Author Topic: Space Launch System: How to launch NASA’s new monster rocket  (Read 20034 times)

Offline JohnFornaro

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SLS has been mandated by Congress, but not funded sufficiently to make it happen quickly.

This is only partially true, in my view.  For a "legacy" system, it promises to cost nearly as much as the Ares development path, doesn't it?

NASA and ATK also found out that by not recovering the SRB's they could save a couple of hundred million dollars worth of recovery-inspection-refurbishment cost.

To which, a guy like me asks:  Why is disposable always cheaper than re-usable?  What's going on; don't build it (re-usable) and they will surely never come?
Sometimes I just flat out don't get it.

Offline Mark S

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SLS has been mandated by Congress, but not funded sufficiently to make it happen quickly.

This is only partially true, in my view.  For a "legacy" system, it promises to cost nearly as much as the Ares development path, doesn't it?


From what I understand, the answer is "no". The Ares (CxP) plan involved two completely separate systems: Ares-I and Ares-V. Other than the J2X upper-stage engine, they had nothing in common: separate design and testing efforts, separate production lines, separate launch facilities, distinct hardware, and separate management teams.

Whereas SLS is a single development effort for a single launcher that can be flown in multiple configurations. True, NASA has taken the lean and efficient design concepts of DIRECT and turned them into bloated oversized inefficient and unimaginative parodies of what could have been, but hey, this is the government we're talking about here. And it's not even all NASA's fault, Congress bears a lot of responsibility for that with their 130 ton mandate.

Now take the cost of that bloated oversized inefficient and unimaginative SLS and multiply it by two, and you'll have an idea of what CxP would have really cost in the long run. Remember, they spent $10 billion on CxP and the design for Ares-V was never even finalized, much less gotten into the "bending metal" stage.

Quote
NASA and ATK also found out that by not recovering the SRB's they could save a couple of hundred million dollars worth of recovery-inspection-refurbishment cost.

To which, a guy like me asks:  Why is disposable always cheaper than re-usable?  What's going on; don't build it (re-usable) and they will surely never come?

In my view, they want to fly two missions with the solids simply to pay lip service to Congress's mandate to maximize re-use of Shuttle and CxP investments, then wipe their hands of it. And then we're off on a whole 'nuther development and qualifiaction effort for the advanced boosters, pushing costs up and schedule to right as far as the eye can see.

And if it sounds like I'm down on SLS, it's mostly due to the timelines involved, as you can see from my previous posts. Anything that makes the schedule worse is not welcome in my book, even super-ultra-mega-advanced boosters. They should do the super-ultra-mega-booster development concurrently with ongoing missions, not use it as an excuse to not fly. NASA needs to get some missions defined and get flying. Even if SLS is not everything it could have been, it is certainly all we are likely to get, so let's make the most of it.

Cheers!
Mark S.

Offline edkyle99

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Why is disposable always cheaper than re-usable?  What's going on; don't build it (re-usable) and they will surely never come?

Disposable is not always cheaper.  It is only cheaper when the flight rate is low - say less than 50 or 60 flights per year. 

The U.S. has not launched a single rocket system more than 50 times per year to orbit since - ever.  It got close in 1962 when it launched 38 Thor-based rockets on orbital attempts.  But that rate soon declined.

The USSR's R-7 rocket family launched more than *60* times per year during the early 1980s, but even then the Soviet's stuck to disposable. 

SLS, of course, will never approach flight rates that would make reusable pay off.

 - Ed Kyle
« Last Edit: 02/23/2012 04:48 PM by edkyle99 »

Online Chris Bergin

Trying to keep this thread on anything mildly to do with what I wrote about, which is what this thread is about. Had to trim it earlier.

Seriously, when people start wandering into bollocks like Baby Boomers, all I hear is my e-mailing going PING PING PING with report to mod e-mails, so have a think before posting.
« Last Edit: 02/23/2012 04:50 PM by Chris Bergin »

Offline JohnFornaro

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SLS has been mandated by Congress, but not funded sufficiently to make it happen quickly.

This is only partially true, in my view.  For a "legacy" system, it promises to cost nearly as much as the Ares development path, doesn't it?

From what I understand, the answer is "no". The Ares (CxP) plan involved two completely separate systems: Ares-I and Ares-V. ...

Whereas SLS is a single development effort for a single launcher that can be flown in multiple configurations. True, NASA has taken the lean and efficient design concepts of DIRECT and turned them into bloated oversized inefficient and unimaginative parodies ... but hey, ... Congress bears a lot of responsibility for that with their 130 ton mandate.

Now take the cost of ... SLS and multiply it by two, and you'll have an idea of what CxP would have really cost in the long run. Remember, they spent $10 billion on CxP ...

Quote from: JF
NASA and ATK also found out that by not recovering the SRB's they could save a couple of hundred million dollars worth of recovery-inspection-refurbishment cost.

To which, a guy like me asks:  Why is disposable always cheaper than re-usable?  What's going on; don't build it (re-usable) and they will surely never come?

In my view, they want to fly two missions with the solids simply to pay lip service to Congress's mandate to maximize re-use of Shuttle and CxP investments, then wipe their hands of it. And then we're off on a whole 'nuther development and qualifiaction effort for the advanced boosters, pushing costs up and schedule to right as far as the eye can see.

And if it sounds like I'm down on SLS, it's mostly due to the timelines involved, as you can see from my previous posts. ...

Thanks, but I see that I didn't word my question well enough.  What I was getting at was that Ares cost $10 or $11B, for one empty test rocket.  By the time SLS, built from "leagacy" pieces, launches for the first unmanned time, it will also have consumed about the same amount.  I wasn't even thinking about the total projected costs of Ares I and Ares V.

Your observation about the solids is pretty much in line with mine.

Why is disposable always cheaper than re-usable?  What's going on; don't build it (re-usable) and they will surely never come?

Disposable is not always cheaper.  It is only cheaper when the flight rate is low - say less than 50 or 60 flights per year. 

The U.S. has not launched a single rocket system more than 50 times per year to orbit since - ever.  ...

The USSR's R-7 rocket family launched more than *60* times per year during the early 1980s, but even then the Soviet's stuck to disposable. 

SLS, of course, will never approach flight rates that would make reusable pay off.

Which in a way supports my contention:  Don't build a new cislunar economy, then you don't need to build enough rockets to launch enough so that the flight rates ever get high enough, so re-usable never becomes economically feasible.

Don't build it, and they won't come.  It's worked for forty years.  Unless something changes, SLS will continue the legacy.
Sometimes I just flat out don't get it.

Offline clongton

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Reusability v.s Disposable: It really comes down to the flight rate. Unless a system is going to fly multiple times per year the scales tip in favor of disposable. Reusability comes into it's own only with heavy reuse.

There is a lot to be said for reusability and Shuttle showed us that it can work quite well. But Shuttle also showed us that the cost for that can be extremely high. Shuttle Program Manager John Shannon stated as much at one of the Augustine Commission hearings (in D.C. IIRC) that it would have been more cost effective to replace the SSME's with new ones every time rather than refurbish the flown engines and the same could be said for the SRB's. That was only because of the low flight rate however. Had Shuttle actually flown as often as she was designed to, reuse of the SRB's and SSME's would have been more cost effective than replacement.

When John made those statements at the hearings he didn't bring with him the reams of data that backs it all up. He did state that all the data at his disposal, which meant literally everything, lead to that conclusion. I've met John several times, enough to know that my gut tells me to trust his judgement. But there are others here on NSF that know him extremely well and have worked with him constantly for years, such as OV-106, and what I get from them is that his judgement is impeccable. He is one of the few management people at NASA that I trust without question.

So for really the expensive items like SSME's and SRB's it all comes down to flight rate. Applying that lesson-learned to SLS and this thread, we have down-selected to disposable v.s. reusable, based on program cost. At the projected flight rate for SLS it simply makes no sense to incur the very large cost that reusability exacts for that capability.
« Last Edit: 02/24/2012 10:41 AM by clongton »
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Offline edkyle99

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  What I was getting at was that Ares cost $10 or $11B, for one empty test rocket.  By the time SLS, built from "leagacy" pieces, launches for the first unmanned time, it will also have consumed about the same amount.  I wasn't even thinking about the total projected costs of Ares I and Ares V.
The Constellation expenditures did not merely buy one suborbital test flight.  They bought J-2X and a massive new vacuum test stand at Stennis.  They bought five segment booster, which will be used for SLS.  They bought tooling at Michoud, which will be used for SLS and Orion.  And Orion, of course, paid for by Constellation, built at Michoud and KSC in facilities paid for by Constellation, lowered on chutes and protected by LAS tested during Constellation.  They bought a new launch platform at KSC, which will be modified for SLS.  And so on.
Quote
Don't build a new cislunar economy, then you don't need to build enough rockets to launch enough so that the flight rates ever get high enough, so re-usable never becomes economically feasible.

Don't build it, and they won't come.  It's worked for forty years.  Unless something changes, SLS will continue the legacy.

We live in an economy that moves at breathtaking speed, exploiting every conceivable profit alternative.  If there was an economic reason for lunar exploration, it would already have happened.   

Regardless, SLS is not going to the Moon.

 - Ed Kyle

Offline clongton

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Regardless, SLS is not going to the Moon.

 - Ed Kyle

SLS isn't supposed to go to the moon. It only goes to LEO.  :D
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Warren Platts

Quote
If there was an economic reason for lunar exploration, it would already have happened.

 - Ed Kyle

Which of course follows from the general principle:

x (If there is an economic reason for x, then x would already have happened.)
« Last Edit: 02/24/2012 02:18 PM by Warren Platts »
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Offline ChileVerde

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They bought five segment booster, which will be used for SLS.  They bought tooling at Michoud, which will be used for SLS and Orion. 

Just to make another try at this, what production rate could that facility sustain without needing to be enlarged?
"I can’t tell you which asteroid, but there will be one in 2025," Bolden asserted.

Offline Robotbeat

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FWIW, Lockheed thinks that partial reusability can make sense as low as 8 flights per year.
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Offline edkyle99

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They bought five segment booster, which will be used for SLS.  They bought tooling at Michoud, which will be used for SLS and Orion. 

Just to make another try at this, what production rate could that facility sustain without needing to be enlarged?

The tooling was being set up to support two Ares V and two Ares I missions per year.  Ares I is obviously gone, with its space possibly being reassigned for future SLS upper stages, and the SLS launch rate is projected to be lower than the Ares V launch rate, so Michoud will clearly be able to handle SLS.  My guess is that the place could produce more than two cores in a year if needed.

RS-25E production rate may be more of a limiting factor than core structure fabrication and assembly. 

 - Ed Kyle

Offline ChileVerde

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The tooling was being set up to support two Ares V and two Ares I missions per year.  Ares I is obviously gone, with its space possibly being reassigned for future SLS upper stages, and the SLS launch rate is projected to be lower than the Ares V launch rate, so Michoud will clearly be able to handle SLS.  My guess is that the place could produce more than two cores in a year if needed.

RS-25E production rate may be more of a limiting factor than core structure fabrication and assembly. 

 - Ed Kyle

Thanks much. Those are the kinds of numbers we should have available when thinking about future SLS-supported missions and programs.
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Offline veedriver22

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Reusability v.s Disposable: It really comes down to the flight rate. Unless a system is going to fly multiple times per year the scales tip in favor of disposable. Reusability comes into it's own only with heavy reuse.

There is a lot to be said for reusability and Shuttle showed us that it can work quite well. But Shuttle also showed us that the cost for that can be extremely high. Shuttle Program Manager John Shannon stated as much at one of the Augustine Commission hearings (in D.C. IIRC) that it would have been more cost effective to replace the SSME's with new ones every time rather than refurbish the flown engines and the same could be said for the SRB's. That was only because of the low flight rate however. Had Shuttle actually flown as often as she was designed to, reuse of the SRB's and SSME's would have been more cost effective than replacement.

When John made those statements at the hearings he didn't bring with him the reams of data that backs it all up. He did state that all the data at his disposal, which meant literally everything, lead to that conclusion. I've met John several times, enough to know that my gut tells me to trust his judgement. But there are others here on NSF that know him extremely well and have worked with him constantly for years, such as OV-106, and what I get from them is that his judgement is impeccable. He is one of the few management people at NASA that I trust without question.

So for really the expensive items like SSME's and SRB's it all comes down to flight rate. Applying that lesson-learned to SLS and this thread, we have down-selected to disposable v.s. reusable, based on program cost. At the projected flight rate for SLS it simply makes no sense to incur the very large cost that reusability exacts for that capability.
It occurs to me that there is a little more to reusability than flight rate.
A high flight rate is needed but the rebuild frequency also matters.
If you have to rebuild it every other launch I think it would still cost more.
Shuttle engines were rebuiilt each flight weren't they?
« Last Edit: 02/24/2012 05:17 PM by veedriver22 »

Offline baldusi

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It occurs to me that there is a little more to reusability than flight rate.
A high flight rate is needed but the rebuild frequency also matters.
If you have to rebuild it every other launch I think it would still cost more.
Shuttle engines were rebuiilt each flight weren't they?
SSME Block III was going to solve that. That work did include most of what is going to be the RS-25E. But that work was suspended after the decision to shutdown the Shuttle program. And as Ares V was going to use RS-68K, there was no point in keeping spending money  ::)

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