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Liberty good idea or cross pond pork barrel?

Posted by: SANEAlex - Tue Feb 08, 2011 9:35 pm
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Liberty good idea or cross pond pork barrel? 
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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Thu Feb 24, 2011 4:39 am
Solids can't be shut down therefore you have to add the original velocity of the booster to your escape vehicle velocity. That adds up to quite substantial g forces on your crew. Ares 1 studies indicated a substantial chance of killing your crew in attempting to escape.
The fact that you can shut down you liquid stage if you detect any anomolies in flight before escape means your escape vehicle doesn't have to generate the g forces that you must for a solid. Unless you have a catastrophic explosive event but that's not as likely for liquids as solids since the engine is removed from the fuel and stop valves are incorporated again, unlike solids.
A couple of advantages for liquids.

Liberty's just a desperate attempt to stay in the game. NASA won't have the budgets to engage in big program like they used to. Elon also mentioned in passing that if you retain the legacy systems, then you retain the legacy cost structures. That's a telling point.

Another is that you'll be voting to send your tax dollars offshore. I wouldn't think that was a winning position.

My belief is that you'll find they won't be able to compete on price or technology. Even the existing EELV's are cheaper. In addition, there's Delta Heavy already there that can do the job and that'll be cheaper than any Liberty monster as would Falcon 9H which SpaceX are moving to fast-track.

And again, what's the payload. In spending your dime on the SLS and /or MPCV, you've got nothing left for a mission.

No, NASA is going to be reliant on commercial for it's future missions and HSF. And their relationship with commercial won't be based around fixed-prices. NASA leadership realises this which is why they've been so conspicuious at commercial centres recently. It's just some in Congress that haven't worked it out yet.

So Liberty, good idea, or cross pond pork barrel? It was never an idea, good or bad.

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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Fri Mar 04, 2011 3:30 am
JamesG wrote:
A launch escape system will function as well with an SRB as any other system. Better perhaps if you can separate from an intact rocket and let it go its own way, vs trying to escape a shockwave/fireball.

There's no reason to escape an intact rocket, but if you were to, solids are worse there because they tend to accelerate harder and have higher peak dynamic pressure. Which means the launch abort has to accelerate even harder; max accel on Ares launch abort was 25g. Crushing.

When they do inevitably explode, solids have shitty blackout zones. Because the pieces of the engine are flying everywhere and putting out a lot of radiant heat, any parachute the capsule deploys will be melted or burned. So if it explodes near the ground, the capsule has hit the ground before it can safely deploy parachutes. Most liquid failures just mean shutting off the engine(s), but in the rare case that bursts the tanks you get a much shorter-lived fireball.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Fri Mar 04, 2011 3:23 pm
lol


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Fri Mar 04, 2011 5:35 pm
Now that was a very useful post James... :?

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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Tue Mar 08, 2011 1:43 pm
Sorry, that was the most tactful thing I could think of.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Tue Mar 08, 2011 4:08 pm
So be untactful. Or read the Air Force report on the blackout zones of the Ares, rather than just idly conjecturing.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Tue Mar 08, 2011 5:54 pm
I make a point of not arguing with people who's minds are already made up. Esp. on the internet.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Wed Mar 09, 2011 12:17 am
This is a forum, not a private dialogue -> there are a lot of people whose minds are not yet made up. Maybe you want to elaborate to us why your mind is already made up? (Which obviously has to be the case judging your reactions to Ben's posts on this topic...)

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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Wed Mar 09, 2011 1:56 am
Nope, I don't care enough about the minutia of this rocket vs another to go on and on about it with some one with an obvious biased opinion (which is what the laugh was in reference to).

But if you would like to help yourself, be my guest. Or are you just trolling by proxy?


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Wed Mar 09, 2011 9:06 am
JamesG wrote:
Nope, I don't care enough about the minutia of this rocket vs another to go on and on about it with some one with an obvious biased opinion (which is what the laugh was in reference to).

But if you would like to help yourself, be my guest. Or are you just trolling by proxy?


Probably not the best things to argue with Ben since he actual does work for a rocket company. Maybe that does give a biased opinion, but it's certainly an *informed* biased opinion. Perhaps JamesG also works for a rocket company? Dunno.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Wed Mar 09, 2011 2:59 pm
Something like that.

Was I arguing with him? No, I just declined to give chase.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Mon Mar 14, 2011 3:05 am
JamesG wrote:
I make a point of not arguing with people who's minds are already made up. Esp. on the internet.

Quite fortuitous, as I don't debate with people who become whiners when someone disagrees with them.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Wed Mar 16, 2011 1:38 am
That was mature.


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Post Re: Liberty good idea or cross pond pork barrel?   Posted on: Thu Mar 17, 2011 4:22 am
Your SNR is astonishingly low.

Here's a bit on the report from the Air Force:
http://www.spaceref.com/news/viewsr.html?pid=31792
"CAPSULE ~100% FRATRICIDE by SECONDARY RADIATIVE WILTING of NYLON CHUTES The capsule will not survive an abort between MET's of ~30 and 60 seconds - as the capsule is engulfed until water-impact by solid propellant fragments radiating heat from 4,000F toward the nylon parachute material (with a melt-temperature of ~400F)."
http://articles.orlandosentinel.com/200 ... ket-ares-i


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