Author Topic: ULA claim gap reducing solution via EELV exploration master plan  (Read 205420 times)

Offline jongoff

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One slight clarification to what Jon just mentioned, there needs to be a slow venting of GH2 throughout the transfer in order to keep the propellants settled the whole time, not just to start the process.

Well, you don't actually have to vent continuously.  You just have to provide enough propulsive force to overwhelm all the unsettling forces/disturbances on the vehicles.  In some cases this would mean a continuous settling thrust, in other cases it can actually be intermittent.  Centaur IIRC uses a pulsed vent to keep settled during coast phase.

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I understand that 0.0004g is all that's required to ensure the propellant remains settled correctly.   And a pressure differential in the order of just 4psi between the delivery and receiving tanks is all that is required to enable 100mT of transfer in about 1-2 hours.

Yeah, it's pretty low thrust.  Centaur's actually demonstrated settling at quite a bit less than .0004g, IIRC.  And yeah, it's amazing how much liquid you can shove through a decent sized connection with very little dP.

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This is exactly how Von Braun proposed to do cryo prop transfer for advanced Apollo missions.   Also, everything needed to perform this has already been flown and fully tested in micro-gravity, with the sole exception being the coupling mechanisms.

Even the coupling mechanism aren't as hard as most people think.  Remember:

1) The coupling doesn't have to engage at the same temperature as the fluid--it can be chilled down after it's attached.
2) If you couple them at room temperature, it can actually be *very* similar to a non-cryo coupling.  The only trick at all is making sure you use materials with similar coefficients of thermal expansion, so you don't get one shrinking more than the other.
3) You've got nature's own vacuum jacket surrounding the couplings--no need to worry about air liquifying on LH2 couplers, no need to worry about moisture freezing up connections.

~Jon

Online ugordan

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Well, you don't actually have to vent continuously.  You just have to provide enough propulsive force to overwhelm all the unsettling forces/disturbances on the vehicles.  In some cases this would mean a continuous settling thrust, in other cases it can actually be intermittent.  Centaur IIRC uses a pulsed vent to keep settled during coast phase.

I believe D-IV US also uses timed pulses to keep the propellant settled and dissipate slosh energy after engine shutdown.

Offline infocat13

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Well, you don't actually have to vent continuously.  You just have to provide enough propulsive force to overwhelm all the unsettling forces/disturbances on the vehicles.  In some cases this would mean a continuous settling thrust, in other cases it can actually be intermittent.  Centaur IIRC uses a pulsed vent to keep settled during coast phase.

I believe D-IV US also uses timed pulses to keep the propellant settled and dissipate slosh energy after engine shutdown.

Ugordan,
is this the technology you speak of?
I am a member of the side mount fanboy universe however I can get excited over the EELV exploration architecture fanboy universe.Anything else is budgetary hog wash
flexible path/HERRO

Online ugordan

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Yes, that's the one.

Offline jongoff

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I am glad to finally see a solid EELV proposal. One only needs to look back about 2 to 3 years and we were all practically begging for ULA to put something, anything, on the table, the DIRECT team included. Of course only a few knew then how ULA and USA had been silenced. If this had been on the table back then the past 2-3 years would have been very different.

AIUI, ULA had been planning on presenting a paper like this at last year's Space 2009 conference, but it got pulled (at the insistence of one of the parent companies).  As it is though, I think there's been a lot of improvement over the past year in this architecture, so I'm not too heartbroken that they weren't able to release the concept last year.  I've only been somewhat involved, on the edges, but it's been cool seeing things unfold as the concept has been further explored.

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It's funny though on 2 scores:

1. So many people pooh poohed the Propellant Depot idea when we made it part of our architecture over 2 years ago but now that ULA integrates it into theirs, suddenly everybody thinks it's a good idea. In spite of saying over and over again that we were getting all our data for the depot from industry, few people listened. Now the same industry makes it public and everybody loves it.

2. Everybody now loves the ACES upper stage. This upper stage combines the best of the Atlas and Delta cryogenic upper stages. Once again, we went to industry to get help with the JUS and what we delivered is pretty much what the ACES is, only bigger diameter; 8.4 meter diameter to match the Shuttle ET manufacturing tooling and using 6 RL-10’s vs. 4 RL-10s. Again, the design data came directly from industry but few people listened and tons of people severely criticized it. Now that the same industry releases an architecture that uses that same data everybody loves it.

Well, to be fair, how many of the people that were pooh-poohing depots for direct, or pooh-poohing the JUS are singing the praises of the EELV approach?  I know that most of us who were fans of the EELV approach actually thought the depot was the best part of Direct, and didn't think that the JUS was stretching it too much.  The people who pooh-poohed depots for DIRECT, and the JUS numbers for DIRECT will also probably pooh-pooh this.  Trust me, you DIRECT guys aren't the only people who have lots of skeptical opposition.

~Jon

Offline Lee Jay

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The people who pooh-poohed depots for DIRECT, and the JUS numbers for DIRECT will also probably pooh-pooh this.

I believe the JUS numbers, but don't like the depot (well, done like this).  So you don't have to be one or the other.

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In reality, no single industrial entity can entirely support this architecture.
"The production and launch rates are simply not sustainable by a single team. It must be a concerted effort of several launch providers, perhaps a consortium linking industry and NASA.”

Right.  No heavy lift = zillions of small lifts = high cost and high complexity.
« Last Edit: 09/11/2009 10:44 PM by Lee Jay »

Offline rv_rocket

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Great article Chris! Well written and easy to follow, even for a non-techie like me! This is wonderful news indeed.

And there is certainly no one asking 'Who are you guys?' on this one!

It appears to be a good solid proposal with practical, achievable goals. That fact that ULA is proposing using mostly existing components and infrastructure, with just the needed incremental improvements, seems a reasonable and achievable plan. Gosh, what a Direct-ly wonderful idea!

One chink in the proposal does seem to be the political implications. I do wonder how the folks at ATK and the various NASA centers (and their friends in congress) would feel about ULA getting almost all of the toys. Maybe it's just me, but I'm betting they will have to share!
 
It's too bad that so few have been listening to the Direct team's recommendations about EELV’s and fuel depots, but now that ULA has put their foot forward with this proposal, it certainly adds a lot of credibility to the Direct team's proposals. I just hope that the other aspects of the Direct proposals benefit and receive further support too.
 
It's been a long day, and it's after 5 on a Friday. I'm leaving now and will visit my local refreshment establishment to raise a 'we told you so' toast! 

Go Direct! :)

Offline Robo-Nerd

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Did anyone figure out why they proposed an L2 depot instead of an L1 depot? Is the delta-V significantly different? Thanks,
Read Simon paper, very instructive :
http://forum.nasaspaceflight.com/index.php?topic=17564.0

That was an excellent link, thanks!
Osa E. Fitch
"Garden Earth, Industrial Moon, Resource Space" - William Barton

Offline sewand

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Very informative article!

It appears that annual expenses with the EELV architecture will be around $7 billion for 4 missions.   Does that compare favorably with Direct?   I thought Direct was slightly cheaper - around $6 Billion.  I would really like to see a side-by-side cost comparison of EELV and Direct architectures. 

How would this architecture work for Flexible Path?   Would the ACES41 be sufficient for NEO rendezvous?     



Online Chris Bergin

Just a quick post inbetween 128 fun to say thanks again for the nice words about the article. Seems a bit fluffy to post this, but it does mean a lot and it's really appreciated.

Offline jongoff

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Right.  No heavy lift = zillions of small lifts = high cost and high complexity.

Well, if by zillions you mean 2-8 per mission (depending on what you're trying to do), I guess so.  But I usually reserve zillions for much bigger numbers.  Like the development and fixed costs of Heavy Lift launch vehicles....

;-)

~Jon

Offline infocat13

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Just a quick post inbetween 128 fun to say thanks again for the nice words about the article. Seems a bit fluffy to post this, but it does mean a lot and it's really appreciated.

That's right Chris, we appreciate you for posting the ULA article.
Just as I was entering post commission report, post shuttle flight and post Ares blues this weekend reading comes along!
Thanks
« Last Edit: 09/11/2009 11:32 PM by Andy USA »
I am a member of the side mount fanboy universe however I can get excited over the EELV exploration architecture fanboy universe.Anything else is budgetary hog wash
flexible path/HERRO

Offline nooneofconsequence

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A enjoyable read on many fronts Chris - made my weekend. I had given up on ULA as being too craven to other interests to ever have the balls to do anything with their considerable talents. After a while you wonder if they even believe in themselves. Which is why I've been less than enthusiastic of any change from the EELV status quo.

What a completely different turnabout! What audacity (L'audace, l'audace, toujours l'audace!). Even if they get shot to pieces, at least they've added to the debate the considerable accomplishments of Delta and Atlas heritage.

One might even say this approach is "Centaur on Steroids"  ;D

From the earth to the moon on the best propulsion system off the planet!
« Last Edit: 09/12/2009 01:05 AM by nooneofconsequence »
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline Eric Hedman

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I guess in a lot of cases that the data doesn’t matter. It comes down to who says it.
Go figure.
I have found this to be true with most audiences.  It is so much easier if you don't have to think.  Data is just noise.  Just trust the expert.  The one with the best speaking voice must be right.  A little gray hair on the temples really increases the credibility.

Offline Eric Hedman

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One might even say this approach is "Centaur on Steroids"  ;D
I vote for removing the words "... on Steroids" from the English language.  I want the ARES nightmare to just go away.

Offline drdave

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Notice many of these ULA documents also state that their components  can be incorporated into a directly shuttle derived architecture.
they are reading tea leaves.IE a mixed fleet.
 

Given Ross's comments starting here http://forum.nasaspaceflight.com/index.php?topic=18139.msg472488#msg472488 about
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a new company merging ATK, Boeing and Lockheed-Martin to develop and operate the Jupiter systems.
, it looks like ULA (and its parents) wants the business no matter which way NASA and the White House proceed - pure EELV, Mixed Fleet, whatever.  If someone is going to build it and fly it, they want to do it.
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are.  If it doesn't agree with experiment, its wrong - Richard Feynman

Offline Jim

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Can we have the 1.5 CxP ? Direct single launch cargo only to the moon base ?


no, because it is too expensive and the .5 launch vehicle doesn't work.

Offline Marsman

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Don't forget that this architecture is limited to 2 missions per year total, so 2 crew missions, 2 cargo missions, or 1 crew and 1 cargo mission per year.

Offline jongoff

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Don't forget that this architecture is limited to 2 missions per year total, so 2 crew missions, 2 cargo missions, or 1 crew and 1 cargo mission per year.

I haven't had a chance to fully read the published version of Frank's paper, but wasn't someone mentioning earlier that they were talking about 4 missions per year, not 2?

The nice thing about a depot-centric architecture like this is also that as more and improved launch services come online, you can continuously increase the affordability of lunar missions.  It doesn't take much in the way of small commercial RLVs (which would finally have a market, BTW) to make it possible to do a lot more missions for the same overall cost.  With an HLV-centric, non-depot architecture, you're pretty much locked in to a set of fixed costs that you can never really do much about.

~Jon

Offline Marsman

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Don't forget that this architecture is limited to 2 missions per year total, so 2 crew missions, 2 cargo missions, or 1 crew and 1 cargo mission per year.

I haven't had a chance to fully read the published version of Frank's paper, but wasn't someone mentioning earlier that they were talking about 4 missions per year, not 2?

The nice thing about a depot-centric architecture like this is also that as more and improved launch services come online, you can continuously increase the affordability of lunar missions.  It doesn't take much in the way of small commercial RLVs (which would finally have a market, BTW) to make it possible to do a lot more missions for the same overall cost.  With an HLV-centric, non-depot architecture, you're pretty much locked in to a set of fixed costs that you can never really do much about.

~Jon

From the article “Initial crewed landing would occur in 2018. Either a single crewed mission per year coupled with 20mT of cargo or two crewed missions per year can be supported within the anticipated budgets. The assumed cost of transport to LEO ranged from 9.2 to 10.2 $M/mT depending on launch vehicle. This scenario also assumes the cost of flights to the ISS are included at a rate of 2/year commencing in 2013.”

I have no doubt that RLV's etc can increase the number of missions, but increasing the number of flights will increase the budget requirement, even though the launch costs have come down due to the economies of scale. Remember you would have to pay for the development of these new high rate launch vehicles.

Perhaps if we brought international partners in the mission rates can go up. Proton and Ariane V can carry propellant.

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