Author Topic: "DIRECT" Goes Live  (Read 350631 times)

Offline Kasponaut

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RE: "DIRECT" Goes Live
« Reply #1940 on: 05/10/2007 04:48 PM »
Hi Ross among others...

My name is Kasper.
I am not a rocket scientist and I am not an American - just for your information.
I don't have access to data and numbers from within NASA and I don't know how to calculate all this stuff. So I am not an engineer either.
I just try to use common sense and logic on what I see, read and hear.

To me, Ares 1 and Ares 5 are logical choices. What is so neat about Ares 1 is it's simplicity. And yes - it is simple. One engine on the first stage, one engine on the second plus one on Orion. All in one straight line. And it looks beautiful in my opinion - althought that is irrelevant ;).
(The 5-segment SRM will be the most powerfull rocket engine ever in history and developing it is not a waste of money - but an investment in the future of space travel. We need this monster to do the heavy lifting!)

NASA is in the process of developing Ares 1 - please let them do that in peace. The people who are doing the work are no doubt both skillfull and talented. Nobody said it wouldn't be without it's difficulties!
There were huge discussion about technical problems like this one during the development of the Saturn 1B and Saturn 5 also. You just don't throw a concept in the trash can because you hit bumps on the road.

Please also remember that NASA is flying the Space Shuttle and completing the ISS at the SAME time they are developing the Ares 1 and Orion. That is not easy -  especially with the money it has available.

I am also tired of the conspiracy theories about NASA and complains about NASA being THIS BIG government organisation that is only wasting your money and time and never learnt anything from the past. Please try to do it better.
NASA is doing a great job - not always perfect - but in general great.
(The Space Shutte was not a mistake, although not without its flaws - by the way.)

I presented the Ares 1 and Ares 5 concept compared to DIRECT to a friend of mine (he is a very talented engineer!!!). I just explained the two different concepts and problems and asked his opinion.
He preferred Ares 1 and Ares 5 because they do different jobs - as he said - compared to the Jupiter rocket. Ares 1 is for crewed flight and Ares 5 is for cargo - don't mix those two. What happens when you design a machine (in this case a rocket) that can do more things, is that you get a compromise - and a compromise is not good. The Jupiter is way to big and complex for launching humans - it is fine for cargo , not humans. But the Ares 5 will carry that cargo and more of it, so we don't need Jupiter. That was just his thoughts.

And again: Ares 1 has been chosen - not DIRECT - remember that!

I bet - but cannot prove it - that if DIRECT should be chosen (certainly don't hope or think that will happen) it will be more expensive and more problem plaqued that you THINK it will.

Just my 2 cents,

Kasper



Offline Crispy

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Re: \
« Reply #1941 on: 05/10/2007 04:51 PM »
But 'complexity' is not the issue, cost is. With the projected flight rates, Direct works out cheaper because it has far less upfront and static costs.

Offline JIS

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RE: "DIRECT" Goes Live
« Reply #1942 on: 05/10/2007 05:05 PM »
Quote
RedSky - 10/5/2007  4:46 PM

I'm just wondering WHY the safesimplesoon mythbuster page was put up NOW, at this point in time.  Who is the target audience?  Congress? NASA heads? Disillusioned employees? Is it just to get back at NSF pro-Direct posters?  ...because a Direct v2 is just about to come out?  Or maybe that May 23rd "meeting"?  I just wonder why?  ...and why now?  ... for what purpose?

On the other side I'm missing a point of the Direct. Everybody has it's own launch vehicle alternative. Longfellow, ATKs 3xRS-68 core with 5seg SRBs, Direct, LockMart, etc......
NASA is considering these options and constantly rejecting them in favour of Ares1. The argument is always the same - simple, safe (and soon).
I'm wondering how long will it last. Hopefully until Ares 1 is built or VSE is scraped.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline JIS

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RE: "DIRECT" Goes Live
« Reply #1943 on: 05/10/2007 05:07 PM »
Quote
wiinum - 10/5/2007  5:48 PM

I bet - but cannot prove it - that if DIRECT should be chosen (certainly don't hope or think that will happen) it will be more expensive and more problem plaqued that you THINK it will.


Every rocket is.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline Wolverine

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RE: "DIRECT" Goes Live
« Reply #1944 on: 05/10/2007 05:10 PM »
Quote
wiinum - 10/5/2007  12:48 PM

NASA is in the process of developing Ares 1 - please let them do that in peace.


 Many here (not me) are engineers that do work for NASA.  There are engineers here who have the technical know-how and the "numbers" that they've seen bother them.  Also we taxpayers and space enthusiasts alike want the best solution for the VSE.  We aren't here to kill it.  I don't think you understand the hornet's nest you just hit with a stick by coming to this forum proclaiming "Eat this".

Offline clongton

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RE: "DIRECT" Goes Live
« Reply #1945 on: 05/10/2007 05:21 PM »
Quote
JIS - 10/5/2007  1:05 PM

NASA is considering these options and constantly rejecting them in favor of Ares1. The argument is always the same - simple, safe (and soon.
Simple: The vehicle has become more complex as more and more of it’s “launch” capability have been transferred to Orion, just to get to a suborbital insertion point. “Simple” went out the window last year.

Safe: Some safety system contingencies are no longer included on the vehicle because they are too heavy. Performance has deleted them.

Soon: Originally we were to fly in less than 1 year after Shuttle, but no later than 2014. Then it became no sooner than 2012, then no sooner than 2013, then “on-target” for 2014, now it’s 2015, and credible sources inside program office are whispering (therefore not official) 2016 at the earliest.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Kasponaut

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RE: "DIRECT" Goes Live
« Reply #1946 on: 05/10/2007 05:25 PM »
And I respect that of course!

I just think that you worry WAY too much about Ares 1.

Sorry about the 'eat this' comment, but you alle seem so confident - I couldn't help it.


Kasper


Offline kraisee

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RE: "DIRECT" Goes Live
« Reply #1947 on: 05/10/2007 05:43 PM »
Quote
wiinum - 10/5/2007  12:48 PM

Hi Ross among others...

My name is Kasper.
I am not a rocket scientist and I am not an American - just for your information.
I don't have access to data and numbers from within NASA and I don't know how to calculate all this stuff. So I am not an engineer either.
I just try to use common sense and logic on what I see, read and hear.

To me, Ares 1 and Ares 5 are logical choices. What is so neat about Ares 1 is it's simplicity. And yes - it is simple. One engine on the first stage, one engine on the second plus one on Orion. All in one straight line. And it looks beautiful in my opinion - althought that is irrelevant ;).
(The 5-segment SRM will be the most powerfull rocket engine ever in history and developing it is not a waste of money - but an investment in the future of space travel. We need this monster to do the heavy lifting!)

NASA is in the process of developing Ares 1 - please let them do that in peace. The people who are doing the work are no doubt both skillfull and talented. Nobody said it wouldn't be without it's difficulties!
There were huge discussion about technical problems like this one during the development of the Saturn 1B and Saturn 5 also. You just don't throw a concept in the trash can because you hit bumps on the road.

Please also remember that NASA is flying the Space Shuttle and completing the ISS at the SAME time they are developing the Ares 1 and Orion. That is not easy -  especially with the money it has available.

I am also tired of the conspiracy theories about NASA and complains about NASA being THIS BIG government organisation that is only wasting your money and time and never learnt anything from the past. Please try to do it better.
NASA is doing a great job - not always perfect - but in general great.
(The Space Shutte was not a mistake, although not without its flaws - by the way.)

I presented the Ares 1 and Ares 5 concept compared to DIRECT to a friend of mine (he is a very talented engineer!!!). I just explained the two different concepts and problems and asked his opinion.
He preferred Ares 1 and Ares 5 because they do different jobs - as he said - compared to the Jupiter rocket. Ares 1 is for crewed flight and Ares 5 is for cargo - don't mix those two. What happens when you design a machine (in this case a rocket) that can do more things, is that you get a compromise - and a compromise is not good. The Jupiter is way to big and complex for launching humans - it is fine for cargo , not humans. But the Ares 5 will carry that cargo and more of it, so we don't need Jupiter. That was just his thoughts.

And again: Ares 1 has been chosen - not DIRECT - remember that!

I bet - but cannot prove it - that if DIRECT should be chosen (certainly don't hope or think that will happen) it will be more expensive and more problem plaqued that you THINK it will.

Just my 2 cents,

Kasper

Kasper, you are where I was about two years ago.   We are not very dissimilar.   I too was a hard-line advocate for "The Stick" at one time - even going so far as to write pro-Stick articles for this website.

However, since that time I have learned differently.   The team working Ares-I know of its problems and are working feverishly to get around them all.   The problem is that the concept has so many problems that whenever they get around one, it shaves performance off, and increased the budget.   This has happened time and time again throughout the development so that now the Ares-I bears little real-world resemblance to the original concept for the Stick.

The numbers still show a very weak performance with design concerns still unsolved.   For a start, the Ares-I requires the CEV itself to act as a third stage - a 'fix' which results in extra propellant tank mass in the CEV having to be pushed all the way to the moon and back again, which is a *critically* bad thing when weight is such a killer issue on lunar missions.   While the CEV masses about 26 tons at liftoff, by the time it actually reaches orbit, having burned 4 tons of propellant during ascent, it will only mass about 22mT for the actual mission itself.   The simple fact is that a 22mT CEV could be lifted by the existing Delta-IV Heavy without needing to fire the Orion's engine at all.

Now recall this engine which has to fire three times to reach Earth orbit is also the same engine which the astronauts must rely upon to get them home from the moon.   Firing, shutting down and purging an engine that many times opens up a up a whole can of worms and potential problems which could ultimately leave a 4-man crew stranded in Lunar orbit to die of asphyxiation.   I personally don't think that's the best route to be pursuing and I believe Jupiter offers far better options to NASA.


Regarding cost - anyone can see that developing one rocket costs half as much as two.  While this is obviously a simple representation, the factual budget analysis proves that this is indeed the fundamental case.   Ares-I and Ares-V together, will cost twice as much to develop and operate every year as a single mid-sized LV solution.   We have chosen Jupiter's specification to deliberately reduce the costs as much as possible by removing all of the costly long lead time items (5-seg SRB and J-2X) from the initial deployment path, and only requiring the lower spec J-2X"D" variant even in the longer term.   Instead we use existing, proven, and currently flown engines with little to no modifications at all.


As for separate Cargo and Crew, that is only partially the story.   Mixing cargo and crew was ideally suited to accomplishing the Apollo missions.   It was also absolutely essential to accomplishing the Apollo/Soyuz rendezvous.   Shuttle had to have that capability to install a suitable docking module at MIR.   Every Gemini mission flew with a module on the rear containing useful "payload" cargo which was not part of the spacecraft itself.

For CEV, if any hardware needs to be launched it is going to require lifting on a second launch vehicle becasue it can not be lifted with the CEV on the Ares-I.   For example for future Hubble Servicing Missions, a payload module will have to be launched on something like a Delta-IV or Atlas-V, costing at least $150m for that flight.   Then the crew will have to rendezvous & dock with that module, and then rendezvous & dock with the Hubble.   Is this easier, safer or more logical than bringing up your tools with you when you fly the first time - especially when your flight costs are only $10m different from Ares-I - but you saved $20 billion by not having to develop Ares-V as well?

And please don't make the mistake in thinking that Ares-V is Cargo only.   It is not.   Initially it is planned to launch the EDS and LSAM for Lunar missions.   But NASA ultimately plans to replicate Saturn-V missions also - flying crew on the top.   If Ares-V is good enough to fly crew with 8 all-new engines, why isn't Jupiter, with half the number of engines - all of which are proven to be reliable today already?

I am sure all program would prove more problematic than first assessed.   However, by deliberately reusing already proven hardware (4-seg SRBs and standard RS-68 main engines) we are safeguarding ourselves against all of the major development programs which are always the prime sources of such 'problems'.   Also by flying a modified variant of the External Tank, we start with about 70% of what we ultimately require already flight-proven too.   This combination reduces programmatic risk massively.

And there is still time for NASA to change.   Most of the work they have done on Ares-I & Ares-V so far is transferable.   The Ares-I U/S work transfers very nicely over to the Jupiter EDS, the J-2X work ditto.   The avionics work is all usable. Really, only the 5-segment booster work is unrequired - although Jupiter still offers the potential to have Ares-V *as well*.   Jupiter costs no more than Ares-I to field, yet the RS-68, J-2X and EDS are all certified by Jupiter and that makes Jupiter a much closer 'partner' vehicle to evolve from if NASA does get the money to build Ares-V next decade.   If NASA doesn't get the money (very likely in the present political and economic climate) , then Jupiter is still capable of getting us back to the moon.   Ares-I on the other hand has no chance in hell without Ares-V.

Why not take a chance to be persuaded?

Take this information back to your engineer friend and see what he says then.   There are quite a few more arguments for the change which I haven't gone into, but can if you need.

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

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RE: "DIRECT" Goes Live
« Reply #1948 on: 05/10/2007 06:18 PM »
I see what you are saying Ross.

Do you think that Ares 1 will work if it is build?

And can you explan to me why NASA should defend Ares 1 so much if it didn't work?

What is you personal guess of the chances of NASA changing to DIRECT ? Honestly?

I think that if you belive so strongly in DIRECT you should contact the right people and do it real QUICKLY - I mean senators, poiliticians and my be even the White House.

Kasper

Offline Norm Hartnett

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Re: "DIRECT" Goes Live
« Reply #1949 on: 05/10/2007 06:35 PM »
I think it was extraordinary that Dr. Stanley took the time to evaluate DIRECT v1 and I think it is indicative of how seriously DIRECT is being taken in some quarters. I believe that the ATK web page should be taken as a complement although I find the timing rather interesting.

I would suggest that mention should be made in the DIRECT v2 proposal of Dr. Stanley’s findings and that they are fully addressed in DIRECT v2. It might even be wise to reference the ATK page and affirm that the issues raised there have been addressed within the new proposal. This is one of the reasons that I suggested changing the name of the proposal, to avoid any confusion.
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Offline DMeader

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RE: "DIRECT" Goes Live
« Reply #1950 on: 05/10/2007 06:52 PM »
Quote
kraisee - 10/5/2007  1:43 PM
As for separate Cargo and Crew, that is only partially the story.   Mixing cargo and crew was ideally suited to accomplishing the Apollo missions.   It was also absolutely essential to accomplishing the Apollo/Soyuz rendezvous.   Shuttle had to have that capability to install a suitable docking module at MIR.   Every Gemini mission flew with a module on the rear containing useful "payload" cargo which was not part of the spacecraft itself.

I was under the impression that equipment needed to complete the goals of a mission was not considered "cargo".  Therefore, consumables in the Gemini adapter section, the ASTP docking module, and the Apollo LM,  not cargo.  Beans, blankets, toilet paper and t-shirts to the ISS, cargo. Correct? If we are going to make the "no cargo with crew" argument, we have to keep the  definitions consistent.

Offline sandrot

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RE: "DIRECT" Goes Live
« Reply #1951 on: 05/10/2007 07:05 PM »
Quote
kraisee - 10/5/2007  1:43 PM

For CEV, if any hardware needs to be launched it is going to require lifting on a second launch vehicle becasue it can not be lifted with the CEV on the Ares-I.   For example for future Hubble Servicing Missions, a payload module will have to be launched on something like a Delta-IV or Atlas-V, costing at least $150m for that flight.   Then the crew will have to rendezvous & dock with that module, and then rendezvous & dock with the Hubble.   Is this easier, safer or more logical than bringing up your tools with you when you fly the first time - especially when your flight costs are only $10m different from Ares-I - but you saved $20 billion by not having to develop Ares-V as well?


Or (my fingers crossed) we can launch mission packages with Falcon 9 at a lower $$$ per flight.
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Offline SolarPowered

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Re: "DIRECT" Goes Live
« Reply #1952 on: 05/10/2007 07:15 PM »
My understanding of the origin of the "no crew with cargo" concept is that it comes from three basic points:

1.  It's really, really dumb to risk the lives of seven astronauts to launch a satellite that could just as well be launched by an unmanned launcher,

2.  It's kind of stupid and wasteful to keep launching this huge "truck" (Shuttle) into space when all it's ever re-entering with is the crew, and

3.  There are basically three categories of things that you are sending into orbit:
     i.  Human beings
     ii.  Expensive cargo, like Hubble telescopes and ISS modules, and
     iii.  Cheap cargo, like food, water, and propellents.
With category (i), you go to extreme lengths to reduce risk of loss.  For categories (ii) and (iii), you can make cost vs. risk tradeoffs.

None of these points argues for never launching cargo along with a crew.  Indeed, it would appear to often be safer to launch the cargo that is needed to carry out a mission along with the crew, avoiding an unnecessary rendezvous.

On the other hand, these points do argue for designing a vehicle for crew launch that is as safe as you can possibly make it, while possibly having other launch vehicles for launching things like moon or Mars mission stacks that make tradeoffs for greater launch capability at the expense of higher risk.  There is no reason why said crew-launch vehicle can't be designed with the capacity to carry more than just the crew.

Offline kraisee

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RE: "DIRECT" Goes Live
« Reply #1953 on: 05/10/2007 07:39 PM »
Quote
wiinum - 10/5/2007  2:18 PM

I see what you are saying Ross.

Do you think that Ares 1 will work if it is build?

And can you explan to me why NASA should defend Ares 1 so much if it didn't work?

What is you personal guess of the chances of NASA changing to DIRECT ? Honestly?

I think that if you belive so strongly in DIRECT you should contact the right people and do it real QUICKLY - I mean senators, poiliticians and my be even the White House.

Kasper

I think Ares-I could be integrated into a lunar program ultimately, but I believe that far too much money will be spent on it for the performance it will offer, and it will only serve to tie the hands of every other aspect of the program.

Already, because the CEV has to be so small, it can't perform the Lunar Orbit Injection burn to stabilise the CEV/LSAM into a lunar orbit before the crew descends.   This job has had to be passed to the LSAM Descent stage instead - which means it has heavier fuel tanks which have to be taken all the way to the lunar surface.   This is an horrifically wasteful use of the lunar downmass performance - which is what this is all about ultimately.   This change alone has cost about 2 tons of useful performance to the lunar surface on every mission.   That's a LOT of waste and I'm darn sure a lot of people could come up with far better uses for 2 tons of extra performance.   But Ares-I eliminates all chances of ever doing it a different way - because it simply can't lift a heavier (read: "more capable" in this context) CEV.

There are other issues with Ares-I, but that's a critical one "they" don't want to admit to.

Ross.
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Offline Wolverine

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RE: "DIRECT" Goes Live
« Reply #1954 on: 05/10/2007 07:59 PM »
Quote
kraisee - 10/5/2007  3:39 PM

Quote
wiinum - 10/5/2007  2:18 PM

I see what you are saying Ross.

Do you think that Ares 1 will work if it is build?

And can you explan to me why NASA should defend Ares 1 so much if it didn't work?

What is you personal guess of the chances of NASA changing to DIRECT ? Honestly?

I think that if you belive so strongly in DIRECT you should contact the right people and do it real QUICKLY - I mean senators, poiliticians and my be even the White House.

Kasper

I think Ares-I could be integrated into a lunar program ultimately, but I believe that far too much money will be spent on it for the performance it will offer, and it will only serve to tie the hands of every other aspect of the program.

Already, because the CEV has to be so small, it can't perform the Lunar Orbit Injection burn to stabilise the CEV/LSAM into a lunar orbit before the crew descends.   This job has had to be passed to the LSAM Descent stage instead - which means it has heavier fuel tanks which have to be taken all the way to the lunar surface.   This is an horrifically wasteful use of the lunar downmass performance - which is what this is all about ultimately.   This change alone has cost about 2 tons of useful performance to the lunar surface on every mission.   That's a LOT of waste and I'm darn sure a lot of people could come up with far better uses for 2 tons of extra performance.   But Ares-I eliminates all chances of ever doing it a different way - because it simply can't lift a heavier (read: "more capable" in this context) CEV.

There are other issues with Ares-I, but that's a critical one "they" don't want to admit to.

Ross.

Ross, you have a great and knowledgeable grasp of this.  Kudos!

Offline Jim

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RE: "DIRECT" Goes Live
« Reply #1955 on: 05/10/2007 08:20 PM »
Quote
kraisee - 10/5/2007  3:39 PM

Already, because the CEV has to be so small, it can't perform the Lunar Orbit Injection burn to stabilise the CEV/LSAM into a lunar orbit before the crew descends.   This job has had to be passed to the LSAM Descent stage instead - which means it has heavier fuel tanks which have to be taken all the way to the lunar surface.   This is an horrifically wasteful use of the lunar downmass performance - which is what this is all about ultimately.   This change alone has cost about 2 tons of useful performance to the lunar surface on every mission.   That's a LOT of waste and I'm darn sure a lot of people could come up with far better uses for 2 tons of extra performance.   But Ares-I eliminates all chances of ever doing it a different way - because it simply can't lift a heavier (read: "more capable" in this context) CEV.

There are other issues with Ares-I, but that's a critical one "they" don't want to admit to.

Ross.

Ross,

Don't use that arguement.  It will be shot down quickly.  The intend was to always have the LSAM perform the LOI burn.  This was to allow for sortie LSAM missions without the CEV.  The LSAM would have to do the same maneuver by itself anyway.  The CEV propellant tanks were never sized for this nor was the engine thrust level.  That is why the CEV engine is sized around 5-15k lb thrust because it was never intended to be as big as the Apollo SPS.  Look at the ESAS.  Big engine like that is not needed for ISS or MTV mission neither.   Use of an EELV would not have changed this.

Offline kraisee

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Re: "DIRECT" Goes Live
« Reply #1956 on: 05/10/2007 08:38 PM »
Actually that misses the point that a cargo-only LSAM does not require braking of the CEV mass into LLO on top of the LSAM mass.   The dV requirements are much lower.   Optimizing for crew use is more worthwhile because it's the most common configuration we're going to fly.   For cargo-only flights, you "suck up" the 800kg or so of lost payload performance which you suffer from in that configuration (you're not braking the CEV and all it's propellant, and you've started with a smaller cargo than the Ascent Stage mass by doing a one-launch, no crew, flight anyhow).

The analysis actually shows that the difference is massively in favour of making CEV perform the LOI whenever possible.

Ross.
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Offline Chris Bergin

RE: "DIRECT" Goes Live
« Reply #1957 on: 05/11/2007 12:25 AM »
Thread locked, as this concept moves into Direct v2: http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=7868&start=1

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