Author Topic: Why a RS-68B based SHLV is more likely to be picked than a SSME based SHLV  (Read 103366 times)

Offline ares-mojo

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A few reasons:

1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.

2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.

3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.

This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.

Offline Analyst

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Could be, because NASA (and some folks here) think the bigger the better. I am sure it would be unaffordable. I am not even sure a smaller (SSME-based) HLV would be affordable enough to have something left over for the payloads. I could live without HLV at all. EELV (with some growth or not) and we are done (and realistic again).

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Offline Downix

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A few reasons:

1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.

2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.

3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.

This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.
The problem comes in that anything based on the RS-68 will not be a SDHLV, but an all new design, new 10m tank.  NASA's reports already discuss in detail the performance loss with the RS-68 in detail.  Add to it that the Ares V Lite can only lift 145mT vs the Ares V Classic which could do 155mT, to start. 

No, NASA is ordered to close the gap, and closing the gap means SSME at this point.  They no longer have the time to develop the RS-68 Regen and the 10m tank.  If they had begun work in '07, sure, but they wasted time on the Ares I instead.

Analyst has a point.  I've been looking at the EELV's, and they could do the growth into HLV if need be.  Wrapping 7 Atlas V cores together as a first stage would look quite similar to a Saturn I, but have far more capability.  Also would reduce the cost of the Atlas V itself due to economies of scale.
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Offline Idol Revolver

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The RS-68B would not be an option due to base heating. You would have to develop a regen version.

Offline John Duncan

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The RS-68B causes the HLLV to scale past what is affordable and likely to be buildable.  A 10m core results in widespread infrastructure upgrades which is even more invisible cash that you need.

There is little more funding available for anything so why start new developement when the existing components will do the job?

Could it be that "I've got to have a shiny new rocket" syndrome.  Probably.

Offline ares-mojo

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The RS-68B would not be an option due to base heating. You would have to develop a regen version.

The RS-68B IS the Regen version of the RS-68 engine.

Offline ares-mojo

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The problem comes in that anything based on the RS-68 will not be a SDHLV, but an all new design, new 10m tank.  NASA's reports already discuss in detail the performance loss with the RS-68 in detail.  Add to it that the Ares V Lite can only lift 145mT vs the Ares V Classic which could do 155mT, to start. 

1. 10m tank - yes.
2. Performance loss compared to what? Compared to a 5 SSME based 8.4m Ares V? Not really. Please provide a link for the Ares V Classic (5segment SRB, 5 SSME at core stage, J2x upper stage) having a 155mt lift capacity.

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No, NASA is ordered to close the gap, and closing the gap means SSME at this point.  They no longer have the time to develop the RS-68 Regen and the 10m tank.  If they had begun work in '07, sure, but they wasted time on the Ares I instead.

This is not correlating well with reality. "Closing the gap" (at least in the sense you appear to use the term "gap") isn't possible. If we are talking about US HSF, there is no gap (US astronauts will fly continuously to the ISS), if we are talking about a US launch vehicle with US manned spacecraft, the gap will not be closed by a SHLV development program but either by Ares I/Orion or by a commercial US dedicated CLV alternative. If we are talking "programmatic gap", we need to look to the end of the ISS program and the start of exploration, in which case there is no reason at all to go for a SSME-based 8.4m core HLV just for schedule reasons over an RS-68B 10m HLV. We'll start operating an HLV at the end of the next decade at the earliest (budget wise) no matter what (yes, I know some folks disagree, but reality dictates that we won't have a 100mt+ vehicle ready before 2018+ AND have lunar hardware or other deep space hardware ready).

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Analyst has a point.  I've been looking at the EELV's, and they could do the growth into HLV if need be. 
An EELV-derived exploration architecture has been dismissed already. It would be a political miracle and an epic paradigmatic shift if this really happens.

Offline Namechange User

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A few reasons:

1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.

2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.

3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.

This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.

The problem is none of these statements have any real meat behind it (obviously you do say it is your opinion) besides *I want a giant mega booster for some reason* and ignore economics, infrastructure changes, facility and tooling changes and, perhaps most importantly, using what we have now that would not require as much development money and a heavily loaded development schedule.  Basically, the exact same plan now just sans Ares 1. 
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Offline Idol Revolver

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1. 10m tank - yes.
2. Performance loss compared to what? Compared to a 5 SSME based 8.4m Ares V? Not really. Please provide a link for the Ares V Classic (5segment SRB, 5 SSME at core stage, J2x upper stage) having a 155mt lift capacity.
The performance loss is in isp. RS-68 has less isp than SSME, hence the need for a 10m tank to make up.

Offline ares-mojo

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1. 10m tank - yes.
2. Performance loss compared to what? Compared to a 5 SSME based 8.4m Ares V? Not really. Please provide a link for the Ares V Classic (5segment SRB, 5 SSME at core stage, J2x upper stage) having a 155mt lift capacity.
The performance loss is in isp. RS-68 has less isp than SSME, hence the need for a 10m tank to make up.

That's like saying a 100hp gasoline based engine has less performance than an 80hp diesel based engine, just because the diesel engine is more fuel efficient.

At the end, for an HLV (if we disregard schedule, which we can in our situation), it all boils down to costs and net payload to LEO. The AC report clearly indicates that Ares V Lite outperforms the more closely shuttle-derived vehicle options AND has the upper hand in life-cycle costs.

Offline ares-mojo

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A few reasons:

1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.

2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.

3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.

This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.

The problem is none of these statements have any real meat behind it (obviously you do say it is your opinion) besides *I want a giant mega booster for some reason* and ignore economics, infrastructure changes, facility and tooling changes and, perhaps most importantly, using what we have now that would not require as much development money and a heavily loaded development schedule.  Basically, the exact same plan now just sans Ares 1. 

I recommend that you look at the AC report in detail again. I know people around here think it is a flawed report and everyone has long forgotten about it already, but that is just not the case. There are valid reasons why the conclusions in the report were made - including taking into account infrastructure changes, facility and tooling changes, development schedule, risk assessment, schedule etc. etc.

And yes, what I said is basically the current plan without Ares 1. Do I think this would be the best way forward back in 2004/2005? No. But I strongly believe this is what NASA, the WH and Congress will go for.

Offline Namechange User

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This is not correlating well with reality. "Closing the gap" (at least in the sense you appear to use the term "gap") isn't possible. If we are talking about US HSF, there is no gap (US astronauts will fly continuously to the ISS), if we are talking about a US launch vehicle with US manned spacecraft, the gap will not be closed by a SHLV development program but either by Ares I/Orion or by a commercial US dedicated CLV alternative. If we are talking "programmatic gap", we need to look to the end of the ISS program and the start of exploration, in which case there is no reason at all to go for a SSME-based 8.4m core HLV just for schedule reasons over an RS-68B 10m HLV. We'll start operating an HLV at the end of the next decade at the earliest (budget wise) no matter what (yes, I know some folks disagree, but reality dictates that we won't have a 100mt+ vehicle ready before 2018+ AND have lunar hardware or other deep space hardware ready).


Correlating well with reality?  What you have described here is a very convienent way to think of things to fit your hoped for reality if you live in Huntsville.  Clearly you work for MSFC. 
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Offline Namechange User

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A few reasons:

1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.

2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.

3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.

This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.

The problem is none of these statements have any real meat behind it (obviously you do say it is your opinion) besides *I want a giant mega booster for some reason* and ignore economics, infrastructure changes, facility and tooling changes and, perhaps most importantly, using what we have now that would not require as much development money and a heavily loaded development schedule.  Basically, the exact same plan now just sans Ares 1. 

I recommend that you look at the AC report in detail again. I know people around here think it is a flawed report and everyone has long forgotten about it already, but that is just not the case. There are valid reasons why the conclusions in the report were made - including taking into account infrastructure changes, facility and tooling changes, development schedule, risk assessment, schedule etc. etc.

And yes, what I said is basically the current plan without Ares 1. Do I think this would be the best way forward back in 2004/2005? No. But I strongly believe this is what NASA, the WH and Congress will go for.

If this wasn't the best way forward in 2004/2005, then why on earth would it be the best way forward in 2009 when the situation is even more urgent?
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Offline ares-mojo

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If this wasn't the best way forward in 2004/2005, then why on earth would it be the best way forward in 2009 when the situation is even more urgent?

Decisions have been made already, development contracts awarded, program continuity is more important than getting it right "perfectly" by canceling everything just to go for an architecture that we right now believe fits the budget we expect to have in the next 10 years best. The programmatic risk for a complete architecture change is just too high. A lot of Ares I development work can be salvaged. The question that really remains is 8.4m SSME-core or 10m RS-68B core and due to schedule not being a factor any more for HLV development (we got 10 years in any event), 10m RS-68B just wins the trade.

Offline Idol Revolver

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10m RS-68B just wins the trade.
That may be your opinion, but in my opinion, your opinion will not be the way forwards. The cost to change all the infrastructure would be enormous.

Offline Namechange User

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If this wasn't the best way forward in 2004/2005, then why on earth would it be the best way forward in 2009 when the situation is even more urgent?

Decisions have been made already, development contracts awarded, program continuity is more important than getting it right "perfectly" by canceling everything just to go for an architecture that we right now believe fits the budget we expect to have in the next 10 years best. The programmatic risk for a complete architecture change is just too high. A lot of Ares I development work can be salvaged. The question that really remains is 8.4m SSME-core or 10m RS-68B core and due to schedule not being a factor any more for HLV development (we got 10 years in any event), 10m RS-68B just wins the trade.

All I can really say is that is......incorrect.  Your wishful thinking for the Huntsville-centric (sorry, need to stop here for a second and just say that I have to use stupid words to get my point across. I know that means I must have a weak argument, but that's why I use bad words). is the programatic danger.  It is easy to say development contracts have been awarded (and they have not for any kind of Ares 5 style rocket) and therefore it is too late to change. 

You are wanting to sacrafice all our futures and assuming that any super booster is going to be affordable and operationally feasible where the costs per launch in operations and sustaining engineering support do not crush the entire effort. 

The statement at the top shows how out of touch with reality you are unfortunately.  According to you, it doesn't matter if we get it "quite right" because we don't know what budgets will be in ten years.  Here are the major problems with that:

1.  Do you think they are going to be better? 
2.  Even if they are, doesn't it make supreme sense to still spend as little as possible on launch costs so you can actually do something off world?
3.  Ten years seems like a long time to build a rocket.  That is the mentality that must be changed.  Ten years development time and it will never see reality. 
4.  I point to past MSFC based projects where this kind of mentality has doomed the project.  (X-33, X-34, SLI, ISS prop module and the list could go on)
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Offline dad2059

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If this wasn't the best way forward in 2004/2005, then why on earth would it be the best way forward in 2009 when the situation is even more urgent?

Decisions have been made already, development contracts awarded, program continuity is more important than getting it right "perfectly" by canceling everything just to go for an architecture that we right now believe fits the budget we expect to have in the next 10 years best. The programmatic risk for a complete architecture change is just too high. A lot of Ares I development work can be salvaged. The question that really remains is 8.4m SSME-core or 10m RS-68B core and due to schedule not being a factor any more for HLV development (we got 10 years in any event), 10m RS-68B just wins the trade.

I don't know jack about chemical rocket engineering, so I probably shouldn't voice an opinion about this, but I have to agree somewhat with ares-mojo for the following reasons:

1. According to the Obama/Bolden meeting "leak" (to the best of my knowledge), the President looked at four options, and all without Ares 1 in them. So the consensus is that Ares 1 is headed for the scrap-pile, but most of the work can be salvaged if:

2. A "simpler" heavy-lift launch vehicle is chosen, which in local parlance means an "Ares V lite" or whatever "lite" means.Thus this:

3. The date for the "simpler" HLV is 2018, so eight to nine years, more likely ten given the budget. So this fits in ares-mojo time frame for the 10m RS-68B since the lead time is ten years anyway.

But the "simpler" could really mean the 8.4m SSME core, so this falls well within 8-9 years.

Just MHO y'see.

But these "leaks" have a purpose. Does that mean they come true?

No.

But I give it 60/40.
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Offline kfsorensen

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The RS-68B would not be an option due to base heating. You would have to develop a regen version.
Yup. That engine does not cluster well at all.  There's a reason that the F-1 and J-2's manifolded their gas-generator exhausts into the nozzle.

Offline Namechange User

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If this wasn't the best way forward in 2004/2005, then why on earth would it be the best way forward in 2009 when the situation is even more urgent?

Decisions have been made already, development contracts awarded, program continuity is more important than getting it right "perfectly" by canceling everything just to go for an architecture that we right now believe fits the budget we expect to have in the next 10 years best. The programmatic risk for a complete architecture change is just too high. A lot of Ares I development work can be salvaged. The question that really remains is 8.4m SSME-core or 10m RS-68B core and due to schedule not being a factor any more for HLV development (we got 10 years in any event), 10m RS-68B just wins the trade.

I don't know jack about chemical rocket engineering, so I probably shouldn't voice an opinion about this, but I have to agree somewhat with ares-mojo for the following reasons:

1. According to the Obama/Bolden meeting "leak" (to the best of my knowledge), the President looked at four options, and all without Ares 1 in them. So the consensus is that Ares 1 is headed for the scrap-pile, but most of the work can be salvaged if:

2. A "simpler" heavy-lift launch vehicle is chosen, which in local parlance means an "Ares V lite" or whatever "lite" means.Thus this:

3. The date for the "simpler" HLV is 2018, so eight to nine years, more likely ten given the budget. So this fits in ares-mojo time frame for the 10m RS-68B since the lead time is ten years anyway.

But the "simpler" could really mean the 8.4m SSME core, so this falls well within 8-9 years.

Just MHO y'see.

But these "leaks" have a purpose. Does that mean they come true?

No.

But I give it 60/40.

Your tag line at the bottom is "if it ain't broke, don't fix it".  Why front load a new HLV with more development, where major problems can always arise, if not necessary?  We have the tooling for an 8.4 meter core now.  We have SSME's where it has been studied for years on how to make expendable versions.  We have all the infrastructure in place to accomodate that configurationm, etc. 

So use 5 segment boosters someday if necessary, fine and that gives you a little more performance.  However, those are not ready and we have 4 segments today.  The simple fact is there is no reason to throw the baby out with the bath water and fund MSFC for a decade to maybe eventually field a new mega booster that will not be cost effective when complete just because MSFC employees *think* we need it.  This is about power at their center and their center alone.  Don't fool yourself that it is anything else. 
« Last Edit: 12/29/2009 01:57 pm by OV-106 »
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Offline dad2059

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Your tag line at the bottom is "if it ain't broke, don't fix it".  Why front load a new HLV with more development, where major problems can always arise, if not necessary?  We have the tooling for an 8.4 meter core now.  We have SSME's where it has been studied for years on how to make expendable versions.  We have all the infrastructure in place to accomodate that configurationm, etc. 

So use 5 segment boosters someday if necessary, fine and that gives you a little more performance.  However, those are not ready and we have 4 segments today.  The simple fact is there is no reason to throw the baby out with the bath water and fund MSFC for a decade to maybe eventually field a new mega booster that will not be cost effective when complete just because MSFC employees *think* we need it.  This is about power at their center and their center alone.  Don't fool yourself that it is anything else. 

I agree with that, but politics being what they are, it may be necessary to throw MSFC a "bone."

I think we should go right to the 8.4m SSME design just for the reasons you state. I don't even think it would take the 8-9 years for the development if we went that way.

Mr. Obama however, being a man of consensus building, might be willing to sacrifice that design.
NASA needs some good ol' fashioned 'singularity tech'

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