Author Topic: All EELV VSE architecture  (Read 73692 times)

Offline Danny Dot

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Re: All EELV VSE architecture
« Reply #20 on: 07/01/2009 08:46 PM »
i have seen some of the studies...

Can you post them here or give us a link?

Danny Deger
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Offline Danny Dot

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Re: All EELV VSE architecture
« Reply #21 on: 07/01/2009 08:51 PM »
Mark Wade's summary of the Boeing CEV proposal:

http://www.astronautix.com/craft/cevoeing.htm

Sure looks to me like an American version of Soyuz!

snip


Great link.  I sent Mark a note asking for a copy of the report.  I am thinking a minor modification to have Delta IV Heavy launch the current Orion design might be all that is needed.  I am a big fan of using past studies as much as possible.  Most of my Crew Survival engineering was done by digging up Mercury, Gemini, and Apollo documents.

Danny Deger
« Last Edit: 07/01/2009 08:58 PM by Danny Dot »
Danny Deger

Offline Danny Dot

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Re: All EELV VSE architecture
« Reply #22 on: 07/01/2009 08:57 PM »
Danny,
I've got copies of most of the CE&R reports sitting on my computer here at work.  If you want, I can email them to you later.

I'm actually supposedly working on a White Paper for propellant depots, so I don't know how much time I'll have to contribute, but I'll try to keep an eye on this thread.

~Jon

See if you can filter down to the ones that look at current and Phase I EELVs.

Danny Deger
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Offline HIP2BSQRE

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« Last Edit: 07/01/2009 09:02 PM by HIP2BSQRE »

Offline renclod

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« Last Edit: 07/01/2009 09:38 PM by renclod »

Offline Bill White

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Re: All EELV VSE architecture
« Reply #25 on: 07/01/2009 09:11 PM »
Boeing initial proposal (September 2004)

http://www.nasa.gov/pdf/65843main_boeing.pdf

Andrews initial proposal (September 2004)

http://www.nasa.gov/pdf/65842main_andrews.pdf

I believe the rest can be found by searching the NASA site. I found the above using "Boeing CEV" as the search term

= = =

However, the politics remains paramount.

Recall that the EELV advocates have already failed to persuade Congress & President Bush to stay this course in 2004 / 2005 so how the heck are you going to persuade President Obama to adopt this path now?

Especially since an all EELV VSE could only be adopted by driving a steamroller over Senators Nelson (D-FL) and Shelby (R-AL).
« Last Edit: 07/01/2009 09:20 PM by Bill White »
EML architectures should be seen as ratchet opportunities

Offline Antares

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Re: All EELV VSE architecture
« Reply #26 on: 07/01/2009 09:29 PM »
So you're saying Pratt can start building kerosene engines right away if they get the call? (Just follow the blueprints?) They've spent years concentrating on hydrogen but can switch over without significant delay?

Not all kero engines, but RD-180 specifically yes.  They wouldn't run in guns blazing, but they've already built the hardest part.  Just send money.  Like some of what has been is planned to be wasted on no new technology for Ares 1.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline renclod

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Re: All EELV VSE architecture
« Reply #27 on: 07/01/2009 09:52 PM »
...
they've already built the hardest part....

...mementos acrylic-encased machine chips from the components that were manufactured under co-production.  It has been demonstrated.  It's doable but not necessary,

Just send money.




Offline nooneofconsequence

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Re: All EELV VSE architecture
« Reply #28 on: 07/01/2009 10:17 PM »
So you're saying Pratt can start building kerosene engines right away if they get the call? (Just follow the blueprints?) They've spent years concentrating on hydrogen but can switch over without significant delay?

Not all kero engines, but RD-180 specifically yes.  They wouldn't run in guns blazing, but they've already built the hardest part.  Just send money.  Like some of what has been is planned to be wasted on no new technology for Ares 1.
I thought they were still stopped because they couldn't reproduce the coatings critical to that engine. Did they finally master that, or are they just claiming to?
"Wise men talk because they have something to say; fools, because they have to say something" - Plato

Offline Antares

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Re: All EELV VSE architecture
« Reply #29 on: 07/01/2009 10:25 PM »
I thought they were still stopped because they couldn't reproduce the coatings critical to that engine. Did they finally master that, or are they just claiming to?

The components produced were not completely tested.  The next step in tests and production would have required a much higher funding profile, so their customer put the effort on hiatus.  All went well up to that point.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Online butters

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Re: All EELV VSE architecture
« Reply #30 on: 07/01/2009 11:59 PM »
My understanding is that Phase 1 EELV refers to the existing Atlas V and Delta IV CBC with a new 5m Centaur-derived upper stage.  Are these growth options the basis of this thread, or are we actually talking about the existing EELV lineup (perhaps with RS-68A for Delta IV)?

The critical path for launch vehicle sizing is that the CEV can't be much less than 10 mT at SM burnout and still support a crew of four over a 10-day round trip.  That means 20 mT through TLI or 60 mT IMLEO.

If each spacecraft did its own LOI burn rather than the LSAM decelerating their combined mass, then the LSAM would mass somewhat less then the CEV through TLI.

Being as existing EELVs don't provide 60 mT IMLEO, we need multiple launches.  The EDS to push 20 mT through TLI is roughly 40 mT IMLEO, but existing EELVs don't provide 40 mT IMLEO, either.

So we're basically looking at three EELVs for the CEV round trip: two 20-25 mT IMLEO EDSs for either staged TLI or post-ascent propellant transfer and a 20-25 mT IMLEO CEV.

The story is similar for the LSAM: three more EELVs for a total of six per mission.   Note that it would also take six EELVs to supply a propellant depot for a DIRECT Phase 3 mission (plus one J-24x).

I prefer a DIRECT/EELV hybrid approach: develop a 45 mT GLOW 5m Centaur upper stage that can be used (with some modifications) either as an upper stage for EELV or as an EDS for J-130.

J-130 is perfectly sized for a two-launch profile, each with a 25 mT spacecraft (LSAM or CEV) and a 45 mT EDS.  The EELVs get their Phase 1 common upper stage, and when they grow their respective first stages in Phase 2, they could potentially replace J-130.

Offline nooneofconsequence

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Re: All EELV VSE architecture
« Reply #31 on: 07/02/2009 12:07 AM »
I thought they were still stopped because they couldn't reproduce the coatings critical to that engine. Did they finally master that, or are they just claiming to?

The components produced were not completely tested.  The next step in tests and production would have required a much higher funding profile, so their customer put the effort on hiatus.  All went well up to that point.
Yeah - they needed a production commitment. Same as when I left the topic many years back.

Unfortunately that isn't a predictable manufacturing and test process. It was my understanding at the time that there was more than a little art/alchemy involved. The kind of thing that has "budget overrun" written all over it.

To be fair, an acceptable risk at the time to take.
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Offline deltaV

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Re: All EELV VSE architecture
« Reply #32 on: 07/02/2009 12:28 AM »
In flight refueling will probably be needed, this will make cryo a problem.  Boil off is not the only problem.  The simplest in-flight refueling is to use a diaphragm to push to prop out of the tank.  I don't think a diaphragm can be used at cryo temperatures.
Why reinvent the wheel? Upper stages push cryo fuel out of tanks all the time using a combination of "gravity", compressed gas, and/or turbopumps. Why not reuse these techniques for propellant transfer?

Here are two methods for cryo propellent transfer that come to mind.

Two-hose approach. Hook up two hoses connecting the receiving and donor tanks, one for liquid and one for returning ullage gas. To settle the tanks create artificial gravity either by spinning or using a low thrust rocket engine. Pump the liquid or the gas gently (a few PSI?) from one tank to the other.

If you create the artificial gravity by spinning you would not be any hurry to finish so you could probably transfer the liquid by gravity alone. Just put the donor tank "above" the recipient tank and let the liquid flow from one to the other.

One-hose approach. Use only one hose (for liquid). Use artificial gravity as above to settle tanks. Create ullage gas in the donor tank in whatever way is normally done, e.g. inject hot helium gas. Remove excess gas (if any) from the recipient tank by venting it.

My uninformed intuition is that the two-hose approach sounds better for a depot since nothing is wasted but the one-hose approach sounds better for non-depot propellant transfer since very little hardware is required. If the donor tank is an upper stage it already has the ability to create ullage gas (though this might not be usable if it requires the rocket engines to be run) and has some sort of thrusters that could presumably be used for tank settling if given more fuel. The only pieces of extra hardware would be the hose, a couple of valves, a gas vent for the recipient tank, and possibly a tow rope.

What am I missing that makes cryo fuel transfer so scary?

Offline infocat13

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Re: All EELV VSE architecture
« Reply #33 on: 07/02/2009 12:40 AM »
Heh! We could start by dusting off the various proposals first floated back in 2004.

There actually were some interesting ones.

Step Two however might require that someone defeat Senator Richard Shelby in the Republican Senate primary next year.

HAAA !
remember the Mississippi congressmen who championed the SERB at yellow creek?
after 80% of the funds had been spent the congressmen retired thinking....well.................
this project is safe!

well if we had today filament wound SRB AND a 5 segment one and Schuttle C or Shuttle Z
and he was a democrat I think (my party)
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 Jim

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Re: All EELV VSE architecture
« Reply #34 on: 07/02/2009 12:46 AM »
Everything I know about these studies I found on the internet, much of it hosted at a NASA web site. How much remains available to the public? I dunno.


Here is the website

http://www.nasa.gov/missions/solarsystem/vision_concepts.html

Concept Exploration and Refinement (CE&R) contracts

Offline Jim

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Re: All EELV VSE architecture
« Reply #35 on: 07/02/2009 12:48 AM »
My understanding is that Phase 1 EELV refers to the existing Atlas V

Phase I only refers to Atlas. There is no comparable "phasing" for Delta IV

Offline wannamoonbase

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Re: All EELV VSE architecture
« Reply #36 on: 07/02/2009 12:59 AM »
I'd love a RP-1 powered booster and I love the RD-180. 

However politically I don't think a US built, Soviet designed engine won't fly.
Jonesing for a copy of 'Tales of Suspense #39'

Offline nooneofconsequence

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Re: All EELV VSE architecture
« Reply #37 on: 07/02/2009 02:49 AM »
What am I missing that makes cryo fuel transfer so scary?
1. fittings
2. corona discharge
3. venting
4. materials issues
...
N. experience
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Re: All EELV VSE architecture
« Reply #38 on: 07/02/2009 03:22 AM »
I'd love a RP-1 powered booster and I love the RD-180. 

However politically I don't think a US built, Soviet designed engine won't fly.

IMHO, if the United States wants to move away from solid rocket boosters and is politically-averse to producing or deriving Russian oxidizer-rich staged combustion LOX/RP-1 designs, then the best bang for the development buck would be LOX/paraffin hybrid rocket boosters.

The paraffin wax would offer similar or better specific impulse compared to RP-1 (depending on fuel additives), the thrust-to-mass ratio would be better, and it would be considerably less expensive than a bipropellant liquid rocket engine.

Offline jongoff

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Re: All EELV VSE architecture
« Reply #39 on: 07/02/2009 04:24 AM »
What am I missing that makes cryo fuel transfer so scary?
1. fittings
2. corona discharge
3. venting
4. materials issues
...
N. experience

It's important to remember though, that while this stuff is complicated, we're further along the path to propellant depots than NASA was to doing orbital rendezvous when they picked the LOR mode.  The various pieces still need to be pulled together and demonstrated as a system, but most of the technologies and techniques are pretty mature.  The Russians were doing orbital propellant transfer (of non cryogens) before I was born.  Cryogens add some difficulties, but not 30 years worth of difficulties.  This is stuff that could've been figured out in the 60s if it had been on the critical path, though with all the cryo upper stage experience we now have, and with new cryo fluid management testbeds like the ones ULA is working on, we're in a much better position to move on this technology now than we've ever been before.

~Jon

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