Author Topic: VSE falling apart?  (Read 24800 times)

Offline Bruce H

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VSE falling apart?
« on: 01/18/2006 02:53 pm »
Why does this feel like a reaccuring nightmare?

Design problems, NASAWatch.

Downselect postponed rumor, NASASpaceflight.

We've all been here before. :(

Online Chris Bergin

RE: VSE falling apart?
« Reply #1 on: 01/18/2006 02:58 pm »
I've not yet confirmed the downselect delay - waiting on a couple of more people to say.
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Offline Dobbins

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RE: VSE falling apart?
« Reply #2 on: 01/18/2006 04:20 pm »
Maybe it would be helpful to look at the past. From day one NASA knew that the Mercury capsule was a short term project, plans for a follow on started almost at once. Apollo can trace it's roots to the Goett Committee in April of 1959. By Early January of 1960 NASA had decided that orbiting the Moon in about 10 years would be the focus of Apollo. By October of 1960 Von Braun and Faget had reached an agreement to work together on plans for a landing instead of just a lunar orbit. Contrary to popular opinion Apollo didn't suddenly start in May of 1961 with Kennedy's Moon speech, the program was already underway. The final selection of a contractor didn't occur until November of 1961, over 2 1/2 years after work had started with the Goett Committee. The selection of the contractor proved to be controversial in both Apollo and the later Shuttle program.

Gemini, Apollo, and the Shuttle all went through some tough finical times in the early days of the projects, there were periods when it looked likely that all three programs would fall victim to the budget ax.

John B. Dobbins

Offline STS Tony

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RE: VSE falling apart?
« Reply #3 on: 01/18/2006 06:09 pm »
Maybe they should go with the Sling, check out that video!

Offline Lunar Dreamer

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RE: VSE falling apart?
« Reply #4 on: 01/18/2006 07:07 pm »
Don't know about falling apart, but if you read NASAwatch you would think so.  It's hardly looking good!

Offline Jamie Young

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RE: VSE falling apart?
« Reply #5 on: 01/18/2006 08:22 pm »
Why do they need to make a bigger booster??

Online Chris Bergin

RE: VSE falling apart?
« Reply #6 on: 01/18/2006 08:25 pm »
Quote
Jamie Young - 18/1/2006  9:22 PM

Why do they need to make a bigger booster??

When they removed the requirement of Methane, weight was added to the extra propulsion alternative (Hypergols) required, thus a bigger booster - is how I'm reading it.
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Offline JulesVerneATV

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RE: VSE falling apart?
« Reply #7 on: 02/02/2006 04:37 pm »
No VSE, Red Planet, no manned flights to the Moon and Mars were not to be found in this year's Union address but President Bush laid out an agenda that  warned against isolationism, urged Americans to stay in Iraq, and reforms social security....President Bush's State of the Union address Tuesday made no mention of the Vision for Space Exploration or space policy in general.


Offline Avron

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RE: VSE falling apart?
« Reply #8 on: 02/03/2006 04:23 am »
Quote
Lunar Dreamer - 18/1/2006  3:07 PM

Don't know about falling apart, but if you read NASAwatch you would think so.  It's hardly looking good!

Its the design process, it needs time to evolve. The first option selected without detailed analysis beyond conceptual design, is rearly the design that flies. The architecture presented is no more than that, its conceptual in nature. Lets give the design teams the time to do the right selection, then we can watch the fun and games in the downselecting, where the money is at play..

Offline Hotol

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RE: VSE falling apart?
« Reply #9 on: 02/03/2006 08:05 am »
Quote
JulesVerneATV - 2/2/2006  11:37 AM

No VSE, Red Planet, no manned flights to the Moon and Mars were not to be found in this year's Union address but President Bush laid out an agenda that  warned against isolationism, urged Americans to stay in Iraq, and reforms social security....President Bush's State of the Union address Tuesday made no mention of the Vision for Space Exploration or space policy in general.


I doubt it deserved a place in the State of the Union address.

Offline WylieC

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RE: VSE falling apart?
« Reply #10 on: 02/03/2006 11:16 am »
Some time in the first 6 months after Bush announced the VSE I remember watching one of those Sunday morning news show. A member of Congress was asked about Bush not talking about the VSE after he announced it. The answer was that he wanted to make it none partisan and that if he pushed it personally it would become a partisan issue and the Democrats would come out against it. Later on in a news conference I remember 'Okeefe saying something very similar. Over the past two years this strategy seems to have worked fairly well. Based on the House and Senate votes a large portion of Democrats seem to be behind VSE.

Don't see any need to change the strategy if its working.   ;)

Offline JulesVerneATV

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RE: VSE falling apart?
« Reply #11 on: 02/08/2006 11:12 pm »
Quote
Avron - 2/2/2006  11:23 PM

Quote
Lunar Dreamer - 18/1/2006  3:07 PM

Don't know about falling apart, but if you read NASAwatch you would think so.  It's hardly looking good!

Its the design process, it needs time to evolve. The first option selected without detailed analysis beyond conceptual design, is rearly the design that flies. The architecture presented is no more than that, its conceptual in nature. Lets give the design teams the time to do the right selection, then we can watch the fun and games in the downselecting, where the money is at play..

NASA's "Bizarre" Cuts
http://www.technologyreview.com/BizTech-Manufacturing/wtr_16302,309,p1.html
The director of the Planetary Society says the space agency is robbing science missions and manned exploration.

Offline Avron

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RE: VSE falling apart?
« Reply #12 on: 02/09/2006 03:50 am »
Quote
JulesVerneATV - 8/2/2006  7:12 PM

Quote
Avron - 2/2/2006  11:23 PM

Quote
Lunar Dreamer - 18/1/2006  3:07 PM

Don't know about falling apart, but if you read NASAwatch you would think so.  It's hardly looking good!

Its the design process, it needs time to evolve. The first option selected without detailed analysis beyond conceptual design, is rearly the design that flies. The architecture presented is no more than that, its conceptual in nature. Lets give the design teams the time to do the right selection, then we can watch the fun and games in the downselecting, where the money is at play..

NASA's "Bizarre" Cuts
http://www.technologyreview.com/BizTech-Manufacturing/wtr_16302,309,p1.html
The director of the Planetary Society says the space agency is robbing science missions and manned exploration.


I don't think that they are Bizarre at all, but I feel the Pain, so to speak. The cuts are in line with direction given...

Offline MartianBase

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RE: VSE falling apart?
« Reply #13 on: 04/08/2006 05:47 am »

Offline discovery_fan

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RE: VSE falling apart?
« Reply #14 on: 04/09/2006 10:07 am »
Just overflying the linked site (http://www.astronautix.com/Mambo/) I read:
Airlines regularly fly with fuel gauging systems completely inoperative (with rare catastrophic consequences, as with the recent airliner crash off Sicily and the dead-stick landing of a DC-10 on a Canadian drag strip in the 1980’s).
- I think that this is not really a proper comparison to the shuttle systems fuel sensor issues and the latest sensor changeout. Because on an airliner you can fairly well calculate the fuel status with fuel flow and your FMS etc., and if you lose fuel pressure on an engine it just goes out (while the SSME running oxygen rich more or less explodes). By the way the infamous "Gimli glider" incident in Canada was no DC-10 (a 767-200 it was)...

Offline rcaron

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RE: VSE falling apart?
« Reply #15 on: 04/11/2006 03:11 am »
Argh! I can't believe that they're avoidance of developing methane/lox is going to end up completely destroying the VSE's capability. Can we not develop new technologies when they're warranted (and aren't we going to Mars after this?)

The diameter resizing, going J2-S/X instead of air-start SSME, that's all reasonable. But limiting the LSAM to barebone capability (2 crew, equatorial only, short duration) is useless. This isn't supposed to be Apollo!

As a aerospace engineering student, I'm slowly seeing a promising future erode away.
Thank you Delta II & ICESat-2!

Offline Jim

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RE: VSE falling apart?
« Reply #16 on: 04/11/2006 03:14 am »
Quote
rcaron - 10/4/2006  11:11 PMArgh! I can't believe that they're avoidance of developing methane/lox is going to end up completely destroying the VSE's capability. Can we not develop new technologies when they're warranted (and aren't we going to Mars after this?)The diameter resizing, going J2-S/X instead of air-start SSME, that's all reasonable. But limiting the LSAM to barebone capability (2 crew, equatorial only, short duration) is useless. This isn't supposed to be Apollo!As a aerospace engineering student, I'm slowly seeing a promising future erode away.

The deletion of Methane has nothing to do with the current issues.  It is matter of lift capability.

Offline DigitalMan

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RE: VSE falling apart?
« Reply #17 on: 04/11/2006 03:36 am »
It is early in the process.  Better to be frustrated now than later.   The big question I have is how much of the issues are related to contraints that would raise political problems?

On another note, I am not a rocket scientist, but simply a software developer, so this is probably a crazy idea...

1. Build a 1st stage using three shorter 5M tanks strapped together or in a reasonable framework
2. use 3 SRBs (or none if you think they're not needed) and a bunch of RS-68's.
3. Now you have options for the 2nd stage, since the 1st stage is shorter.

Of course it would be big enough to probably have to be put together at the launch site.

Offline vt_hokie

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RE: VSE falling apart?
« Reply #18 on: 04/11/2006 04:09 am »
Quote
rcaron - 10/4/2006  11:11 PM
As a aerospace engineering student, I'm slowly seeing a promising future erode away.

That's how I felt after watching more ambitious programs like NASP and X-33 fail.  In fact, X-33 was the first program I was assigned to work on after college, but obviously that didn't go anywhere (unless they funneled money into some black program).  For me, our promising future eroded away years ago.

Offline Jim

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RE: VSE falling apart?
« Reply #19 on: 04/11/2006 04:55 am »
Quote
vanilla - 10/4/2006  11:26 PM
Quote
Jim - 10/4/2006  10:14 PMThe deletion of Methane has nothing to do with the current issues.  It is matter of lift capability.
On the contrary, it seems that much of the weight growth in the VSE vehicles is due to the shift from methane to hypergols.

I didn't think it was that much

Offline kraisee

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RE: VSE falling apart?
« Reply #20 on: 04/11/2006 07:06 am »
Quote
vanilla - 10/4/2006  11:26 PM

Quote
Jim - 10/4/2006  10:14 PM
The deletion of Methane has nothing to do with the current issues.  It is matter of lift capability.
On the contrary, it seems that much of the weight growth in the VSE vehicles is due to the shift from methane to hypergols.

I'd like to see the specs from before this change, just for comparison's sake...

I'll try working the numbers here, just roughly...

LOX would be the oxidant in both scenario's, so the only difference is whether Liquid Hydrogen or Liquid Methane is the main propellant for the descent stage of the LSAM.

The density for Liquid Hydrogen (LH2) is 1.14g/ml, and Liquid Methane (LCH4) is only 0.42g/ml. So for the exact same amount of fluid, the LH2 masses roughly 3 times as much - requiring stronger fuel tanks and supports for it.

But...   The efficiency (Isp) of LH2 is higher at 381 sec, compared with 300 sec for the LCH4, so you need less Hydrogen to get the same power, by about 3/4.

So, unless my math is wrong (!), for a given amount of required engine power, you would need *roughly* 2 to 2.5 times the amount of LH2 than LCH4, to do the same job.

In the Lunar Reference Architecture baseline model, we're talking about 25mT of LH2 in the decent stage.   The ascent stage uses hypergolics, so is irrelevant.   So to do the same work using Methane, you'd need about 10-12mT of the LCH4 propellant, and the fuel tanks required would only need to contain half the amount of physical liquid, so they would be lighter too.

That's an awfully big difference.   It would seem to scrape the LRA baseline in under the closure curves with about 1mT to spare!

Of course, that assumes there were a working Methane engine available, or there was sufficient funding to make and man-rate one in time!

Someone please check my math though, it's 3am and I'm on lots of pain-killers right now.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
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Offline Jim

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RE: VSE falling apart?
« Reply #21 on: 04/11/2006 11:37 am »
The change was only in the ascent stage.  It went from methane to hypergols.  The Descent remains LH2/LO2

Offline rcaron

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RE: VSE falling apart?
« Reply #22 on: 04/11/2006 04:31 pm »
The change to hypergols was also in the Service Module, which was also supposed to me LCH4/LOX. Since this where the TEI burn comes from (i.e. ticket home), there needs to be a lot of dV there and as such the mass penalty obviously isn't trivial.

Sending CEV to L2 is just plain silly. In what's proposed now, we're sending two people down in the LSAM while two people remain in CEV. Since L2 is conveniently located behind the moon, that means we'll have some guys out of radio contact for days at a time. A lunar comsat is obviously needed, but with this exploding mass growth where would it fit?
Thank you Delta II & ICESat-2!

Offline kraisee

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RE: VSE falling apart?
« Reply #23 on: 04/11/2006 06:44 pm »
Quote
rcaron - 11/4/2006  12:31 PM

The change to hypergols was also in the Service Module, which was also supposed to me LCH4/LOX. Since this where the TEI burn comes from (i.e. ticket home), there needs to be a lot of dV there and as such the mass penalty obviously isn't trivial.

Sending CEV to L2 is just plain silly. In what's proposed now, we're sending two people down in the LSAM while two people remain in CEV. Since L2 is conveniently located behind the moon, that means we'll have some guys out of radio contact for days at a time. A lunar comsat is obviously needed, but with this exploding mass growth where would it fit?

Sending just two people down, I agree, is plain silly.   But the more I learn about the L2 option, the more that idea is really starting to grow on me.

I'm still getting to grips with the concept myself, but parking the CEV in Low Lunar Orbit (LLO) around the moon itself does not provide for the 'leave anytime' requirement: CEV must be in the right patch of sky for a successful rendezvous at the end of the surface mission.   Having CEV in orbit around the moon also actually becomes a bit of a pain if you're trying to do non-equatorial landings too, because it requires significantly more fuel.   We really want to explore the poles for ice, so that's not the best approach.

The L2 rendezvous option actually seems to offer some quite serious advantages to the missions.   L2 is reachable from anywhere on the moon with zero waiting times.   The propellant for the LSAM descent stage is about 5mT lighter than in the "traditional" mission, and the ascent stage is about 5mT heavier, so there's no real difference ultimately there.   But the CEV's SM propellant can be dramatically reduced by 6.5mT if going to L2 instead of LLO, and 6.5mT is a *huge* difference and may ultimately be the difference we need to get four people to the moon instead of just 2.

And as I just learned, the plan isn't to actually park the CEV at L2 itself, but to rather place it into a 'Halo orbit' around the L2 point, at a sufficient distance to keep the CEV in line-of-sight communications with Earth at all times.   The CEV itself can then actually be used as a relay station to and from Lunar crews working on the far side of the moon.

Here is an image I've compiled over the last few hours which shows the Halo Orbit as a part of the Earth Moon Lagrange system.   In reality, the Halo orbit *should* really be a straight line, because you could only see it side-on from this perspective, but I've used an elipse to demonstrate that it is around L2 in the plane of view...

http://65.33.118.71/Public/EM_Lagarange.jpg">

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

Online Chris Bergin

RE: VSE falling apart?
« Reply #24 on: 04/11/2006 07:17 pm »
Quote
DigitalMan - 11/4/2006  4:36 AM

It is early in the process.  Better to be frustrated now than later.  

That's an important point. Heck, we can all be glum about things, but as I've kept saying, look at the positives. We were all moaning about no news of things moving ahead recently.

I know NASA people automatically think the media is evil (well some do, and they are usually right!) but they should take heart in the fact that there's enough people out there that give a sh-t. There's huge interest in the process and it's good to read into some of the evalautions (not all, just some) and have a good debate.

Those that think its a bad idea don't understand media - and the power of it.

Any NASA people here that disagree. Mail me. I'll talk to you - which is more than what one can expect the other way around half the time.
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Offline kraisee

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RE: VSE falling apart?
« Reply #25 on: 04/11/2006 07:40 pm »
Quote
Jim - 11/4/2006  7:37 AM

The change was only in the ascent stage.  It went from methane to hypergols.  The Descent remains LH2/LO2

Okay, the math didn't seem to interest anyone last time, so I'll cut to the chase.   Using the LRA-0 baseline; it has 9.2mT of hypergolic propellant currently.

If LOX/Methane were to be used instead, there is a reduction in mass, but only by about 1/3rd, a total saving of, maybe, 3mT or so.

I don't think that's enough of a difference to justify the difficult and costly development of such a propulsion system.   We'd have to make a brand-new Methane powered rocket engine suitable for the job, and then go through all the extra hastle of making it man-rated and so completely reliable that it can be used on the CEV as the only get-you-home-or-bust engine.

Hypers make more sense to me for the first generation of CEV SM.

But I could see an advantage in developing a Methane for the Descent Stage of the LSAM.   It would need to be as a future upgrade at some point, not in the initial spec.   That change would appear to offer significant increases performance.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
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Offline rcaron

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RE: VSE falling apart?
« Reply #26 on: 04/11/2006 09:43 pm »
Quote
kraisee - 11/4/2006  3:40 PM
If LOX/Methane were to be used instead, there is a reduction in mass, but only by about 1/3rd, a total saving of, maybe, 3mT or so.

I don't think that's enough of a difference to justify the difficult and costly development of such a propulsion system.   We'd have to make a brand-new Methane powered rocket engine suitable for the job, and then go through all the extra hastle of making it man-rated and so completely reliable that it can be used on the CEV as the only get-you-home-or-bust engine.

Hypers make more sense to me for the first generation of CEV SM.

3mT is alot! Until the TEI burn, that 3mT is payload that has to go all the way to the Moon. To put this in perspective, LRO (with its 2ndary payload and spent upper stage !) weighs ~3mT. That mass savings would allow us more dV, get everybody down to the surface, and maybe even get us a real airlock on the LSAM (which is currently scrapped because it weighs too much w/ the hypergol).

Point is that when you switch to hypergols things don't fit and you have to start sacraficing capabilities to make ends meet. I trust the recent NASA analysis is accurate, and that means that we're in real trouble. Equatorial landings of a partial crew are useless. This isn't supposed to be "flags and footprints".

Concerning leaving CEV in L2, my only concern is that leaving it there requires more ascent dV for the LSAM, which could be troublesome. I don't know if a halo L2 orbit can be sufficiently large to maintain comms w/ Earth. That'd simplify things. How far away is L2 from lunar surface?

I'm a hugefan of independant comsats personally. Small, simple radio relays placed in high orbits can be an amazing asset, and they'd allow us to start exploring the far side. I just mentioned it because we're either going to have to fly a comsat or two on every CEV mission or rely on already placed assets like we do on Mars (Odyssey, MGS, Express relaying for MER, MRO relaying for future MSL, etc). Its just another piece of the puzzle...
Thank you Delta II & ICESat-2!

Offline nacnud

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RE: VSE falling apart?
« Reply #27 on: 04/11/2006 11:02 pm »
Quote
I don't know if a halo L2 orbit can be sufficiently large to maintain comms w/ Earth.

Yes it can, the details are on this site - somewhere...

Offline kraisee

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RE: VSE falling apart?
« Reply #28 on: 04/12/2006 05:51 am »
I spoke tonight with an engineer at KSC who's been working Shuttle since the 70's, and who recently moved across to CLV.

Anyway, they said that there is a group of proponents within NASA who would prefer to start the VSE by just aiming to replicate the Apollo missions, and build towards better things once you've proved those "simple" (!) missions can be done again now.   Aparently they are the ones actually responsible for the "Walmart" lander concept.

Now, I'm not a fan of the cut-down concept, but I'll describe their thinking - as I understand it...

The belief seems to be that its a difficult enough proposition just going back to the moon thirty years after we threw away all the capability to do so.   Just getting there is the big unknown right now, and that additional capabilities over Apollo should only be added once we've proven we can do a repeat of what was already proven to work.

I must concede some good logic in starting out by retracing the previous steps as closely as possible for a venture as awesomely difficult as a moon landing mission.

The argument continues that Apollo proved that the spacecraft can evolve very quickly once it is proven to work.   The Apollo LM improved enormously with every mission, even though the program only landed 6 on the moon.   The crews were managing to get more and more useful work done as the program went along, and the program guys were getting more and more payload to the surface with each successful missions too.

For the first time, I'm wondering if maybe that isn't such a bad route to go.   Starting simple, retracing a path well-trod before and then evolving the design over a period of time from there, instead of leaping in head-first and trying to do everything right from the get-go.

As it was, across just 12 missions, we lost one Apollo crew, and nearly lost another crew too.   I know I'd hate to lose a VSE crew just because we tried to bite off too much, too soon.

I want to see the full VSE realised as soon as possible.   If there is real wisdom in taking things slowly, then I think NASA should do so and make sure they build the full VSE, even if it takes a little longer to get there.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
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Offline MATTBLAK

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RE: VSE falling apart?
« Reply #29 on: 04/12/2006 06:37 am »
A balanced, thoughtful and not hysterical post. I salute you, kraisee.
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Offline MartianBase

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RE: VSE falling apart?
« Reply #30 on: 04/12/2006 08:19 am »
Here's Bell from Honolulu

Sometimes I really can't stand the rants of JeffreyBell, he sometimes comes across as anti-NASA, bitter, anti-Shuttle, anti-space you name it...
but as much as we love to hate a heretic or anti-space infidel we can't just dismiss Bell outright, at times he comes up with some really good points

Here's his take on the exclusive nasaspaceflight story and LRA0study
http://www.spacedaily.com/reports/Vision_For_Space_Exploration_Facing_Critical_Juncture.html
Vision For Space Exploration Facing Critical Juncture

Online Chris Bergin

RE: VSE falling apart?
« Reply #31 on: 04/12/2006 08:28 am »
We're pro VSE here, in case a load of new people come here thinking we're trying to bash it in the same light as op-eds.
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Offline abacus

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RE: VSE falling apart?
« Reply #32 on: 04/12/2006 02:39 pm »
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kraisee - 12/4/2006  6:51 AM
Anyway, they said that there is a group of proponents within NASA who would prefer to start the VSE by just aiming to replicate the Apollo missions, and build towards better things once you've proved those "simple" (!) missions can be done again now.   Aparently they are the ones actually responsible for the "Walmart" lander concept.

Ross.

I see no problem going with the "Walmart" approach initially.  The problem seems to be though that the CaLV will not be able to carry anything much better.  We can have a simple starting point as long as there is ample room to expand it.  That is not what is being proposed - "Walmart" seems to have been proposed because the better alternatives don't work - not just to give the program a simpler start.

Offline publiusr

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RE: VSE falling apart?
« Reply #33 on: 04/12/2006 06:02 pm »
I think we would count ourselves lucky if we see CaLV built at all. I would be willing to forgo the stick and start CaLV now while Congress is as favorable as it is every likely to be. Get it under contract. I always thought that the Stick should have been used as a barganing chip to get the primes to lower costs, with a threat of the stick being used for satellites at a future time as an EELV-killer. Then the ULA could be persuaded to lower costs on CaLV construction.

Offline josh_simonson

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RE: VSE falling apart?
« Reply #34 on: 04/12/2006 07:39 pm »
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abacus - 12/4/2006  9:39 AM

Quote
kraisee - 12/4/2006  6:51 AM
Anyway, they said that there is a group of proponents within NASA who would prefer to start the VSE by just aiming to replicate the Apollo missions, and build towards better things once you've proved those "simple" (!) missions can be done again now.   Aparently they are the ones actually responsible for the "Walmart" lander concept.

Ross.

I see no problem going with the "Walmart" approach initially.  The problem seems to be though that the CaLV will not be able to carry anything much better.  We can have a simple starting point as long as there is ample room to expand it.  That is not what is being proposed - "Walmart" seems to have been proposed because the better alternatives don't work - not just to give the program a simpler start.

An orbital fuel depot that can reliquify cryogenics and refill the second stage/EDS would double its TLI capacity.  Compared to increasing the size of the launcher this would be a very economical approach.  Reliquification would also push the EDS loiter ability out to infinity.  Griffin has stated his support for this concept a number of times.  There are ways to improve things, even with a payload constraint.

Offline modavis

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RE: VSE falling apart?
« Reply #35 on: 04/15/2006 07:31 pm »
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MartianBase - 12/4/2006  3:19 AMSometimes I really can't stand the rants of JeffreyBell, he sometimes comes across as anti-NASA, bitter, anti-Shuttle, anti-space you name it...but as much as we love to hate a heretic or anti-space infidel we can't just dismiss Bell outright, at times he comes up with some really good points

Maybe it makes me a heretic too, but I think Bell gets a lot of flak simply because 95% of what's written about space is more or less cheerleading. Space enthusiasts spend so much time preaching to the choir that a cool, objective look at ideas that really don't have much chance of working (or more often, of getting funded) strikes them as hostile.

Offline Tap-Sa

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RE: VSE falling apart?
« Reply #36 on: 04/16/2006 08:22 am »
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MartianBase - 12/4/2006  12:19 PM

Here's Bell from Honolulu


From the article:

he use of LCH4 in the CEV and LSAM ascent stage had to be dropped because of the 6-month space storage requirement for these modules. Methane is significantly harder to keep liquid than LOX, and over 180 days on or near the Moon much of it would boil off due to heating of the tanks by sunlight.

Methane boiling point is 111.5K versus oxygen 90.2K, it would seem that methane is actually easier to keep liquid than LOX. Is this just writer's little slip up or is there some other consideration that changes the picture? I thought methane got axed due to lack of experience on methane engines and developing one would have costed too much.

I like Bell's proposition of ditching the Stick and going for 2xCaLV. The 'mundane' LEO-ISS flights would be outsourced to EELV+CEV while NASA folks could concentrate their army to work on only one NASA-specific launcher. Even ATK should be happy with this because one moon mission consumes four SRBs instead of three. The CaLV development ought to be a bit cheaper since instead of 100+ ton behemoth it would be 'just' 50-60 ton giant, and it's flight rate would double ie disperse the R&D costs nicely. NASA would need to worry about just one type of pad, buy service from EELV contractors and let them worry about the EELV+CEV pad, they'll probably do required modifications much cheaper.

About starting with taking babysteps using Walmart LSAM; that would be OK if it meant also Walmart pricetag. And preferably faster timetable. It should not take more than a decade to repeat what was done in less than a decade forty years ago.

Offline rcaron

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RE: VSE falling apart?
« Reply #37 on: 04/16/2006 08:59 am »
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Tap-Sa - 16/4/2006  4:22 AM
Methane boiling point is 111.5K versus oxygen 90.2K, it would seem that methane is actually easier to keep liquid than LOX. Is this just writer's little slip up or is there some other consideration that changes the picture? I thought methane got axed due to lack of experience on methane engines and developing one would have costed too much.

Methane is one of the easier cyrogenics to store. Bell frequently gets things wrong; I've on more than one occassion contemplated dropping spacedaily.com from my list of news websites because of him.

Quote
Tap-Sa - 16/4/2006  4:22 AM
I like Bell's proposition of ditching the Stick and going for 2xCaLV. The 'mundane' LEO-ISS flights would be outsourced to EELV+CEV while NASA folks could concentrate their army to work on only one NASA-specific launcher. Even ATK should be happy with this because one moon mission consumes four SRBs instead of three. The CaLV development ought to be a bit cheaper since instead of 100+ ton behemoth it would be 'just' 50-60 ton giant, and it's flight rate would double ie disperse the R&D costs nicely.

NASA would need to worry about just one type of pad, buy service from EELV contractors and let them worry about the EELV+CEV pad, they'll probably do required modifications much cheaper.

About starting with taking babysteps using Walmart LSAM; that would be OK if it meant also Walmart pricetag. And preferably faster timetable. It should not take more than a decade to repeat what was done in less than a decade forty years ago.
2xCaLV was reviewed in the ESAS report, as were EELV launchers for crewed flights (EELV-based cargo flights are simply not realistic). Crewed flights are past the upper limit of current EELV hardware. At a minnum (Delta IV-Heavy being the closest contender), a new upper stage would be needed. Atlas 5 would have to have 3 parallel cores, closely remembling the Delta IV-Heavy. An "Atlas Phase 2" vehicle is the least complex EELV option, except for the fact that it barely has any heritage with the current Atlas line. As such, NASA can't just hand over CEV/ISS flights to USAF/EELV and have them "take care of it". There'd be a lot of R&D needed to make EELV work for this, and I doubt that there upgrades would be used by anybody but NASA, so they'd have to foot the bill. New stages, new engines, it isn't trivial.

Its obvious that we don't need even a 60mT CaLV for CEV/ISS flights, since ISS construction will have (hopefully) been completed with Shuttle. So having the CEV flying on the top of the CaLV is just a big waste. Thus, the CLV/pogo stick is born. The idea is actually fairly old; Griffin propsed it while working on a study for the Planetary Society and contractor reports had played around with it before that too.

Alas, we need the 100+mT behemoth CaLV if we want to get this done right. This thing is supposed to be taking us to Mars; we can't really afford to be this upmass-strapped  so soon! The Walmart LSAM does not guarantee faster timelines or lower pirces. Its a comprimise of capability to fit within the mass reqs once the cyro fuels were pulled.

Bring methane back!
Thank you Delta II & ICESat-2!

Offline Jim

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RE: VSE falling apart?
« Reply #38 on: 04/16/2006 12:14 pm »
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rcaron - 16/4/2006  4:59 AMThe 'mundane' LEO-ISS flights would be outsourced to EELV+CEV while NASA folks could concentrate their army to work on only one NASA-specific launcher.  NASA would need to worry about just one type of pad, buy service from EELV contractors and let them worry about the EELV+CEV pad, they'll probably do required modifications much cheaper.At a minnum (Delta IV-Heavy being the closest contender), a new upper stage would be needed. Atlas 5 would have to have 3 parallel cores, closely remembling the Delta IV-Heavy. An "Atlas Phase 2" vehicle is the least complex EELV option, except for the fact that it barely has any heritage with the current Atlas line. As such, NASA can't just hand over CEV/ISS flights to USAF/EELV and have them "take care of it". There'd be a lot of R&D needed to make EELV work for this, and I doubt that there upgrades would be used by anybody but NASA, so they'd have to foot the bill. New stages, new engines, it isn't trivial. 

There is an Atlas V Heavy with 3 cores, it was stopped at CDR.  Phase 2 Atlas has a lot of heritage with the current line, only structures are different.  NASA already buys EELV's and the Air Force is not involved.  NASA did all the oversight for the RTG flying on New Horizons.  NASA was ready to fly OSP on EELV's and much of the planning including pad mods was completed

Offline Tap-Sa

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RE: VSE falling apart?
« Reply #39 on: 04/16/2006 03:08 pm »
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rcaron - 16/4/2006  12:59 PM
 Crewed flights are past the upper limit of current EELV hardware.  

The Lunar CEV with massive SM yes. But why ESAS quotes ISS Crew CEV about as massive as the lunar version, including 1500+ m/s dv capability is beyond me. Do you really need as big SM to LEO missions as lunar ones??

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Bring methane back!

Hear hear.

Offline HailColumbia

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RE: VSE falling apart?
« Reply #40 on: 04/16/2006 03:16 pm »
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Tap-Sa - 16/4/2006  4:22 AM

About starting with taking babysteps using Walmart LSAM; that would be OK if it meant also Walmart pricetag. And preferably faster timetable. It should not take more than a decade to repeat what was done in less than a decade forty years ago.

Definatly not a good idea, NASA will never get the full LSAM that way.  Once they have a capability, congress will never fund the new one.  Imagine if after the first few shuttle missions NASA said "Ok, well now we want to build a new orbiter, but this time, it will be extra kickass"  Congress wouldent go for that, and they wont fund TWO LSAMS. maybe they would say they would, but when it comes time, NASA would be stuck with the walmart model.
-Steve

Offline Jim

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RE: VSE falling apart?
« Reply #41 on: 04/16/2006 03:35 pm »
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Tap-Sa - 16/4/2006  11:08 AM
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rcaron - 16/4/2006  12:59 PM Crewed flights are past the upper limit of current EELV hardware.  
The Lunar CEV with massive SM yes. But why ESAS quotes ISS Crew CEV about as massive as the lunar version, including 1500+ m/s dv capability is beyond me. Do you really need as big SM to LEO missions as lunar ones??
Quote
Bring methane back!
Hear hear.

It saves money having only one SM.  It doesn't have to be fully fueled for LEO missions.

Offline rcaron

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RE: VSE falling apart?
« Reply #42 on: 04/16/2006 07:59 pm »
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Jim - 16/4/2006  8:14 AM
There is an Atlas V Heavy with 3 cores, it was stopped at CDR.  Phase 2 Atlas has a lot of heritage with the current line, only structures are different.  NASA already buys EELV's and the Air Force is not involved.  NASA did all the oversight for the RTG flying on New Horizons.  NASA was ready to fly OSP on EELV's and much of the planning including pad mods was completed
Its too bad we didn't go OSP - I like lifting bodies alot, although optimization-wise they're strictly LEO. I hope the Russian Klipper pans out.

But anyways, back to EELV. Delta IV-H is closest to meeting reqs, and at least it flew once (anybody know when the next flight is?) The ISS CEV SM is 6mT lighter than the lunar variant because of the lower propellant, at least in theory. Other charts show the ISS variants weighing as much as lunar, but this is because they use the excess dV capability for better launch abort coverage. IIRC, abort coverage isn't as great going to 51.6 as 28.5, so they needed all the abort dV they could get their hands on. So it doesn't look like the SM is actually offloaded much (if at all) for ISS flights, keeping payload mass above what current EELVs can offer.  

I'm not so sure the OSP could have flown on the current EELVs either - they're inherently more heavy than capsules, although they're better L/D could lower abort propellant requirements.

My apologies about my earlier post concerning the heritage concerning Atlas Phase 2. It just looks nothing like the current Atlas line, and I guess I just balk at changing the vehicle diameter. Structure isn't trivial, and I don't think Atlas facilities are designed to handle such large diameters. If I were to guess, Phase 2 structure & tanks would have to be built at Michoud, making Atlas Phase 2 a hybrid of Shuttle-derivation and EELV. It'd be interesting, and if we were not going to pogo-stick this is the closest thing we have to a "clean sheet" design that is optimized for this mission. But there isn't the money (ESAS says the development cost factor of Phase 2 is 1.79 - by far the highest of the options), and we probably don't have the time either.
Thank you Delta II & ICESat-2!

Offline vt_hokie

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RE: VSE falling apart?
« Reply #43 on: 04/16/2006 08:04 pm »
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rcaron - 16/4/2006  3:59 PM
Its too bad we didn't go OSP - I like lifting bodies alot, although optimization-wise they're strictly LEO. I hope the Russian Klipper pans out.

Me too!  I also hope that "Blackstar" actually exists, because it would be nice to think that this country can still follow through on something more ambitious than a simple capsule based on the Apollo CM design.

Offline rcaron

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RE: VSE falling apart?
« Reply #44 on: 04/16/2006 08:12 pm »
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vt_hokie - 16/4/2006  4:04 PM
Me too!  I also hope that "Blackstar" actually exists, because it would be nice to think that this country can still follow through on something more ambitious than a simple capsule based on the Apollo CM design.

Funny you bring that up. Blackstar has a really high "cool" factor, and it's representative of a lot of capabilities we're still trying to aquire. But I agree with Bell on this one - its just a pipe dream. The things couldn't possibly have been orbital with Boron-based fuel or what have you. There just isn't enough chemical energy. His article on blackstar is actually what kept me going to spacedaily.com

I still want the X-38 for emergency crew return for ISS.
Thank you Delta II & ICESat-2!

Offline Jim

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RE: VSE falling apart?
« Reply #45 on: 04/16/2006 08:48 pm »
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rcaron - 16/4/2006  3:59 PM
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Jim - 16/4/2006  8:14 AMThere is an Atlas V Heavy with 3 cores, it was stopped at CDR.  Phase 2 Atlas has a lot of heritage with the current line, only structures are different.  NASA already buys EELV's and the Air Force is not involved.  NASA did all the oversight for the RTG flying on New Horizons.  NASA was ready to fly OSP on EELV's and much of the planning including pad mods was completed
Its too bad we didn't go OSP - I like lifting bodies alot, although optimization-wise they're strictly LEO. I hope the Russian Klipper pans out. But anyways, back to EELV. Delta IV-H is closest to meeting reqs, and at least it flew once (anybody know when the next flight is?) The ISS CEV SM is 6mT lighter than the lunar variant because of the lower propellant, at least in theory. Other charts show the ISS variants weighing as much as lunar, but this is because they use the excess dV capability for better launch abort coverage. IIRC, abort coverage isn't as great going to 51.6 as 28.5, so they needed all the abort dV they could get their hands on. So it doesn't look like the SM is actually offloaded much (if at all) for ISS flights, keeping payload mass above what current EELVs can offer.  I'm not so sure the OSP could have flown on the current EELVs either - they're inherently more heavy than capsules, although they're better L/D could lower abort propellant requirements.My apologies about my earlier post concerning the heritage concerning Atlas Phase 2. It just looks nothing like the current Atlas line, and I guess I just balk at changing the vehicle diameter. Structure isn't trivial, and I don't think Atlas facilities are designed to handle such large diameters. If I were to guess, Phase 2 structure & tanks would have to be built at Michoud, making Atlas Phase 2 a hybrid of Shuttle-derivation and EELV. It'd be interesting, and if we were not going to pogo-stick this is the closest thing we have to a "clean sheet" design that is optimized for this mission. But there isn't the money (ESAS says the development cost factor of Phase 2 is 1.79 - by far the highest of the options), and we probably don't have the time either.

The next D-IV  Heavy is after the GOES vehicle(fall timeframe).

The OSP spacecraft were capsules. 

Atlas Phase 2 diameter is the same as the current large fairing.  Only VIF platforms would need to be modified



Offline vt_hokie

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RE: VSE falling apart?
« Reply #46 on: 04/16/2006 10:17 pm »
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rcaron - 16/4/2006  4:12 PM
Funny you bring that up. Blackstar has a really high "cool" factor, and it's representative of a lot of capabilities we're still trying to aquire. But I agree with Bell on this one - its just a pipe dream.

Well, making such a "pipe dream" into reality is the type of thing that made me go into engineering!  I'd rather be involved in something like than than in re-creating Apollo using old designs and old hardware.

Offline rcaron

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RE: VSE falling apart?
« Reply #47 on: 04/17/2006 12:08 am »
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Jim - 16/4/2006  4:48 PM

The OSP spacecraft were capsules

Only 1 of the 4 big OSP designs was capsule shaped, I refer to this spaceflightnow article. Remember OSP started before Columbia, and back then the idea of going with a capsule design was just silly.  Capsule obviously got more traction afterwards, but it was still 50/50 when the OSP program got folded into CEV.


Quote
Jim - 16/4/2006  4:48 PM
Atlas Phase 2 diameter is the same as the current large fairing.  Only VIF platforms would need to be modified
I'm glad that's all it takes. It is obvious that a lot of thought went into Atlas Phase 2. Its really too bad we can't use it.
Thank you Delta II & ICESat-2!

Offline rcaron

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RE: VSE falling apart?
« Reply #48 on: 04/17/2006 12:21 am »
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vt_hokie - 16/4/2006  6:17 PM

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rcaron - 16/4/2006  4:12 PM
Funny you bring that up. Blackstar has a really high "cool" factor, and it's representative of a lot of capabilities we're still trying to aquire. But I agree with Bell on this one - its just a pipe dream.

Well, making such a "pipe dream" into reality is the type of thing that made me go into engineering!  I'd rather be involved in something like than than in re-creating Apollo using old designs and old hardware.

The technology doesn't exist yet to make SSTO or Blackstar actually work - we're always getting closerthough. I wouldn't mind working on some of those fundamental technologies either - but you can't base a new manned program on that. There's a timeline to keep, gotta keep to keep the budget low because otherwise missions and science are cut, etc.

I should point out that ESAS/CEV is not Apollo, or at least it shoudn't be. We're looking for much higher capabilities. Sure, the launch vehicle is made from pieces that already exist, but that's good in my book. The shuttle stack is a capable system, we've just been using it wrong.

I'd just like to be working on space, period. GSFC turned me down for internship again :-/. Anybody looking for an aerospace undergrad?
Thank you Delta II & ICESat-2!

Offline vt_hokie

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RE: VSE falling apart?
« Reply #49 on: 04/17/2006 12:41 am »
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rcaron - 16/4/2006  8:21 PM
The technology doesn't exist yet to make SSTO or Blackstar actually work - we're always getting closerthough.

Who knows.  I'm sure there's something to the "Blackstar" story, whether they have an orbital vehicle or not.  Maybe we'll find out sooner or later.

Offline Jim

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RE: VSE falling apart?
« Reply #50 on: 04/17/2006 12:48 am »
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rcaron - 16/4/2006  8:08 PM
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Jim - 16/4/2006  4:48 PMThe OSP spacecraft were capsules
Only 1 of the 4 big OSP designs was capsule shaped, I refer to this spaceflightnow article. Remember OSP started before Columbia, and back then the idea of going with a capsule design was just silly.  Capsule obviously got more traction afterwards, but it was still 50/50 when the OSP program got folded into CEV.
Quote

Incorrect, at the end of the OSP program, when it was only LM and Boeing, they were all capsules.  I was at the pre SRR.  That article was old news when it was published. 

Offline spacefire

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RE: VSE falling apart?
« Reply #51 on: 04/17/2006 02:35 am »
I am surprised that anyone is surprised at how things have turned out.
'Vision'  was never the first word in VSE.

Offline Super George

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RE: VSE falling apart?
« Reply #52 on: 04/17/2006 03:10 am »
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spacefire - 16/4/2006  9:35 PM

I am surprised that anyone is surprised at how things have turned out.
'Vision'  was never the first word in VSE.

How do you mean "Turned out"?

Offline James Lowe1

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RE: VSE falling apart?
« Reply #53 on: 04/17/2006 03:11 pm »
This goes to three users. 1) No personal attacks on members or individuals. 2) To one user, posting about having two accounts here has nothing to do with the subject discussed here.

Carry on.

Offline hyper_snyper

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RE: VSE falling apart?
« Reply #54 on: 04/17/2006 03:50 pm »
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spacefire - 16/4/2006  10:35 PM
...
'Vision'  was never the first word in VSE.

The first word in VSE is 'the'.

The Vision for Space Exploration. ;)


Offline rcaron

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RE: VSE falling apart?
« Reply #55 on: 04/17/2006 06:12 pm »
Well, am I wrong to think that the majority of current technical problems with VSE stem from the move to hypergolics instead of methane/lox? Everything else seems technically feasible - we need to get cracking at methane engines. IMO, we should give that to NASA Glenn for them to work on now, especially since according to nasawatch they currently aren't getting a lot of relevent work anymore.

I know the VSE has never been terribly strong politically, but it looks like its been gaining some good traction in the House of Represenatives finally. There has been talk of giving NASA a lot more (like a few billion more) so everything can be worked on w/out cutting science to hell. I think the main proponent of that was DeLay, but there has been support for such an increase from the Democrats too, name just escapes me at the moment.
Thank you Delta II & ICESat-2!

Offline kraisee

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RE: VSE falling apart?
« Reply #56 on: 04/17/2006 06:59 pm »
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rcaron - 17/4/2006  2:12 PM

Well, am I wrong to think that the majority of current technical problems with VSE stem from the move to hypergolics instead of methane/lox? Everything else seems technically feasible - we need to get cracking at methane engines. IMO, we should give that to NASA Glenn for them to work on now, especially since according to nasawatch they currently aren't getting a lot of relevent work anymore.

The difference for using Hypergolics instead of Methane/LOX on the CEV Service Module (CEV-SM) and LSAM Ascent Stage (LSAM-AS) is not as big a factor as people think.   In the spacecraft system which is going to mass probably 60 tons when it arrives at the moon, we're talking about a difference of just two or three tons.   But to get that difference we first would have to spend billions of dollars extra to develop the Methane engines to the point that they are so reliable we'll risk crews lives on them.   For every billion we spend on Methane engines, we could use it instead to launch a complete extra mission to the moon.

Even if we switch to Methane is will not allow the baseline LSAM as originally planned to fly.   Other changes will still be required.

There are an awful lot of changes which can be done ahead of Methane, which will result in far greater changes to the mass of the spacecraft at a far lower cost.   Those are worthwhile pursuing more aggressively than Methane – and NASA is doing that pursuit right now.   The results will eventually be made public and I think we’ll be pleased with those results when we see them.

Lets try to remember that there is no Methane on the moon.   So we won’t be filling the tanks at the moon – which is the primary reason for having Methane.   Methane only comes into its own for Mars missions where we can land a vehicle and refuel it on the surface there, meaning we won’t have to send all that fuel mass to Mars, which makes things much easier.   But the Mars program is still probably 20 years away, so we have plenty of time to develop the necessary tech.

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

Offline kraisee

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RE: VSE falling apart?
« Reply #57 on: 04/17/2006 07:16 pm »
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rcaron - 17/4/2006  2:12 PM

I know the VSE has never been terribly strong politically, but it looks like its been gaining some good traction in the House of Represenatives finally. There has been talk of giving NASA a lot more (like a few billion more) so everything can be worked on w/out cutting science to hell. I think the main proponent of that was DeLay, but there has been support for such an increase from the Democrats too, name just escapes me at the moment.

I think you're right.

More money is great.   Any new money in large civil programs always helps to bolster the national economy.   It creates jobs, those employees buy cars and houses, they all then need doctors, dentists, accountants lawyers, shops and superstores, which all creates more jobs.   It is believed that every dollar invested in the space program during the 60's was returned to the US Economy *SEVEN* times over within 12 months of its original expenditure.   If that could be done again now, lets invest quadruple the budget and get things really shifting!

As for the politics, the White House has been sensible not to publicly back this program after making the initial announcement.   Doing so would just have made it yet another stick to beat the different parties over the head with, and I think a lot of the politicians on both sides of the aisle know that Space Exploration is worth more than that.

It appears to me have been handed entirely to Congress, which has been able to take the VSE and make it theirs - in a bipartisan fashion, which is so rare these days.

I think if it stays that way, we will continue to see strong support.   But if the next White House (2009-2012) is strongly anti-manned-space-exploration, we could see bad things from the political world.

Also, if one more Shuttle has an accident I think it will be extremely bad for NASA.   What bothers me with that is that there are 17 more flights on a vehicle which has proven to have a 1 in 57 failure rate so far, which means we're banking the entire VSE on a vehicle which has roughly a 1 in 3 chance of failing on one mission during the remaining STS program.   I don't like putting all our eggs in that basket with those sorts of odds, just to finish the damn albatros station.

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

Offline rcaron

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RE: VSE falling apart?
« Reply #58 on: 04/18/2006 12:17 am »
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kraisee - 17/4/2006  2:59 PM

The difference for using Hypergolics instead of Methane/LOX on the CEV Service Module (CEV-SM) and LSAM Ascent Stage (LSAM-AS) is not as big a factor as people think.   In the spacecraft system which is going to mass probably 60 tons when it arrives at the moon, we're talking about a difference of just two or three tons.   But to get that difference we first would have to spend billions of dollars extra to develop the Methane engines to the point that they are so reliable we'll risk crews lives on them.   For every billion we spend on Methane engines, we could use it instead to launch a complete extra mission to the moon.

Even if we switch to Methane is will not allow the baseline LSAM as originally planned to fly.   Other changes will still be required.

There are an awful lot of changes which can be done ahead of Methane, which will result in far greater changes to the mass of the spacecraft at a far lower cost.   Those are worthwhile pursuing more aggressively than Methane – and NASA is doing that pursuit right now.   The results will eventually be made public and I think we’ll be pleased with those results when we see them.

Lets try to remember that there is no Methane on the moon.   So we won’t be filling the tanks at the moon – which is the primary reason for having Methane.   Methane only comes into its own for Mars missions where we can land a vehicle and refuel it on the surface there, meaning we won’t have to send all that fuel mass to Mars, which makes things much easier.   But the Mars program is still probably 20 years away, so we have plenty of time to develop the necessary tech.

Ross.

From another thread: 103s 90kN lox/methane testfire @ NASA Marshall <=== FINALLY!

I'm so glad to see somebody working on methane, I was about to start hoping XCOR or someone took it on in the meantime since I didn't know Marshall was working on it. My philosophy with methane/lox is that while you can't get methane on the moon, you can make oxygen. Thus, a reasonable size (if not all) of the ascent stage lox could be replaced with payload-to-surface. Since oxidizer weighs more than fuel due to the the optimizer fuel/oxidizer ratio, this could be really useful. As such, I was more disapointed that lox was cut from ascent stage than methane.

Besides, in 20 years when we're finally talking about Mars someone is going to balk at  the use of methane because it doesn't have the flight hertigate of other systems (like hypergolics). And then the Mars mission will start looking more like Battlestar Galactica than Mars Direct.  I think methane engines are worthwhile enough in the long run to take the short-term risk and get ISS and lunar flight experience with methane/lox. I don't see NASA's budget crunch easing anytime soon - with CaLV, CLV, CEV, and LSAM development we could easily postpone methane/lox development until 2025. That's not a situation I want to find myself in. So I say start the work now, which thankfully Marshall has.


Kraisee, you obviously know more about this than I, but I'm still curious on why the original LSAM as outlined in ESAS can't fly. What wasn't accounted for? I read the report, and while I can't say I agree with all the decisions I thought the analysis was fair and realistic. I mean, what changes are left to make? LOI is LH2/LOX in the LSAM descent stage, supplemental radiation shielding is minimal/nonexistant, avionics will be lighter, and LSAM airlock capability has been minimized to keep the mass down. Other than CEV @ L2, it doesn't look like things are going to get much lighter. But you say there are changes in the works, and as always I early await to hear them.

What I'm not pleased to hear is that some of the changes are being made "in the dark". Maybe I'm just an idealist (and a very curious aerospace-engineer-in-training), but NASA is civilian and their work should be open. So the process isnt dressed up in a nice & pretty PR package. So what? NASA is an technical agency, and we should expect and promote seeing the process as it happens. /end rant.
Thank you Delta II & ICESat-2!

Offline kraisee

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RE: VSE falling apart?
« Reply #59 on: 04/18/2006 07:38 am »
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rcaron - 17/4/2006  8:17 PM

Kraisee, you obviously know more about this than I, but I'm still curious on why the original LSAM as outlined in ESAS can't fly. What wasn't accounted for? I read the report, and while I can't say I agree with all the decisions I thought the analysis was fair and realistic. I mean, what changes are left to make? LOI is LH2/LOX in the LSAM descent stage, supplemental radiation shielding is minimal/nonexistant, avionics will be lighter, and LSAM airlock capability has been minimized to keep the mass down. Other than CEV @ L2, it doesn't look like things are going to get much lighter. But you say there are changes in the works, and as always I early await to hear them.

Well thanks, but I'm no professional at this.   I just play a rocket scientist on the internet :)

But I'll have a crack at this.   The ESAS report was pretty good, but was based on VERY early information, and in some cases pure estimates and even educated guesswork.   It's purpose was to narrow down which options were the best to follow up, and which ones should be discarded early on.   The spec for the CLV and CaLV was chosen for a variety of reasons, but it always required significantly more detailed studies had to be done to confirm and all the small details.   Once the basic outline for the process was identified, the process started into investigating the details of all the different elements and getting really accurate information.

We have seen changes to the ESAS report already, which are the results of these more detailed studies into individual elements of the project.   PBAN propellant back in the SRB's again.   Single J-2X upper stages on both vehicles.   5m diameter CEV.   I guarantee that all these changes come from conclusions of detailed studies we have not actually yet seen in public.   We know of other changes still being worked on, such as RS-68 being considered for CaLV instead of SSME.   There has been no public announcement on that change so far, but it looks pretty assured.   There is a report out there somewhere detailing all the pro's and cons of that change.

Anyway, one of those elements was a study we saw briefly on this site called the Lunar Reference Architecture, or LRA.   The site editor, Chris, got hold of a document from the LRA study which appeared to provide a lot of the details.

Now, we knew from the ESAS report that the launchers we've already seen can send a certain amount of mass to the moon - somewhere around 60-65mT.   But that figure depends on a LOT of different factors.   It depends on which module performs the slow-down burn to get into Lunar Orbit.   It depends on the Lunar orbit chosen, which depends entirely on exactly where you wish to land on the moon.   It depends on if you want to park the CEV in an orbit where it never loses contact with Earth, or not.   There are lots of factors involved which can change the maximum mass figure you can send to the moon.

Anyway, this document showed that the mass of the LSAM and CEV as described in the original ESAS report, when calculated very carefully indeed, were going to be heavier than the launchers were capable of sending to the moon.   The difference appeared to be about 10mT from what can be pushed to the moon by the rockets we have.

BUT!!!   A big but here - the document which was posted here was VERY early in the whole process.   The figures it contained were NOT completed when it was posted here on the site.   The LRA work is still very much a 'work in progress' and the figures it indicated were still likely to change.

I believe Chris is on the inside track for the LRA stuff still, and I'm sure when it is ready he will post the final version ASAP.


Quote
What I'm not pleased to hear is that some of the changes are being made "in the dark". Maybe I'm just an idealist (and a very curious aerospace-engineer-in-training), but NASA is civilian and their work should be open. So the process isnt dressed up in a nice & pretty PR package. So what? NASA is an technical agency, and we should expect and promote seeing the process as it happens. /end rant.

I've already suggested that Chris try to get this information for us.

The problem though is that information that says "this can't be done quite as easily as we first planned and needs us to work on it a bit more to get things working just right" is very quickly interpreted by people as "NASA's already failed before it has even started".   This site demonstrated exactly this sort of over-reaction - anyone who saw the LRA thread knows exactly what I mean!

Many people now blame dropping Methane as the reason why it 'doesn't work' because of that article.   That's just not true though, and is why Chris has chosen to voluntarily remove the article.   Even if Methane had been used, the LRA we saw would still not have 'worked' anyway - the difference was about 10mT.   If Methane had been used it only saves AT MOST 3-4mT, and requires other hardware which reduces even that.   The truth is that Methane engines would be extremely costly to develop, and FAR cheaper things can be done to reduce the weight AND increase the lift capability of the launchers to bring the CEV & LSAM under the closure line to get them to the moon.

This study was simply a 'lets check to see if it works straight out of the box?   No?   Oh, okay, we need to do some more checks and see what we can do to make it work".   Now NASA is going to "go off and try something better instead", and the LRA will be re-done afresh.   Probably, this process will happen a lot of different times before a suitable solution is found.   Just because the 2-man option was the only option which seemed to work at this stage means NOTHING.   The configuration will be altered and the LRA re-run.   It will probably improve each time it is re-worked.

The problem is NASA is incredibly sensitive to these sorts of documents being leaked because NASA is 100% reliant on positive and supportive public opinion.   People who are not in the know just do not understand what these reports are actually saying.   They react very badly to unqualified information like this, and that can hurt NASA's public image really badly.

They WILL release the information, but when they have completed the study and have something positive for the general public and the mass-media to focus upon.   With luck Chris will be able to also get hold of the research data behind HOW they got to their conclusions too - for those of us interested enough to go into that detail while CNN makes a lot of noise over how cool the new stuff will be.

I'm with you:   I want to realy understand the whole "process" too, not just be fed the final conclusions.   Sounds very "zen" - it's the path which is important not (just) the destination.

But I will happily wait for that information in order to protect NASA's image - because without a good image, the political interest we have right now evaporates and if that happened, we would lose EVERYTHING.   I'm happy to wait so the engineers can work out an approach which works better that the very first one they tried.   I'll just hope that we can one day look back and see how and why they chose the options they do.

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

Online Chris Bergin

RE: VSE falling apart?
« Reply #60 on: 04/18/2006 08:08 am »
Very little to add to Ross' post, but I'll say this:

Accuracy is everything. Speed of publication is a key part of the media equation. Positioning (not killing your position for the sake of one story) and source protection is your moderation.

While the decision to pull the document in question was mine (no one can force me to pull anything - simple as), it was the only decision available to me, given "accuracy is everything", added to a couple of other issues which fall under the unwritten rules of journalism.

My audience is you - the readers. If I'd left that document on, knowing I've got people who "do know the score" saying there are errors in the document, added to the process continuing, leaving it in the public domain would allow for an inaccurate point of reference for their deliberations. Accuracy is an over-riding rule of what goes on site and stays on site. Not to pull this would have been highly irresponsible.

The result of our actions has not ended the coverage on this specific element of the current process. To the contrary, it's strengthened our ability to gain more accurate information, which I hope you'll see in the coming days by way of a follow-up.
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Offline kraisee

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RE: VSE falling apart?
« Reply #61 on: 04/18/2006 08:18 am »
I'm looking forward to seeing more of this complicated process whenever its ready Chris.

Take your time, get us the right info when its ready, and I'm sure everyone here will appreciate your efforts.

Thanks,

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
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Offline Hotol

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RE: VSE falling apart?
« Reply #62 on: 04/18/2006 10:30 am »
I second that. I was half expecting you to attack Jeff Bell over his follow up where he refused to believe it was inaccurate.

Online Chris Bergin

RE: VSE falling apart?
« Reply #63 on: 04/18/2006 10:57 am »
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Hotol - 18/4/2006  11:30 AM

I second that. I was half expecting you to attack Jeff Bell over his follow up where he refused to believe it was inaccurate.

He's totally entitled to his opinion....and with him being an op-ed, that's going to be the basis of his articles. He didn't attack me...he noted his reasons for disagreeing - and I'm totally fine with that. I did, however, send that site an e-mail prior to my notice....but got nothing back from them, and obviously I don't think it was a good move to re-publish our document scans, for the reasons I noted when I pulled them. I couldn't note the evidence I have to support my position for reasons of confidentiality, but I'll run my site and they'll run theirs.

Also, journalists place accreditation high up the list, and they fully adhered by that.

Besides, I'd sooner have people talking about the process, positive or negative, on the VSE, than no one giving a sh-t. :)
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Offline Spacely

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RE: VSE falling apart?
« Reply #64 on: 04/18/2006 09:47 pm »
I was just looking over some of those SEI presentations from 1991. It's amazing that two years after Bush I gave the SEI speech, NASA was still in the planning stages.

http://www.marsinstitute.info/rd/faculty/dportree/rtr/9105.html

Meanwhile, two years after Bush II gave the VSE speech, NASA is closing in on a downselect for the primary spacecraft, and issuing contracts for work on the CLV.

Is the VSE already much more successful after two years than the SEI, or am I missreading things?

Offline lmike

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RE: VSE falling apart?
« Reply #65 on: 04/19/2006 05:29 am »
Well, both unfounded negativism and cheerleading are bad when there there is no data.  Any attempts to analyze and speak out based on given data should be welcome.  And I agree with Chris, I'd be more frustrated with apathy than with spirited discussion that the report (as incomplete as it was) sparked.  The thing is there may be a fundamental problem (as I can see now it's possibly too 'brittle' with respect to mitigating mass underestimates)  with the chosen approach and we won't know it until much later.  

Although, I disagree that NASA has 'plenty of time' to settle on a plan, and it's 'just' a study.  There's been plenty of time already and the political clock is ticking.  Besides, there is nothing really new here.  All been studied before, several times.  The Planetary Society report that Dr. Griffin participated on, ATK studies, Zubrin, etc..., previous admin's studies also considered an HLV architecure.  So, there's been a huge head-start.  But, for myself, I'll be more careful about ESAS specifics until there is more hard data on what they are shooting for.

Offline Doug Stanley

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RE: VSE falling apart?
« Reply #66 on: 04/26/2006 02:27 pm »
Yes...I am back!  I have been reviewing some recent threads here since the publication of the internal NASA charts a couple of weeks ago.  

Everyone take a deep breath, the sky is not falling!  The NASA VSE architecture is not "broken" in any significant way.  As a consultant, I am very familiar with all that is going on in internal to NASA at this moment concerning architecture work and am not worried...so please don't be either.  The charts that were posted were for internal use only, used working data that had not been reviewed and was not technically accurate in many respects, and were selectively edited to promote a particular solution.  They were from an ongoing effort called the Lunar Architecture Requirements Preparatory Study being done at NASA Langley that is not at all in the mainstream of current NASA Constellation Architecture Design efforts and is not currently being used or reviewed by any NASA decision makers.  It is simply an effort to explore in more detail the lunar architecture design space (not always using the same data and models as Constellation and ESAS), including number of crew, staging points, surface time, cargo, time of flight/return, landing site locations, etc... No one outside of this Team has even seen (much less considered changing to) the "Wal-Mart " lander...in fact the number of crew would be one of the last things our Beloved Administrator would consider changing...

I would also like to thank Chris for doing the responsible thing and pulling the data off of the server.  I have agreed to answer a number of questions that he sent me last week concerning the latest on the architecture.  I was busy with a project until yesterday and am leaving for a family vacation tonight...so I may not get to it until next week.  He was going to post the responses on L-2.  Since I have been lax in getting back to him, I will also volunteer to do a thread answering all of your questions as well next week...

Ad Astra,

Doug

Online Chris Bergin

RE: VSE falling apart?
« Reply #67 on: 04/26/2006 02:57 pm »
Welcome back on Dr Stanley. Have a good vacation. I'm sure we'll all still be here upon your return  ;)
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Offline Delta Manager

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RE: VSE falling apart?
« Reply #68 on: 04/26/2006 03:26 pm »
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Doug Stanley - 26/4/2006  9:27 AM

Everyone take a deep breath, the sky is not falling!  The NASA VSE architecture is not "broken" in any significant way.

I'm not sure if you are fluent with this site's forum, but you might find this section more interesting by way of questions being posed on why a large amount of people have concerns.

http://forum.nasaspaceflight.com/category-view.asp?catlock=3

Offline Doug Stanley

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RE: VSE falling apart?
« Reply #69 on: 04/26/2006 04:12 pm »
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Delta Manager - 26/4/2006  10:26 AM

Quote
Doug Stanley - 26/4/2006  9:27 AM

Everyone take a deep breath, the sky is not falling!  The NASA VSE architecture is not "broken" in any significant way.

I'm not sure if you are fluent with this site's forum, but you might find this section more interesting by way of questions being posed on why a large amount of people have concerns.

http://forum.nasaspaceflight.com/category-view.asp?catlock=3

Yes, I have recently reviewed these forums and believe a very large percentage of the "concerns" are based on speculation without adequate information on what is really going on.  I don't have time to go through and post on the myriad of threads, so, like we did a couple of months ago, Chris is going to set up a thread that you can bring your questions/concerns to, and perhaps I can help address most of them.  This will save me time!

Doug

Online Chris Bergin

RE: VSE falling apart?
« Reply #70 on: 04/26/2006 04:18 pm »
That'd be helpful, especially when it'll keep everything in one place.

I'll set that up today, link up the previous Q and A thread (to avoid - hopefully - repeat questions) and it should be ready for you to trawl through once you've returned from vacation.
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Offline Doug Stanley

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RE: VSE falling apart?
« Reply #71 on: 04/26/2006 06:27 pm »
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Chris Bergin - 26/4/2006  11:18 AM

That'd be helpful, especially when it'll keep everything in one place.

I'll set that up today, link up the previous Q and A thread (to avoid - hopefully - repeat questions) and it should be ready for you to trawl through once you've returned from vacation.

You might want to post a notice to multiple relevant threads when you do this to herd folks over there that have questions...

Online Chris Bergin

RE: VSE falling apart?
« Reply #72 on: 04/26/2006 06:43 pm »
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