Author Topic: DIRECT v3.0 - Thread 1  (Read 1228117 times)

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #1560 on: 06/24/2009 09:19 pm »
Which reminds me -- I just heard that NASA has gone and produced a new "Analysis" into DIRECT 3.0 in which the same old BS is apparently doing the rounds -- yet again.

While I've only heard a few details, they're b*tching about the pmf being something which NASA is unable to build (yeah, we know that, which is precisely why we want Industry to handle that element because of their much greater experience instead, duh!).

And they're trying to depict the architecture as only being able to send a 29mT lander through TLI.


I find these claims to be quite remarkable when you consider that ESAS itself included a configuration rather similar to Jupiter-246 (LV-25 + EDS S1A = Jupiter-234, which uses just three SSME's on the Core (4 is much better) and four RL-60-class engines on the EDS).   Yet, even with less performance than the DIRECT configurations this vehicle is sufficient, in 2-launch profile, to comfortably exceed CxP's current performance requirements of 71.1mT thru TLI.   In fact, ESAS claims the lower-power configuration can actually send 74.3mT thru TLI.   See attached.

I find it just "amazing" how, suddenly, this sort of vehicle magically "loses" about 15 tons of performance as soon as it threatens the Ares systems.   Just amazing, that, eh?

Seems the BS continues to be shoveled to anyone willing to swallow it.   Jeez.

Ross.
« Last Edit: 06/24/2009 09:22 pm by kraisee »
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Offline butters

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Re: DIRECT v3.0 - Thread 1
« Reply #1561 on: 06/24/2009 09:21 pm »
Since the Direct baseline architecture is 2 J-246's, with two JUS's, one fully fueled, one fueled just enough for LEO of CEV/LSAM.

Could both JUS's be partially fueled, and have a rendevous in LE1 or LLO?  You have to expend two anyway, couldn't the docking procedures be simplified that way? 

Also, in that vein, if a Centaur or D4US (are they the same?  Don't know much about them, if they are two terms for the same upper stage or not) can take Orion around the moon for an Apollo 8 type flyby, could one be used to take the LSAM there too, again for a LE1 or LLO rendevous?
I know fueled LSAM is heavier than Orion, so I don't know.
But now I'm curious.

You've just stumbled upon what, in my view, is the biggest weakness of the EOR-LOR mission profile.  Try as you might, you can't distribute the total payload evenly among multiple identical launch vehicles without on-orbit propellant transfer. 

If the DIRECT ethos can be distilled to "one kind of vehicle launched multiple times", then EOR-LOR is a questionable mission profile, a holdover from the 1.5-launch approach that doesn't make as much sense in a 2-launch architecture.

The DIRECT 3.0 architecture calls for one launch of about 100 mT and another of about 70 mT.  It's not really a 2-launch architecture, hence the heavily-offloaded J-24x CLV and the barely-viable J-130 CLV alternative.

With LOR-LOR, L1R-L1R, or (especially) L2R-L2R, the CEV and LSAM each have their own upper stage for TLI and insert themselves into rendezvous orbit separately.

The key thing to understand is that the LSAM actually masses less than the CEV when it separates for lunar descent.  The LSAM is only heavier than the CEV at liftoff because it does the LOI burn for itself and the attached CEV.

Remember, the Apollo CSM was much more massive than the LM, mostly because the CSM did the LOI burn for the combined mass.  Whichever spacecraft does LOI becomes much bigger than the other.

But if both spacecraft do LOI and their rendezvous masses are similar, then their TLI masses are similar, and therefore their LEO requirements are similar, and they can be lofted on identical launch vehicles.

With LOR-LOR, the rendezvous mass of the CEV is notably higher than the LSAM, because now it has to do its own LOI instead of relying on LSAM.  So the CEV drives launch vehicle requirements.

But with L1R-L1R or (especially) L2R-L2R, the CEV takes a cheaper round trip to the rim of the moon's gravity well.  This increases LSAM mass, but it decreases CEV mass by a much greater amount, and the combined effect helps even out the rendezvous masses.

With L2R-L2R, CEV liftoff mass is roughly the same as with EOR-LOR (depending on trajectory), even though it does its own LOI, and LSAM liftoff mass is dramatically reduced to about 20 mT, not much less than the CEV.

Either J-130 or Not Shuttle-C could lift a 25 mT spacecraft with a 45 mT EDS to put it through TLI.  With a 2-launch L2R-L2R profile, this is enough for the baseline lunar mission.

Additionally, this same 5m Centaur-derived EDS could double as the new upper stage for EELV, and it would only make sense for ULA to lead the development, rather than NASA/MSFC.

This mission profile allows for the development of a significantly smaller upper stage that's much more versatile and would see higher flight rates.  It also allows for the development of a significantly smaller LSAM descent stage with a lower center of gravity for landing stability.

The number of SSMEs expended per mission is reduced to six, global access to the lunar surface without expensive plane-change maneuvers, and global communications relay to earth via CEV at EML2.

If you try to replicate a 1.5-launch EOR-LOR architecture with one kind of launch vehicle, the closest you can get is DIRECT.  But for a true 2-launch architecture, L2R-L2R makes more sense.
« Last Edit: 06/24/2009 09:28 pm by butters »

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #1562 on: 06/24/2009 09:25 pm »
The Direct team mentioned that someone had verified Direct's claims to performance with 1%.  Will they ever publish the review\study before the Commission is finished in Auguest?

I don't know.   The team responsible are trying to get their Exec's to sign-off on it.   I guess we will only know when/if they decide to get into the ring and fight for what they want, or not.

Ross.
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Offline gladiator1332

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Re: DIRECT v3.0 - Thread 1
« Reply #1563 on: 06/24/2009 09:27 pm »
Which reminds me -- I just heard that NASA has gone and produced a new "Analysis" into DIRECT 3.0 in which the same old BS is apparently doing the rounds -- yet again.

While I've only heard a few details, they're b*tching about the pmf being something which NASA is unable to build (yeah, we know that, which is precisely why we want Industry to handle that element because of their much greater experience instead, duh!).

And they're trying to depict the architecture as only being able to send a 29mT lander through TLI.


I find these claims to be quite remarkable when you consider that ESAS itself included a configuration rather similar to Jupiter-246 (LV-25 + EDS S1A = Jupiter-234, which uses just three SSME's on the Core (4 is much better) and four RL-60-class engines on the EDS).   Yet, even with less performance than the DIRECT configurations this vehicle is sufficient, in 2-launch profile, to comfortably exceed CxP's current performance requirements of 71.1mT thru TLI.   In fact, ESAS claims the lower-power configuration can actually send 74.3mT thru TLI.   See attached.

I find it just "amazing" how, suddenly, this sort of vehicle magically "loses" about 15 tons of performance as soon as it threatens the Ares systems.   Just amazing, that, eh?

Seems the BS continues to be shoveled to anyone willing to swallow it.   Jeez.

Ross.

Sad part is, they're NASA, they can get away with it. If you try to argue they "fudged" the numbers in Ares' favor, then you guys look like your trying to start conspiracy theories.

Let's just hope the panel can see through these types of things. But I have the pessimistic feeling they won't.

The funny part is, if Jupiter is chosen, we get to see NASA say, "WOW! We just found 15 extra tons of performance! Were did that come from?!?!?"  ::)

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #1564 on: 06/24/2009 09:27 pm »
Okay, to lighten the mood...   Who's seen this in Today's Florida Today -- Editorial Cartoons" section?




Its just *begging* to have a couple of photo re-touches...   Adding names to the back of shirts etc...

Ross.
« Last Edit: 06/24/2009 09:31 pm by kraisee »
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Offline clongton

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Re: DIRECT v3.0 - Thread 1
« Reply #1565 on: 06/24/2009 09:30 pm »
Seen this in Today's Florida Today -- Editorial Cartoons" section?


Its just *begging* to have a couple of photo re-touches...   Adding names to the back of shirts etc...

Ross.

Ah, that is beautiful!
« Last Edit: 06/24/2009 09:30 pm by clongton »
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline PaulL

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Re: DIRECT v3.0 - Thread 1
« Reply #1566 on: 06/24/2009 09:31 pm »
Ross, would it help if the structure of the Jupiter rocket was lighter/optimized for the J-130 instead of the J-246?  What I am thinking here is designing a lighter Jupiter core able to be fitted with 2 optional vertical support beams for the J-246 version. These support beams, which would be bolted on the core in the VAB, would be placed 90 degrees from the SRBs. The beams would be able to support the extra mass of the US on top of the LO2 tank and the extra compression on the LH2 tank caused by the 4th SSME.

PaulL 

As soon as you optimize for the J-130 you create a *new* launch vehicle and the cost savings for DIRECT go away. Even though the 2 LVs (J-130 and J-246) would look very similar, they would in fact be 2 different vehicles and we will have lost the foundational fundamental fo DIRECT: build ONE launch vehicle able to do both jobs.

That's actually one of our major fears; that after NASA adopts DIRECT, they will optimize the J-130, as you suggest. We do NOT advocate that. It's spending money (a lot of money) for nothing.

I am not looking here at developing 2 Jupiter cores. What I am suggesting is to develop a lighther core which could be used with 3 SSME engines and an engine plug for the J-130. The same core could be used with 4 SSME engines, two vertical support beams and an upper stage to create a J-24x.  The idea here is to permit the use of the J-130 for the lunar CEV+LSAM flight. The EDS flight on a J-24x is not the problem here as it has plenty of margin compared to the J-130 CLV flight.

PaulL

Offline gladiator1332

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Re: DIRECT v3.0 - Thread 1
« Reply #1567 on: 06/24/2009 09:31 pm »
Okay, to lighten the mood...   Who's seen this in Today's Florida Today -- Editorial Cartoons" section?




Its just *begging* to have a couple of photo re-touches...   Adding names to the back of shirts etc...

Ross.

That just made my day.  :)

Offline Drapper23

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Re: DIRECT v3.0 - Thread 1
« Reply #1568 on: 06/24/2009 09:36 pm »
Maybe Buzz Aldrin should bring up this new NASA Direct 3 analysis & demonstate to the Augustine Committee why it is totally inaccurate.

Offline JAFO

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Re: DIRECT v3.0 - Thread 1
« Reply #1569 on: 06/24/2009 09:37 pm »

Call me strange or peculiar (and some might), but even though I respect the old guy for his accomplishments before I was born, I'm still going to hire the guy who has successfully built the 757, 767, 777 and now the 787, not the guy who's last involvement in this business was on the 707.

Ross.

Ross,

Based on the latest news from Boeing, I'd compare the 787 to Ares I and Jupiter to a good, solid 756/777.


Respectfully,
« Last Edit: 06/24/2009 09:37 pm by Envious »
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Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #1570 on: 06/24/2009 09:40 pm »
I am not looking here at developing 2 Jupiter cores. What I am suggesting is to develop a lighther core which could be used with 3 SSME engines and an engine plug for the J-130. The same core could be used with 4 SSME engines, two vertical support beams and an upper stage to create a J-24x.  The idea here is to permit the use of the J-130 for the lunar CEV+LSAM flight. The EDS flight on a J-24x is not the problem here as it has plenty of margin compared to the J-130 CLV flight.

Paul, its not quite as simple as that :)   (is it ever?)

Adding hardware to a stage designed for one thing, in order to make it do another is not as easy as it might first appear.   What you're talking about there is moving some pretty massive loads into a separate structure operating in parallel to the regular one.   And that second structure doesn't have the weight benefits of being a pressure vessel, so it must be mechanically strong all on its own -- and that means its not likely to be light-weight.

The most critical factor in any 2-launch Lunar mission architecture is maximizing the amount of propellant lofted to LEO for the TLI.   Anything which might reduce that capacity, reduces Lunar performance by a factor of more than 3, so if you lose just 300kg of TLI propellant to LEO, the effect is actually that you lose about 1 full ton of payload performance actually being sent to the moon.

I would suggest that maximizing TLI propellant lift capacity is probably 90% of the entire ball game.

So the critical factor must always be to heavily optimize the system for the EDS role and only then begin to examine what else the same hardware can do in other situations.

And besides, performance-wise, the J-130/J-246 architecture works already.   The concerns are now primarily about the procedures which are necessary to make it as safe as can be.


Of course, Propellant Depot's change the whole dynamic, but it is not wise to include such unproven technologies in the critical path to early success.

Ross.
« Last Edit: 06/24/2009 09:44 pm by kraisee »
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Offline marsavian

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Re: DIRECT v3.0 - Thread 1
« Reply #1571 on: 06/24/2009 09:44 pm »
Which reminds me -- I just heard that NASA has gone and produced a new "Analysis" into DIRECT 3.0 in which the same old BS is apparently doing the rounds -- yet again.

While I've only heard a few details, they're b*tching about the pmf being something which NASA is unable to build (yeah, we know that, which is precisely why we want Industry to handle that element because of their much greater experience instead, duh!).

And they're trying to depict the architecture as only being able to send a 29mT lander through TLI.


I find these claims to be quite remarkable when you consider that ESAS itself included a configuration rather similar to Jupiter-246 (LV-25 + EDS S1A = Jupiter-234, which uses just three SSME's on the Core (4 is much better) and four RL-60-class engines on the EDS).   Yet, even with less performance than the DIRECT configurations this vehicle is sufficient, in 2-launch profile, to comfortably exceed CxP's current performance requirements of 71.1mT thru TLI.   In fact, ESAS claims the lower-power configuration can actually send 74.3mT thru TLI.   See attached.

I find it just "amazing" how, suddenly, this sort of vehicle magically "loses" about 15 tons of performance as soon as it threatens the Ares systems.   Just amazing, that, eh?

Seems the BS continues to be shoveled to anyone willing to swallow it.   Jeez.

Ross.

None of the ESAS TLI claims have proved accurate including Ares V which has had to be enlarged considerably from the SSME Classic to what they have now and it still comes up short so you can't rely on ESAS. Perhaps what you should also have done for argument's sake was take NASA's pmf figure and produced a DIRECT version that could have done the mission with it, 2 * Ares V Classics (with one J2-X) with a J-130H/J-140H ISS version ?  It could have been added as a rebuttal appendix. NASA is the encumbent, they get to chose the rules of the game and not meeting those rules for whatever valid reasons may just be counted as an automatic fail in this game as Mars is Wet is claiming. I'm not sure you guys are grasping this basic fact.
« Last Edit: 06/24/2009 09:45 pm by marsavian »

Offline robertross

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Re: DIRECT v3.0 - Thread 1
« Reply #1572 on: 06/24/2009 09:50 pm »

Seems the BS continues to be shoveled to anyone willing to swallow it.   Jeez.

Ross.

Sad part is, they're NASA, they can get away with it. If you try to argue they "fudged" the numbers in Ares' favor, then you guys look like your trying to start conspiracy theories.

Let's just hope the panel can see through these types of things. But I have the pessimistic feeling they won't.

The funny part is, if Jupiter is chosen, we get to see NASA say, "WOW! We just found 15 extra tons of performance! Were did that come from?!?!?"  ::)

Answering to both:

Well if the Augustine panel requests additional info, or a one-on-one meeting...you can flat out tell them THIS is what is now taking place, the same way it happen last time, which brought about the rebuttal. You can set them straight, because you don't REALLY need to impress NASA at the moment, you need to impress the panel.

And as I pointed out in that thread, I saw the presentation for the second time, and it was still great. We  have all been over-analyzing, myself included. Still a little weak on the lunar architecture though and too heavy on science, which begs the question if there was some purpose to that?

Offline Drapper23

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Re: DIRECT v3.0 - Thread 1
« Reply #1573 on: 06/24/2009 10:00 pm »
Ross or Chuck, Does the Augustine Committee allow you to submit additional of follow-up data? In other words, can you just voluntarily give them additional data or request a follow-up meeting?
« Last Edit: 06/24/2009 10:07 pm by Drapper23 »

Offline gladiator1332

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Re: DIRECT v3.0 - Thread 1
« Reply #1574 on: 06/24/2009 10:18 pm »
I agree. But until this data is made public, or at least shows itself in some documented form, there is no way to alert the panel. Telling them you heard water-cooler talk that NASA did another review of Direct is not going to help.

You need to have the documents from NASA and the ESAS documents right there to show them side by side, and ask where the missing 15 tons went.

Offline fotoguzzi

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Re: DIRECT v3.0 - Thread 1
« Reply #1575 on: 06/24/2009 10:28 pm »
Jeez.
too heavy on science, which begs the question if there was some purpose to that? (robertross said this (I missed with the scissors.))
I think it is clear that the presentation was a rushed 1/2 hour version of an hour presentation that was cut to 20 minutes right at the last second.  A lot of good points were made, however, in that limited time.
My other rocket is a DIRECT Project 2

Offline butters

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Re: DIRECT v3.0 - Thread 1
« Reply #1576 on: 06/24/2009 10:30 pm »
It really seems like a DIRECT/ULA alliance would be the best way to counter NASA's FUD about upper stage pmf.

The alliance should propose a common upper stage (5m Centaur with 45 mT GLOW) to be used on Atlas/Delta (expended after ascent) and Jupiter (fueled EDS).

With this common upper stage as the EDS, J-130 puts a 25 mT spacecraft through TLI.  With L2 rendezvous, both CEV and LSAM are less than 25 mT through TLI.

ULA needs a new upper stage to get the most out of their existing first stages.  DIRECT needs a new upper stage to get out of earth orbit.  NASA can't develop these upper stages, but ULA can.

So tell ULA that if NASA chooses DIRECT for lunar missions, they'll get funding to develop the 5m Centaur they've been wanting, but they need to convince NASA that it doesn't violate the laws of physics.

Offline robertross

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Re: DIRECT v3.0 - Thread 1
« Reply #1577 on: 06/24/2009 10:34 pm »
Jeez.
too heavy on science, which begs the question if there was some purpose to that? (robertross said this (I missed with the scissors.))
I think it is clear that the presentation was a rushed 1/2 hour version of an hour presentation that was cut to 20 minutes right at the last second.  A lot of good points were made, however, in that limited time.

I was only wondering about the mindset going in:

If you know the WH is more interested in science, servicing the ISS, and a Mars architecture some day, then they hit the right notes. Did they have prior knowledge? Probably not, but one never knows. The Direct team has been pushing the moon since DAY 1, why would you 'seemingly' abandon it in front of the panel???

That's my mind thinking in weird ways.

Offline guru

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Re: DIRECT v3.0 - Thread 1
« Reply #1578 on: 06/24/2009 10:38 pm »

None of the ESAS TLI claims have proved accurate including Ares V which has had to be enlarged considerably from the SSME Classic to what they have now and it still comes up short so you can't rely on ESAS.

Ares V classic wasn't dumped because of a performance deficit (it probably would have worked pretty well), it was dumped on a supposed cost of engine basis.  So, NASA picked less efficient engines, and then wondered why making Ares V bigger and bigger wasn't having the desired effect... it didn't help any that upgrades to the RS-68 weren't hitting their performance targets (per Ross statements), or that the core stage was too heavy for the crawlerway.

Ares I on the other hand, was dumped because the upper stage engine supposedly couldn't be made to air start, so they picked a less efficient engine, made the first stage bigger, and wondered why making the thing bigger wasn't having the desired effect... it didn't help any that the J-2X design was having a hard time hitting its performance targets (again, per Ross' statements), or that the first stage was too long to avoid resonance with the upper stage.

I don't know for sure what the real (as opposed to supposed) motivation was for dumping Space Shuttle Main Engines, Space Shuttle External Tanks (or at least very close approximations), and Space Shuttle SRBs from vehicles that were supposed to be Space Shuttle derived, but replacing them with unbuilt (hence needed development), untested (hence unknown performance), and unproven (hence unknown reliability) hardware sure has made the whole process a lot more complicated

Offline butters

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Re: DIRECT v3.0 - Thread 1
« Reply #1579 on: 06/24/2009 10:54 pm »
Ares V classic wasn't dumped because of a performance deficit (it probably would have worked pretty well), it was dumped on a supposed cost of engine basis.  So, NASA picked less efficient engines, and then wondered why making Ares V bigger and bigger wasn't having the desired effect... it didn't help any that upgrades to the RS-68 weren't hitting their performance targets (per Ross statements), or that the core stage was too heavy for the crawlerway.

Ares I on the other hand, was dumped because the upper stage engine supposedly couldn't be made to air start, so they picked a less efficient engine, made the first stage bigger, and wondered why making the thing bigger wasn't having the desired effect... it didn't help any that the J-2X design was having a hard time hitting its performance targets (again, per Ross' statements), or that the first stage was too long to avoid resonance with the upper stage.

I don't know for sure what the real (as opposed to supposed) motivation was for dumping Space Shuttle Main Engines, Space Shuttle External Tanks (or at least very close approximations), and Space Shuttle SRBs from vehicles that were supposed to be Space Shuttle derived, but replacing them with unbuilt (hence needed development), untested (hence unknown performance), and unproven (hence unknown reliability) hardware sure has made the whole process a lot more complicated

That's a pretty concise summary of the situation.  As I've argued before, RS-68 and J-2X are disappointing engines whose development has come at the cost of fielding much more promising engines such as RS-84 and RL-60.  Delta IV will probably be the first and last vehicle to use RS-68, and J-2X (aka Vulcain reinvented for the NIH-afflicted) will probably never fly.

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