jongoff - 24/1/2008 11:35 AMWilliam,Quote500mT 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
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.
clongton - 24/1/2008 12:06 PMJon,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.
clongton - 24/1/2008 9:06 AMDIRECT 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 . . .
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.
rsp1202 - 24/1/2008 12:53 PMI 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.
PeteJ - 24/1/2008 7:15 AMExcellent job Ross as always,
PeteJ - 24/1/2008 4:15 AMExcellent 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
jongoff - 24/1/2008 12:53 PMWilliam,QuoteOf 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
tankmodeler - 24/1/2008 10:07 AMQuotePeteJ - 24/1/2008 7:15 AMExcellent 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.RegardsPaul
William Barton - 24/1/2008 4:40 AMQuotekhallow - 24/1/2008 4:33 AMQuoteSMetch - 23/1/2008 12:45 PMI 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.
khallow - 24/1/2008 4:33 AMQuoteSMetch - 23/1/2008 12:45 PMI 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?
SMetch - 23/1/2008 12:45 PMI 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.”
William Barton - 24/1/2008 8:44 AMThe hypothetical maximum for EELV (assuming you're allowedd to consume the entire Delta IV + Atlas V capacity) is maybe 1000mT per year
SMetch - 24/1/2008 2:02 PMPaul, 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.
khallow - 24/1/2008 2:25 PMQuoteWilliam Barton - 24/1/2008 4:40 AMQuotekhallow - 24/1/2008 4:33 AMQuoteSMetch - 23/1/2008 12:45 PMI 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.
savuporo - 24/1/2008 2:29 PMQuoteWilliam Barton - 24/1/2008 8:44 AMThe hypothetical maximum for EELV (assuming you're allowedd to consume the entire Delta IV + Atlas V capacity) is maybe 1000mT per yearBoth 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.
- 23/1/2008 10:45 PMThis 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.”
renclod - 24/1/2008 5:19 PM {Griffin}"Dual- launch EOR with vehicles of similar payload class does not meet the requirementto support the ISS in any sort of a cost-effective manner."
- 25/1/2008 12:34 AMSigh