CEV & CLV moving target

[gunsandrockets]

"You do the same job as a 4 seg SRB and a SSME with a 5 seg SRB and J2X for less cost. That's cost savings in anyone's book..."<br /><br />No money is saved by spending an extra $2 billion for the 5-segment SRB development.<br /><br />"You propose doing less FOR less. How does that reflect on $/lb to orbit? That's the most important metric." <br /><br />It should be damn clear by now that $/lb to orbit is the least important priority of the NASA ESAS plan. The ESAS plan boils down to two goals: a safer manned vehicle and a 100+ tonne payload cargo lifter. That's it. Not cheaper access to orbit.<br /><br />The main cost driver for NASA now is lowering development costs, for two reasons: first, to reduce development time, and secondly to squeeze costs to fit inside the NASA budget during the declining years of the Space Shuttle.<br /><br /><br />"The larger CEV will be able to return ISS science materials to earth, and bring enough lunar samples back that NASA doesn't have to guard them like the crown jewels. That's not a trivial capability."<br /><br />Downmass is not an important part of the ESAS plan. In fact very damn little. If it was important than NASA wouldn't have chosen an Apollo capsule clone for a reentry vehicle and would have gone with something like the Lockheed-Martin lifting body instead. The Lockheed vehicle in addition to a four-man crew had a downmass of 5,000 pounds. The ESAS block one CEV for ISS missions has a crew of three and 400 kg of cargo.

 

[gunsandrockets]

"NASA *is* following the ESAS plan."<br /><br />Ah the infallible ESAS plan. So what happened to the 5.5m capsule, the SSME, the stretched Space Shuttle external tank, and methane propellant for the CEV service module and LSAM ascent stages? Is that what you believe constitutes NASA following the ESAS plan?<br /><br />-- sarcasm on -- Cleary the ESAS plan is beyond question or dispute! -- sarcasm off --

 

[nacnud]

Well the ESAS was an archetecture study, it chose the 1 1/2 launch mission archetecture and suggested the LVs to do the job.<br /><br />Further refinment of the 1 1/2 Shuttle derived LVs came up with the changes. I'm sure you know all this any way.

 

[radarredux]

> <i><font color="yellow">Is that what you believe constitutes NASA following the ESAS plan?</font>/i><br /><br />There is a saying that goes something like: Battle plans are usually thrown out with the first shot, but the process of planning is invaluable.<br /><br />I see the ESAS as the planning effort, but if over time earlier assumptions prove to be false or facts change, to dogmatically stick to a plan for a plan's sake seems foolish to me. Griffin doesn't seem foolish to me.</i>

 

[geminivi]

I can see the logic of NASA's initial decision to sole source a 4 seg SRB in the early days of VSE. It was cheap to develop and they already had it flying. But once they changed direction and wanted, in essence a new first stage, how did they get away without doing a competitive bid? $3 billion is alot of dough to simply hand to ATK without a contest to keep everyone honest.<br /><br />As for opting for a 5 seg to spread the development costs between the CLV and the heavy, nice in theory. I doubt the heavy will fly before 2020-2025 given politics as they are. Over the next 13.5 years, I doubt the heavy will have high fidelity to the current drawings. So why pair the CLV to the heavy?

 

[gunsandrockets]

"There is a saying that goes something like: Battle plans are usually thrown out with the first shot, but the process of planning is invaluable."<br /><br /><br />My complaint is not that the ESAS plan is completely wrong, I merely protest against anyone who waves around the ESAS report as the final word on the topic, in a transparent attempt to shut down debate. My citation of the many instances in which the ESAS report got the details wrong is to prove that every aspect of the report is open to dispute and debate, including the choice of HLV over MLV, selecting LOR over L-1 rendezvous and the abandonment of EELV.

 

[edkyle98]

"Actually Apollo had plenty of room to move around in, enough room for a galley, a toilet and to put on or take off a pressure suit. "<br /><br />A galley? A toilet? You mean the space under the couches where the plastic bags for "fecal disposal" and "relief tube" for urination were located? Have you ever looked inside an Apollo capsule? Each astronaut could float around within the equivalent volume of a four foot square box - about half the size of my desk. Small compared to even a closet or a phone booth. A bit more room than a casket, though.<br /><br /> - Ed Kyle

 

[edkyle98]

"My complaint is not that the ESAS plan is completely wrong, I merely protest against anyone who waves around the ESAS report as the final word on the topic, in a transparent attempt to shut down debate."<br /><br /><br />It isn't that the ESAS report is the final word. It is that it is the only word, because no one has published an authoritative rebuttal. Those who don't like its carefully considered findings can, at present, only wave their hands and say "It must be wrong!", but they have yet to offer any equivalent cost analysis, or design trade studies etc., to support their claims.<br /><br /> - Ed Kyle

 

[gunsandrockets]

"A galley? A toilet? You mean the space under the couches where the plastic bags for "fecal disposal" and "relief tube" for urination were located? Have you ever looked inside an Apollo capsule? Each astronaut could float around within the equivalent volume of a four foot square box - about half the size of my desk. Small compared to even a closet or a phone booth. A bit more room than a casket, though."<br /><br />Your opinion on living space is wildly at odds with the published numbers including the numbers from the ESAS report. Numbers which you continually dodge and refuse to confront. <br /><br />Well, I tried. The old saying about leading a horse to water comes to mind...

 

[gunsandrockets]

Ah, comedy gold it is...<br /><br />"It isn't that the ESAS report is the final word. It is that it is the only word, because no one has published an authoritative rebuttal."<br /><br />No one? How about NASA? Every publication NASA has put out justifying every change since the original release of the ESAS report is 'an authoritative rebuttal'.<br /><br />

 

[j05h]

The trade studies that preceded ESAS release included several EELV and other launchers. The SpaceHab, Schaefer, Draper and maybe Boeing reports all used existing launch assets. I used to have the PDFs, but can't find them online or my drive right now. <br /><br />To say that "no one" offered an alternative to CEV/CLV/CALV shows a lack of research.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[nacnud]

Here is one EELV derived solution<br /><br />Eveolved Atlas [pdf warning]

 

[j05h]

Thanks Nac! There used to be a page that had about 20 different architecture studies, but I can't find it.<br />josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[edkyle98]

An interesting document, but it doesn't show that Atlas would be cheaper or more reliable than CLV. In fact it shows that Lockheed would first have to replace the existing Centaur with a new fat Centaur with more than four RL-10s. Then it would have to replace the existing Atlas first stage with a new fat Atlas powered by two RD-180s. Simple! All that Lockheed would have to do would be to develop an all-new rocket! Billions of dollars and years of development. No sweat.<br /><br />Concepts like these are why NASA was driven to consider an SRB-derived launcher. <br /><br /> - Ed Kyle

 

[edkyle98]

"The trade studies that preceded ESAS release included several EELV and other launchers. The SpaceHab, Schaefer, Draper and maybe Boeing reports all used existing launch assets. I used to have the PDFs, but can't find them online or my drive right now.<br /><br />To say that "no one" offered an alternative to CEV/CLV/CALV shows a lack of research. "<br /><br /><br />I said that "no one has published an authoritative rebuttal [to the ESAS report]." Trade studies that preceeded ESAS clearly do not offer a rebuttal to ESAS. The ESAS report itself shows how the committee considered, and discarded, dozens of such alternatives due to cost or safety considerations.<br /><br /> - Ed Kyle

 

[edkyle98]

"Every publication NASA has put out justifying every change since the original release of the ESAS report is 'an authoritative rebuttal'. "<br /><br /><br />You don't seem to understand the purpose of an "architecture study". NASA is still following paths identified in the ESAS report. The only substantial launch vehicle changes have been based on the sound decision to discontinue use of the very costly SSME.<br /><br /> - Ed Kyle

 

[edkyle98]

"Your opinion on living space is wildly at odds with the published numbers including the numbers from the ESAS report. Numbers which you continually dodge and refuse to confront."<br /><br /><br />Apollo CM had 6.17 cubic meters (218 cubic feet) of habital volume. That's 72.575 cubic feet per astronaut, equivalent to the volume in a square box 4 feet, 2 inches in height, width, and depth.<br /><br /> - Ed Kyle

 

[gofer]

OK. I guess I need to clarify re: Big Gemini, it didn't appear as clear as I thought it would. The Big Gemini was within the MOL program and not meant to go to the Moon (AFAIK). The CEV Block 1A is an ISS CEV at 22 tonnes total mass and also is not meant to go to the Moon. But it's still a/the CEV. This is all from the 'notorious' ESAS document. And it looks 'a bit bloated' compared to the Big Gemini in terms of mass and capabilities of the *CM* (the lunar burns fuel goes into the SM of the CEV Block II). *Irregadless* of the fuel needed to do the Moon related burns. Just as an Earth descent vehicle. 9 people + 2.5 tonnes of supplies vs. 6 people + 400 kg of supples *OR* 3.5 tonnes of supplies (in the 1b cargo version). Sheer LEO numbers, no Moon. But even there the CEV is an underperformer, *even* compared to the 40 old levels.<br /><br />As to the G-levels, the mass of the second stage is a function of (among other things) what's needed to hold the SRB down. If we reduce the mass of the CEV to the reasonable levels we'd need to fill the 2nd stage with lead if we are to get the CLV to fly properly. That would be even sillier than oversizing the CEV. Totals: one of the reasons the CEV is so "capable" (i.e. heavy) is that it goes up on the CLV.

 

[gofer]

If one figures that the current CEV is 'overweight' for the task at hand, one obvious advantage of the ELVs that requires no extra documents is that the needed launchers *already exist and have a track record*. This notion is even more dear to me than the "man-rating documents" that are a holy grail of the ESAS study, but nevertheless are mysteriously waived for the STS and the Soyuz. The CLV won't (exist) and won't (have a track record) for at least 2 years. That's an ace that can't be beat, no matter how many 'proper' studies you do, in my book. <br /><br />[edit] In fact, this "man rating concept" is one of the major pegs in the reasoning behind many of the ESAS document's conclusions. Remove it (and both me and Griffin think it's an outdated concept), and it (the ESAS document) should go back to the drawing board. <br /><br />Aside, if it's okay for the ESAS report to be so drastically revised, then what on earth was this fuss all about? There is absolutely nothing new in the study, it's mostly a repeat of the old Planetary Society plans with some of the Mars Society's drawingws thrown in. If they still got it so wrong after so much time and money has been spent, what is its value? To the taxpayer, to the VSE? There isn't much left from the original except the 1.5 Moon shot scheme and the justification for the HLV. Where is the Lunar infrustructure? It simply looks they hired the wrong people to do it at this point, as little of it is actually being adopted.

 

[gofer]

Sorry, I was wrong, the CEV BlockIa is crewed with 3 people, not 6! Plus 400 kilo of cargo. All at 23 tonnes. http://www.spaceref.com/news/viewsr.html?pid=19067 Figure 1-17. I'm not a cynic, and I wish the VSE all the success, but if some folks have called the CLV "porklauncher", that may be not far off...

 

[gunsandrockets]

To compare like vs like, you should look at the mass and pressurized volume of a Big Gemini reentry vehicle vs the mass and pressurized volume of the CEV reentry vehicle. I think you will find little difference between the two vehicles if you do.

 

[gunsandrockets]

For a wildly mischaracterized summary of the Atlas report...<br /><br />"An interesting document, but it doesn't show that Atlas would be cheaper or more reliable than CLV. In fact it shows that Lockheed would first have to replace the existing Centaur with a new fat Centaur with more than four RL-10s. Then it would have to replace the existing Atlas first stage with a new fat Atlas powered by two RD-180s. Simple! All that Lockheed would have to do would be to develop an all-new rocket! Billions of dollars and years of development. No sweat. Concepts like these are why NASA was driven to consider an SRB-derived launcher."<br /><br />Wheras in reality the 6 x RL-10 + 2 x RD-180 version of the Atlas is for an 80 tonne payload launcher! That Atlas version has no relationship with a 25 tonne payload class CLV launcher.<br /><br />

 

[gunsandrockets]

"You don't seem to understand the purpose of an "architecture study". NASA is still following paths identified in the ESAS report. The only substantial launch vehicle changes have been based on the sound decision to discontinue use of the very costly SSME."<br /><br />You don't seem to understand the primary discussion has not been about the ESAS architecture, but the best way to fill the jobs in the ESAS architecture, in particular the CLV job.<br /><br />Even though you limited your remark to 'substantial launch vehicle changes' you still made a statement with huge omissions of fact. Most likely in an attempt to prop up the ESAS report despite the ESAS report's numerous incorrect assumptions.<br /><br />NASA has not just dropped the SSME, it has also dropped the stretched Space Shuttle external tank and the 4-segment SRB. The whole flavor of the original ESAS report was the maximum use of Space Shuttle components. Now NASA will use virtually nothing from the Space Shuttle. Now it is more accurate to describe the NASA launch vehicle projects as 'Saturn V' derived or 'Delta IV' derived than as 'Shuttle Derived'.

 

[gofer]

<blockquote><font class="small">In reply to:</font><hr /><p> To compare like vs like, you should look at the mass and pressurized volume of a Big Gemini reentry vehicle vs the mass and pressurized volume of the CEV reentry vehicle. I think you will find little difference between the two vehicles if you do. <p><hr /></p></p></blockquote> <br /><br />I'm glad you asked! <img src="/images/icons/wink.gif" /> <br /><br />(not sure if you trust this site but nevertheless)<br /><br />BigG:<br /><br />(note: 9 people + 2.5mt of cargo)<br />http://www.astronautix.com/craft/bigemini.htm <br /><br />Habitable Volume: 18.70 m3. Mass: 15,590 kg (34,370 lb). Payload: 2,500 kg (5,500 lb)<br /><br />CEV CM:<br /><br />(note: 3 people according to ESAS)<br /><br />http://www.astronautix.com/craft/cevcm.htm<br /><br /><br />Habitable Volume: 12.00 m3. Mass: 9,506 kg (20,957 lb). <br /><br />PLUS! the CEV SM<br /><br />http://www.astronautix.com/craft/cevsm.htm<br /><br />Habitable Volume: 0; Mass: 13,647 kg (30,086 lb). <br /><br />(totals for the CEV 22+ tonnes)<br />

 

[gofer]

Of course if you say "but CEV ISS block 1a" has more volume PER person, I won't argue. The question (raised by someone) is: is maximizing the volume per person in a what basically is a taxiing craft *that important*? If so, why not launch 2 people in the CEV. Could get a bathtub in there.