Author Topic: RS-68 CLV First Stage  (Read 60743 times)

Offline Avron

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Re: RS-68 CLV First Stage
« Reply #40 on: 07/14/2006 02:36 PM »
Granted... on total impulse normalized ... do the numbers change? still an order of magnitute?

Offline edkyle99

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RE: RS-68 CLV First Stage
« Reply #41 on: 07/14/2006 03:35 PM »
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I got thinking the other day (dangerous, I know), about how you could replace the (soild) first stage of the Ares I with a drop-in liquid replacement.

This works, but it would probably be less expensive to simply put a new upper stage on top of an existing Delta IV Heavy 3xCBC cluster (with reduced propellant loading in the CBCs).  The latter approach, unlike NASA's current Ares I plan, could be accomplished with a first stage that already exists, saving billions of development dollars.  The Heavy approach would also mitigate the main weakness of a 2xRS-68 design, which is low liftoff thrust-to-weight ratio.  

 - Ed Kyle

Offline Smatcha

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Re: RS-68 CLV First Stage
« Reply #42 on: 07/14/2006 03:50 PM »
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R&R - 13/7/2006  2:51 PM

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yinzer - 13/7/2006  10:03 PM

The lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events.  The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.

In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage.  And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV.  If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available.  NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.

Did you find something more than the "hallway chatter" that I see described on NASA Watch?

I have a hard time believing NASA would make another significant design change like they did going from Revised Shuttle to RS68 engines, especially going to RD180's.  Since PW&Rocketdyne are very far from building them in the US if ever I wonder if NASA can avoid the political backlash of once again relying on the Russians as significantly as they have been with Soyuz flights to ISS.

Not withstanding the Russian source of the RD180 it’s important to remember while LOX/Kerosene is a good first stage choice the current Shuttle configuration of using SRB’s in combination with low thrust LOX/LH2 is fairly equivalent.  Effectively, while the LOX/LH2 engines are burning from launch they are really part of an equivalent upperstage after the SRB are jettisoned.  LOX/LH2 is really the best choice for upper stages.  The fact that they also burn thru some of the fuel prior to SRB jettison just means a little larger tank than if the engines fired up as a true second stage.  When you consider the weight of inter tanks and lower stage jettison, structure and engines plus tank, it kind of washes out in the end.

The RD180 would essentially get rid of ATK and Boeing at the same time in favor of Lock/Mart.  Not going to happen.  There is a better way that works both technically and politically, with significant amounts of future work focused on the particular areas of expertise for all three.
“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 edkyle99

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Re: RS-68 CLV First Stage
« Reply #43 on: 07/14/2006 04:11 PM »
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SMetch - 14/7/2006  10:37 AM

The RD180 would essentially get rid of ATK and Boeing at the same time in favor of Lock/Mart.  

Assuming we are talking about the Crew Launch Vehicle here, wouldn't NASA split the work regardless of main engine?  For example, Energomash/Pratt&Whitney Rockedyne (PWR) would do the RD-180s, PWR would do the J-2X, Lockheed might do the first stage and Boeing the upper stage, or vice-versa.  ATK would still have escape rockets, separation rockets, etc., though an admitedly much smaller piece of the pie but pie nonetheless.  On top of these, of course are the lucrative CEV contracts to be awarded.

 - Ed Kyle

Offline Avron

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Re: RS-68 CLV First Stage
« Reply #44 on: 07/14/2006 04:48 PM »
Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #45 on: 07/14/2006 07:21 PM »
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Jim - 13/7/2006  4:23 PM

Landing of an orbiter has nothing to do with the delivery of a satellite.  I am going to harsh again, but it is the same as the failure of the SRB parachutes on STS-4.  The SRB's were not recovered.  Is this a mission failure.

"The traditional description of "payload" is orbited, separated mass" is wrong.  Payload adapters, spintables, dual payload adapter assemblies are payload mass and not separated.  The cradles of the spacecraft that used to fly on the shuttle were not separated.   If the cradle was a damaged........  aeroshells and parachute are part of the spacecraft and not equivilent to the shuttle orbiter.

I have more thoughts on this, but they seem to belong in a different thread, so I will post them in the General Discussion area.

 - Ed Kyle

Offline general

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Re: RS-68 CLV First Stage
« Reply #46 on: 07/15/2006 12:24 AM »
I fear the "division of work".  This is not the best way to design, develop and field a new launch vehicle.  Looking at recent failure reports, they ALWAYS point out a lack of Systems Engineering and Integration.  Unless you have a strong SE&I, most programs are doomed to delays, cost escalation, or failures.

This is the problem with "divsion of work".  Work is parsed out for political reasons, then NASA is left trying to integrate the whole thing.  Their SE&I experience for LV development is rooted in Saturn, which is certainly not current.  

Why not simply put out an RFP and let the best company (ones with recent LV development experience) win?  Clearly Boeing and LockMart have the necessary experience for successful LV development.  NASA (and their toady ATK) clearly do not.

Offline quark

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Re: RS-68 CLV First Stage
« Reply #47 on: 07/18/2006 04:34 AM »
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Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The 2X RD-180 booster works at the 5m diameter.  LM did a lot of work on it.  On the other hand, 2 RS-68's will not fit within a 5m diameter.  Not sure what diameter it takes, probably 6 or 7m.

The 2X RD-180 booster delivers substantially more energy than the 5-seg SRB.  So much more that you don't need the J-2x any more and can deliver 25mT with 4 RL-10's.  So two major propulsion development programs obviated and 25mT performance resotored.

Offline meiza

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Re: RS-68 CLV First Stage
« Reply #48 on: 07/18/2006 11:11 AM »
What about an ULAriane: two Atlas V first stages with shortedened tank around a widened or lengthened RS-68-powered delta4ish stage (nozzle extension?). Top off with an appropriate number of RL10:s, although it can probably orbit some stuff without any upper stage. :)
All liquid, possible to shutdown on pad if the readings are not good for liftoff. And easy abort always possible. Drawback is at least weird load paths and vehicle dynamics. Is the staging too hard on the fragile Atlas first stages? (Compared to the rugged shuttle srb:s?)

Just a thought excercise.

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #49 on: 07/18/2006 12:32 PM »
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quark - 17/7/2006  11:21 PM

Quote
Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The point is:
When you want to go to Moon or Mars you need super heavy lift vehicle. And there is already one – STS (thanks to SRB). You would need around 10 x RD-180 to match Saturn V first stage. So the choice is:

1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline lmike

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Re: RS-68 CLV First Stage
« Reply #50 on: 07/18/2006 12:38 PM »
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JIS - 18/7/2006  5:19 AM
...When you want to go to Moon or Mars you need super heavy lift vehicle. ...

Well, that doesn't seem to be the point.  First of all what is exactly a "super heavy lift vehicle"?  15tonnes?  How about 50 tonnes?  500 metric tonns?  Which one and why exactly?  And why do we want it?  I mean, really?

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #51 on: 07/18/2006 12:52 PM »
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JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #52 on: 07/18/2006 01:21 PM »
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Jim - 18/7/2006  7:39 AM

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JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

But it's needed for Ares V.
Or do you think that there will be enough resources to develop and prepare Moon stuff for Ares V before 2018?
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #53 on: 07/18/2006 01:31 PM »
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lmike - 18/7/2006  7:25 AM

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JIS - 18/7/2006  5:19 AM
...When you want to go to Moon or Mars you need super heavy lift vehicle. ...

First of all what is exactly a "super heavy lift vehicle"?

The haavier the better.
In reality landing 20t at Moon in one shoot is enough.
Landing less is not enough for manned missions. More shoots are too complex.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #54 on: 07/18/2006 01:53 PM »
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JIS - 18/7/2006  9:08 AM

Quote
Jim - 18/7/2006  7:39 AM

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JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

But it's needed for Ares V.
Or do you think that there will be enough resources to develop and prepare Moon stuff for Ares V before 2018?

CaLV is Ares V.

Yes, If you eliminate all the Ares I changes and go with cheaper EELV derivitives

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #55 on: 07/18/2006 09:11 PM »
Quote
JIS - 18/7/2006  7:19 AM

Quote
quark - 17/7/2006  11:21 PM

Quote
Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The point is:
When you want to go to Moon or Mars you need super heavy lift vehicle. And there is already one – STS (thanks to SRB). You would need around 10 x RD-180 to match Saturn V first stage. So the choice is:

1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

As Jim said, it doesn't have to be either/or.  One alternative ESAS option, for example, called for the development of only one, "mid-size" launch vehicle (90-100 tonnes to LEO).  The study found that a lunar mission performed with two such launchers would cost less than the current "1.5 Launch" mission.  

 - Ed Kyle

Offline josh_simonson

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Re: RS-68 CLV First Stage
« Reply #56 on: 07/19/2006 12:23 AM »
The core stage of the Aries V with RS-68s and 10m tank has enough fuel fraction to send CEV to ISS in a single stage that NASA intends to build anyway.  Launching crew on the Aries V core would double it's economies of scale because crew/cargo LVs roll off the exact same assembly line, and developing the CLV will get halfway to having an HLV.  This would put NASA's ducks in a row instead of scattered willy-nilly tinkering with ELVs or designing dead-end rockets with components that don't exist yet.  No other CLV option also serves to make the HLV significantly cheaper.

Online HailColumbia

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Re: RS-68 CLV First Stage
« Reply #57 on: 07/19/2006 01:06 AM »
wouldent the Ares V core be overkill?

How much can the core lift alone? Plus, wouldent an ares V core cost more then the Ares I ?
-Steve

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #58 on: 07/19/2006 01:09 AM »
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josh_simonson - 18/7/2006  8:10 PM

The core stage of the Aries V with RS-68s and 10m tank has enough fuel fraction to send CEV to ISS in a single stage that NASA intends to build anyway.  Launching crew on the Aries V core would double it's economies of scale because crew/cargo LVs roll off the exact same assembly line, and developing the CLV will get halfway to having an HLV.  This would put NASA's ducks in a row instead of scattered willy-nilly tinkering with ELVs or designing dead-end rockets with components that don't exist yet.  No other CLV option also serves to make the HLV significantly cheaper.

This won't work.  It was shown in another thread.  Anyways can't use the SM as a 2nd stage because it wouldn't be able to complete its lunar mission.

Offline kraisee

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RE: RS-68 CLV First Stage
« Reply #59 on: 07/19/2006 05:34 AM »
Sadly it is an either/or situation guys.   It's not the technology which is the limit, but the political and economic realities of the USA today in the mid 2000's:-

We all know and accept that the Ares-V won't fly until 7 years after STS has been retired.

If there isn't *something* to keep all the ET manufacturing staff at Michoud, the SRB manufaturing staff in Utah, and the thousands of staff at the various NASA center busy during that seven year gap, there would be zero reason to keep that huge workforce employed just twiddling their thumbs while they wait half a decade to do something useful.

Current staff would be released at the end of the Shuttle pProgram and they'd try re-hiring afresh about five years later, two years before the new vehicle is ready, so we would just have an identical repeat of the post-Apollo era.

The EELV guys are already staffed, so would not be in a position to hire thousands of extra workers, so the result would be thousands of aerospace engineers and administrators from around the country all looking for work in an already depressed aerospace industry.

That's a political and economic nightmare scenario.

People waaaaaaay above Griffin on the foodchain have already made that decision and have directed NASA as to how to proceed.   This reality is the only reason why we're finishing ISS with the Shuttle instead of with another launcher - because it saves jobs.   It's why the SDLV's will be chosen for both new vehicles - unless another vehicle could offer massively higher safety margins or and hugely beneficial economic benefits - and I'm sorry to say, but the alternatives out there just can't offer huge advantages in either field, so they never stood a chance.

While the technology would allow for the Crew launcher to come from one family of LV's, and the Cargo lifter to come from a separate family, the political and economic realities of the nation will preclude such a thing from ever actually happening.   Whichever the first comes from, the second is assured to follow directly from the same lineage.

All IMHO.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

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