Wingo Op Ed: Establishing the VSE

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Author Topic: Wingo Op Ed: Establishing the VSE  (Read 9313 times)
jml
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« on: 04/23/2008 02:56 AM »

Dennis Wingo (a.k.a. wingod around these forums) has written a thought provoking article about the VSE on Spaceref. ( http://www.spaceref.com/news/viewnews.html?id=1285 ) The article makes the very valid point that VSE is focusing too much on how to get to the moon instead of what we should do on the moon (and that because of this, VSE doomed to failure just like SEI).

Here's a little quote for the Direct and/or EELV supporters:
"The problem is not the rocket, it is the plan of what we do when we get to the Moon. While there are many who would strenuously argue that the transportation architecture represented by the ESAS study as implemented with billions of dollars of taxpayer money is the wrong one, in the end, this argument misses the greater point."

I have to agree with the notion that the goal of VSE should be not simply returning to the moon as a stepping stone to mars, but actually doing something useful there too.

But I do think that the rocket is a big part of the problem too. More specifically, the problem is what the architecture choice does to NASA's budget.

Ares I and V suck up all the budget NASA has available and then some, bringing us back to the budgetary unsustainability of the Saturn V era.  While NASA's VSE pays lip service to the idea of a permanent lunar base, enacting Constellation means that no money is left to even bother planning the details of more than Apollo style boots-and-flag missions within NASA's current financial envelope. Conversely, the financial estimates I've seen suggest that Delta and/or Atlas EELV would mean very expensive lunar missions launched in very tiny segments: the costs would quickly add up to outweigh even Constellation. Delta and Atlas make great economic sense if all we want is LEO crew and cargo launches to ISS, but very little economic sense for lunar missions.

So... only an not-too-big, not-too-small, just-right "Goldilocks" solution would allow NASA to still have some budget dollars left to fund actually doing something of any significance on the Lunar surface. And that leaves us with true SDLV heavy-lift as the only way I see for NASA to get to the moon and  still be able to afford to do something useful there.

This is starting to sound familiar: 8.4m core, 4-seg SRB, disposable RS-68 engines, and either an in-line payload (Direct) or side-mounted payload (disposable Shuttle-C type fairing).  The difference in the costs between these two options seems practically negligible (a few hundred million on a $300-billion program). Shuttle-C may save some initial development and infrastructure costs, but side mount payload implies a need for an EELV to serve as crew launcher. And that, in-turn, implies a "gap" with the very real political risks of the loss of STS infrastructure, workers, and knowledge.  Direct can serve as the launcher for everything needed for LEO, lunar, and even Mars missions, but costs more up front to develop the in-line config and the needed pad and MLP changes at KSC.

Nothing else will get NASA back to the moon within the next decade. (Except Branson, Carmack, Bezos, and Musk, of course :laugh: ).

Any thoughts?

(Of course, I expect that a few people here may somewhat disagree with my views in the most polite and genteel manner....)  :)
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« on: 04/23/2008 02:56 AM »

 
tankmodeler
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« Reply #1 on: 04/23/2008 04:45 AM »

I must agree that this is one of the best space pieces I've seen in a long long time.

Bloody well done, Dennis.

As to the point:

Quote
But I do think that the rocket is a big part of the problem too. More specifically, the problem is what the architecture choice does to NASA's budget.

Well, on a tactical level, I think you're right, but Dennis' piece is at the strategic level and if NASA had been going down the self-sufficient architecture route from the beginning, the entire discussion of Ares/Direct/EELV might be quite moot.

You're arguing whether we should be bunting or going for the home run. Dennis is suggesting that perhaps we should be playing hockey.

:)

Paul
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« Reply #2 on: 04/23/2008 04:50 AM »

Your summary is earning no disagreement from me :)

Dennis wrote a really excellent piece there.   My hat is off to the man.

An interesting exercise, given this approach, is to look and see just how badly Ares fits into this model.

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« Reply #3 on: 04/23/2008 04:52 AM »

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jml - 22/4/2008  9:56 PM

Shuttle-C may save some initial development and infrastructure costs, but side mount payload implies a need for an EELV to serve as crew launcher.

Why?
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« Reply #4 on: 04/23/2008 06:04 AM »

My understanding is that a side mount SDLV places the CEV in the same location as the Shuttle crew cabin, which is unacceptable after Challenger and Columbia.  This would put the CEV right in the potential debris field from rapid unscheduled disassembly of the ET or an SRB.  Even with a launch abort system to pull the CEV away from a disintegrating LV stack, the risk to crew is higher than with the CEV mounted atop the LV.

Of course, I may well be wrong. Anyone have in-line vs. side-mount SDLV LOC numbers from ESAS handy?
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« Reply #5 on: 04/23/2008 06:31 AM »

Abort options are severely constrained in any situation where the ET is disintegrating at the time of LAS firing.   The 'cone' of LAS flight away from the side-mount position intersects with potential debris coming from the top of the tank.

That is unless you fly on a particularly large Shuttle-C variant placing the crew module at a station height above the ET, such as Shuttle-Z - but that vehicle's LOC/LOM numbers are too low to be considered safe anyway.

Its a catch-22 situation.   Small causes problems, large causes other problems.   I have yet to see any variant of Shuttle-C with a better-than 1:600 LOC if used for crew launch ops.

Here is the relevant section from ESAS Section 6, Page 385:-

Quote
The Shuttle-derived options considered were of two configurations: (1) a vehicle configured much like today’s Shuttle, with the Orbiter replaced by a side-mounted expendable cargo carrier, and (2) an in-line configuration using an ET-diameter core stage with a reconfigured thrust structure on the aft end of the core and a payload shroud on the forward end. The ogiveshaped ET LOX tank is replaced by a conventional cylindrical tank with ellipsoidal domes, forward of which the payload shroud is attached. In both configurations, three SSMEs were initially baselined. Several variants of these vehicles were examined. Four- and five-segment RSRBs were evaluated on both configurations, and the side-mounted version was evaluated with two RS–68 engines in place of the SSMEs. The J–2S+ was not considered for use in the CaLV core due to its low relative thrust and the inability of the J–2S+ to use the extended nozzle at sea level, reducing its Specific Impulse (Isp) performance below the level required. No variant of the side-mount Shuttle-Derived Vehicle (SDV) was found to meet the lunar lift requirements with less than four launches. The side-mount configuration would also most likely prove to be very difficult to human rate, with the placement of the CEV in close proximity to the main propellant tankage, coupled with a restricted CEV abort path as compared to an in-line configuration. The proximity to the ET also exposes the CEV to ET debris during ascent, with the possibility of contact with the leeward side TPS, boost protective cover, and the LAS. The DDT&E costs are lower than the in-line configurations, but per-flight costs are higher—resulting in a higher per-mission cost. The side-mount configuration was judged to be unsuitable for upgrading to a Mars mission LEO capability (100 to 125 mT).

Essentially, if you include Shuttle-C in the mix, you need a separate CLV again - with all the associated additional costs, albeit you could opt to use an EELV as a cheaper substitute instead of developing the Ares-I.   But then you end up sharing your flight rate between two vehicles again and neither gets the economic benefits of a really robust flight rate...   You end up paying through the nose again for two different vehicles which you aren't using either one often enough to make it economical.   And they just don't close the performance requirements with only two flights.

Wingo and I have locked horns on this issue before :)

We actually agree in most other respects regarding the wider program, but on this one isolated issue - launch vehicle selection - I depart company with him and have to side with NASA on the in-line configuration being the better option.

I believe side-mount SDLV or side-mount SDLV+EELV are both dead-end solutions for the Exploration program financially speaking, driving the cost of exploration high enough that it will result in the Shuttle side of the equation ultimately just being canceled, leaving us with EELV's servicing ISS and no further capability beyond LEO again.

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« Reply #6 on: 04/23/2008 04:43 PM »

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jml - 23/4/2008  1:04 AM

My understanding is that a side mount SDLV places the CEV in the same location as the Shuttle crew cabin, which is unacceptable after Challenger and Columbia.  This would put the CEV right in the potential debris field from rapid unscheduled disassembly of the ET or an SRB.  Even with a launch abort system to pull the CEV away from a disintegrating LV stack, the risk to crew is higher than with the CEV mounted atop the LV.

Of course, I may well be wrong. Anyone have in-line vs. side-mount SDLV LOC numbers from ESAS handy?

Never said Shuttle-C config was optimal but it is not impossible and would not have to drive seperate crew and cargo launchers.  Challenger and Columbia do not really apply since shuttle has no escape system anyway and the CEV will be protected by the LAS.  The heat sheild will have multiple layers of protection.  The LAS engines would probably have to be canted, etc for a shuttle-C config.  

The point is this would be another design trade but saying it automatically drives a two launch vehicles I don't believe is valid.
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« Reply #7 on: 04/23/2008 04:54 PM »

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OV-106 - 23/4/2008  12:43 PM
Never said Shuttle-C config was optimal but it is not impossible and would not have to drive seperate crew and cargo launchers.  Challenger and Columbia do not really apply since shuttle has no escape system anyway and the CEV will be protected by the LAS.  The heat sheild will have multiple layers of protection.  The LAS engines would probably have to be canted, etc for a shuttle-C config.  

The point is this would be another design trade but saying it automatically drives a two launch vehicles I don't believe is valid.

It is valid.
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« Reply #8 on: 04/23/2008 05:17 PM »

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Jim - 23/4/2008  11:54 AM


It is valid.

I don't believe it is.  We'll leave it at that.
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« Reply #9 on: 04/23/2008 05:38 PM »

Wingo's piece is, unfortunately, riddled with factual errors and analytical fallacies. For one thing, any article that quotes Barney Frank as the voice of both the Congress and the people cannot be taken seriously.
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« Reply #10 on: 04/23/2008 05:43 PM »

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MarkWhittington - 23/4/2008  1:38 PM

Wingo's piece is, unfortunately, riddled with factual errors and analytical fallacies. For one thing, any article that quotes Barney Frank as the voice of both the Congress and the people cannot be taken seriously.

instead of slinging muck due to your personal differences with Dennis, point out and list the errors
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« Reply #11 on: 04/23/2008 06:08 PM »

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MarkWhittington - 23/4/2008  1:38 PM

Wingo's piece is, unfortunately, riddled with factual errors and analytical fallacies. For one thing, any article that quotes Barney Frank as the voice of both the Congress and the people cannot be taken seriously.
I don't think Barney's presence in the discussion makes a strong argument either way, even if Rep. Frank himself is a polarizing figure.  Didn't some "anti-Mars" language make it all the way to the President's pen in the FY 2008 omnibus appropriations bill?  If so, that implies there is likely bipartisan "support" for this particular position.  All he's basically saying is "I don't want to spend lots of money on that," which is much easier to support than what to actually fund.

I agree with Jim -- I'd be interested in your rebuttal if it enumerates and explains those errors and fallacies.
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« Reply #12 on: 04/23/2008 06:13 PM »

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Jim - 23/4/2008  12:43 PM

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MarkWhittington - 23/4/2008  1:38 PM

Wingo's piece is, unfortunately, riddled with factual errors and analytical fallacies. For one thing, any article that quotes Barney Frank as the voice of both the Congress and the people cannot be taken seriously.

instead of slinging muck due to your personal differences with Dennis, point out and list the errors
Jim, I don't have any personal differences with Dennis at all and I rather resent that you would accuse me of them. I've never met him. Indeed, I rather liked his book on lunar resources. But this article is just wrong. Besides the Barney Frank quote, it tends to assume that space politics have not changed since 1969, a supposition that is laughable on its face. It claims that NASA is not contemplating using lunar resources for its lunar base, also untrue. The article also mischarecterizes the level of political and public support VSE enjoys.

The main fallacy of the article, and that seems to be a common one for critics of VSE, is that it assumes that it is NASA's job to create a commercial transportation infrastructure. Does anyone remember how the space shuttle came to be? The proper way NASA could help enable a translunar transportation system is through a lunar version of COTS. But, of course, that can't happen until there is an actual lunar base to go to.
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« Reply #13 on: 04/23/2008 06:16 PM »

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psloss - 23/4/2008  1:08 PM

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MarkWhittington - 23/4/2008  1:38 PM

Wingo's piece is, unfortunately, riddled with factual errors and analytical fallacies. For one thing, any article that quotes Barney Frank as the voice of both the Congress and the people cannot be taken seriously.
I don't think Barney's presence in the discussion makes a strong argument either way, even if Rep. Frank himself is a polarizing figure.  Didn't some "anti-Mars" language make it all the way to the President's pen in the FY 2008 omnibus appropriations bill?  If so, that implies there is likely bipartisan "support" for this particular position.  All he's basically saying is "I don't want to spend lots of money on that," which is much easier to support than what to actually fund.

I agree with Jim -- I'd be interested in your rebuttal if it enumerates and explains those errors and fallacies.

On the Mars language, it actually originated with House Democrats. While annoying, it did not rise to the level of being a sufficient reason to veto the bill and cause a government shut down.
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« Reply #14 on: 04/23/2008 06:32 PM »

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MarkWhittington - 23/4/2008  2:16 PM

On the Mars language, it actually originated with House Democrats. While annoying, it did not rise to the level of being a sufficient reason to veto the bill and cause a government shut down.
Fair enough.  This is really an op-ed piece, and there are plenty of opinions here.  I also don't know if it sways those opinions much, but I think it's a thoughtful op-ed piece.  That doesn't mean you have to respond with something equally as long (or at all), but it's harder to see your point of view.
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