Author Topic: Griffin speech - Why one STS derived launch system would not work for Constellation  (Read 93756 times)

Offline William Barton

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jongoff - 24/1/2008  11:35 AM

William,
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500mT to LEO consumes 25 EELV launches, which is about the infrastructure limit for one EELV type for a year (one launch every two weeks). That imposes a robustness limit for the program, whatever it might be. To me, the EELV/20mT high flight rate paradigm points straight at making a true RLV development program worthwhile. Politics made our first attempt at that into STS.

And to me that last bit is precisely why I prefer an EELV based architecture.  Sure, you still use the EELVs for launching the hardware part of things, but if the demand for propellants, people, and light cargo is high enough to strain the EELV flight infrastructure, it's also more than high enough to provide a large enough market to close the business case for RLVs (probably more than one).  Right now, all RLVs can point to as *existing* markets are a couple of people to ISS per year, and a couple of small LEO sats.  Nowhere near the numbers that are needed for an RLV to really make a dent in the launch price.  There are some potential markets that should improve things--ie if Bigelow pulls off his station, and if he's able to get the kind of customer interest he's banking on, that would be almost 100 passengers per year.  For a smaller RLV (pilot plus two passengers) that might be enough to start making things interesting.  But if you have 100-250 tonnes of propellant needed on orbit every year, that's *definitely* big enough, and big enough for multiple providers.

DIRECT is never going to be able to handle more than 12-16 people out of LEO in a given year.  An RLV based commercial architecture could potentially be a *lot* more capable once it gets going.  And even if it takes the RLVs a while to come on-line, EELVs aren't *that* bad when bought in large numbers.

~Jon

Of course that's true, but it begs off the EELV architecture's major benefit, that the LVs and infrastructure already exist. Hypothetical markets justify almost anything, which is how we got STS in the first place. I vividly remember full page ads in 1970-era space magazines showing a Saturn V lifting off, overprinted with "The Space Shuttle will go up and down and... (x100) ...for the price of one of these." And what were we going to do with those several hundred "free" launches? The rate-driven price reduction for EELVs is just another hypothetical. It sounds plausible, but will the price come down meaningfully if the LV production rate capability and launch infrastructure remain unchanged? The same arguments can be made for DIRECT (or anything else). If we launch a Jupiter 232 every two weeks, we can put megatons of cargo in orbit every year. Trouble is, the infrastructure to manufacture and fly more than 16 of them a year doesn't exist. The same thing is effectively true of EELV, unless you imagine the infrastucture will grow to fill the need. I am inclined to doubt that, and instead think the need will instead be curtailed by the infrastructure (which is one of the big justifications for ESAS and "go as you pay"). The commercial provider variant of the EELV architecture is essential "build it and they will come." I don't think so.

Offline William Barton

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clongton - 24/1/2008  12:06 PM

Jon,
DIRECT isn’t supposed to handle much more than 12-16 people out of LEO per year. That’s not its mission. It is not designed to be a people carrier. Because NASA has decided to use a SDLV architecture, DIRECT’s mission is to get the best bang for the buck from that architecture that we can, not to try to prove that the EELV/RLV architectures couldn’t do the same job. You’ve seen me state over and over again that as long as we must use a SDLV, that it has to be done in concert with a wise use of the existing capabilities. I don’t want to cut the EELV and potential RLVs from the picture. I want to use them as much as possible. I want to bring the flight rate up as high as we can, as much as the SDLV architecture will allow. I want to see People shuttles going back and forth to LEO on EELV-class commercial launchers. I want to see propellant depots in space being operated by commercial entities. DIRECT is not designed to eliminate EELVs or RLVs. It’s designed to eliminate Ares. We’re just trying to get the best value we can for the path Griffin has put us all on, that’s all. Griffin put us all on the path that eliminates the EELV from consideration, not us, and then he clamped down on the release of any information that could serve to challenge the correctness of his decision. What the DIRECT people did was, not agree with his decision, but to survey the landscape and try to get the most from it that we could. It wasn’t that hard to show that Ares was not the best SDLV solution, so we provided a different one, but still STS based, in the hope that he would adopt it, instead of Ares. With Ares, the EELV class of launcher won’t get much use in the VSE and propellant depots will remain tomorrow’s technology for a long time. With the DIRECT architecture, use of the EELV will be maximized as much as possible and propellant depots will be brought online fairly quickly, specifically to allow the EELV to participate much more in the VSE. Of course, the Jupiter would benefit from the depot as well, but hey – spread the wealth.

To me, one of the most important features of DIRECT is it brings VSE to the budget sustaining point fairly quickly, by getting Jupiter-120 on the pad by 2012, while at the same time bringing exo-LEO capability within easy reach. The biggest danger of the gap is, it's easy for a politician to cancel something that doesn't exist. Had there been no STS, I bet AAP would have struggled on. As it is, STS will have flown for 30 years, in large measure because it could be perceived as "being in place."

Offline rsp1202

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clongton - 24/1/2008  9:06 AM

DIRECT isn’t supposed to handle much more than 12-16 people out of LEO per year. That’s not its mission. It is not designed to be a people carrier. Because NASA has decided to use a SDLV architecture, DIRECT’s mission is to get the best bang for the buck from that architecture that we can . . .

I think a lot of your time is taken up by restating this over and over. Maybe posting a sticky on the Direct thread, stating such salient points as addressed above, would help. You could then just refer to that.

Offline jongoff

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William,
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Of course that's true, but it begs off the EELV architecture's major benefit, that the LVs and infrastructure already exist. Hypothetical markets justify almost anything, which is how we got STS in the first place. I vividly remember full page ads in 1970-era space magazines showing a Saturn V lifting off, overprinted with "The Space Shuttle will go up and down and... (x100) ...for the price of one of these." And what were we going to do with those several hundred "free" launches? The rate-driven price reduction for EELVs is just another hypothetical. It sounds plausible, but will the price come down meaningfully if the LV production rate capability and launch infrastructure remain unchanged? The same arguments can be made for DIRECT (or anything else). If we launch a Jupiter 232 every two weeks, we can put megatons of cargo in orbit every year. Trouble is, the infrastructure to manufacture and fly more than 16 of them a year doesn't exist. The same thing is effectively true of EELV, unless you imagine the infrastucture will grow to fill the need. I am inclined to doubt that, and instead think the need will instead be curtailed by the infrastructure (which is one of the big justifications for ESAS and "go as you pay"). The commercial provider variant of the EELV architecture is essential "build it and they will come." I don't think so.

You're missing my point.  My point is this--if you design an architecture that is based around EELV-sized payloads and propellant depots, it may start out as an EELV-only (or EELV plus Falcon IX) architecture, but is open to becoming an EELV/Falcon IX *plus* RLV architecture.  The RLVs won't be "if you build it they will come" because by the time they start development on them, there will be a much larger, proven market.  And even if they don't come, an EELV only architecture is still capable of doing a reasonable job of things.  

~Jon

Offline clongton

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rsp1202 - 24/1/2008  12:53 PM

I think a lot of your time is taken up by restating this over and over. Maybe posting a sticky on the Direct thread, stating such salient points as addressed above, would help. You could then just refer to that.
The post is primarily intended for those who are “relatively” new to the subject and don't have the history behind them of how we got from there to here. Doing as you suggest would only work for a while because as the thread continues to grow it will get lost in the many and varied posts. So it's good to respectfully restate things like that; once in a while. But I will try to keep that to a minimum.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline tankmodeler

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PeteJ - 24/1/2008  7:15 AM

Excellent job Ross as always,
Yes, a really good letter.

I would like to suggest that you reinforce the point that the Jupiter configuration is really just a modification of NASA's own NLS studies brought up to date with current engines & a little addtional work. I wouldn't emphasise that the current Jupiter numbers were arrived at by a large number of NASA & contractor personnel as that might be seen as fomenting "dissention in the ranks" as it were. But if the origins of Direct/Jupiter in NLS are pushed, it becomes much easier for a change from the poilitical perspective. Much less face to save if the alternate solution comes from within as opposed to from without.

You might want take out the two uses of the specific word "vitriol" as the news hounds may just start looking for those posts to stir the pot. Talk more about setting aside any "percived disrespect" and that issue becomes more diffuse and less likely to stick in anyone's craw or draw unwanted attention.

Regards

Paul
Sr. Mech. Engineer
MDA

Offline Smatcha

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PeteJ - 24/1/2008  4:15 AM

Excellent job Ross as always,

A few observations for you to consider.

1) You have done an excellent job of keeping numbers out of the debate and focusing on the principles, therefore would point 7 in your summary be better described as a percentage saving rather than quote the raw figures.

2) You have concentrated on the two launch vehicles Jupiter 120 and Jupiter 232, what you are actually advocating is an architecture to build a wide range of launch vehicles up to Jupiter 244, and NASA has to work out which to develop depending on it's needs, this demonstrates the flexibility to adapt to future requirements.

3) You have alluded to the pedigree of this concept with reference to NLS, but could you comment that this development of the concept has been done with the help of NASA staff, in order to confirm that NASA are the owners of this, would this help ?

Thanks

Pete

Ross, an excellent write-up that is very concise and rational at every point.  I’m just not sure if anything short of storming the castle walls at this point will work.  Mike makes a number of assertions that are absolutely false as you well know.  If I have learned anything about Mike is that when he thinks he is right he won’t move unless he can improve the level of entrenchment.  All type A personalities, to one extent or another, share this but to paraphrase Charlie Brown, of all the Mike Griffin’s in the world he is Mike Griffinest.

The only possible opening for the pensive fuzzy bunny approach is if Mike has in fact been fed these false assertions.  If this is the case and assuming we can slip your letter past those guarding him from these facts we might stand a chance using this approach.  Assuming of course that these false assertions are not his for whatever reason which is by far more likely and better supported scenario based on what we know from the inside.

But failing this approach we need to get the GAO, OMB and/or CBO involved in comparing the life cycle cost of the Ares-I vs. the Jupiter-120 if we want to have a chance at making some real progress.  This one false assertion of many he made is the Achilles heal of his argument against DIRECT relevant to the near term problems.

I also think we have basis for what NASA response is to the November request that they review both the Jupiter-120 and EELV will be back to Congress.  For them to switch in the foreseeable future after these public statements is placing hope ahead of experience.

The reason that the serious technical and programmatic issues with Ares-I doesn’t cause Mike to reassess his current approach is that he would be perfectly happy to eventually ditch the Ares-I after the Ares-V is up and running for a DIRECT’s 2xHLV approach so at least we have made some progress, go team.  For him the Ares-I is a means to the end which is Ares-V.  The Ares-V is no where near it best performance as well because the core is underpowered as currently configured.

As long as the Ares-I can deliver six passengers to the ISS he is good to go.  What is ironic is that in the likely time frame this will happen under his plan their won’t be a need for NASA to do this anyway because COTS has good shot at ISS support in the 2016 frame.  Elon is shooting for 2010 for cargo as it is and it’s not a stretch for the EELV organizations either should they finally be allowed to play in the sand box.

Assuming we have arrived at 2016 with an 18mT capable Ares-I (better known as the most dangerous paint shaker ever flown in space) the general attitude will be let’s get rid of the Ares-I and get going on the Ares-V.  After decimating the STS workforce and infrastructure, enduring the largest gap in American based human space flight since the space age all for a 15 Billion dollar launch system composed of Ares-V precursor parts the would confuse even Rube Goldberg I would have to agree with the idea to ditch the stick and get going on the Ares-V.

I believe in the end this has been his plan all along.  All these seemingly irrational assertions and decisions used to support the approach put on the table for public consumption are simply to protect the actual a plan he doesn’t think he could sell on its own merits, that being the Ares-V.  Everything else will be sacrificed for that objective and that objective alone.

“Do we want to go to the moon or not?”
John C. Houbolt - November 15, 1961
Question posed in Letter to Dr. Robert C. Seamans Jr, NASA Associate Administrator

Ralph Ellison “I was never more hated than when I tried to be honest”




Offline William Barton

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jongoff - 24/1/2008  12:53 PM

William,
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Of course that's true, but it begs off the EELV architecture's major benefit, that the LVs and infrastructure already exist. Hypothetical markets justify almost anything, which is how we got STS in the first place. I vividly remember full page ads in 1970-era space magazines showing a Saturn V lifting off, overprinted with "The Space Shuttle will go up and down and... (x100) ...for the price of one of these." And what were we going to do with those several hundred "free" launches? The rate-driven price reduction for EELVs is just another hypothetical. It sounds plausible, but will the price come down meaningfully if the LV production rate capability and launch infrastructure remain unchanged? The same arguments can be made for DIRECT (or anything else). If we launch a Jupiter 232 every two weeks, we can put megatons of cargo in orbit every year. Trouble is, the infrastructure to manufacture and fly more than 16 of them a year doesn't exist. The same thing is effectively true of EELV, unless you imagine the infrastucture will grow to fill the need. I am inclined to doubt that, and instead think the need will instead be curtailed by the infrastructure (which is one of the big justifications for ESAS and "go as you pay"). The commercial provider variant of the EELV architecture is essential "build it and they will come." I don't think so.

You're missing my point.  My point is this--if you design an architecture that is based around EELV-sized payloads and propellant depots, it may start out as an EELV-only (or EELV plus Falcon IX) architecture, but is open to becoming an EELV/Falcon IX *plus* RLV architecture.  The RLVs won't be "if you build it they will come" because by the time they start development on them, there will be a much larger, proven market.  And even if they don't come, an EELV only architecture is still capable of doing a reasonable job of things.  

~Jon

I'm not missing your point, I just don't agree with it completely. I do think your last sentence is true, so long as you're careful about how you define "reasonable." I just think since all single-architecture models are infrastructure limited, a bigger infrastructure is a more capable infrastructure. The hypothetical maximum for EELV (assuming you're allowedd to consume the entire Delta IV + Atlas V capacity) is maybe 1000mT per year, whereas the hypothetical maximum for DIRECT is around 1700mT. The advantage of EELV is that the capacity and infrastructure already exist. The disadvantage is, to get that 1000mT you're talking about something like 50 launch/rendezvous events. The advantage for DIRECT is, it's only 17 launch events, and 8+ rendezvous events. The disadvantage of DIRECT is, it doesn't exist yet (though a great deal of the ground infrastructure does). If Shuttle is retired and then Ares is cancelled, and the Shuttle infrastructure is destroyed, then EELV is all that's left and, I agree, it's capable of doing a reasonable job that's considerably better than nothing.

If Falcon 9/H/Dragon all succeed (defined as, they fly and SpaceX doesn't wind up in receivership) there's an architecture there as well that could go to NEOs without much else (other than obvious upgrades for Dragon).

Offline Smatcha

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tankmodeler - 24/1/2008  10:07 AM

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PeteJ - 24/1/2008  7:15 AM

Excellent job Ross as always,
Yes, a really good letter.

I would like to suggest that you reinforce the point that the Jupiter configuration is really just a modification of NASA's own NLS studies brought up to date with current engines & a little addtional work. I wouldn't emphasise that the current Jupiter numbers were arrived at by a large number of NASA & contractor personnel as that might be seen as fomenting "dissention in the ranks" as it were. But if the origins of Direct/Jupiter in NLS are pushed, it becomes much easier for a change from the poilitical perspective. Much less face to save if the alternate solution comes from within as opposed to from without.

You might want take out the two uses of the specific word "vitriol" as the news hounds may just start looking for those posts to stir the pot. Talk more about setting aside any "percived disrespect" and that issue becomes more diffuse and less likely to stick in anyone's craw or draw unwanted attention.

Regards

Paul

Paul, no disrespect but I have been to the 9th floor and let me assure you that even when we are blessed with comparatively open mind leadership it’s the exact opposite of the “It’s a Small World” ride at Disneyland.

You should read of the history surround John Houbolt’s attempt to get NASA to accept LOR.  The words describing NASA management as hair brained, dimwitted and worse in his letters can be found on the NASA HQ web site no less (link below);

http://www.hq.nasa.gov/office/pao/History/monograph4/splash2.htm

The only difference is that under the present management John would have been shown the door in a New York minute for being even 1/100th as aggressive as he was back then.  I was ever the fuzzy bunny good solider like in Ross is in his letter in the past but I wasn’t fuzzy enough so here I am.  At least back in John’s day they actually tolerated informed descent from whatever the group think view was at the time.  Today it’s systematically hunted down and removed.

Also never confuse the current NASA culture with the Lunar Program culture that actually took us to the Moon they are as different as night and day.  Ares-I vibration problems the Jupiter-232 vs Ares-V debate aside , this is the key problem we need to fix or we aren’t going anywhere soon short of hitching a ride with some aliens.

Not that this core management problem at NASA, that generates all others, hasn’t been described in great detail multiple times by official sources.  You can find these problems described in great detail by reading the Challenger and Columbia reports.  At least this time we are only destroying money, jobs, infrastructure, talent and schedule and not astronauts.  Well not until the Ares-I flies at least.

The really frustrating thing is that NASA engineers, that haven’t yet been burned out by this caustic management environment, are among the best and most dedicated you will find anywhere.  They are the ultimate victims in this mess.  I have talked to more than a few that want to leave over it since they can’t bring any of their talent to solve the problem.  They are given a ‘solution’ by Mike and the darn well better make it work or else.
“Do we want to go to the moon or not?”
John C. Houbolt - November 15, 1961
Question posed in Letter to Dr. Robert C. Seamans Jr, NASA Associate Administrator

Ralph Ellison “I was never more hated than when I tried to be honest”




Online A_M_Swallow

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Try and get some big advantages of Jupiter into the first two paragraphs, otherwise people will abort reading the letter.

Offline khallow

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William Barton - 24/1/2008  4:40 AM

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khallow - 24/1/2008  4:33 AM

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SMetch - 23/1/2008  12:45 PM

I hope we’re smart enough that we never again try to place such a large system in orbit by doing it in twenty-ton chunks. I think we all understand that fewer launches of larger payloads requiring less on-orbit integration are to be preferred. Thus, a vehicle in the Saturn V class –some 300,000 lbs in LEO – allows us to envision a Mars mission assembly sequence requiring some four to six launches, depending on the packaging efficiency we can attain. This is something we did once and can do again over the course of a few months, rather than many years, with the two heavy-lift pads available at KSC Complex 39.”

Perhaps it's just due to my EELV fetish, but why is putting something large in orbit 20 tons at a time a bad idea? What am I missing?

Added: I guess what I'm puzzled by is how would the Shuttle and ISS observations indicate that assembly in such a manner is a problem?

Just to satisfy my curiosity, where do you think the point of diminishing returns is for shipping up pieces and parts (and loads of fuel)? I think the main objection to assembling any large structure in orbit in 20mT chunks is, it has taken more than 10 years to assemble ISS that way, using a mixture of STS, Proton, and Soyuz/Progress launches. A secondary objection is infrastructure cost. The advantage of EELV is, they and their infrastructure already exist. The disadvantage is, infrastructure imposes limits. 500mT to LEO consumes 25 EELV launches, which is about the infrastructure limit for one EELV type for a year (one launch every two weeks). That imposes a robustness limit for the program, whatever it might be. To me, the EELV/20mT high flight rate paradigm points straight at making a true RLV development program worthwhile. Politics made our first attempt at that into STS.

I suppose the point of diminishing returns occurs when the value of what goes up is less than the cost of putting it in orbit. Keep in mind that the ISS is several years behind due to its dependence on the Shuttle and several more years behind because of the redesigns of the ISS. Observing that a single EELV type could put up an ISS in a year is  an unpersuasive argument against EELV launched space stations.

Second, I don't understand the point of your observations about infrastructure. If an EELV is actually launching 25 times a year, then that means strong incentive to use more effiicently and expand the existing infrastruture, create new infrastructure, and to improve the launch vehicle's capabilities. And NASA need not spend money to make that happen.
Karl Hallowell

Offline savuporo

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William Barton - 24/1/2008  8:44 AM
The hypothetical maximum for EELV (assuming you're allowedd to consume the entire Delta IV + Atlas V capacity) is maybe 1000mT per year
Both of you completely neglect the fact that EELVs plus whatever that SpaceX manages to fly eventually are not the only operating rockets in the world, or even in US. Even leaving aside prospects about RLVs that we all wish for, but may not come ..
There is always Orbital with their current and planned rockets, there is Sea Launch, theres H-IIA and Ariane , even ATK mulls the idea about operating an ELV.
So the thing is, even if you plan your hardware launches around EELVs, for propellant, which is the bulk of the upmass required, you have the entire worlds launch market to call upon, or half the worlds if you leave Russians aside.
In fact, throwing out the requirement for 1000mT per year propellant launches may make quite a few launchers appear on the market from organizations you never would have guessed, because you just closed a business case.

Its valid to question about maximum capacity of EELV infrastructure, but its as important to understand that EELVs are not the limit, not now and by far not by the time we actually get around to assembling a manned martian stack.

Oh, and on the ISS concerns. ISS has not been assembled using Soyus and Proton etc, of course. It has been, for all intents and purposes, assembled by one launcher, the STS system, and thats the critical fault of the entire plan.
Also observe that ISS is not 5 parts propellant 1 part hardware.
Orion - the first and only manned not-too-deep-space craft

Offline tgrundke

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Ross -

By far and away the most succinct, comprehensive and clear explanation of the differences between the Ares and Direct approaches to future launch vehicles. Bravo.

With clear explanations like yours it places the burden on NASA to explain *precisely* where the Ares program is the better proposal.

Barring NASA's ability to provide logical counter-arguments to those you made, we can only assume one thing: the Ares decision is 100% political, not logistical, engineering-based nor practical for the future needs of the American space program.

My suggestion moving forward is this:
1) Get your letter into the hands of people who can get in front of the political leaders and be heard
2) Get your letter into trade publications
3) Get your letter into the hands of NASA engineers directly

Whatever you do, remember this: your arguments at this point are clear as day and should sell just about anyone without a vested interest in the Ares system within minutes.  Excellent work.

Offline david-moon

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Ross, that's an excellent open letter, very well written.  I just have one suggestion, concerning this paragraph:

While I have previously been a vocal and sometimes bitter critic of both Dr. Griffin and .... While there has been vitriol aplenty, I actually find I support NASA's Administrator far more than I oppose him.

The natural reaction of anyone inside NASA to this would be "who are you and why should I care whether you support or oppose my plans."  That reaction might even stop some from reading the rest of the letter, which would be unfortunate.

I suggest that you edit down the discussion of your personal history and just focus on your point about two separate launch vehicles versus one launch vehicle with two configurations.  I would limit the personal stuff to at most an apology for any intemperate comments you may have made in the past.  Actually as far as I can remember, the intemperate vitriol on these forums came from other fans of DIRECT, not from you.

Offline tankmodeler

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SMetch - 24/1/2008  2:02 PM
Paul, no disrespect but I have been to the 9th floor and let me assure you that even when we are blessed with comparatively open mind leadership it’s the exact opposite of the “It’s a Small World” ride at Disneyland.
Wow, you sound more cynical then I am & I teach grad level cynicism courses here at work!  :)

Seriously, no disrespect taken at all and I am more than willing to belive you are correct in this assessment. However, such an open letter as Ross has written really isn't for the NASA HQ staff anyway. It's for Congress and the press and should be posted to any press outlets you can think that might be interested. It is the press who really don't need an incentive to go looking for interpersonal dirt that may or may not exist to spice up a story. Get it out to Congress and let them see if they can get a response out of the NASA Administration that jives with the letter & the speach.

That's where the hope lies. Not, really, with senior NASA HQ, whose ability to remove their rectally emplaced craniums I am seriously in doubt of. At least not without Congress' help.

Paul
Sr. Mech. Engineer
MDA

Offline William Barton

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khallow - 24/1/2008  2:25 PM

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William Barton - 24/1/2008  4:40 AM

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khallow - 24/1/2008  4:33 AM

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SMetch - 23/1/2008  12:45 PM

I hope we’re smart enough that we never again try to place such a large system in orbit by doing it in twenty-ton chunks. I think we all understand that fewer launches of larger payloads requiring less on-orbit integration are to be preferred. Thus, a vehicle in the Saturn V class –some 300,000 lbs in LEO – allows us to envision a Mars mission assembly sequence requiring some four to six launches, depending on the packaging efficiency we can attain. This is something we did once and can do again over the course of a few months, rather than many years, with the two heavy-lift pads available at KSC Complex 39.”

Perhaps it's just due to my EELV fetish, but why is putting something large in orbit 20 tons at a time a bad idea? What am I missing?

Added: I guess what I'm puzzled by is how would the Shuttle and ISS observations indicate that assembly in such a manner is a problem?

Just to satisfy my curiosity, where do you think the point of diminishing returns is for shipping up pieces and parts (and loads of fuel)? I think the main objection to assembling any large structure in orbit in 20mT chunks is, it has taken more than 10 years to assemble ISS that way, using a mixture of STS, Proton, and Soyuz/Progress launches. A secondary objection is infrastructure cost. The advantage of EELV is, they and their infrastructure already exist. The disadvantage is, infrastructure imposes limits. 500mT to LEO consumes 25 EELV launches, which is about the infrastructure limit for one EELV type for a year (one launch every two weeks). That imposes a robustness limit for the program, whatever it might be. To me, the EELV/20mT high flight rate paradigm points straight at making a true RLV development program worthwhile. Politics made our first attempt at that into STS.

I suppose the point of diminishing returns occurs when the value of what goes up is less than the cost of putting it in orbit. Keep in mind that the ISS is several years behind due to its dependence on the Shuttle and several more years behind because of the redesigns of the ISS. Observing that a single EELV type could put up an ISS in a year is  an unpersuasive argument against EELV launched space stations.

Second, I don't understand the point of your observations about infrastructure. If an EELV is actually launching 25 times a year, then that means strong incentive to use more effiicently and expand the existing infrastruture, create new infrastructure, and to improve the launch vehicle's capabilities. And NASA need not spend money to make that happen.

The basis of the infrastructure observations is based on the fact that a primary enphasis of both the EELV and DIRECT approaches depend on the fact that, for EELV, the ground infrastructure (manufacturing and launch) already exists, and for DIRECT, the infrastructure is a modification of the STS infrastructure, which already exists. Expanding the infrastructure, either with taxpayer $$$ or via the invisible hand of the marketplace, is talking about something that doesn't exist.

As for using a single EELV to put up ISS in a year, I certainly have not suggested that. As far as I know, the manufacturing infrastructure couldn't produce 25 Delta IVH's in a year. And how many have been flown since the beginning of the program? Two? Besides which, having a rocket that can lug 20mT to LEO doesn't build a space station. One of the handy things about Shuttle is, you don't need a space tug because it is a space tug.

Offline William Barton

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savuporo - 24/1/2008  2:29 PM

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William Barton - 24/1/2008  8:44 AM
The hypothetical maximum for EELV (assuming you're allowedd to consume the entire Delta IV + Atlas V capacity) is maybe 1000mT per year
Both of you completely neglect the fact that EELVs plus whatever that SpaceX manages to fly eventually are not the only operating rockets in the world, or even in US. Even leaving aside prospects about RLVs that we all wish for, but may not come ..
There is always Orbital with their current and planned rockets, there is Sea Launch, theres H-IIA and Ariane , even ATK mulls the idea about operating an ELV.
So the thing is, even if you plan your hardware launches around EELVs, for propellant, which is the bulk of the upmass required, you have the entire worlds launch market to call upon, or half the worlds if you leave Russians aside.
In fact, throwing out the requirement for 1000mT per year propellant launches may make quite a few launchers appear on the market from organizations you never would have guessed, because you just closed a business case.

Its valid to question about maximum capacity of EELV infrastructure, but its as important to understand that EELVs are not the limit, not now and by far not by the time we actually get around to assembling a manned martian stack.

Oh, and on the ISS concerns. ISS has not been assembled using Soyus and Proton etc, of course. It has been, for all intents and purposes, assembled by one launcher, the STS system, and thats the critical fault of the entire plan.
Also observe that ISS is not 5 parts propellant 1 part hardware.

We're not ignoring the other 20mT launchers, they're just not germaine to  the discussion. Assuming VSE continues to be an all-US endeavor, it makes sense to rule out non-US launchers. In another thread (God knows which one), there was a discussion of world wide launch capacity that looked at what you could do with EELVs, Ariane V, H2, Proton, etc.

By the way, IIRC some parts of ISS were lugged up by Proton, and wasn't the Russian airlock lugged up by a Soyuz (the rocket, not the capsule)? As far as ISS not being 5 parts propellant 1 part hardware, what difference does it really make? You still have to get the pieces and parts to one spot in LEO and make them work together, whether its berthing bits of ISS together and hooking up electricals or docking tankers to a fuel depot and pumping fuel/oxydizer. ISS is the only example we have of orbital assembly, unless you want to count Mir.

It'd be a lot easier to embrace the EELV architecture if the EELV flight rate were already high. Remember that's the same sales tool was used to promote STS. EELV proponents are certain it can be brought to a high flight rate, but then most people believe the thing we believe in will work the way we hope. What if it doesn't?

Offline renclod

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- 23/1/2008  10:45 PM
This is where Mike goes off the rails.
- But it is quite another thing to render government logistics support to ISS so expensive that the Station is immediately judged to be not worth the cost of its support. Dual launch EOR with vehicles of similar payload class does not meet the requirement to support the ISS in any sort of cost-effective manner.”
my transcript from K.Cowing's audio, 29min 38sec into the speach; emphasize for what's not in the pdf :

"...it's quite another to produce a plan, that, for government logistics support of ISS - which is so expensive - that the station is immediately judged to be not worth the cost of its support.
Dual- launch EOR with vehicles of similar payload class does not meet the requirement
to support the ISS in any sort of a cost-effective manner.

Now, if you don't like the ISS, then you don't care about that. Actually though, that was not one of my free variables [hilarity in the audience]

On the other end of the scale [heartfull laughs in the audience] - I never did before to be correct all that well - on the other end of the scale, we must judge..."


Offline clongton

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renclod - 24/1/2008  5:19 PM

 
{Griffin}"Dual- launch EOR with vehicles of similar payload class does not meet the requirement
to support the ISS in any sort of a cost-effective manner."
Just goes to show that the man is totally ignorant of the difference between a Jupiter-120 and a Jupiter-232. He thinks we are going to use a 100mT launch vehicle to resupply the ISS. The basic concept of the DIRECT architecture seems to be beyond him. Let's see; fly with or without an upper stage. Can it really be that simple? Nah. I didn't think of it first so it must not be true.
Sigh
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline renclod

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- 25/1/2008  12:34 AM
Sigh
You're quoting past my point.

The distaste for ISS is in Dr. Griffin's clear showcase. And that is significant. Think Machiavelli, think real-politik. If the ISS is a heavy stone tied to the goverment's neck, the last thing a gov't agency wants is a new system to perpetuate the status-quo. You think J-120's ability to replace the STS is a feature. Some may think it's a bug.


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