Quote from: OV-106 on 12/29/2009 12:39 pmYour tag line at the bottom is "if it ain't broke, don't fix it". Why front load a new HLV with more development, where major problems can always arise, if not necessary? We have the tooling for an 8.4 meter core now. We have SSME's where it has been studied for years on how to make expendable versions. We have all the infrastructure in place to accomodate that configurationm, etc. So use 5 segment boosters someday if necessary, fine and that gives you a little more performance. However, those are not ready and we have 4 segments today. The simple fact is there is no reason to throw the baby out with the bath water and fund MSFC for a decade to maybe eventually field a new mega booster that will not be cost effective when complete just because MSFC employees *think* we need it. This is about power at their center and their center alone. Don't fool yourself that it is anything else. I agree with that, but politics being what they are, it may be necessary to throw MSFC a "bone."I think we should go right to the 8.4m SSME design just for the reasons you state. I don't even think it would take the 8-9 years for the development if we went that way.Mr. Obama however, being a man of consensus building, might be willing to sacrifice that design.
Your tag line at the bottom is "if it ain't broke, don't fix it". Why front load a new HLV with more development, where major problems can always arise, if not necessary? We have the tooling for an 8.4 meter core now. We have SSME's where it has been studied for years on how to make expendable versions. We have all the infrastructure in place to accomodate that configurationm, etc. So use 5 segment boosters someday if necessary, fine and that gives you a little more performance. However, those are not ready and we have 4 segments today. The simple fact is there is no reason to throw the baby out with the bath water and fund MSFC for a decade to maybe eventually field a new mega booster that will not be cost effective when complete just because MSFC employees *think* we need it. This is about power at their center and their center alone. Don't fool yourself that it is anything else.
A few reasons:1. Whoever ever took a look into the Augustine report (just review page 87...) should know that a 5 RS-68B Ares V Lite based SHLV received a ringing endorsement by the report over any SSME-based SDLV.2. NASA likes the concept. They want as big an HLV (with growth option) as they can get. A 5 RS-68B, 5-segment SRB Ares V Lite provides 145mt to LEO AND still offers 20% in growth at a later stage.3. The RS-68B development effort just has a bigger lobby (at MSFC, at Rocketdyne, at NASA headquarters, in other industry lobbyists) behind it vs. an RS-25e development effort.This is my opinion. If Ares I is canceled and an SHLV only is developed, it will be a RS-68 based, 5-segment, J-2x rocket.
The president is not a rocket scientist and therefore will not be doing any design from the oval office.
MSFC will get a bone by being the lead agency on the launch vehicle, as they always have been historically. In other words, the project office will be based there as it always has been. What needs to be stopped from happening by the Program office and the HQ level, is caving and allowing that project office to cram their mega booster down everyone's throat at the expense of cost and schedule to only add technical risk.
That's like saying a 100hp gasoline based engine has less performance than an 80hp diesel based engine, just because the diesel engine is more fuel efficient.
Quote from: Idol Revolver on 12/29/2009 09:08 amThe RS-68B would not be an option due to base heating. You would have to develop a regen version.The RS-68B IS the Regen version of the RS-68 engine.
The RS-68B would not be an option due to base heating. You would have to develop a regen version.
ares-mojo;RS-68 Regen is a $1 billion dollar development program. In these economic times it is nothing short of an act of blind hope to believe that we will spend that kind of money to replace an engine that we already have that can already do the job required. The civilian space program does not and will not have that kind of money to spend on unnecessary engine development and the US Air Force will not share development costs for it because they simply have no need of it.
Add to it that the Ares V Lite can only lift 145mT vs the Ares V Classic which could do 155mT, to start.
The 10m Core would cost over $1bn in higher costs at MAF compared to the 8.4m Cre and a further $3bn at KSC to modify the facilities there too (VAB, MLP, Propellant Storage facilities etc).Because of those extra costs, the Bolden HLLV Study found that option was unaffordable. That option has already been removed from the remaining considered options list. To use NASA-Speak: 10m Tanking is no longer in the Active Trade Space.If you aren't going with 10m tanking, SSME is the far, far better option -- especially given the $1bn costs involved in making the RS-68 engines compatible (Regen nozzle) with the Base Heating environment on these much larger vehicles.Keep dreaming if you choose to. But reality is moving on without you.Ross.
Quote from: kraisee on 12/29/2009 04:02 pmThe 10m Core would cost over $1bn in higher costs at MAF compared to the 8.4m Cre and a further $3bn at KSC to modify the facilities there too (VAB, MLP, Propellant Storage facilities etc).Because of those extra costs, the Bolden HLLV Study found that option was unaffordable. That option has already been removed from the remaining considered options list. To use NASA-Speak: 10m Tanking is no longer in the Active Trade Space.If you aren't going with 10m tanking, SSME is the far, far better option -- especially given the $1bn costs involved in making the RS-68 engines compatible (Regen nozzle) with the Base Heating environment on these much larger vehicles.Keep dreaming if you choose to. But reality is moving on without you.Ross.So, if MSFC gets a bone, it's gonna have an 8.4m core, eh? That means Ares V is dead, right?
No because the original ESAS Ares V had 5 SSMEs in a 8.4m core. It is the leading candidate now but with PBAN SRBs and one J2-X.
So, if MSFC gets a bone, it's gonna have an 8.4m core, eh? That means Ares V is dead, right?
Folks seem to have the (big) rocket in mind only, not the mission (spacecraft, payloads) it just supports for a few minutes. "What I can see is important, everything else does not matter much."Analyst
"Ares is dead, long live Ares".