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gaetanomarano
2009-Jul-04, 05:59 PM
.

Look better!

Direct is only a slightly resized Ares-5 (http://www.ghostnasa.com/posts/046directdesignflaws.html), since...

if you do compare, side by side, the Space Shuttle, the Direct concept and the 130 tons payload version of the Ares-5, you can discover that, except the two SRBs, Direct has nearly NOTHING in common with the Space Shuttle (so, it not so much a Shuttle-derived rocket) since it has no Orbiter, it has no SSME, it hasn't the Shuttle's attitude control system, it hasn't the same fueling system, while, Direct, needs several new non-Shuttle things, like 2-4 RS-68 (same engines of the Ares-5) an engines basket (like the Ares-5) a new attitude control system (like the Ares-5) a reinforced, redesigned and enlarged core-stage tank (like the Ares-5) its own avionics and instruments (like the Ares-5) a modified launch pad (like the Ares-5) the interstage (like the Ares-5) a second stage (like the Ares-5) the new J-2X engine for the second stage (like the Ares-5) many payload fairings (more than Ares-5) a different flight profile (pretty similar to an Ares-5) more propellants, for its two stages (like the Ares-5) and, in general, Direct looks much more like an Ares-5 (rather than a Shuttle) has a shape and a stack configuration similar to the Ares-5, it fly like an Ares-5, the stages separation is similar to those of the Ares-5 (rather than a Shuttle) will be assembled like an Ares-5, should have the same kind, time and R&D costs (around $20 billion) of the Ares-5, the Direct hardware should cost only a few million$ less the hardware of an Ares-5, it is even painted like an Ares-5

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Antice
2009-Jul-04, 06:30 PM
while comparing direct to ares V is pretty fair you could maybe stop using those cursed colors on a white background. you are causing me headhaches.

The real difference between direct and the constellation ares V is that the direct people are advocating for a different 2 launch architecture than what was chosen by NASA.
thing is. if you drop Ares I and go straight for Ares V you have already done the switch-over to the direct architecture.
with single launch Apollo style excursion type landings, and a 2 launch mobile base type mission for extended stays.
I have the feeling that that was always a fall back option for the constellation program. also. the Ares I was more meant to give a crew only launch option that would be unaffected by mission type. it would basically mean that all missions would use LEO as a staging area and start point.

I prefer the flexibility that having a separate launcher for the crew allows in mission types. it allows one to freely use a 2 or more launch assembly sequence followed by a separate CEV Launch just prior to departure from LEO.

gaetanomarano
2009-Jul-04, 06:37 PM
while comparing direct to ares V is pretty fair you could maybe stop using those cursed colors on a white background. you are causing me headhaches.

look better... below, in the same article, there is a B/W version of the text without bolds, colors, etc.

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gaetanomarano
2009-Jul-05, 03:13 AM
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from 2006, the Direct-LOBBY is trying to "sell" to NASA a rebranded but WORSE and LESS EFFICIENT version of the Ares-5, already designed by NASA and that it ALREADY OWNS from years... that's EXACTLY like try to "sell" a "rebranded" Statue of Liberty to New York City... or... try to "sell" a "rebranded" Eiffel Tower to France... or... try to "sell" a "rebranded" White House to the US President... :lol:

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JonClarke
2009-Jul-05, 03:17 AM
Sinces Ares V can put 188 tonnes into LEO and and Jupiter 232 less than 100 tonnes, it seems a really good idea to drop a more capable booster with several years of development for a less capable one that is just vapourware. Not.

And the constant posting of links to your site is gettinh close to spamming.

gaetanomarano
2009-Jul-05, 03:24 AM
Sinces Ares V can put 188 tonnes into LEO and and Jupiter 232 less than 100 tonnes, it seems a really good idea to drop a more capable booster with several years of development for a less capable one that is just vapourware.

yes, the Ares-5 has a SUV engine but is big and capable like a SUV, while Direct is an Honda Civic with an heavy SUV engine... :(

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Nicolas
2009-Jul-05, 07:43 AM
there is a B/W version of the text without bolds, colors, etc.


Oh the irony. :lol:

djellison
2009-Jul-05, 10:09 AM
Five minutes ago Gaetanomarano, you were telling us of your outrage at having invented Direct yourself without getting the credit. This, was, of course, a complete fabrication as inline STS derived LV's have been on the board since before the shuttle first flew. Is it garbage, or did you invent it, or is it both.

If you think Direct and Ares V are essentially the same, then essentially...you're wrong.

gaetanomarano
2009-Jul-05, 11:41 AM
...you were telling us...

you have that confusion in mind because you haven't followed the full story...

ok, it's not a so important story you "must" follow it, but, at least, don't say that without know the truth

in shorth, 3.5 years ago, I've found absurd to build two rockets, use non-shuttle hardware, the 5-seg.SRB, etc. and I've suggested MY concept o a FAST-SLV

the Direct-LOBBY (born in 2005 to contrast the new NASA administrator) was in search of an idea... an alternative... something to say to Griffin "you are worng and we are right, then, go away and leave your seat to us!"

finally, they have found the winning idea in the single and cheaper Ares... and have pushed all the energy and mone of the LOBBY to promote """their""" idea...

of course, MY idea was (and still is) excellent (if made with Shuttle parts) but, unfortunately, NASA and Griffin decided to scrap the SSME, use the RS-68, develop the J-2X, add a 2nd stage, enlarge the Altair, etc.

so, they was FORCED to follow the new NASA decision, and MY very good idea of a TRUE shuttle-derived and cheaper rocket, in their hands, has become, day by day... a resized version of the the Ares-5...

in other words, the IDEA (single rocket, standard SRB, shuttle hardware, etc.) was the SAME of MY concept of a FAST-SLV, while, the final design (engines, 2nd stage, etc.) was the SAME already developed by NASA, the Ares-5, but smaller and with less payload (due to the standard SRB and two-three RS-68 less)

they started from MY (good) idea, have modified it to match the NASA requirement, then resized to a scale-model Ares-5

but, after all, one of the "leader", press agent and "minds" ( :) ) behind the Direct-LOBBY is Ross Tierney, that, before join the lobby, was known only to build and sell... rockets models... :)

being boys that did not like to study... they have copied the work of two other students... but copied (both) wrong... :)

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Nicolas
2009-Jul-05, 12:38 PM
Yes, the idea is so unique, clever and overall genious that you must have been the first one to come up with anything like that. Sure. It's not like anyone ever though about using Shuttle hardware for other launchers or about a single rocket design for lunar missions before. Out of the question.

Shuttle-C and the like were islands on their own, without any slightly different configuration ever being considered. That must be the case, because that is how engineering works.

*NOT*

Just one snippet:


The ESMD began a series of two 'Analysis of Alternatives" beginning in mid-2004 and extending into the spring of 2005. According to study documents obtained by the authors, these reviews covered 35 cargo launch system configurations in a trade analysis termed "integrated launch systems study". Two separate sets of boosters were studied; those derived from the EELV fleet of Delta IV and Atlas V vehicles, and those configured from shuttle derived elements. A separate study conducted at JSC looked at a heavy lifter derived from Ariane 5 and the Russian Energia, although these were believed to have been looked at mainly for comparison.

gaetanomarano
2009-Jul-05, 02:22 PM
...the idea is so unique...

compared to Direct-LOBBY that is breaking the balls to the whole world, from three years, with its scale-model of the Ares-5 ... :lol: :( :shhh: :wall: :exclaim: :sad: :rolleyes:

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Nicolas
2009-Jul-05, 02:42 PM
That's totally not the point.

djellison
2009-Jul-05, 05:52 PM
MY idea

Stop it. Just stop it.

It has never been 'your' idea. In line shuttle derived launch vehicles were being talked about IN THE 1980's.

Nicolas
2009-Jul-05, 09:05 PM
At best, you came up independently with an idea that has been around for a long time, without you being aware of it. That's fine, that's possible (happens to us all the time). That doesn't mean anyone stole your idea.

joema
2009-Jul-06, 02:47 AM
...except the two SRBs, Direct has nearly NOTHING in common with the Space Shuttle...has no SSME...Direct...needs several new non-Shuttle things, like 2-4 RS-68...
The current Direct 3.0 design uses SSMEs, not RS-68 engines: http://www.directlauncher.com/

Direct 3.0 presentation to Augustine commission: http://www.youtube.com/watch?v=WvgqWlGp30M&feature=related

samkent
2009-Jul-06, 03:46 AM
Am I correct in thinking that the SSMS's are more expensive to produce than the RS68's because they are expected to be reused? Plastic forks vs silverware?

Damon Hill
2009-Jul-06, 06:09 AM
Am I correct in thinking that the SSMS's are more expensive to produce than the RS68's because they are expected to be reused? Plastic forks vs silverware?

It's not really a simple answer.

The SSME (aka RS-25) is a complex, high performance engine that took a lot of effort to be actually reuseable in spite of itself. Most rocket engines >are< reusable, they're just not recovered; SSME really pushed the limits of technology.

The RS-68 was designed from the beginning to be just high thrust and moderate Isp while being less expensive through a simpler design that doesn't have to operate at exceptional pressure and temperature. Unfortunately, the lower unit cost of the RS-68 seems to be compromised by its lower Isp and heavier weight--the Ares V has had to be redesigned larger and larger to keep the desired payload to the point that it's become impractical.

An uprated regeneratively-cooled RS-68 would help matters, but it'd be a major development program--as would just about anything other than a stock SSME or RS-68 would be.

A RS-25E is being proposed but I'm not sure how much of SSME would actually carry over. Trying Googling for COBRA, an engine development program that would incorporate new manufacturing technologies and a simpler powerhead design with existing SSME turbopumps. If the upper end of thrust at 1 million pounds could be reached, this could allow for a smaller and less impractical Ares V. I kind of like COBRA, but it's still not cheap or quick to develop.

Consider the Russian RD-0120. It's an example of an expendable SSME-like engine that flew on the Energia. I'm such they'd love to quote prices on whatever quantity you'd care to order, as Lockheed-Martin did with the RD-180 ($1 billion for 101 engines, not a bad deal, eh?). It might be a great choice, and it's essentially off-the-shelf. Politically...even I'm not much in favor of it.

A significantly higher-thrust SSME-like engine would benefit Direct just as much as Ares V, and Direct is a more sustainable architecture. But alas, we're trying to do an inherently expensive program on the cheap in the middle of a major economic downtown, and adequately funding a real program seems unlikely in these modern times. (Ah, for the glory days of Apollo, when Federal money flowed like water...I was in high school then.)

mugaliens
2009-Jul-06, 08:23 AM
Am I correct in thinking that the SSMS's are more expensive to produce than the RS68's because they are expected to be reused? Plastic forks vs silverware?

I believe so, yes, hence my concern that they be recovered and reused.

Easy enough with JPADS (http://en.wikipedia.org/wiki/Joint_precision_airdrop_system) technology - steerable chutes, pinpoint accuracy....

RGClark
2009-Jul-06, 09:15 AM
.

Look better!

Direct is only a slightly resized Ares-5 (http://www.ghostnasa.com/posts/046directdesignflaws.html), since...

if you do compare, side by side, the Space Shuttle, the Direct concept and the 130 tons payload version of the Ares-5, you can discover that, except the two SRBs, Direct has nearly NOTHING in common with the Space Shuttle (so, it not so much a Shuttle-derived rocket) since it has no Orbiter, it has no SSME, it hasn't the Shuttle's attitude control system, it hasn't the same fueling system, while, Direct, needs several new non-Shuttle things, like 2-4 RS-68 (same engines of the Ares-5) an engines basket (like the Ares-5) a new attitude control system (like the Ares-5) a reinforced, redesigned and enlarged core-stage tank (like the Ares-5) its own avionics and instruments (like the Ares-5) a modified launch pad (like the Ares-5) the interstage (like the Ares-5) a second stage (like the Ares-5) the new J-2X engine for the second stage (like the Ares-5) many payload fairings (more than Ares-5) a different flight profile (pretty similar to an Ares-5) more propellants, for its two stages (like the Ares-5) and, in general, Direct looks much more like an Ares-5 (rather than a Shuttle) has a shape and a stack configuration similar to the Ares-5, it fly like an Ares-5, the stages separation is similar to those of the Ares-5 (rather than a Shuttle) will be assembled like an Ares-5, should have the same kind, time and R&D costs (around $20 billion) of the Ares-5, the Direct hardware should cost only a few million$ less the hardware of an Ares-5, it is even painted like an Ares-5

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How about a variant of the Buran(Energia), without the Russian shuttle just a payload canister, since it didn't use the problematical solid rockets for its boosters:

Energia.
http://en.wikipedia.org/wiki/Energia


Bob Clark

djellison
2009-Jul-06, 09:34 AM
At best, you came up independently with an idea that has been around for a long time, without you being aware of it. That's fine, that's possible (happens to us all the time). That doesn't mean anyone stole your idea.

Well - lets consider for a moment, the process of coming up with a new LV design.

You research the components, you research alternatives, you research similar vehicles, and you come, carefully, to a conclusion.

Either our OP did NO research AT ALL (because 5 seconds with google will show you historic Direct-like LV designs). OR, he DID do research, and thus is fully aware that inline shuttle derived LV's are a quarter-century old idea.

Nicolas
2009-Jul-06, 01:13 PM
How about a variant of the Buran(Energia), without the Russian shuttle just a payload canister, since it didn't use the problematical solid rockets for its boosters:

Energia.
http://en.wikipedia.org/wiki/Energia


Bob Clark

How are the solid rocket boosters problematic?

NEOWatcher
2009-Jul-06, 01:17 PM
...in other words, the IDEA (single rocket, standard SRB, shuttle hardware, etc.) was the SAME of MY concept of a FAST-SLV, while, the final design (engines, 2nd stage, etc.) was the SAME already developed by NASA, the Ares-5, but smaller and with less payload (due to the standard SRB and two-three RS-68 less)...
Your IDEA was started in 1978 with variants throughout the decades.

RGClark
2009-Jul-06, 01:32 PM
How are the solid rocket boosters problematic?

Astronauts don't like them since once started they can't be shut down and they can't be throttled either.
They also have have less performance compared to liquid fueled rockets as measured by Isp, as witnessed by the piling on of segments on the Ares solid rocket boosters.


Bob Clark

joema
2009-Jul-06, 02:22 PM
Astronauts don't like them since once started they can't be shot down and they can't be throttled either....Bob Clark
It's not that clear cut. Both solid and liquid engines are problematic -- just different problems.

Liquid engines can be shut down, but this can cause spurious shutdown. The ability to shut down can't always be used, as evidenced by the Saturn V first 15 sec of flight. It takes more liquid engines to produce the same thrust, which drives up failure probability. E.g, if a Saturn V F-1 engine had 98% reliability, the total reliability for all five engines was about 90% -- and you must have all five working for some regimes. Those aren't actual numbers, but it illustrates that overall reliability goes down quickly with multiple engines.

Liquid engine throttling produces additional complexity and failure modes. There are various shuttle abort scenarios caused by throttle failures. We tend to think about previous failures, and evaluate risk on that basis. However if a shuttle or crew is lost due to a stuck throttle, that would quickly change.

Man-rated solid engines aren't simply manufactured and "hope for the best" -- they are X-rayed and tested hundreds of times. The shuttle SRBs are designed and built with a 200% structural margin, vs the normal practice of 140% or 150% for airframe and liquid engines.

Liquid engines require highly stressed turbomachinery which can have an uncontained failure and destroy the vehicle. Even with shutdown, that remains a risk. E.g, each shuttle fuel turbopump rotates at 30,000 rpm, and produces 76,000 shaft horsepower -- in the volume of a trash can.

It's true that solid rockets simply must work. However the same is true for various aspects of liquid engines. E.g, the shuttle propellent lines from the ET to orbiter require complex pyrotechnics and disconnect couplers. If they malfunction (fail to separate, separate but umbilical doors don't close, etc) -- the vehicle is lost.

Nicolas
2009-Jul-06, 02:30 PM
Astronauts don't like them since once started they can't be shot down and they can't be throttled either.


Is it a real problem that they can't be throttled? (we've had this discussion before)? Do you have any quotes of astronauts not liking them or do you just say so? How many astronauts don't like them? With a real life reliability of over 199 in 200 (and a 100% reliability since the redesign after Challenger), I'd think astronauts would kiss and hug them.




They also have have less performance compared to liquid fueled rockets as measured by Isp, as witnessed by the piling on of segments on the Ares solid rocket boosters.


And a large, no huge thrust. Especially for the cost. They're simple and reliable, have very few failure modes. Something that may be quite important for manned launchers indeed. Is a lower Isp all that bad for a first stage if it gives you a huge thrust in a simple, safe and relatively cheap way?

Antice
2009-Jul-06, 04:33 PM
thrust are more important than ISP for a first stage. You can lift a much heavier second stage if you can get the brute oomph going. solids deliver this. And their safety to thrust ratio is excelent. Their ISP is a lot less important because quite frankly. you do not burn them for long. ISP has a lot more effect on performance on a second or third stage than the first.
The Ares I first stage solid will get the orion off the pad 99% or so of the time if historical failure rates on solids is anything to go by.
Solid rockets have been around for a very long time. and their workings are well understood.
I have no qualms about being launched atop a solid booster. however I'm not an astronaut. Unless you count daydreaming... :whistle:

Nicolas
2009-Jul-06, 05:09 PM
I have no qualms about being launched atop a solid booster.

I certainly have. However, if you'd design a capsule to fit onto them, that's a whole different thing. ;)

RGClark
2009-Jul-06, 05:17 PM
Is it a real problem that they can't be throttled? (we've had this discussion before)? Do you have any quotes of astronauts not liking them or do you just say so? How many astronauts don't like them? With a real life reliability of over 199 in 200 (and a 100% reliability since the redesign after Challenger), I'd think astronauts would kiss and hug them.
And a large, no huge thrust. Especially for the cost. They're simple and reliable, have very few failure modes. Something that may be quite important for manned launchers indeed. Is a lower Isp all that bad for a first stage if it gives you a huge thrust in a simple, safe and relatively cheap way?

We disagree on their reliability. We have had no failures in manned missions of liquid fuel engines which counts many more missions than the solids. Von Braun didn't like using solids for manned missions because they couldn't be shut down or throttled. That opinion suffused down through the ranks to the astronaut corp as well.
For the Ares, astronauts don't like the solids because of the shaking which alone, even if the solids don't fail, can cause catastrophic mission failure:

Is NASA's Project Ares Doomed?
Published on 10-26-2008
http://www.roguegovernment.com/news.php?id=12535

Vehicle shaking is an inherent part of solid rocket motors because of uneven burning. It is worse for the Ares since the first stage is completely powered by solids. I saw an interview of a space shuttle astronaut who described the early part of the launch as involving extreme shaking because of the solid rocket boosters. But after SRB separation, he said, it was smooth sailing when under the liquid fueled engines alone.


Bob Clark

RGClark
2009-Jul-06, 05:21 PM
...
The Ares I first stage solid will get the orion off the pad 99% or so of the time if historical failure rates on solids is anything to go by.
Solid rockets have been around for a very long time. and their workings are well understood.
I have no qualms about being launched atop a solid booster. however I'm not an astronaut. Unless you count daydreaming... :whistle:

That is not a reassuring number when if they do fail it means catastrophic mission failure.
For liquid fueled engines because you can have shut down failure does not have to mean catastrophic loss of mission.


Bob Clark

Antice
2009-Jul-06, 05:54 PM
solids generally do not catastrophically fail. when they fail the either fail to start or go out of control due to control system failure. the rate of control system failure for solids are on par with liquids. that is what you have the LES for. to get off the booster IF it fails. liquids have some failure modes that are quite spectacular. the LES will be less effective at outrunning a big fireball than an out of control solid.
when it comes to bumpy rides.... that is what the dampening system is added to help with. As long as the bumps can be kept within safe limits then the booster is fine. cant always cruise on the highway you know.
besides. even going with most other launchers you aren't getting away from solids completely.
Apart from swapping over to EELV's that still has major no abort zone issues if they are to lift something like the Orion you either do a clean sheet or a solid. Direct is IMHO to big for this particular task.
having no abort capability in areas of the launch profile like the EELV's has is a show stopper for crewed launches. it turns a LOM into a guaranteed LOC if it happens at the wrong time during launch. and that is totally unacceptable IMHO.

Siguy
2009-Jul-06, 06:01 PM
Gaetanomorano, nobody is going to take you or your website seriously if you insist on using BIG BOLD CAPITAL LETTERS, colored italicized words, and excessive highlighting. Your website is like a SPACE TABLOID. Total in-your-face formatting overload.

*underlining substitutes highlighting

NEOWatcher
2009-Jul-06, 06:11 PM
With a real life reliability of over 199 in 200 (and a 100% reliability since the redesign after Challenger),We disagree on their reliability. We have had no failures in manned missions of liquid fuel engines which counts many more missions than the solids.
Please define failures in both your cases.
We have had no catastrophic failure of the solid booster itself, although the booster failure caused a catastrophic failure of the liquid tank.
From what I remember, the solids still seemed to be running.

On the same token, how many liquid engine shutdowns have there been. I recall at least one during the Apollo flights. So; although not catastrophic, and planned redundancy saved it, it was still a failure.


Von Braun didn't like using solids for manned missions because they couldn't be shut down or throttled.
There also wasn't sophisticated computer modelling, high tech quality control techniques or such high technological tolerances in the manufacturing at the time either. I wonder what Von Braun would think of solids in today's environment.


For the Ares, astronauts don't like the solids because of the shaking which alone
That could be a factor, but I do see solid components of any proposed architecture. So, shaking may still be an issue, although buffered by some degreee.


I saw an interview of a space shuttle astronaut who described the early part of the launch as involving extreme shaking because of the solid rocket boosters. But after SRB separation, he said, it was smooth sailing when under the liquid fueled engines alone.
I saw interviews of Apollo astronauts talk about the violent shaking of the SatV, but after first stage separation it was smooth sailing.

Nicolas
2009-Jul-06, 06:12 PM
We have had no failures in manned missions of liquid fuel engines which counts many more missions than the solids.

Say what? Liquid fueled engines have failed many times in manned launchers. Not catastrophically (I'm not counting the catastrophic N1 failures, because they happened to not have men in them. But face it: catastrophic liquid fuel engines caused the Russians to not reach the moon), but they certainly have failed a lot. How many solid fueled engines have failed on the more than 200 flown? 1. And that was because it was launched beyond its weather envelope, and afterwards a design change was made.


Von Braun didn't like using solids for manned missions because they couldn't be shut down or throttled. That opinion suffused down through the ranks to the astronaut corp as well.

How many of the astronauts that have flown the shuttle didn't like its SRB's?


For the Ares, astronauts don't like the solids because of the shaking which alone, even if the solids don't fail, can cause catastrophic mission failure:

Yes, but now you're suddenly making a general rant against SRB's into a particular case where there is a design issue yet to be solved. That's not how you started.


Vehicle shaking is an inherent part of solid rocket motors because of uneven burning. It is worse for the Ares since the first stage is completely powered by solids. I saw an interview of a space shuttle astronaut who described the early part of the launch as involving extreme shaking because of the solid rocket boosters.

And I've heard accounts of astronauts saying that getting launched in the shuttle was a sunday afternoon ride with their grandma compared to earlier launchers. So that ain't saying a lot. Ares 1 is different as it uses only one SRB, that's true. But again, that was not the argument you started with.

Nicolas
2009-Jul-06, 06:16 PM
We have had no catastrophic failure of the solid booster itself, although the booster failure caused a catastrophic failure of the liquid tank.
From what I remember, the solids still seemed to be running.

Good point. Ignoring the design change that solved the issue, a Challenger incident would more than likely not have crippled an Ares 1. I don't know whether it would have reached orbit (I can imagine the leak causing decreased performance, but I'm not sure about that), but at least it would have gone smooth and allow for a clean capsule separation with the escape system.

Larry Jacks
2009-Jul-06, 06:33 PM
During climbout, the Challenger SSMEs were gimballing pretty heavily to correct the thrust from the leak. It's unknown at this time if the thrust vectoring ability of the Ares I configuration would be sufficient to counter a segment leak. Following the redesign, such a leak is much less likely. Prior to Challenger, there was evidence of leaks on a few Shuttle flights. Apparently, none of them were directed at the ET.

As for liquid engine shut downs, there were a few second stage engine failures during the Apollo era (Apollo 13 immediately comes to mind and that may not have been the only one). There were a few Shuttle SSME shutdowns as well. All of the vehicles made it to orbit. That's why you build redundancy into a design.

RGClark
2009-Jul-06, 07:09 PM
Say what? Liquid fueled engines have failed many times in manned launchers. Not catastrophically (I'm not counting the catastrophic N1 failures, because they happened to not have men in them. But face it: catastrophic liquid fuel engines caused the Russians to not reach the moon), but they certainly have failed a lot. How many solid fueled engines have failed on the more than 200 flown? 1. And that was because it was launched beyond its weather envelope, and afterwards a design change was made.
...

I'm specifically talking about the robustness of the liquid fueled engines where if they fail they can be shut down. Note in those cases where they had to be shut down in manned missions they did NOT cause catastrophic loss of mission.
For me if a failure of an engine solid or liquid is the direct cause of catastrophic mission loss, well then that is a catastrophic failure on the part of that engine.
You brought up failures of unmanned liquid fueled engines but of course there have been many failures of unmanned solid rocket engines! That's one of the main reasons rocket scientists such as von Braun had a distrust of them for manned flight.
This Wikipedia page gives the failure rate of solids as 1 in 100 and notes they usually involve immediate and catastrophic mission loss:

Solid rocket booster.
http://en.wikipedia.org/wiki/Solid_rocket_booster

That catastrophic loss of the Challenger mission took about a minute after the solid rocket booster failed is hardly reassuring.


Bob Clark

RGClark
2009-Jul-06, 07:21 PM
..Yes, but now you're suddenly making a general rant against SRB's into a particular case where there is a design issue yet to be solved. That's not how you started.
...

The Ares solids have the inherent dangers of all solid rockets AND on top of that because they are the only propulsion for the first stage their higher than normal shaking can also cause catastrophic mission failure.


Bob Clark

Warren Platts
2009-Jul-06, 07:32 PM
My main problem with SRB's are the externalized environmental costs associated with them. Perchlorates are nasty stuff. SRB's are acceptable now only because they are so rarely used. If space travel ever gets as routine as we would like, SRB's would have to be outlawed. Better to get used to using LOX and wind generated LH2 now, because in the future, that's all that's going to be allowed.

NEOWatcher
2009-Jul-06, 07:39 PM
The Ares solids have the inherent dangers of all solid rockets AND on top of that because they are the only propulsion for the first stage their higher than normal shaking can also cause catastrophic mission failure.
Nice of you to have changed the discussion of this thread.
Shame on me for having got suckered into the SRB discussion.

How about we get back to the subject at hand? How does Direct differ from Ares V ?

Nicolas
2009-Jul-06, 08:12 PM
I'm specifically talking about the robustness of the liquid fueled engines where if they fail they can be shut down. Note in those cases where they had to be shut down in manned missions they did NOT cause catastrophic loss of mission.

You ignore the N1 failures of the engine's turbopumps, which caused catastrophic failure of the vehicle. Not surprisingly, when these turbopumps decide to blow to pieces at 30000 rpm.

There's also the risks involved in the fuel itself. A Soyuz failed catastrophically when its liquid fuel ignited on the pad.


That catastrophic loss of the Challenger mission took about a minute after the solid rocket booster failed is hardly reassuring.

You ignore the fact that the SRB's continued to work after the liquid fuel part of the craft blew to pieces.


This Wikipedia page gives the failure rate of solids as 1 in 100 and notes they usually involve immediate and catastrophic mission loss:

Solid rocket booster.
http://en.wikipedia.org/wiki/Solid_rocket_booster
Let's play it fair. If you're only counting manned missions for liquids, do the same for solids. So that leaves only the shuttle SRB, with a failure rate of less than 1 in 200, and no failures whatsoever since the redesign after Challenger. And on top of that, as said, even in the Challenger accident the SRB's continued to work. They were the cause of the accident, but only the rest of the stack (liquid fueled) failed because of it.


The Ares solids have the inherent dangers of all solid rockets AND on top of that because they are the only propulsion for the first stage their higher than normal shaking can also cause catastrophic mission failure.
A liquids-only craft has all the inherent dangers of a liquid fueled rocket AND on top of that because there are multiple engines, a multiplication of catastrophic failure modes (turbopump explosions to name one).

The shaking of a single SRB is taken into account in the design of Ares1.

It's normal when defending an idea to use the arguments to support the idea, but imo you haven't shown there really is a disadvantage in using an srb as first stage.

Nicolas
2009-Jul-06, 08:14 PM
My main problem with SRB's are the externalized environmental costs associated with them. Perchlorates are nasty stuff. SRB's are acceptable now only because they are so rarely used. If space travel ever gets as routine as we would like, SRB's would have to be outlawed. Better to get used to using LOX and wind generated LH2 now, because in the future, that's all that's going to be allowed.

That's a completely different argument, and a valid one.

How environmentally friendly is the creation and storage of LOX and LH2 at the moment?

And how environmentally friendly is the burning of them in a rocket in reality (including all (by)products of combustion that occur in reality)

I'm not trying to bash the argument through fake questions, I'm seriously asking because I don't know these details.

Nicolas
2009-Jul-06, 08:16 PM
Nice of you to have changed the discussion of this thread
Shame on me for having got suckered into the SRB discussion.

How about we get back to the subject at hand? How does Direct differ from Ares V ?

Ares V uses 2 SRB's, so that makes the derailed discussion twice as on topic! :liar:

Allrighty then, on topic.

RGClark
2009-Jul-06, 08:25 PM
You ignore the N1 failures of the engine's turbopumps, which caused catastrophic failure of the vehicle. Not surprisingly, when these turbopumps decide to blow to pieces at 30000 rpm.

There's also the risks involved in the fuel itself. A Soyuz failed catastrophically when its liquid fuel ignited on the pad.
You ignore the fact that the SRB's continued to work after the liquid fuel part of the craft blew to pieces.
Let's play it fair. If you're only counting manned missions for liquids, do the same for solids. So that leaves only the shuttle SRB, with a failure rate of less than 1 in 200, and no ...

Still worse than manned liquid fueled engine caused catastrophic losses: 0%.



Bob Clark

RGClark
2009-Jul-06, 08:32 PM
...
The shaking of a single SRB is taken into account in the design of Ares1.
It's normal when defending an idea to use the arguments to support the idea, but imo you haven't shown there really is a disadvantage in using an srb as first stage.

?????

Read this article in its entirety:

Is NASA's Project Ares Doomed?
Published on 10-26-2008
http://www.roguegovernment.com/news.php?id=12535

The extreme shaking problem is specifically because it is a solid rocket booster that is providing all the thrust at the first stage.


Bob Clark

Nicolas
2009-Jul-06, 09:07 PM
I am aware of the problem. So are the designers. They're looking how to make the thing work.

Do you really think that it is uncommon for a craft to encounter issues like these during the design phase?

The design phase is when the thing doesn't work yet. The design phase is finished when it works. Don't fall off your chair because Ares 1 has a problem to be overcome during design. If it hadn't, you wouldn't need a design phase. You'd just wake up with the idea, go to the workshop, bolt the thing together and fly the baby. It doesn't work that way.

Had you designed a craft using liquid fueled engines, you would also have gotten into problems along the road. And you'd solved them, unless they truly were so-called showstoppers. Likely there wouldn't have been mass hysteria about it, because the novelty factor would be lower and therefore it wouldn't be as superficially interesting.

Wait & see until the final design of Ares 1 is there and how it performs. Only then you can evaluate how good a craft it is. It's unfare to cry doom over problems before they've finished solving them.

It's like letting an architect design the foundation of your house, and then when he encounters a weak spot in the bottom call the thing off before he even had time to grad a calculator and come with a suitable solution for the problem. If on the other hand the house is built and still collapses, than it was a badly designed foundation indeed. If the architect tried his best but couldnt find a theoretically OK foundation, then the current technique wasn't suitable indeed. But before he's finished his design phase, you can't yet say that.

GeorgeLeRoyTirebiter
2009-Jul-06, 10:45 PM
Still worse than manned liquid fueled engine caused catastrophic losses: 0%.

Your math is faulty; that exploding Soyuz was manned. The crew was saved by the launch escape system.

If you're limiting the definition of "catastrophic" to failures that caused the loss of mission, vehicle, and crew, then you're unfairly targeting the shuttle. It may be the first manned spacecraft (in service) to use large solid motors, but, more importantly, it's also only the second manned spacecraft to lack an adequate LES (the first was Voskhod). This won't be the case for Ares. A Challenger-type joint failure, even if it caused a loss of control, would be survivable because of the LES. Even a destructive case rupture (like the 1993 Titan 4 or 1997 Delta II failures) would likely be survivable.

mugaliens
2009-Jul-07, 07:40 AM
I am aware of the problem. So are the designers. They're looking how to make the thing work.

Internal turbinators differentiated in size by prime factors.

I thought we had this discussion?

It's the harmonic reinforcement which causes most of the grief, just like the Tacoma Narrows bridge. So, just avoid harmonics. Primes aren't harmonic.

Nicolas
2009-Jul-07, 08:15 AM
Do said primes include 1? And if so, do they include 0.999... for infinite 9's? Shall we retype everything ever put on BAUT? ;) :D

but yeah, I agree that there likely is a way to design away from the problem. It may come at a mass penalty (to change the eigenfrequencies), but what is considered a "system" and what is considered a "mass penalty" eh. Is a turbopump a system or a mass penalty? A solid rocket doesn't need one, a liquid one needs one to make it work. So... :)

djellison
2009-Jul-07, 09:12 AM
http://vimeo.com/5339573

Just to prove a point, Direct 3.0's own presentation shows the 1978 initial heritage of the Shuttle Derived Inline LV.

NEOWatcher
2009-Jul-07, 02:29 PM
Ares V uses 2 SRB's, so that makes the derailed discussion twice as on topic! :liar:

Allrighty then, on topic.
Huh? That seems like a very loose connection to me.

Direct vs Ares-5... Both have SRB's. I don't see how solid vs liquid applies.
Maybe the choice of putting the capsule on Direct instead of the 1.5 architecture... Both have SRB's. I don't see how solid vs liquid applies.

The only reason I care though, is that I was hoping to hear the major and minor differences between Direct and Ares-5.

RGClark
2009-Jul-07, 04:00 PM
Your math is faulty; that exploding Soyuz was manned. The crew was saved by the launch escape system.

If you're limiting the definition of "catastrophic" to failures that caused the loss of mission, vehicle, and crew, then you're unfairly targeting the shuttle. It may be the first manned spacecraft (in service) to use large solid motors, but, more importantly, it's also only the second manned spacecraft to lack an adequate LES (the first was Voskhod). This won't be the case for Ares. A Challenger-type joint failure, even if it caused a loss of control, would be survivable because of the LES. Even a destructive case rupture (like the 1993 Titan 4 or 1997 Delta II failures) would likely be survivable.

No, I'm allowing catastrophic mission failure to include cases where the crew manages to survive. I hadn't heard of this case before:

Soyuz launch escape system.
http://suzymchale.com/kosmonavtka/soyescape.html

This is rather a gray area since this happened on the launch pad before the engines had even fired. However it was due to a liquid fuel leak so could be said to be due to liquid fueled systems in general.


Bob Clark

Nicolas
2009-Jul-08, 07:07 AM
Huh? That seems like a very loose connection to me.

Direct vs Ares-5... Both have SRB's. I don't see how solid vs liquid applies.
Maybe the choice of putting the capsule on Direct instead of the 1.5 architecture... Both have SRB's. I don't see how solid vs liquid applies.

The only reason I care though, is that I was hoping to hear the major and minor differences between Direct and Ares-5.

You may or may not have noticed an emoticon depicting a growing nose. I used it to imply "not so correct reasoning". ANd I think you misinterpreted my second line.

SRB vs liquids has little to do here indeed, since both Direct and AresV use SRB's. So, on to the differences between both was what I meant with "allrighty then, [let's get] on topic".

mugaliens
2009-Jul-08, 07:39 AM
It may come at a mass penalty (to change the eigenfrequencies), but what is considered a "system" and what is considered a "mass penalty" eh. Is a turbopump a system or a mass penalty? A solid rocket doesn't need one, a liquid one needs one to make it work. So... :)

Engineers have been designing out harmonics in high-performance turbines for years so they don't self-destruct. They don't use primes (except for the number of turbine blades - sometimes), but they do use variable-geometry inlets and outlets. Straight shots tend to have resonant problems at certain turbine frequencies.

NEOWatcher
2009-Jul-08, 11:52 AM
You may or may not have noticed an emoticon depicting a growing nose. I used it to imply "not so correct reasoning". ANd I think you misinterpreted my second line.
Ah; humor. What a concept. Actually; I don't see much use of that emoticon, so it seemed to have slipped in context for me. Thanks for clearing that up.

Nicolas
2009-Jul-08, 01:43 PM
Engineers have been designing out harmonics in high-performance turbines for years so they don't self-destruct. They don't use primes (except for the number of turbine blades - sometimes), but they do use variable-geometry inlets and outlets. Straight shots tend to have resonant problems at certain turbine frequencies.

It's being used in all kinds of places. Some speakers are designed specifically not as a box to reduce harmonics.

Agreed, unless you're Spinal Tap, a speaker can't be compared to an SRB. But the principle remains: there are known ways to design yourself out of vibration trouble, so there's a good chance it'll work for Ares 1 too. Which is off topic, but anyway. :)

Antice
2009-Jul-08, 06:29 PM
humm.. i humbly disagree. a speaker and an SRB have a lot in common. both are open ended objects that have shock waves exiting the opening at specific wavelengths.
the harmonics of the SRB are quite similar to a tubular loudspeaker, and the mathematics for both are the same. Now apart from spinal tap i cant think of many bands wanting one of those SRB's for their bass. well.. mabe Dimmu borgir.. that lead singer do kinda sound like a big rocket sometimes :shifty:

Nicolas
2009-Jul-08, 08:24 PM
On top of that, it saves on on-stage fireworks costs considerably.

SRB: Solid Rocking Band.

ahem, on topic maybe?

mugaliens
2009-Jul-09, 04:51 AM
humm.. i humbly disagree. a speaker and an SRB have a lot in common. both are open ended objects that have shock waves exiting the opening at specific wavelengths.

SRB's velocity flows are beyond MACH, so "shock wave" is technically correct.

A speaker's velocity flows are well under MACH, so "shock wave" is incorrect. "Sound wave" is correct.


...the harmonics of the SRB are quite similar to a tubular loudspeaker, and the mathematics for both are the same.

They are most certainly not the same!

Here's (http://blackmilk.fr/loudspeaker/index.C)an online loudspeaker graphic calculator. Here's (http://www.ajdesigner.com/)a collection of many more, most of which show the math. This $248 book (http://www.amazon.com/Theory-Design-Loudspeaker-Enclosures-Benson/dp/0790610930)entitled, Theory & Design of Loudspeaker Enclosures is chock full of math. In fact, unless you're either a mathematician, a physicist, or an aero engineer, you probably won't understand much of it.

Here's a web page showing the mathematics typically used in loudspeaker Transmission Line (http://www.quarter-wave.com/TLs/Advanced_Models.pdf), that is, a driver in a tube, the closest parallel between a speaker and an SRB.

Please show me the online SRB calculator, or the mathematics used in SRB design.

Thank you.

Nicolas
2009-Jul-09, 07:08 AM
Subsonic/supersonic makes the required set of formulae different.

This would drag us back to the likes of the discussion of Bernouilli and lift. Don't make me link That One Post again. ;)

And it's not really on topic. :)