. My source is astronautix, however I could not find more information.

http://www.astronautix.com/lvs/seabee.htm
« Last Edit: 08/18/2008 07:26 pm by Ronsmytheiii »


Offline guru

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Offline publiusr

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Re: Sea Dragon class LV thead
« Reply #59 on: 10/03/2008 08:09 pm »
What I find interesting is that simple, ship-building technology would allow large rugged, but simple designs. There were folks in NASA at the time that claimed the concept was "technically uninteresting."

These are no doubt the same folks who think that RS-68 shouldn't have been built--and who cry over the costs of Ares V, while wanting more expensive SSTO designs--just because they look cool and have wings, scramjets, lifting-body construction, etc.

But building a simple tube that just happens to be large--no--THAT is 'too hard'...'too expensive'... 

One of the big charges lobbed at me is that I am more in love with the rocket than with the payload.

This charge is actually a better critique of the enemies of big dumb boosters who want LVs to be overly complex for their own sakes.

 THEY are the ones who care more for the platform than the payload.

Same with Ares V. Ares allows large simple payloads, and anti-HLLV forces tell lies about Ares V craft being more complex--when complexity is all but forced upon smaller vehicles due to smaller shrouds and lower lift capability. More complex engines and more launches are what drive costs up.

Six engines cost less than 21.

Sea Dragon is the ultimate Big Dumb Booster, allowing massive amounts of raw materials/propellant loads to be orbited via large (but simple) payloads.

LVs could become even larger with MLLV or Nexus, but Sea Dragon is simple compared to them--and should be the next step after Ares V. With any luck, some Asia Pacific power will give Truax's vision new life.
« Last Edit: 10/03/2008 08:16 pm by publiusr »

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