Author Topic: DIRECT v3.0 - Thread 1  (Read 1228323 times)

Offline MP99

Re: DIRECT v3.0 - Thread 1
« Reply #660 on: 06/08/2009 09:02 pm »
Useable Post-Ascent propellant for J-246 is 99,896 kg. LEO Payload for D-IVH is 22,560 kg. I'd say about 4 or 5. Numbers listed are for 130nmi, 29 deg and 220nmi, 28.7 deg circular orbits for the Jupiter and Delta respectively, so take that into account.

On this same vein...
I'm sure this has already been explored by the direct team, but I am curious.
Currently, the base line for a moon shot is 2 J-246's.  They are working on launching the CSM and LSAM on a J-130, so they only need one JUS for the mission.  Makes sense.  Then, with a propellent depot, Direct can launch the whole CSM/LSAM/JUS (unfueled) stack on a single J-246, for rendezvous with the depot, fueling up, and going to the moon.

But, before there is a dept, could you launch the depot-dependent stack, and have it rendezvous with a fuel tank launched on a J-130 with an OMS sytem.  This way, your docking is a little simpler, as the stack stays in tack, and you are just doing a fueling docking.  Then ullage motors de-orbit the tank and the stack heads off to TLI.

<snipped>

In effect, the J-130 would launch a sinlge use "propellent depot", which would basically be a JUS with an OMS, rear docking ring, ullage motor, and less engines.


Hmm, try it the other way around.

Start with the existing 2x J-246 architecture. The downside of this (the attraction of using J-130 CLV) is that ~15mT of CLV launch capacity remains unused because of limited fuel in the EDS. This is fantastic margin for the early flights.

However, once the standard 2-launch is mature, ~15mT of extra EDS fuel would be able to fully optimise this architecture:-

1) Launch J-246 EDS. (Current plan).

2) Launch a single EELV fuel tanker with maybe 20mT of fuel, rendezvous immediately, and top up the EDS. Thru-TLI mass is now approaching 100mT.

3) Once the EDS is safely re-fuelled, launch a fully-loaded J-246, which can now be pushed through TLI with loads of margin to spare.



3a) This can also be used to augment a single-Jupiter cargo mission. A 20mT fuel boost would give a substantial increase in single-Jupiter thru-TLI mass. (Not the full ~10mT, due to the mass of PT hardware, and not being able to fly a direct-injection profile).



Think of it this way - the EELV lifts a "mini-PD" that has to "loiter" only long enough to rendezvous and transfer. There should be enough extra fuel left over to allow a long EDS loiter period. This would really relax the requirement to launch CLV shortly after CaLV, and allows a long window for the EELV flight.

Residual fuel in the mini-PD could be used for longer duration PD tests.

My thinking is this would make a superb milestone along the way to a full PD and phase 3.

Call it phase 2.5.

cheers, Martin


Edit: actually, presuming the mini-PD is predecessor to a fully-fledged PD, swap (1) & (2), and launch the mini-PD first. Don't launch EDS until the mini-PD checks out OK.

Much less risky than a full PD for early missions, and even if PT fails, crew & Orion / Altair / Lunar payload (most expensive elements of the mission) are still safely on the ground. You might even be able to save the EDS with a second mini-PD launch.
« Last Edit: 06/08/2009 09:15 pm by MP99 »

Offline adamsmith

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Re: DIRECT v3.0 - Thread 1
« Reply #661 on: 06/08/2009 09:04 pm »

1.  reply to 1: Maybe

2.  reply to 2: Correct that is why this is a phase 4 item that NASA does not have to pay for until proven by events.

3.  Why Falcon 9 first stage?  It is already planned to be a booster to Falcon 9 heavy in an arrangement similar to the Jupiter Core.


1.  Not maybe, it is too many

2. NASA would still have to pay for the mods to the F9 which would be like a new vehicle.  It isn't plug and play. 

3.  No they are not in a similar arrangment.  The SRB's lift from the top and liquid boosters lift from the bottom.     But also,  Atlas V or Delta IV cores can be used as boosters. Delta IV has demonstrated it. 

So again, why F9?  Atlas V or Delta IV cores exist and are operating.



Okay,  Let me remind you that I was speculating in good  faith and I am willing to wait for the passage of decades to find out the truth.  I remember exactly where I was on July 20, 1969 when Neil armstrong said: Houston, Tranquility Base here... the Eagle has landed.  I will wait another 40 years, if necessary.

reply to 1:  I agree to disagree.

reply to 2: You are correct.  but whatever liquid fueled booster to choose from, cheaper to use one that is proven.

Reply to 3 and new point:  Better a cluster of engines than a single one.  Safer liquid than solid.

IMHO

Stan

Offline Bill White

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Re: DIRECT v3.0 - Thread 1
« Reply #662 on: 06/08/2009 09:15 pm »
FWIW,

I am impressed by the ability to Direct 3.0 to function well with or without propellant depots, which is a vital characteristic (IMHO) as we do not know how long it shall take to deploy propellant depots.

As soon as depots come on-line, Direct 3.0 transitions and begins to realize substantial leverage and yet in the meantime NASA can still perform interesting and useful missions beyond LEO as we await depot development and deployment.

And of course, the Direct 3.0 budget charts leave money for depot work, something ESAS does not.

In contrast, an all EELV/COTS approach leaves us trapped in LEO until depots come on-line.
EML architectures should be seen as ratchet opportunities

Offline adamsmith

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Re: DIRECT v3.0 - Thread 1
« Reply #663 on: 06/08/2009 09:39 pm »
FWIW,

I am impressed by the ability to Direct 3.0 to function well with or without propellant depots, which is a vital characteristic (IMHO) as we do not know how long it shall take to deploy propellant depots.

As soon as depots come on-line, Direct 3.0 transitions and begins to realize substantial leverage and yet in the meantime NASA can still perform interesting and useful missions beyond LEO as we await depot development and deployment.

And of course, the Direct 3.0 budget charts leave money for depot work, something ESAS does not.

In contrast, an all EELV/COTS approach leaves us trapped in LEO until depots come on-line.

I think you've got it!

Stan

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #664 on: 06/08/2009 09:40 pm »
I am impressed by the ability to Direct 3.0 to function well with or without propellant depots, which is a vital characteristic (IMHO) as we do not know how long it shall take to deploy propellant depots.

Exactly Bill, you've got it in one.

Cryogenic Propellant Depots are a technology which isn't mature yet and should not be included the critical path to success.

You must implement an architecture which can work without them and can still achieve all your goals.

But then, if/when you do finally get the technology operational, then you can begin using it to expand your horizons considerably.

Ross.
« Last Edit: 06/08/2009 09:41 pm by kraisee »
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Offline Jim

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Re: DIRECT v3.0 - Thread 1
« Reply #665 on: 06/08/2009 10:19 pm »

reply to 1:  I agree to disagree.


I know it is too many, it is not an opinion

Offline MP99

Re: DIRECT v3.0 - Thread 1
« Reply #666 on: 06/08/2009 10:40 pm »
Ross,

From the MLAS Thread about the problems with the current Ares I LAS:

Quote
I got a little more info on this.   The concern is primarily based around the potential of a large SRB exploding.   It's a small risk, but still exists.

I understand that one of the more likely failure modes in this class of "exploding SRB's" would be if a fairly large chunk of propellant ever came away inside the booster during flight and blocked the nozzle exit -- the resulting overpressure inside the booster would make for a very spectacular explosion with lots of heavy steel case fragments flying in every direction -- potentially some towards the Orion.
<snipped>


It sounds like this is an issue inherent to all vehicles using SRBs, not just Ares I. Does Jupiter protect against these failure modes? As was hinted at the end, with the extra performance Jupiter allows, I assume it would be possible to beef-up the boost protection cover that protects the vehicle during launch.


I hesitate to mention this (just way too obvious). A pressure relief valve isn't possible?

Is it just that it would be a big development programme?

cheers, Martin

Offline adamsmith

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Re: DIRECT v3.0 - Thread 1
« Reply #667 on: 06/08/2009 10:42 pm »

reply to 1:  I agree to disagree.


I know it is too many, it is not an opinion

Look, back in the 60's they were evaluating Saturn I configurations with 4 UA 1207 solid rocket boosters each one of which is loosely comparable to a Falcon 9 first stage by thrust and size.  So I think I'll stand by my earlier statement and let the passage of time decide the issue.

Stan

Offline adamsmith

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Re: DIRECT v3.0 - Thread 1
« Reply #668 on: 06/08/2009 10:45 pm »
Ross,

From the MLAS Thread about the problems with the current Ares I LAS:

Quote
I got a little more info on this.   The concern is primarily based around the potential of a large SRB exploding.   It's a small risk, but still exists.

I understand that one of the more likely failure modes in this class of "exploding SRB's" would be if a fairly large chunk of propellant ever came away inside the booster during flight and blocked the nozzle exit -- the resulting overpressure inside the booster would make for a very spectacular explosion with lots of heavy steel case fragments flying in every direction -- potentially some towards the Orion.
<snipped>


It sounds like this is an issue inherent to all vehicles using SRBs, not just Ares I. Does Jupiter protect against these failure modes? As was hinted at the end, with the extra performance Jupiter allows, I assume it would be possible to beef-up the boost protection cover that protects the vehicle during launch.


I hesitate to mention this (just way too obvious). A pressure relief valve isn't possible?

Is it just that it would be a big development programme?

cheers, Martin

I understand that back in the 60's the USAF man-rated the UA 1205 SRB by arranging to have the top blow in the event of failure.  Would this work now, given better sensors and realtime control systems?

Stan

Offline MP99

Re: DIRECT v3.0 - Thread 1
« Reply #669 on: 06/08/2009 10:50 pm »
A quick question:

Roughly how many EELV's flights would be required to top up the Depot with enough propellant for a solo J246 Lunar Mission?

(lets say our EELV is a Delta IV Heavy)

Useable Post-Ascent propellant for J-246 is 99,896 kg. LEO Payload for D-IVH is 22,560 kg. I'd say about 4 or 5. Numbers listed are for 130nmi, 29 deg and 220nmi, 28.7 deg circular orbits for the Jupiter and Delta respectively, so take that into account.

Wow, that many?
How do 4-5 D4H flights stack up against a single J130 (assuming a J130 could get into a circularized LEo orbit for dockign with teh depot) cost wise?
Seems like it still might be cheaper To just use a 2nd Jupiter.

4 or 5 assumes 100% of the EELV's payload would be usable prop delivered to the depot.  This is, of course, not even close to the case.  You still need a spacecraft, it needs its own propellant and you still need the tank and the means of transfer.  I think you'd be lucky if 2/3 of the LEO payload ended up being prop transferred to the depot.  So count more like 6 or 8.  I can't see how in the world that could be cheaper than one Jupiter.

This is why the depot-filled-by-smaller-vehicles thing still doesn't make any sense to me.


One would presume that the "Jupiter EDS" method would be the most efficient way to deliver propellant, ie double the size of the US's tanks (and maybe use an RL-60 engine, if available).

This also gives the advantage that it may be possible to recover some of the residuals (if not required to de-orbit the stage).

Maybe with an ET-style ogive H2 tank on top, it could fly with a very minimal PLF, too (my speculation).

DIRECT have also suggested that fuel tankers may fly with lower margins than a mission carrying a valuable satellite.

There will still be a hit for the fuel transfer hardware, see Jongoff's post re this.

cheers, Martin

Offline Jim

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Re: DIRECT v3.0 - Thread 1
« Reply #670 on: 06/08/2009 10:54 pm »

Look, back in the 60's they were evaluating Saturn I configurations with 4 UA 1207 solid rocket boosters each one of which is loosely comparable to a Falcon 9 first stage by thrust and size.  So I think I'll stand by my earlier statement and let the passage of time decide the issue.


Do you work in the business?   You don't need to cite history.  I didn't say it couldn't be done.  I said it would cost too much to be worth it because the changes to the vehicle and infrastructure are massive. 

Those Saturn I vehicle configurations were not chosen because of the same thing. But back then, there were deeper pockets and sky was the limit.

Rockets are not Legos.  Falcon 9 as a Direct strap on is a non starter.

a.  SRB's are a must.  Direct is a SDLV and therefore requires solids
B.  The F9 can not connect to a shuttle ET. 
C.  Spacex is not a sub contractor to others.  They do not provide hardware to others contractors. 
« Last Edit: 06/08/2009 10:56 pm by Jim »

Offline adamsmith

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Re: DIRECT v3.0 - Thread 1
« Reply #671 on: 06/08/2009 10:58 pm »

Look, back in the 60's they were evaluating Saturn I configurations with 4 UA 1207 solid rocket boosters each one of which is loosely comparable to a Falcon 9 first stage by thrust and size.  So I think I'll stand by my earlier statement and let the passage of time decide the issue.


Do you work in the business?   You don't need to cite history.  I didn't say it couldn't be done.  I said it would cost too much to be worth it because the changes to the vehicle and infrastructure are massive. 

Those Saturn I vehicle configurations were not chosen because of the same thing. But back then, there were deeper pockets and sky was the limit.

Rockets are not Legos.  Falcon 9 as a Direct strap on is a non starter.

a.  SRB's are a must.  Direct is a SDLV and therefore requires solids
B.  The F9 can not connect to a shuttle ET. 
C.  Spacex is not a sub contractor to others.  They do not provide hardware to others contractors. 

Thank you for your input.

Stan

Offline kttopdad

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Re: DIRECT v3.0 - Thread 1
« Reply #672 on: 06/08/2009 11:42 pm »
Of course, with that and unlike them, you'll have to "show your work".  That is one of the down sides of coming from outside of the establishment.


I'm confused.  Does the Ares camp in NASA not have to "show their work"?  Are they free to make any claims they want about performance, cost and schedule without the basis of the claims being open for scrutiny?
« Last Edit: 06/09/2009 02:06 am by kttopdad »
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Offline Danny Dot

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Re: DIRECT v3.0 - Thread 1
« Reply #673 on: 06/08/2009 11:53 pm »
Of course, with that and unlike them, you'll have to "show your work".  That is one of the down sides of coming from outside of the establishment.


I'm confused.  Does the Ares camp in NASA not have to "show their work"?  Are they free to make any claims they want about performance, cost and schedule without the basis of the claims not being open for scrutiny?


This about sums the situation up.  Things will hopefully change June 17th.

Danny Deger
Danny Deger

Offline Mark S

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Re: DIRECT v3.0 - Thread 1
« Reply #674 on: 06/09/2009 12:02 am »
no no no! jupiter and jupiter light. the 130 is the special case.

but I think ross is right. for this panel, technical naming convention is not a problem

I stand corrected.  makes perfect sense in a foward looking architecture, the JL is done to provide a bridge until COTSD and manratedEELVs can service most LEO demands.  Jproper is to facilitate the lunar component of the VSE. 

And later maybe a Jupiter Heavy can be whipped up from the ideas that went into Ares V, VII or X or whatever its upto now (:

So

Jupiter130  = Jupiter Light
Jupiter2XX = Jupiter


Well I hate to start this up again since it finally seems to have petered out.

But I would like to say that I am surprised and humbled that so many smart people would participate in a conversation about a little suggestion that I made two days ago.  It's been very interesting to see the different directions that people take when given a common starting point.

No more suggestions, I just want to say:  Thanks everyone!

Mark S.

Offline Lobo

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Re: DIRECT v3.0 - Thread 1
« Reply #675 on: 06/09/2009 12:10 am »
The real utility of the propellant depot is in allowing higher flight rates and greater numbers of annual missions than the initial two-launch mission profile, given NASA's exploration budget and existing KSC launch facilities and MSFC, ATK, and P&W manufacturing facilities.

Try these "notational" numbers:

Jupiter #1 = $300 million
Spacecraft on Jupiter #1 = $300 million
Jupiter #2 = $300 million
Propellant delivered to KSC: $3 million
Total Cost: $903 million, all paid by NASA.
Limited to perhaps 6 missions per year (12 J-232 launches)

vs.

Jupiter #1 = $300 million
Spacecraft on Jupiter #1 = $300 million
Propellant delivered to Kazakhstan or French Guiana: $3 million
Soyuz for propellant delivery = $75 million * 5 = $375 million
Total Cost: $978 million (pretty much a wash).
But $378 million paid by international partners in exchange for a seat on the mission, leaving $600 million to be paid by NASA.
Enables perhaps 9-12 missions per year.





Why not launch it on the 1 Jupiter, and then offer seats on the mission for a minimum contribution of say $100 million or something to the propellant Jupiter?
I guess the goal is to try to get the commercial EELV's in on the action, and thus drive down there costs with a market to sell to.
I suppose if the cost is about a wash, then these is that advantage to the EELV's.  Just seems more efficient to be able to do it in one launch, rather than 6 or 8 or however many smaller ones.
*shrug*

Offline Lee Jay

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Re: DIRECT v3.0 - Thread 1
« Reply #676 on: 06/09/2009 12:16 am »
Soyuz for propellant delivery = $75 million * 5 = $375 million

5 Soyuz could actually place 100T of propellant in a depot?  I think not.  And why do the spacecraft carrying that propellant all cost zero dollars?

How much does 40 Progress missions cost?

Offline Lobo

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Re: DIRECT v3.0 - Thread 1
« Reply #677 on: 06/09/2009 12:41 am »


Hmm, try it the other way around.

Start with the existing 2x J-246 architecture. The downside of this (the attraction of using J-130 CLV) is that ~15mT of CLV launch capacity remains unused because of limited fuel in the EDS. This is fantastic margin for the early flights.

However, once the standard 2-launch is mature, ~15mT of extra EDS fuel would be able to fully optimise this architecture:-

1) Launch J-246 EDS. (Current plan).

2) Launch a single EELV fuel tanker with maybe 20mT of fuel, rendezvous immediately, and top up the EDS. Thru-TLI mass is now approaching 100mT.

3) Once the EDS is safely re-fuelled, launch a fully-loaded J-246, which can now be pushed through TLI with loads of margin to spare.



3a) This can also be used to augment a single-Jupiter cargo mission. A 20mT fuel boost would give a substantial increase in single-Jupiter thru-TLI mass. (Not the full ~10mT, due to the mass of PT hardware, and not being able to fly a direct-injection profile).

<snipped>


Seems like you are now introducing more docking and complexity to the mission.

I'm just saying, if you could get a J-130 to launch a disposable tank into LEO (it would need an OMS I imagine to prevent it tumbling or something, and ullage motors to deorbit it) and then rendevous your J-246 stack (CSM/LSM/Empty EDS) as a whole unit with that tank and transfer fuel.
It would basicaly be an EDS without the engines.  I supposed it'd be a poor-man's depot, but could launch on a single J-130 rather than need a bunch of EELV's to fill up.  once the CSM/LSAM/EDS stack docks with it and transferrs the propellent, it deorbits and is disposed of.
Yea, you are kinda throwing the "depot" away every mission, but you are throwing away 5-6+ EELV tanks anyway to fill a depot between Lunar missions.  So would you be any money down?  I dunno, that's why I ask.  Seems like one orbital tank, with a docking rink and whatever is needed to transfer propellents would just be a lot simplier than doing it many times over for the EELV's.
Plus your docking maneuvers are almost no different than the planned Ares docking of the CSM to the rest of the stack.  (Not that Direct's docking plan is undoable or anything, but seems like it's be easier)

So, Pro's:
1 fuel launch vs. several EELV launches
 1 simple docking manuever (assuming the stack can simply rear-dock to the tank...I'm no expert, maybe I'm over simplifying this in my head).
Don't waste a 2nd set of JUS engines.

Con's:
requires a propellent transfer for the lunar mission (although this isn't a cont compared to the depot plan, but vs. the baseline architecture).

Requires that the J-130 can loft the tank into a circular LEO Orbit.  I think ROss said something to the effect that that could be done with 5-seg boosters?  But it's predicated on getting that to work.

I know I hear the phrasing of a single launch architecture with a propellent depot, but that's not really accurate, as it requires multiple successful launches and dockings to fill the depot.
If one of those EELV's malfunctions, then the mission's on hold until a replacement gets there, so it's mission critical that multiple EELV launches are successful.

This way gets it done with one Fuel launch.
Just curious.  There may be some glaring reason it won't/can't work.
But since no one has explained very well how they plant to dock the stack to the depot and fuel up for the later depot "single launch" missions, I don't know what those reasons might be.

:)

Does the stack come abreast of the depot and fuel up side by side?
Is Orion still pointing forward and docks with it's docking ring (the way I was assuming)?
How exactly will this happen?

Offline alexw

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Re: DIRECT v3.0 - Thread 1
« Reply #678 on: 06/09/2009 01:27 am »

PS -- Here is a quick teaser for the new cards (same data as the last set, but slightly updated logo's and the "heavy" variants are coming too).

Hi, folks,

Fascinating work; Direct 3.0 looks persuasive. Thank you all (especially the anonymous NASA engineers) for your dedication!

One comment about the "baseball cards": the graphs for ascent dynamics look clearly to have been made in Excel, and could be improved considerably in readability. Microsoft's charting style is a dead giveaway of amateurism, and is regard very poorly in scientific work (e.g., see the writings of Edward Tufte, The Visual Display of Quantitative Information, or Envisioning Information). I urge you to use a real scientific plotting program that produces proper publication-quality output (e.g., Origin, Matlab, or various free software packages).

If you don't have access to real plotting software (which seems unimaginable given all the engineering expertise in the background), it is possible to improve on Excel's default output:

Omit "chartjunk", that is, ink that is getting in the way of the data:
1. Turn off the grey background color (which does nothing useful)
2. Turn off the horizontal-gridlines entirely, or make them less distracting:

If you think you really need a grid (to pick numerical points from the graph), then use both horizontal and vertical rules, and make them *faint*. Consider how a piece of common graph paper looks from the back side: gridlines visible enough to guide the eye when needed, but do not compete with the actual plotted curve (that is, the *data*, the whole point of the graph).

3. Title legibility: if you print out the "baseball card", you can scarcely read the titles. Try a (finer?) font which works better at small sizes, and increase the point size -- there's plenty of room to expand below the existing title but above the curve (and once you get rid of the grey background and horizontal rules, it won't seem to "overlap".)  Also, add more space between the title and the the units, so they don't run together into one block from a distance.

4. Both axes: completely unreadable except on high zoom. Again, font size needs to be bigger (though I realize you have little room).

5. Horizontal axis is probably time, in seconds, but has no label and no units.

6. The numbers are also written sideways, which is usually a bad idea because the reader has to turn their head. The precise times for each segment (e.g. max-q, or staging) probably aren't that important, so write the numbers horizontally, and reduce the number of labels if needed for room (ie, ticks every 100 seconds, instead of every 50).

7. The "Velocity" plot has two curves; what's the difference between the red and the blue? May need a chart legend  (*inside* the chart, not the way Excel defaults) or just label the curves. Also, when printed out on mono printer, the two colors are indistinguishable. Try using different patterns, e.g. a solid line and a dotted line.

After doing the easy stuff above:
7. Since each triple-stack of plots uses the same horizontal axis, and you are pressed for space, try stacking the plots so that they share the x-axis labels. The y-gridlines (if you add them above) or tickmarks (if not) will align the eye with the numbers. One clear set of labels can be much better than three sets of illegibles.

I'm sure that you folks can fix this up in a manner that works well with your workflow for constructing the presentation, but I also realize that it's easy to snipe from the sidelines.  If you're really pressed manpower and time is short, I suppose that I could fix up the plots if you'd be willing to send the data.

In any case, good luck with the presentation!

-Alex

Offline Drapper23

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Re: DIRECT v3.0 - Thread 1
« Reply #679 on: 06/09/2009 01:50 am »
Augustine Committee Website Question About Direct 3  http://hsf.nasa.gov/qa.php  You have to click the arrow at bottom of page to get to the Direct 3 question.

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