Ares V (CaLV) - status

GCNRevenger · 2006-06-13 05:53:23

will have to be replaced

...With the old Apollo 10m rigging thats still at Michoud and the Cape perhaps

and pad infrastructure extensively modified

The launch table hold-downs and umbilicals would have to be moved for the 8.4m CaLV, how much harder would it be for the 10m?

Four RS-68s per booster should be more than adequate to maintain a reasonable thrust to mass ratio and burn time

How do you know that? Wouldn't the CaLV need more thrust to help compensate for the reduced Isp?
(Edit: or perhaps, the 5th engine is for engine-out capacity. "Longfellow" CaLV concept used 4X RS-68)

the propellant needed to make up for this could be accommodated by stretching the core or the EDS

It already is! If they made it any longer, it wouldn't fit in the VAB, and would probably make control difficult. Plus, the upper SRB connect wouldn't run between LOX & LH2 tanks like Shuttle (the STS LH2 tank and orbiter are actually pulled from this structure by the SRBs and is very important.)

Alternately, the the number of SRBs could be increased, which would allow for the use of current stocks of four segment SRBs.

Adding another pair of SRBs would add structural complexity/mass and reduce reliability, and would nessesitate RS-68 air-start probably. Plus there is no such thing as a "stock" of these other then the aging units that lift Shuttle, and infact the cost to reload one is almost as high as building a new one. It will infact save money to eliminate the production line for the old model and build only the five-segment version used on CLV. (Edit: Each SRB reload costs $10-15M more than an RS-68 engine does too, even trading 1 RS-68 for 1 SRB amoratizing over the CaLV's estimated design life is over a billion dollars. Would about pay for the 8.4-10m conversion)

with 5 RD-0120s

Not happening. The production facilities for the engine no longer exsist except in the hyperbole of the Energia PR men, and in the likely event that Russia would not give us the blueprints this would give Russia veto power over the US space program on a whim. Congress would scream for Griffin's head...

hysterically rabid far-right ultra nationalists

Uh huh. Why is it so hard to believe that Russia would stab us in the back over engines on a whim? They have already done it for money over ISS modules, they might do so again when they have VSE under their defacto control too. Thats to say nothing of the small economic penalty for Russia for a sizeable ($300Bn NASA plan, national pride, etc) political weapon.

RD-0120 is in most respects slightly better than SSME while being slightly simpler than RS-68!

I find that hard to believe, since the RS-68 has only 20% of the parts of SSME. (link) How do you know RD-0120 is TEN TIMES simpler then SSME? After all, the RD-0120 is a copy of the SSME too, its similarities are no coincidence, and was the first Russian cryogenic engine (and RS-68 is our 4th). (Edit: however, they are different enough that they would not be readily interchangeable, and if we are flying RD-0120, SSME production lines would be closed.)

And even if it costs half what the "full version" SSME does to make in the States', thats still double what RS-68 costs. Thats $100M a flight extra, not including the cost to set up RD-0120 production lines here in the States'. Oh, and the air-start version of RD-0120 has never flown either if memory serves, eliminating it as an off-the-shelf option for CLV or CaLV/EDS. The current SSME already shares some of the RD-0120's key features, like the simplified regenerative nozzle, but still costs too much.

I also find it hard to believe your story about Aerojet testing RD-0120, especially since there are so few examples of the engine left, much less working models. Or this business about the company trying to sell the blueprints.

the American Reich

You've just gravely insulted 300,000,000 people, but I guess that is the style these days. You've just compared America to a government that launched a brutal a war of conquest against its neighbors (which killed tens of millions) for ideology and topped it off with the industrialized genocide of around seven million people for no reason at all, more-or-less sucessfully wiping out an entire cultures just because of their race. So permit me to return the favor... Way to go, you worthless piece of ****

Oh, and I invoke Godwin's Law too, now shut up and go back to the cess pool where you've been hiding rob

robcwillis · 2006-06-13 16:15:13

No, I have not insulted 300 million people. I have insulted the small minority on the extreme right who want the United States to pursue certain ultra-nationalist, xenophobic policies similar in some respects to those of the 3rd Reich. It is typical for someone like you to accuse anyone who disagrees with your politics of being anti-American. The majority of Germans living under the 3rd Reich were not Nazis, just as the majority of Americans, thank God, are not like you. Suck on that, you worthless piece of ----.

Aside from your personal attacks on me, you have made a number of stupid factual errors. The baseline CLV booster is 4 segment, not five:

http://www.astronautix.com/lvs/clv.htm

Based on your line of reasoning, the new 5 segment boosters should not be produced in order maintain standardization!

I never said RD-0120 was “10 times simpler” than SSME. Stop putting words in my mouth.

RD-0120 is NOT a copy of SSME. The team who developed it was ordered to duplicate its capabilities, and they utilized some of SSMEs better features. That is where the design similarity ends. NASAs own trade studies for Magnum eventually concluded that a set of 3 RD-0120s was a lower cost, higher performance, and better reliability option than 2 RS-68s. You also claim that SSME and RD-0120 are not “readily interchangeable”. Why not? I’m curious as to what story you will make up to answer that one.

What is this crap about “Russia would not give us the blueprints”? You would have us believe that P&W don’t have the “blueprints” for RD-180! CADB (Kosberg), like all other Russian manufactures are actively encouraged by the Russian government (who would take a cut through taxation) to sell anything they possibly can for hard US currency, even if what little revenues earned from such licensing pail before what it really cost to develop the technology in the first place. Aerojet already holds the license to build NK-33 and NK-43. You say you find it “hard to believe” that Aerojet has performed extensive tests on RD-0120. If so, you are an idiot or a liar:

http://darwin.nap.edu/books/0309054370/html/55.html

http://www.fas.org/spp/guide/russia/launch/other.htm

http://www.aiaa.org/TC/ST/yearinreview_97.html

http://www.seds.org/spaceviews/9604.html#deepthrottle

I could go on, and on, and on...

So GCN, why don’t you shut up or stop telling lies?

GCNRevenger · 2006-06-13 17:26:53

Not only have you been in a cesspool, apparently you have been submurged in one until experiencing brain damage and under a rock.

First of all though, its wrong, it is immoral to compare anyone or anything to the evils that Nazi Germany perpetrated on man that were not factually comperable. You used the "American Riche" slur because the Third Riche did evil, and therefore this unavoidably implies that America has done comperable things; if they did not, then there would be no cause to use such a label.

It is wrong to make such a comparison when it is not true, it is a very serious insult and a dishonor not simply to those targeted by it, but the victims of the true evil equated with it by cheapening their lives, suffering and death. Sure you can spin and lie your way with qualifications after the fact about the target of your slur, but unless "some characteristics" includes industrialized genocide and the litany of Nazi terrors you are urinating on the graves of fifty million people...
___________________________________________
*chuckles*
The Astronautix article is... out of date. It has been widely anounced by NASA that the CLV will infact use the five-segment SRB with a modified "beefed up" J-2 for the upper stage.

I will stop putting words in your mouth when you stop opening it and saying silly, ignorant things... RS-68 has 80% fewer parts than SSME, therefore for RD-0120 to have rhetorically signifigant less complexity, it would have around 90% fewer which is about ten times. You spouted this from Russia-worship, to trumpet the allmighty RD-0120 over those pitiful American dogs with their RS-68.

"it was ordered to duplicate its capabilities, and they utilized some of SSMEs better features." = They copied it... its the same size, performance, and developed at the same time as SSME. It was also the Russian's first large cyrogenic engine, they never built one before. The only really different thing about it is the simpler turbopump arrangement and manufacturing tricks.

But the reason they are not interchangeable is largely because of the control mechanisms and mounting, which are very different. RD-0120's gimbaling system and SSME are very different because of their different mounting, the SSME's electronics systems are much different with the latters' extensive use of computers, and the two engines would probably need a total reworking of the failure sensors to achieve man-rating or engine-out on CLV/CaLV. It would take alot of time and money to change either rocket to the other engine. Not that it matters anyway, since NASA isn't planning on using either one.

What is this crap about “Russia would not give us the blueprints”? You would have us believe that P&W don’t have the “blueprints”

*Shakes head* You automatically and thoughtlessly leap from "Russia did" to "Russia will;" they sold the RD-180 plans to us because if we didn't use them, then the USAF would have just used Delta-IV instead of Atlas-V, and Russia would be out money but not have gained anything.

But with RD-0120 on CLV and/or CaLV, this is not the case, since NASA would not have a practical alternative, SSME would be long gone (not to mention unaffordable) and it would take years to switch from RD-0120 to RS-68/J-2X, which is intollerable especially if we have a Lunar base or are launching parts for a Mars mission.

Then, Russia would have the real bennefit of a political weapon to hold against us for almost no cost to them... and you think they would just sign this away? Doubtful, doubtful... You must reguard not their actions, but their motives, as that is where their actions arise: Russia has already demonstrated an almost casual contempt for NASA's space interests whenever it suited them, twice! Once for money to "finish" their contributions to the ISS so that Shuttle would have something to do. The second time, which I think is much graver and more telling, was the business about the INA act dealing with Iran, where they held the ISS against us to prod us into reducing pressure against their ally (who, I might add, is our sworn, proven enemy).

Oh and I don't think I said any "lies," only that I doubted the veracity of your statements.

Edit: and really, there is that little national pride/money-not-spent-here thing... a few engines for cheap dinky rockets like Atlas that we can do without? Sure, but several hundred engines for putting people on the Moon and flags on Mars? Thats a different story.

robcwillis · 2006-06-13 22:38:14

I assume nothing head shaker. CADB Kosberg has already offered to license production of RD-0120 Aerojet or any other interested American firm, and have always had a green light from the Russian government to do so. These are the current facts, past and present tense, not some prediction or assumption on my part. It is the US State Department that actively prohibits CADB and other Russian firms from selling to, for example; China, while the political machinations of people like you make it almost impossible for their products to compete for NASA contracts. This is not a level playing field. You do not want them to be allowed to play at all.

Aerojet already has much of the technical documentation required to start pre-production of an RD-0120 copy. The only thing preventing them from doing so is a lack of any orders, and the little matter of it being against the law to undertake unlicensed production. Once such a license is purchased, which is, as I said before, already available, there is nothing the Russian government could do to stop it even if they wanted to. Any US based RD-0120 production line would, by definition, be up and running well before the first CaLV launch, making your whole “political weapon to hold against us” argument a steaming pile of crap.

All but a tiny fraction of the cost would be “money spent here”.

Russia is not an Ally of Iran. Russian foreign policy towards Iran is primarily geared towards maintaining stability in the region, partly in the hope of discouraging Iranian support for certain terrorist groups in Chechnya and other Russian provinces with Shia populations. Also, Russia would prefer that the US not attack and/or invade Iran. Although US/multinational corporations actually do more business with Iran (albeit partly through 3rd parties) than do Russian firms, Russian economic interests are likely to suffer somewhat if the US invades. Although Halliburton, for example, does fairly well in Iran, their business is likely to explode (excuse the pun) just as it did in Iraq if Iran is occupied by U.S. forces. In contrast, you can bet that not many Russian companies would be getting any fat “reconstruction” contracts.

Russia would also prefer that Iran not be made into an Al-Qaeda mass recruiting machine like Iraq has become since Bush invaded. Russia actually shares a very large border with Iran, and would have a lot to worry about if this occurred, although I suppose the Russians could take comfort in being completely surrounded by yet more US military bases.

I have no pro-Russian/anti American bias. Chelomei, for example, is widely considered one of the greatest personalities of the Soviet space programme. I consider him nothing but a vindictive political hack who contributed nothing useful to the field of spaceflight. Proton was a total disaster for the 1st five or ten years, and it is unfortunate that this ultra-toxic monstrosity remains in production. It is you, GCN, not me, who have spewed vitriolic and largely unfounded criticism on SSME, STS etc. These are American systems. I think RS-68 is a fine engine. RD-0120 is even better. You seem to loathe Bob Zubrin, whom I admire as perhaps the greatest single contributor to increasing public support for humans to Mars. He happens to be an American. I also consider the NASA DRM version 3 (addendum) to be markedly superior to any past or current Russian manned Mars mission design study. Is this “Russia worship”?

GCNRevenger · 2006-06-14 07:17:22

I assume nothing

Hey, starting off with a lie, thats a good way to try and prove your point, plus parrot what you have already said except with more words while ignoring my point entirely.

The Russians were, I'm sure, happy to find a buyer for their engines back when we had alternatives and the rockets the engines would push were not critical to national security and prominance. But with CLV/CaLV, this is not the case, so I am stating that the Russians now would not sell the blueprints/licence to us. The political bennefit of Russia making an irreplaceable component for VSE would simply be too enticing, and so they would not give us the engine.

Which is where the latter portion of my previous post comes in, where NASA would hypothetically ink a deal to buy only finished units from Russia rather than the blueprints/licence. In which case, this would give Russia a big stick in their political arsenal, defacto veto power over the entire US national space exploration enterprise. This is too good for them to give up for a little cheque for CD-ROM worth of CAD files and a manilla envelope of legal papers.

They might have been happy to sell then, but now things are different.
___________________________________________

Russia is not an Ally of Iran

>Sold Iran advanced air defense missiles
>Sold Iran advanced anti-ship missiles (SS-N-22 "Sunburn" and VA-111e "Shkval" which have no purpose except sinking US warships)
>Sold Iran a graphite-moderatred nuclear reactor (which can make Plutonium, and is almost done)
>Consistantly opposed any use of UNSC authority against Iran, instead pushing for the useless IAEA to resolve the nuclear crisis (M. Al-Beradi says Iran should have Uranium enrichment)

Nope, Russia couldn't be an ally of Iran, no way no how!

prefer that Iran not be made into an Al-Qaeda mass recruiting machine

Uh huh, where they have "revivals" (replete with a heart-felt round of "Death to America!") to sign up suicide bombers and give super-IEDs to Al-Qaeda forces in Iraq for blowing up US armored vehicles.

I have no pro-Russian/anti American bias

So thats why your ignore the obvious about Russia/Iran, ignore the past Russian extortion of NASA for cash and political gains, and trumpet the wonderfulness of their engine over any American engine without even considering the possibility that our engine is just as good or better. Oh, and lest I forget, that business about Russia somehow suddenly coming up with an engine just like SSME and never built a cryogenic engine before but "didn't copy" it.

The SSME is a marvel of engineering in that it is the first engine with its performance and size ever built, and is fairly reliable despite its extreme operating regieme and complex construction. If development had really continued instead of band-aiding the experimental version it might have become a useable RLV engine... The trouble with it is that its a complex beast, much too complex to be expendable, and would never be affordable.

Bob Zubrin... Bob is a genuine dyed-in-the-wool zealot, and while has helped keep Mars on NASA's roadmap he is by-and-large a liability and not an asset. He wants to get to Mars so badly, that he is willing to sacrifice too much, including the usefulness and safety of any Mars program in the name of expedience.

He is also a liar, and said numerous things that sounded reasonable to the laymen but were just not true about NASA Moon plans, thus trying to manipulate the electorate. I believe he also is being deceptive about MarsDirect, that it could never work in its original marketed form marketed to us and Congress, and he secretly plans for a nuclear-powerd Ares to launch his vehicles only after it is too late to cancel. This is a big deal, since he also knows the reactor would not be in a stable orbit before firing, and thus presents a wholey different kind of safety issue.

And lastly, I think he does all of this because he honestly believes mankind is doomed unless we get to Mars right now, and that he is some latter-day prophet with too high of an opinion of himself, which is not the face you want to put on the public head of any Mars movement.

Edit: Oh, and I forgot to add that there is an economic reason for Russia to hold onto those RD-0120 blueprints too. That if we were just going to order two or three dozen for the EELV or X-33 program, Russia would not have made that much money selling the engines only. But now with VSE, NASA will be needing up to 1,000 copies over the estiamted design life of CLV/CaLV... In that case, the potential profits are obivously MUCH higher and so they would be even less likely to sell us the plans.

Mars_B4_Moon · 2006-06-16 05:49:45

Sold Iran advanced air ....
>Sold Iran ....."
Nope, Russia couldn't be an ally of Iran, no way no how!

Selling to Tehran was fair-game at the time, Iran was simply a cold-war battle ground much like Vietnam.
The US was every friendly with the Shah of Iran who was corrupt but a nice friend of America but then came Irangate during the Reagan admin where they tired to give an Ayatollah nutbag Phoenix missiles, spare parts for the F14 Tomcats, millions of dollars, Pratt & Whitney engines, air to air missiles...etc

The Cold war is over
I don't really care who goes to Mars, the Ruskies, Euros, Chinese or UnitedStates...just as long as somebody takes manned missions to the red-planet serious.
Plan-Bush, or the vision to land American on Mars by 2035 or 2040 is a bit of a joke, the way things are going Katrina, the Record-deficit and Iraq will eat up all the money before we even get a funded CEV.

GCNRevenger · 2006-06-16 06:11:39

The US sold Iran weapons before it was taken over by the present evil barbaric theocratic regieme, but all these Russian sales I listed were recent and occured well after the Islamic revolution and not just a year or two. The weapons I noted didn't even exist until after the fall of the Shah, and it doesn't take thirty seven years to build a nuclear reactor.

I'd like to point out that Russia's new bestest buddy today in the region is just short of yelling "we want nukes!," threatend to again commit genocide against the Jews, beyond any question actively supports international and domestic terror, and holds the most important stretch of internaitonal waters in the world hostage.

Edit: And why do you think "plan Bush" will fail to get to Mars? Come on, what are your reasons? Why can't they? We will have a rocket big enough (CaLV), the Lunar lander refitted for Methane burning and stronger structure would make for a Mars lander, and something resembling the CEV for acent and reentry. All thats really lacking are the HABs and the logistical elements.

And since the majority of the media would never say anything good about Bush, I guess you didn't hear how the Nat'l deficit is getting much smaller, and there probably isn't going to be a second Katrina payout, especially after "victims" stole $1,400,000,000.

Rxke · 2006-06-16 09:07:03

Bzzzzzt!

Please stay ontopic, pleaaaaaaseeeeeee... :cry:

publiusr · 2006-06-16 13:46:02

CADB Kosberg has already offered to license production of RD-0120 Aerojet or any other interested American firm, and have always had a green light from the Russian government to do so. These are the current facts, past and present tense, not some prediction or assumption on my part.
Interesting
Aerojet already has much of the technical documentation required to start pre-production of an RD-0120 copy. Any US based RD-0120 production line would, by definition, be up and running well before the first CaLV launch
I have no pro-Russian/anti American bias. Chelomei, for example, is widely considered one of the greatest personalities of the Soviet space programme. I consider him nothing but a vindictive political hack who contributed nothing useful to the field of spaceflight. Proton was a total disaster for the 1st five or ten years, and it is unfortunate that this ultra-toxic monstrosity remains in production.
Well said
I think RS-68 is a fine engine. RD-0120 is even better.

Even so--RS-68 is what we have. Perhaps RD-0120 can come later. Perhaps China will want it. As far as politics (yawn) is concerned, Obey and Frank on the Left are just as much enemies of VSE as Mike Pence is on the right. So let's vote pro-space--without regard to party differences. In this era of 50/50 votes, small comunities (The Elian Gonz crowd in Florida--the Naderites, etc. --all have a power to tilt the balence. What we must do is to put aside our differences and show that space advocates can also be a voice. If Jeb's last name wasn't Bush--his pro-space stance alone might get Florida and Ohio, state with NASA centers. If he runs away from his Woodrow Wilsion brother inhabiting the White House--his center-right pro-space platform might have him win the Presidency.

cIclops · 2006-06-30 12:41:17

Note thread name change to Ares V ... Ares the Roman name for Mars and 5 for the 5 RS-68 engine cluster on the first stage.

(correction: Mars is the Roman name for Ares)

publiusr · 2006-06-30 12:44:21

I saw that.

Nice links:

http://en.wikipedia.org/wiki/Sea_Dragon_%28Rocket%29
http://en.wikipedia.org/wiki/Shuttle_De … ch_Vehicle
http://en.wikipedia.org/wiki/Ares_1

Almost over:
http://www.aero.org/conferences/sclv/

Misc:
http://www.efluids.com/efluids/pages/j_ … d_rock.htm
http://www.lpi.usra.edu/CASS_home.html

OT
R.E. Gold, 'SHIELD: a comprehensive earth protection architecture', Advanced Space Research, vol 28, 2001, pp1149-158

cIclops · 2006-07-01 03:51:26

Latest concept image ripped from Jeff Hanley presentation (PDF)

cIclops · 2006-07-04 11:03:10

Ripped from Ares V factsheet (PDF 5MB)

The versatile, heavy-lifting Ares V is a two-stage, vertically stacked launch system. The launch vehicle can carry about 287,000 pounds to low Earth orbit and 143,000 pounds to the moon.

F1-X!? · 2006-07-06 07:35:17

Ten meters? This is sounding more and more like the ol' Saturn-V's planned sucessors that used solid rocket boosters instead of the massive F-1 first stage.
Well…Griffin said that the Apollo engineers did a lot right.

Actually it wasn't so much the Apollo engineers as the USAF for initiating and funding the F-1 engine in the first place: 1957-8! Without that, it would have been a US N1 type nightmare with 30-40 engines for the launch vehicle. Or Von Brauns' initial EOR technique using multiple launches. Mind you why NASA scrapped the RS-83 & 84 motors is an example of how they've given the impression they've lost their way...3 years to do 16 STS launches: a rate they never achieved even during the heyday

F1-X!? · 2006-07-06 08:37:04

Hopefully this will tie all the CaLV threads together
This report in Flight International says the RS-68 has been selected as the CaLV’s main engine!
Life-cycle cost also drove selection of the Rocketdyne RS-68 as the CaLV’s main engine, rather than the RS-25e. However, this led to an increase in CaLV core structure diameter from 8.38m, the same as the Shuttle’s external tank, to 10m. The wider core was needed to enlarge the fuel tanks to provide the extra propellant required to allow the RS-68 to burn long enough to deliver RS-25e-like performance.

Actually the total specific impulse value of 4x RS-25e burning for a given time can be met by the the more powerful RS-68 with a shorter burn time and trajectory tuning to suit. I imagine though, that the thrust frame for 5xRS-68 will be heavier mass-wise than for 4xRS-25e. More mass: more propellant to compensate!

GCNRevenger · 2006-07-06 16:25:04

Uh, specific impulse is pretty much intrinsic to the engine. SSME (RS-25) has much better specific impulse at altitude than RS-68, but bigger tanks with RS-68 provides the same lift capacity for less money. Also worth noting, that the final Ares configuration that featured SSME used five of them, not four.

The RS-83/84 are suited for RLVs, not for expendable boosters. Since we aren't building an RLV for, oh, thirty years or so then canceling them was a good choice. We already have engines that are good enough for VSE.

F1-X!? · 2006-07-06 22:09:19

Uh, specific impulse is pretty much intrinsic to the engine. SSME (RS-25) has much better specific impulse at altitude than RS-68, but bigger tanks with RS-68 provides the same lift capacity for less money. Also worth noting, that the final Ares configuration that featured SSME used five of them, not four.
The RS-83/84 are suited for RLVs, not for expendable boosters. Since we aren't building an RLV for, oh, thirty years or so then canceling them was a good choice. We already have engines that are good enough for VSE.

You're right. I'd forgotten the '68's vacuo ISP was about 12%less. Enough to make a difference. Still a lot cheaper in unit cost terms. Don't agree about the 83/84; particularly the latter. Seven of em would have given us a nice first stage to play with. Building that kind of reliability into a rocket engine is by no means a bad thing - especially with man-rating et al. Plus using LOX/LH2 in the first stage almost precludes the use of solid strap-ons. The RS84 was a hi-performance/thrust LOX/RP1 design: not too heavy either. Downgrading to EELV standards would not have been a problem. Unless - heaven forbid - we use the Sov-I mean Russian engines of the Atlas ala Energia! but since the ISS is really MIR 2, why not!?

GCNRevenger · 2006-07-07 06:00:41

Seven RS-83s wouldn't have enough thrust to launch a Saturn-class heavy lifter, and the fuel tank(s) would be so large that assembly would be difficult. So if you used Delta-IV style strap on booster cores with RS-83s in them, why bother use SRB instead? Sure you'd get some performance boost with the higher Isp the RS-83 would offer, but the engine still needs several hundred million or a few billion for development, and would probably cost more per-launch than a quintet of RS-68s. The RS-83 also weighs 13MT each versus the RS-68 ~7MT.

RS-84 is probably a fine engine, but you gotta compare its performance to the cost of SRB. The Shuttle SRBs are pretty cheap for the thrust they provide, and are very reliable. The single SRB on the Ares-I provides unique safety features, so since we are going to use it then we might as well use it for the bigger Ares-V too instead of developing a liquid kerosene booster. Maybe sometime down the road, when we are supplying/building a Mars base, then a reuseable flyback booster for Ares-V would be a good idea.

F1-X!? · 2006-07-08 07:57:16

Seven RS-83s wouldn't have enough thrust to launch a Saturn-class heavy lifter, and the fuel tank(s) would be so large that assembly would be difficult. So if you used Delta-IV style strap on booster cores with RS-83s in them, why bother use SRB instead? Sure you'd get some performance boost with the higher Isp the RS-83 would offer, but the engine still needs several hundred million or a few billion for development, and would probably cost more per-launch than a quintet of RS-68s. The RS-83 also weighs 13MT each versus the RS-68 ~7MT.
RS-84 is probably a fine engine, but you gotta compare its performance to the cost of SRB. The Shuttle SRBs are pretty cheap for the thrust they provide, and are very reliable. The single SRB on the Ares-I provides unique safety features, so since we are going to use it then we might as well use it for the bigger Ares-V too instead of developing a liquid kerosene booster. Maybe sometime down the road, when we are supplying/building a Mars base, then a reuseable flyback booster for Ares-V would be a good idea.

In fact, it was the RS-84(and not the RS-83 LOX/LH2 engine) for the first stage booster that I referred to. 7x 1,064,000lbf = 7,448,000lbf; a mere tad below 5xF-1’s and retaining a +12% ISP advantage throughout.
Due mainly to a massive differential in propellent density, LOX/RP1 has an advantage versus the LOX/LH2 combo for booster stages: particularly utilizing the superior liquid propellant engine technology of the Russians - which both the RS-84 & P+W RD-180(the latter being an americanised RD-170: reason it was rejected) do! In any case the structural efficiency of a solid motor is WAY below that of a C.P Booster: especially if one employs the (originally Russian) Al-Li alloy structure technology. A 2Mlb/ 309’(?!) vehicle to loft 12-13T to a 185ml orbit? An efficient LP design would be at least 65% of that; look @ Proton. I'd really like to hear the "unique safety features" an SRB has! ANY failure in a solid motor always means a CATO – as I know to my own cost at LRDS/NERO et al the hard way! Brave boys and girls, those Astronuts!

GCNRevenger · 2006-07-08 09:47:05

Apparently you haven't been following the discussion about SRB safety nor has it even occured to you that there is another and very important variable to consider when designing rockets...

First of all, the Shuttle SRBs, by virtue of their fuel blend have a handy little characteristic: if they leak, they stop burning. The solid fuel only burns rapidly when it is under pressure, so if there is a leak the pressure drops and the combustion slows down. Solid fuels themselves also cannot explode, since the rate of combustion is intrinsicly controlled by the surface area. Modern solid fuels are imbedded in hard rubber, so there is no possibility of a sudden radical increase in surface area or burn rate. Pop-off caps using venerable explosive bolts on the sides would also provide shut down options.

Second, thanks to their sturdy steel construction, if there is a leak around a segment seal it won't lead to a catastrophic explosion like smaller light-weight SRBs. The SRB has sufferd at least two leaks, first with Challenger and a second with Atlantis, but in both cases the SRBs did not explode. In the latter case Atlantis was able to continue on to orbit as the leak didn't face the tank or orbiter.

Since the CEV and its upper stage will be riding on top of the SRB's one-piece steel end cap, no segment seal leak can threaten it. If there is a leak, it will also be obvious and easy to detect since there would be a sudden loss of thrust.

Compare this with a liquid engine, any liquid engine, and these are compelling advantages. Reguardless how its arranged, liquid fuels will always have the possibility of exploding, while the solid fuel doesn't. All modern high-performance liquid engines are also turbopump driven, which carry inherint and "unfixable" safety concerns. When they fail, they usually fail big (maybe ignite the fuel too), and it doesn't take much to tear up a turbine spinning thousands of RPMs cooled to cryogenic temps.

Many high-performance engines also operate at very high chamber & nozzle pressures/temperatures that stretch materials to the limits, increasing the risk of catastrophic failure and the severity of the failure if it does occur. Liquid fueled engines are also much harder to instrument and monitor to provide sufficent warning to shut down or use the crew escape systems, there is little warning when a turbine is about to come apart and monitoring the temperature all around the nozzle would be difficult.

Eliminating the possibility of these occuring with added headaches involved with man-rating and instrumentation in one of the two stages of the CLV is a major bennefit. There is one more bennefit that SRB has that isn't technically related to the engine, that is because of the very high thrust the CLV can accelerate more quickly than an EELV-style liquid fueled rocket which improves the safety by getting off the pad and to orbital velocity faster.

This is good, especially for ISS missions, since if you have to ditch in the sea you can do so closer to shore and further south in warmer water than if you accelerated slowly, plus if you get pretty close to orbit the CEV's extra fuel might permit a once-around abort that avoids a hypersonic backflip in the atmosphere with normal parachute deployment in the US.

GCNRevenger · 2006-07-08 10:05:44

The second part, is your treatise about the wonders of liquid fueled engines ignores the "elephant in the room"...: COST

The Saturn-V, which was a wonderful rocket for its purpose and performed beautifully, would cost around ~$3Bn each today and woudl be an absolute disaster and make NASA go broke. Money and political capital, those are the real propellants for rockets, more so than fuel and oxidizer.

Sure RS-84 or RD-170 first stage could provide comperable performance with the Isp and structural efficiency of liquid tankage, perhaps even a little better, but how much will that cost? An SRB refill is about $30M or so each, and since the five-segment SRB is going to be developed for CLV anyway, its development cost is thus discounted from Ares-V.

You would need between four and six Kerosene engines to replace the Shuttle SRBs I figure, and the chance that you could build them and associated tankage for $10-15M a pop and to almost totally free development is not going to happen. Plus, SRB is built on proven technology, and is presently the most reliable booster engine ever built - better than F-1, better than RD-170, at least as good as the RS-84.

And the infrastructure for it is already in place, no need for new factories, handling/assembly, etc. The SRB has strong political support too I imagine.

Griffin has made good choices with Ares-I and V, the latter could also have the EDS stage swapped out for a cheap kick stage, perhaps delete one or two RS-68s, and this would make a good "light heavy lifter" in the 90MT range for Mars vehicles.

SpaceNut · 2006-07-08 20:56:51

Let the Military fund them if they wish since they were from the OSP that was cancelled with the announcement of the VSE.

F1-X!? · 2006-07-08 23:08:35

GCNRevenger wrote:

Apparently you haven't been following the discussion about SRB safety nor has it even occured to you that there is another and very important variable to consider when designing rockets..."/quote
What discussion: I joined under two weeks ago. Still exploring the site for interesting threads.You're making assumptions on the basis I haven't mentioned other factors. That does NOT mean I 'm not aware of any/them.
Quote/ First of all, the Shuttle SRBs, by virtue of their fuel blend have a handy little characteristic: if they leak, they stop burning. The solid fuel only burns rapidly when it is under pressure, so if there is a leak the pressure drops and the combustion slows down. Solid fuels themselves also cannot explode, since the rate of combustion is intrinsicly controlled by the surface area. Modern solid fuels are imbedded in hard rubber, so there is no possibility of a sudden radical increase in surface area or burn rate. Pop-off caps using venerable explosive bolts on the sides would also provide shut down options."
Oh yes they can explode matey! Ask any Range Safety Officer! PBAN is as volatile as any other SP in the right circumstances. And it is by NO MEANS a new SP combination. Use it myself in my own H-PR's. LOT's going for it. You would need a pretty substantial "leak" to engender the pressure drop characteristics you describe: and they would by no means be consistent. In any case that pressure you speak of is a function of propellant burn, and the surface area as we both know, constantly varies, hopefully with some consistency - mute point , since it usually doesn't, which is why a large performance margin in the SRB has to be catered for elsewhere. Actually the rate of combustion depends upon the burn occuring over the entire constantly varying internal surface area from top to bottom; in effect enlarging the central hole once the star-spigots burn off; in the initial stages. Which, in of itself,implies a pressure drop through increased csa! Hence the regressive thrust characteristics of most solid motors, except those employing a 'D' core design. That asymmetric design also has it's risks...
In any case, as we saw from Challenger, a leak DOES NOT prevent a solid motor from continuing to burn. If it did, the effect in of itself could result in a CATO. The other one is still burning...get it...? Granted that wouldn't apply to "The Stick", but certainly to Ares 5...
QUOTE/ Second, thanks to their sturdy steel construction, if there is a leak around
a segment seal it won't lead to a catastrophic explosion like smaller light-weight SRBs. The SRB has sufferd at least two leaks, first with Challenger and a second with Atlantis, but in both cases the SRBs did not explode. In the latter case Atlantis was able to continue on to orbit as the leak didn't face the tank or orbiter."
Do remember that a solid motor is intrinsically a controlled explosion in of itself. Explosive gases seek the path of least resistance first, so your thrust vector takes on an asymmetric characteristic which has the potential of becoming uncontrollable. It is just that "sturdy" construction that give the segmented SRB it's low structural efficiency. It is the marginal performance predictions that require compensation in the other stages for M.O.E purposes.
Quote/Since the CEV and its upper stage will be riding on top of the SRB's one-piece steel end cap, no segment seal leak can threaten it. If there is a leak, it will also be obvious and easy to detect since there would be a sudden loss of thrust.
A very good argument for the fallacy of the side-by-side booster/payload configuration! Nonetheless, I don't agree for reasons iterated earlier.
QUOTE/Compare this with a liquid engine, any liquid engine, and these are compelling advantages. Reguardless how its arranged, liquid fuels will always have the possibility of exploding, while the solid fuel doesn't. All modern high-performance liquid engines are also turbopump driven, which carry inherint and "unfixable" safety concerns. When they fail, they usually fail big (maybe ignite the fuel too), and it doesn't take much to tear up a turbine spinning thousands of RPMs cooled to cryogenic temps.
Many high-performance engines also operate at very high chamber & nozzle pressures/temperatures that stretch materials to the limits, increasing the risk of catastrophic failure and the severity of the failure if it does occur. Liquid fueled engines are also much harder to instrument and monitor to provide sufficent warning to shut down or use the crew escape systems, there is little warning when a turbine is about to come apart and monitoring the temperature all around the nozzle would be difficult."
Known quantities(for decades), and characteristic of ALL liquid motors including the J2-X and CEV PM of the ARES 1 &V upper stages. But I would remind you that both the Saturn's SI-c and Blue Streak booster stages each had a perfect launch record. As for the instrumentation; standard stuff! How do you think they evaluate Test Flights;guesswork? Just image the SIZE of the vehicle if THOSE were solids for just the very reasons you've outlined. A falacious argument at best. To my mind, the solids are an okay solution, but in terms of optimum performance/overall cost, don't cut the mustard.
QUOTE/ Eliminating the possibility of these occuring with added headaches involved with man-rating and instrumentation in one of the two stages of the CLV is a major bennefit. There is one more bennefit that SRB has that isn't technically related to the engine, that is because of the very high thrust the CLV can accelerate more quickly than an EELV-style liquid fueled rocket which improves the safety by getting off the pad and to orbital velocity faster."
That high thrust only lasts for so long - in the initial stages - such that SRM stage burn-out velocity is usually 1000/1500fps down in deltaV in comparison with a LP Booster, leaving the upper stages with much more work to do. More than offsetting the high initial acceleration:which is merely a function of Thrust to Weight ratio in any case.
QUOTE/This is good, especially for ISS missions, since if you have to ditch in the sea you can do so closer to shore and further south in warmer water than if you accelerated slowly, plus if you get pretty close to orbit the CEV's extra fuel might permit a once-around abort that avoids a hypersonic backflip in the atmosphere with normal parachute deployment in the US."
"Uh Huh"! By the way, the ditching criteria is as much a function of the trajectory parameters as the launcher characteristics itself; particulary with respect to hi-LEO ISS type orbits, where a steep trajectory is employed with downrange distance being markedly reduced.
An atmospheric "hypersonic backflip"!? Do me a favor! A partial orbit scenario has been/is built into every manned launch trajectory in both the U.S and Russia(I remembered!) from the beginning. Even if Orbital Velocity is not achieved, a spacecraft will re-enter much as an ICBM would - with possibly more control.
Your other points aside, the leak/outgassing from the segment joint on Challenger began 180degrees away from the ET/Orbiter also. All the video footage shows that. Which was why I began thinking NASA's explanation of the incident was suspect. As with Columbia, where the video clearly shows the eco-foam chunk hitting the wing well abaft of the lower leading edge and disintegrating down the underside of the wing. Whereas the "experiment" clearly was a direct hit upon the upper surface the wing leading edge itself.
As for your point re the time to orbit, any advantage of initial acceleration is more than offset by the intrinsic long burn time of the J2-X LOX/LH2 stage which burns out at only 63miles altitude, leaving the CEV propulsion module with some 120 miles of altitude to gain - 65% of total: in vacuo, granted. No indicator of the deltaV component required. Most orbital trajectories make the penultimate stage achieve the highest altitude fraction, with - 3+stage configuration - the final stage(s) merely doing kicker duties with usually only a slight altitude gain.
I haven't plugged ARES 1 into my software yet, since accurate mass fractions/structural efficiency and RSRB criteria haven't been provided on the data I have access to(unless the original RSRB is being ressurrected..right! Fudge factors! Why not! Mark Wade to the rescue!), but the CEV PM must have massive reserves to achieve such a huge climb all on it's own.

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