Author Topic: Studies Supporting Use of HLVs for BEO Programs  (Read 21623 times)

Offline Proponent

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Studies Supporting Use of HLVs for BEO Programs
« on: 09/10/2013 01:56 AM »
In the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012).  Which studies compare alternatives and don't recommend depots?  I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I).  There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists.  Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?

Please note that I am looking for pointers to studies only.  Please let us not debate HLVs and depots in this thread.

Offline Robotbeat

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #1 on: 09/10/2013 01:59 AM »
Also, supporters point to some unreleased, internal study supporting depots. Even a member of Congress has requested it, I'm not sure if it ever materialized.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline darkbluenine

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #2 on: 09/10/2013 04:19 AM »
This doesn't answer your question, but I'd include the Golden Spike and Inspiration Mars papers in your list of non-HLV papers.  They demonstrate that bare bones human lunar and Mars missions can be undertaken with a Falcon 9 and an Atlas V (lunar orbit), a ~50t Falcon Heavy-class vehicle with a Centaur-class upper stage and propellant drop tank (lunar landing), and a ~50t Falcon Heavy or two Atlas Vs or an Atlas V and a DIVH (circum-Mars).

http://goldenspikecompany.com/wp-content/uploads/2012/02/French-et-al.-Architecture-Paper-in-AIAA-Journal-of-Spacecraft-and-Rockets.pdf

http://www.inspirationmars.com/Inspiration%20Mars_Feasibility%20Analysis_IEEE.pdf

FWIW...

Offline Robotbeat

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #3 on: 09/10/2013 05:05 AM »
All the Mars DRMs assume HLVs, but I don't believe they actually usually bother comparing with smaller vehicles.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline spectre9

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #4 on: 09/10/2013 10:50 AM »
I have some of the older DRM papers stashed away somewhere on my Hard Drive.

It's amazing how things go "missing" on the internet.

What's googleable there today might not be there tomorrow. I reckon Google will need every second of those 300 years they say it will take to index all the knowledge of the world if it's even possible.

NTRS is like Rome after the empire. It's still there but it's not the same shining jewel it once was.

Ok I've found it.

They show the 200ton+ launch vehicles from DRM1 and explain why they're traded out.

The Magnum is introduced which is less capable than the SLS to LEO (85mt) but has a nuclear TMI stage.

Download this document and keep it safe. I believe it to be a critical piece in the Mars mission puzzle.

Without further ado I give you DRM3.
« Last Edit: 09/10/2013 10:57 AM by spectre9 »

Offline darkbluenine

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #5 on: 09/10/2013 02:23 PM »
They show the 200ton+ launch vehicles from DRM1 and explain why they're traded out.

The Magnum is introduced which is less capable than the SLS to LEO (85mt) but has a nuclear TMI stage.

... Without further ado I give you DRM3.

That is interesting.  A decade-and-a-half ago, we argued we could get to Mars with an 80-ton EELV-derived HLV.  Now we claim it can only be done with a 130-ton Shuttle-derived HLV.

What I also find interesting in both DRM3 and DRM5 is the flight rate and annual or mission payload tonnage requirements and how far short of these requirements the SLS flight rate falls.  DRM3 assumes six 80-ton launches per year or 480 tons per year.  At a production rate of one 130-ton HLV every two years, SLS requirements meet only 14% of DRM3's lift needs.  IIRC, DRM5 assumes three Mars landing missions over a decade massing 800 tons each, or 2400 tons total.  At a production rate of five 130-ton HLVs every decade (or 650 tons total), SLS requirements meet only 27% of DRM5's lift needs.

I'm sure the SLS production rate could be increased from one vehicle every two years with more budget, but it's hard to see how it could be increased nearly four-fold (for DRM5) or nearly ten-fold (for DRM3).  At least based on NASA's human Mars DRMs, it appears that SLS is not on the critical path to human Mars landings.

Offline Proponent

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #6 on: 09/10/2013 06:30 PM »
Now that I think about it, I suppose one could argue that Spudis and Lavoie (2011) consider approaches both with and without a 70-tonne Shuttle-derived HLV and prefer the HLV, though they rely on propellant depots either way.  Their baseline plan includes a couple of HLV launches at a late stage but they can accomplish their goal -- the return of humans to the lunar surface with ISRU -- with just EELVs.  Since the baseline includes HLV, one could say they prefer it to the EELV-only option.

Offline 93143

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #7 on: 09/11/2013 12:59 AM »
I'm sure the SLS production rate could be increased from one vehicle every two years with more budget, but it's hard to see how it could be increased nearly four-fold (for DRM5) or nearly ten-fold (for DRM3).

Not really.  The bottleneck is really the launch infrastructure, which as we've seen can easily handle 10 launches per year.  If they have to upgrade some of the production infrastructure back up to near Shuttle levels, so be it; it's just money.  (IIRC, one of the advantages of RS-25E over RS-25D is that the latter is hard to make faster than 12 per year.)

NASA is designing SLS with the expectation of a launch rate of two per year at design maturity.  They've said as much.  The low maximum flight rate currently being implemented is purely a cost-saving measure.

The reason SLS doesn't launch often is that it has nothing to do.  The reason it has nothing to do is that the politicians can't agree to give it something to do, and the White House and OMB are at least as guilty as Congress.  We'll see what happens after 2016...

Offline darkbluenine

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #8 on: 09/11/2013 02:23 AM »
The bottleneck is really the launch infrastructure, which as we've seen can easily handle 10 launches per year.

Assuming GAO weighs in soon on the Blue Origin/SpaceX spat, before the year is out, the pads available to SLS will be cut in half (from 2 to 1) from what STS enjoyed.

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NASA is designing SLS with the expectation of a launch rate of two per year at design maturity.  They've said as much.

That may be someone's expectation, but it's not what's been written into the NRA requirements appendix.  Over the long run, launch rate can't exceed production.  Although SLS has a requirement for a "maximum rate of three launches" in a single year (presumably by skipping launches and storing hardware for a half decade or so prior), SLS production is being designed and developed to support only "one launch every other year".   

The "expectation" for the launch rate that you refer to and the production _requirement_ are off by a factor of four.

I can believe that SLS production could be doubled from what the requirements are currently driving it to.  Maybe (big maybe) tripled.  But sustained four-, five-, and ten-fold increases don't seem realistic given where the requirements are being set.  It's too big a disconnect -- like the disconnect between what the advertised Shuttle flight rate was during development and what it actually turned out to be. 

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The reason SLS doesn't launch often is that it has nothing to do... the White House and OMB are at least as guilty as Congress.

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If they have to upgrade some of the production infrastructure back up to near Shuttle levels, so be it; it's just money...

Even if there wasn't such a huge disconnect between SLS production requirements and SLS flight rate expectations (or Mars DRM requirements), money is still a problem.  If OMB, the White House, and Congress aren't providing enough funding to give SLS payloads and missions, there won't be any funding to increase SLS production, either.

Offline 93143

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #9 on: 09/11/2013 06:32 AM »
The bottleneck is really the launch infrastructure, which as we've seen can easily handle 10 launches per year.
Assuming GAO weighs in soon on the Blue Origin/SpaceX spat, before the year is out, the pads available to SLS will be cut in half (from 2 to 1) from what STS enjoyed.

Which leaves the known achievable launch rate at...  whaddya know: exactly ten times the frequency you said they could never ever multiply by 4, never mind 10.

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If they have to upgrade some of the production infrastructure back up to near Shuttle levels, so be it; it's just money...
Even if there wasn't such a huge disconnect between SLS production requirements and SLS flight rate expectations (or Mars DRM requirements), money is still a problem.  If OMB, the White House, and Congress aren't providing enough funding to give SLS payloads and missions, there won't be any funding to increase SLS production, either.

You're conflating "can't" and "won't".  Obviously if no one pays for any real exploration, SLS won't launch very often if at all.  But that's an entirely separate question from whether or not it's possible to ramp up production by a significant factor if the government decides it wants something to happen.

Shuttle-derived systems with two pads available are known to be able to launch at least 10-12 times per year without trouble, possibly a lot more.  The legacy production, transportation, and processing infrastructure is known to be able to handle it.  The near-term production requirements do not reflect any physical limit; they are simply an affordability measure intended to minimize the fixed cost of the system, and the only possible impacts are on new infrastructure (tooling and such) and workforce size.  Ramping up would mean expanding the production capability, but there's no reason existing facilities couldn't handle it; it's not a question of building another factory.
« Last Edit: 09/11/2013 06:50 AM by 93143 »

Offline darkbluenine

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #10 on: 09/11/2013 04:25 PM »
Shuttle-derived systems with two pads available are known to be able to launch at least 10-12 times per year without trouble, possibly a lot more.

That's not true.

The STS annual flight rate peaked at 9 in 1985.  It never hit 10, nevertheless 12.

And it was well below 10 in most years.  The average annual flight rate for STS was 4.5 flights per year (135 missions over 30 years).

The actual, proven, annual launch rate for Shuttle systems is slightly more than one-third to less than one-half to of what you think it is in theory.

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Which leaves the known achievable launch rate at...  whaddya know: exactly ten times the frequency you said they could never ever multiply by 4, never mind 10.

That's not realistic over the long-term.  It requires two miracles:

1) SLS has to hit a launch rate per pad (5 launches per pad per year), year after year, that is higher than what STS ever achieved in a single year (4.5 launches per pad in 1985).  That could happen in theory, but the probability is very low given that STS never achieved that rate and give that STS only got close to that rate in one year out of 30.  Even setting aside probabilities, it's hard to see how SLS will not suffer from many of the same, multi-month schedule delays as STS when they use many of the same subsystems (LH2 leaks in tanks and RS-25x engines, ET/core structure cracks, etc.).

2) SLS production has to be increased ten-fold over the very low requirement that it is being designed and developed to.  It's unclear that could be done technically given how much STS production capability has already been turned off, how much more STS production capability will be turned off to achieve that very low production rate cost-effectively, and how little SLS-unique production capability will be developed to achieve that very low production rate cost-effectively.  Anything is possible in theory, but the probability is very low given the order of magnitude difference in production rates and give that about 45 years of NASA budget history post-Apollo never provided anything close to the necessary resources.

I don't think either of these miracles is in the offing, nevertheless both.

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You're conflating "can't" and "won't".

I'd put it a different way.

You're arguing from a theoretical viewpoint.  What flight rate could SLS achieve in a perfect world with an enormous and sustained budget infusion from OMB, the White House, and Congress to pay for: 1) payloads and missions to utilize an existing SLS production rate of 1 unit every 2 years; 2) additional workforce, tooling, and infrastructure to support and maintain a 10-fold-plus increase in SLS production; and 3) payloads and missions to utilize an additional 9-plus SLS launches every 2 years?  And what flight rate could SLS achieve in a perfect world where the production requirement for SLS has no impact whatsoever on whether and how is scales and ramps up 10-fold in the future?  And what flight rate could SLS achieve in a perfect world where SLS performs even better, year after year, than Shuttle's best year in terms of launch rate per pad?

I'm arguing from a realistic viewpoint.  Realistically, what budget resources are OMB, the White House, and Congress going to make available to NASA, given the agency's ~45-year budget history post-Apollo.  And realistically, what launch rate could SLS achieve given the very low production requirement that the system is being designed and developed to.  And realistically, what launch rate could SLS achieve given actual STS flight history.

Call me crazy, but I think it's better to base my expectations for SLS around realistic, not theoretical, assessments.  The world needs hope, but I don't think it's a good foundation upon which to build a multi-billion dollar engineering development program.

My 2 cents... YMMV.

[Edit:  Grammar/spelling.]
« Last Edit: 09/11/2013 07:46 PM by darkbluenine »

Offline Robotbeat

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #11 on: 09/11/2013 04:34 PM »
They could fly 100 SLSes a year with a big enough budget.

What I'd like to see is a study supporting use of HLVs when the budget is flat or slightly declining at current levels.
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Offline 93143

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #12 on: 09/11/2013 07:57 PM »
The STS annual flight rate peaked at 9 in 1985.

And it would have kept climbing, if not for a system vulnerability that SLS doesn't share.

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The average annual flight rate for STS was 4.5 flights per year (135 missions over 30 years).

That's due to the orbiter, mostly.  Difficulties with processing, difficulties with launch constraints (the launch constraints on STS were very severe.  Apollo 12 launched through a rainstorm that was apparently on the verge of being a thunderstorm - if you had suggested to an STS manager that they launch a Shuttle mission in that kind of weather, whether at the Cape or at the TAL sites, he would have assumed it was a bad joke), outright disasters followed by RTF gaps...  Remove those issues and things become much more predictable.

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The actual, proven, annual launch rate for Shuttle systems is less than one-half to slightly more than one-third of what you think it is in theory.

Non sequitur, in this context.

Besides, have you noticed that 4.5 is really close to 5, which is the higher number you were ridiculing, and way larger than 2, which is the lower one?  (Per pad vs. total is not relevant here; the KSC infrastructure proved it could do that rate on one pad in 1985.)

You were actually claiming that SLS would be unable to hit 2 flights per year.  A reality check may be in order.

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it's hard to see how SLS will not suffer from many of the same, multi-month schedule delays as STS when they use many of the same subsystems (LH2 leaks in tanks and RS-25x engines, ET/core structure cracks, etc.).

Not hard at all.  Leaving aside the orbiter-related conditions, SLS is being designed with all those problems already part of the knowledge base.  They won't just re-use a system if it's possible to design out a known flaw.  As for the ET stringer cracking, that was a bad batch of Al-Li alloy, which is known to be fairly brittle in general and which SLS isn't using.  The engines for SLS are a new design iteration (which was well underway 10 years ago but shelved) that completely changes the cooling channel design and is overall much more robust - besides, IIRC all the engine problems had to do with used engines, which SLS won't have a problem with...

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given ~45 years of NASA budget history post-Apollo never providing anything close to those kinds of resources

What kind of resources?  According to the 2011 ESD Integration budget availability report, it seems that adding an SLS Block 1 launch to the future schedule costs about $300M in 2011 dollars.  Add $100M as a rough approximation of the delta for Block 2, and doing five launches per year would only cost about $1.8B extra, or about 10% of NASA's current budget, on top of the infrastructure costs for STS-like flight rates, which multiple sources put at $1.6-2B - but that's before the SLS program's cost-saving measures, not all of which are mere production capacity restrictions, and it's also before the advanced boosters, which should help substantially, especially if they're liquid-fueled.  A Shuttle-like launch rate shouldn't add much more than $3-3.5B per year at worst, which is less than the increase from 1987 to 1991 in 1987 dollars, or about one-third of that increase in 2013 dollars (NASA New Start Inflation Index).

If a future government decides it wants a Mars mission, and the nation isn't in the grip of a series of financial crises, and NASA can avoid the temptation to pull another BSG like during SEI, the required cash for the SLS ramp-up should easily be forthcoming.

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You're conflating "can't" and "won't".
I'd put it a different way.

And then you go right ahead and do exactly what I said you were doing all over again.

Your argument was that SLS would be technically incapable of sustaining the launch rate necessary to do a manned Mars mission.  Now you're arguing not only that the government will never fund a Mars mission, but that the two arguments are the same.

Your "reality" seems to involve low-order extrapolation over at least a decade, probably two.  Six years ago the economy looked like it was in great shape.  Eleven years ago, Columbia was still flying.  Thirteen years ago, VentureStar was the next big thing.  Twenty-two years ago, SEI was still on.

In my opinion, NASA needs a tool to help them get human crews out of LEO and do actual pioneering, before the growth of non-governmental spaceflight in LEO makes their human program entirely redundant.  The nature of the tool doesn't much matter, as long as it isn't extravagantly overblown like Ares.  It would also be great if they were working on cheap access to space, but the government doesn't seem at all interested in that right now, whereas private companies seem to just maybe be on the cusp of cracking it...

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The world needs hope, but I don't think it's a good foundation upon which to build a multi-billion dollar engineering development program.

NASA isn't building SLS in the hope that the government will fund missions for it.  NASA is building SLS because the government told them to.  Once they get it built, the ball is in the government's court again.

If the USG wants a big launcher (and Congress at least does; they've stuck to the idea since 2005), they get to pay to use it or else look like fools.  Not much of a predictor, really...

What I'd like to see is a study supporting use of HLVs when the budget is flat or slightly declining at current levels.

Is there a study that says any exploration is possible with slightly declining budgets?  Remember, most of NASA's budget is stuff other than manned spaceflight and exploration systems...

[Remember also that Congress doesn't fund NASA - Congress funds programs at NASA.  Eliminate a program, and the funding disappears.  Especially if the reason the program is eliminated is so it can be replaced with a different one that does the same thing but without satisfying anyone important's political interests...]

As for flat, SLS/Orion development is around $3B per year, and if NASA isn't blowing smoke with their $500M number for one launch per year (which is possible), the system should be a lot cheaper in operation, at least at a low flight rate.  That could free up a couple billion per year for payload development, procurement and launch...
« Last Edit: 09/11/2013 08:12 PM by 93143 »

Offline Robotbeat

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #13 on: 09/11/2013 08:08 PM »
...
What I'd like to see is a study supporting use of HLVs when the budget is flat or slightly declining at current levels.

Is there a study that says any exploration is possible with slightly declining budgets?  Remember, most of NASA's budget is stuff other than manned spaceflight and exploration systems...
Absolutely! I can show you one. But that is technically off-topic.
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[Remember also that Congress doesn't fund NASA - Congress funds programs at NASA.  Eliminate a program, and the funding disappears.  Especially if the reason the program is eliminated is so it can be replaced with a different one that does the same thing but without satisfying anyone important's political interests...]

As for flat, SLS/Orion development is around $3B per year, and if NASA isn't blowing smoke with their $500M number for one launch per year (which is possible), the system should be a lot cheaper in operation, at least at a low flight rate.  That could free up a couple billion per year for payload development, procurement and launch...
$500 million is the "marginal" cost, meaning the cost you save by not ordering parts and not having extra shifts for the launch pad crew for a launch, etc. It doesn't include the cost to keep up the pad infrastructure, the manufacturing capability, people on staff ready to launch and build, etc. It is a tiny portion of the total cost of SLS per year. If it was really the full cost of SLS per year for one flight, of course I would support SLS full-heartedly, because then we could actually afford to build payloads. But you're misinterpreting what NASA is saying.
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Offline muomega0

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #14 on: 09/11/2013 08:22 PM »
In the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012).  Which studies compare alternatives and don't recommend depots?  I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I).  There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists.  Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?

Please note that I am looking for pointers to studies only.  Please let us not debate HLVs and depots in this thread.

Q:  Is your question directed at LVs in between the 20 mT class and the 70 mT class?
Q:  Are both "depots" and "refueling stages" excluded.
Q:  For lunar only or for Mars class missions?  (one could possible have a two launch ~50 mT for the moon).
 
To complicate depots vs refueling stages:  The ULA paper attempts to answer the question "How do we assure there is propellant demand and that we do NOT sit with a full LEO depot for years"?   IOW:  they did not provide ZBO in LEO, but assumed that they would push the entire "depot" to L2 in short time frame to avoid boiloff.  Consequently, its a depot with engines acting as a transfer stage in addition:  sent to LEO, filled in a month or so, and sent to L2 (See figure 4).

Offline 93143

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #15 on: 09/11/2013 08:28 PM »
$500 million is the "marginal" cost

Evidence?

Working completely from STS and Ares numbers, with no cost savings at all, SLS Block 1's incremental cost comes out to no more than $300M in 2011 dollars.  And NASA did say that the cost doesn't seem to strongly depend on the version of the launcher.

At one flight per year, infrastructure doesn't need to cost anywhere near what it did for Shuttle, especially with Orbiter maintenance deleted.  With advanced liquid-fueled boosters, the SRB fixed costs are gone, and with Aerojet Rocketdyne consolidating rocket engine production lines (and heavily upgrading the RS-25 manufacturing processes), the RS-25 and RL-10/NGE or J-2X (and probably F-1B or maybe AJ-1E6) fixed costs should be lower and shared with the Air Force.

Remember, KSC ground systems are not included in this...

Also note that NASA specifically associated that cost with a flight rate.

It does seem like a bit of a stretch to claim that $500M is the total annual cost, which is why I said it was possible, not definite.  Frankly I find the idea that it's the incremental cost of SLS plus Orion more plausible (but even there it seems to imply negative cost savings over legacy systems).

Or maybe it's related to NASA's odd claim that Shuttle's incremental cost was $450M - perhaps they're including some costs that more properly qualify as fixed costs, which might make it a good estimate of the cost per year to add a flight per year permanently...  though that does seem to match the ESD Integration scenario I got the incremental cost estimate from...

Alternately, NASA could simply have meant $500M in then-year dollars, which depending on when they expect to hit one flight per year with the fully-evolved system could easily make sense as an incremental cost...  though that still leaves the question of why they associated it with a flight rate...
« Last Edit: 09/11/2013 08:59 PM by 93143 »

Offline Proponent

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #16 on: 09/11/2013 09:06 PM »
Q:  Is your question directed at LVs in between the 20 mT class and the 70 mT class?
In the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012).  Which studies compare alternatives and don't recommend depots?  I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I).  There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists.  Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?

Please note that I am looking for pointers to studies only.  Please let us not debate HLVs and depots in this thread.

Q:  Is your question directed at LVs in between the 20 mT class and the 70 mT class?
Q:  Are both "depots" and "refueling stages" excluded.
Q:  For lunar only or for Mars class missions?  (one could possible have a two launch ~50 mT for the moon).

Basically what I'm looking for is studies which conclude "It's better to use a Shuttle-derived HLV to perform mission X than to use Y," where Y is anything.  Actually, any studies concluding "It's better to use an HLV to perform mission X than to use Y" would also be of interest. 

Offline 93143

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #17 on: 09/11/2013 09:32 PM »
As I recall, DIRECT showed that according to their numbers, Jupiter was about a match for Atlas V at two Lunar missions per year, and got cheaper for higher flight rates.  It was a straight tonnage comparison rather than a high-resolution study...

I know of two Mars architecture studies that didn't use HLV, and one of them didn't close while the other relied on Skylon (and may not have been high-enough resolution to compare with NASA's DRMs).  It seems to be accepted that for Mars, you need either an HLV or a preposterously cheap MLV.  Mark Hempsell said something similar, about how even with Skylon involved the trade is "very finely balanced"...  a couple of papers are mentioned here:

http://forum.nasaspaceflight.com/index.php?topic=24621.msg735577#msg735577
« Last Edit: 09/11/2013 09:41 PM by 93143 »

Offline muomega0

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #18 on: 09/11/2013 09:43 PM »
Q:  Is your question directed at LVs in between the 20 mT class and the 70 mT class?
In the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012).  Which studies compare alternatives and don't recommend depots?  I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I).  There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists.  Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?

Please note that I am looking for pointers to studies only.  Please let us not debate HLVs and depots in this thread.

Q:  Is your question directed at LVs in between the 20 mT class and the 70 mT class?
Q:  Are both "depots" and "refueling stages" excluded.
Q:  For lunar only or for Mars class missions?  (one could possible have a two launch ~50 mT for the moon).

Basically what I'm looking for is studies which conclude "It's better to use a Shuttle-derived HLV to perform mission X than to use Y," where Y is anything.  Actually, any studies concluding "It's better to use an HLV to perform mission X than to use Y" would also be of interest.
NASA selects companies for heavy lift

http://en.wikipedia.org/wiki/Shuttle-Derived_Heavy_Lift_Launch_Vehicle

Unfortunately, many of the NASA reports state something to this effect:  "we have studied numerous (even thousands) HLV configurations" and these are the best".   No comparisons to others are provided because.....its the law to build HLV and it would be against the law to study anything else, or show it up.

The studies that do not close usually prohibit technology development 'to explore sooner'.

Offline jongoff

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Re: Studies Supporting Use of HLVs for BEO Programs
« Reply #19 on: 09/11/2013 09:47 PM »
They could fly 100 SLSes a year with a big enough budget.

Reminds me of a quote about tolerancing parts from my freshman CAD professor (back in '96): "Ten thousandths?!? You could send a dog through that if you got it going fast enough!"

I removed the rest of my comment as it was a bit much even for me.

~Jon
« Last Edit: 09/12/2013 02:18 AM by jongoff »

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