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DIRECT v3.0 - Thread 5 - Transition from STS to the new Space Launch System by kraisee on 29 Jul, 2010 12:27
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#1 by kirghizstan on 29 Jul, 2010 12:44
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is there that much confidence that some form of Direct has been selected for SLS to warrent the thread title?
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#2 by aquanaut99 on 29 Jul, 2010 12:55
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is there that much confidence that some form of Direct has been selected for SLS to warrent the thread title?
As I understand it, the new launcher architecture proposed by the Senate bill will be called SLS. Be it DIRECT, DIRECT-derived, a "cousin of DIRECT" or something different entirely.
My guess is it will be a "cousin of DIRECT"; something that looks like DIRECT but will be different enough to satisfy the "anything but DIRECT" crowd by clearly being NOT-DIRECT, while being sufficiently close to Ares to keep the "Ares is the greatest, safest and bestest!" crowd happy.
Probably this means:
- 5 seg SRBs (to keep ATK and Ares amazing peoples happy)
- J2x (to keep Ares amazing peoples happy)
- modified ET in such a way that the modification does not correspond to the DIRECT SH variant. Just out of spite, never mind if it's practical
- new SSME-derived "expendable" engine supposedly "cheaper and more efficient" (although it probably won't be either). Again, just out of spite, because DIRECT proposed SSME. Will be justified by "SSME is no longer produced, workers and contractors laid off, and we have this study that says restarting is more expensive than building a new engine". And this new Engine will have a new name (RS-xx) but will a close copy of the SSME (so what, nobody will notice...)
Do I want this? Ofc not. But that's politics, and that's why I guess even a DIRECT-like SLS will not fly before 2020 and will be a heck of a lot more expensive than what DIRECT would be... -
#3 by kirghizstan on 29 Jul, 2010 13:00
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is there that much confidence that some form of Direct has been selected for SLS to warrent the thread title?
As I understand it, the new launcher architecture proposed by the Senate bill will be called SLS. Be it DIRECT, DIRECT-derived or something different entirely.
but the title seems to imply that direct was officially selected. I would be happy with that, just saying the title is miss leading -
#4 by robertross on 29 Jul, 2010 13:21
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is there that much confidence that some form of Direct has been selected for SLS to warrent the thread title?
As I understand it, the new launcher architecture proposed by the Senate bill will be called SLS. Be it DIRECT, DIRECT-derived or something different entirely.
but the title seems to imply that direct was officially selected. I would be happy with that, just saying the title is miss leading
Until we have a clear winner (sidemunt or inline), we need to continue to have a thread dedicated to Direct. And since the former thread has exceeded the 250 page mark, we can now continue the progression away from CxP onto something much more sensible.
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#5 by HappyMartian on 29 Jul, 2010 13:57
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Thinking positive is fun. What we might get:
- 4 seg SRBs (to keep taxpayers and NASA engineers and Direct members and Direct supporters happy)
- an ET modified into a J-130 core in such a way that it is the practical basis for a reliable and cost effective SSME powered HLV/SLS that can fly in 2014 rather than 2020
- a robust Orion that we can fly for several decades
- J2x (to keep the we are really going to Mars people happy)
- some minimal new research on a SSME-derived "TAN" engine to keep happy the folks in the White House who want a game changing new technology rocket engine (I just had to add this one for fun and because a TAN hyrolox engine seems like a good idea... And I do understand that the resulting engine would be basically a new engine.)
Cheers! -
#6 by MP99 on 29 Jul, 2010 14:04
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- modified ET in such a way that the modification does not correspond to the DIRECT SH variant. Just out of spite, never mind if it's practical
The ET is 8.4m, and has a certain length to accommodate the 4-seg SRB.
There's a certain obvious stretch of the core to accommodate 5-seg SRB's or 4-segs with a dummy segment (ie SH or S options).
Without modifying the aft SRB attach point, that's about it in terms of sizing decisions.
Beyond that, Jupiter has a certain design for the actual tank mods (using the NLS mods as it's base, I believe). However, this is something that NASA will design for themselves, and there's no reason to assume they'd choose a sub-optimal design, whether it happens to be close to the DIRECT design, or not.Quotenew SSME-derived "expendable" engine supposedly "cheaper and more efficient" (although it probably won't be either). Again, just out of spite, because DIRECT proposed SSME. Will be justified by "SSME is no longer produced, workers and contractors laid off, and we have this study that says restarting is more expensive than building a new engine". And this new Engine will have a new name (RS-xx) but will a close copy of the SSME (so what, nobody will notice...)
DIRECT expects the SSME to evolve into an RS-25e, ie expendable. Channel wall skirt, to begin. Other mods may follow.
P&WR restarted production of SSME's (3 of, I think) recently to complete the Shuttle flyout. Unless the tooling and/or expertise has been lost in the meantime, it can be restarted again.
You know, I really don't think the "NASA will do it differently, just to spite DIRECT" talk is helpful. JSC's recent HLLV document shows that some in NASA get the "Shuttle-stack-sized" vehicle thing very well.
cheers, Martin -
#7 by clongton on 29 Jul, 2010 14:13
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Quote from: Nathan
not good if living on the surface at the time. Need propellant depots to fuel spacecraft that aren't designed to fall apart.
That's why the drop tanks would contain enough propellant to do de-orbit, with still more delta-v needed to be expended to complete the de-orbit and land. The drop tanks would overshoot the landing site by a very long way, perhaps a couple of hundred miles.
If dropping into a base of some sort, whether permanent or only a semi-permanent staging area, the "drop zone" for the expendable tanks could serve as a tank collection area to be used as a future material source. -
#8 by TrueBlueWitt on 29 Jul, 2010 14:22
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Thinking positive is fun. What we might get:
- 4 seg SRBs (to keep taxpayers and NASA engineers and Direct members and Direct supporters happy)
- an ET modified into a J-130 core in such a way that it is the practical basis for a reliable and cost effective SSME powered HLV/SLS that can fly in 2014 rather than 2020
- a robust Orion that we can fly for several decades
- J2x (to keep the we are really going to Mars people happy)
- some minimal new research on a SSME-derived "TAN" engine to keep happy the folks in the White House who want a game changing new technology rocket engine (I just had to add this one for fun and because a TAN hyrolox engine seems like a good idea... And I do understand that the resulting engine would be basically a new engine.)
Cheers!
That would make way too much sense.. I would love to see a thread on a TAN SSME based core stage.. use ccb w/o RD-180s as drop tanks
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#9 by MP99 on 29 Jul, 2010 14:40
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Quote from: Nathan
not good if living on the surface at the time. Need propellant depots to fuel spacecraft that aren't designed to fall apart.
That's why the drop tanks would contain enough propellant to do de-orbit, with still more delta-v needed to be expended to complete the de-orbit and land. The drop tanks would overshoot the landing site by a very long way, perhaps a couple of hundred miles.
If dropping into a base of some sort, whether permanent or only a semi-permanent staging area, the "drop zone" for the expendable tanks could serve as a tank collection area to be used as a future material source.
This was in response to the suggestion to discard the drop tanks in LLO, relying on the shape of the Lunar gravitational field to cause them to crash some indeterminate time later.
This avoids the need to discard the tanks under time pressure during the descent (and presumes the lander uses the drop tank prop to perform LOI for itself and the Orion).
cheers, martin -
#10 by MP99 on 29 Jul, 2010 14:41
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- J2x (to keep the we are really going to Mars people happy)
MARS DRA 5 uses RL-10's for TMI / MOI / TEI.
cheers, Martin -
#11 by John Duncan on 29 Jul, 2010 15:17
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We can only hope that Direct is recognizable when NASA/Bolden/Garver gets through with it.
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#12 by kkattula on 29 Jul, 2010 15:39
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Quote from: Drkskywxlt
No...because once the Shuttle retires next year or the year after, that money is just folded into development of SLC/Orion. In the 3 year outlook given by the House and Senate bills, essentially no money is given to payloads. Perhaps 2014 and beyond will see some, but don't hold your breath...that's when the cost overrun projections for SLS and Orion will start coming in along with inevitable schedule slips.
Yes, because it was beyond 2014 I was talking about. If NASA can't ever execute a project close to budget or schedule, and this project has a lot of margin by Direct reckoning, then there is no hope, and we should all just give up.
Those who plan to fail... plan to fail.
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#13 by aquanaut99 on 29 Jul, 2010 15:59
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You know, I really don't think the "NASA will do it differently, just to spite DIRECT" talk is helpful. JSC's recent HLLV document shows that some in NASA get the "Shuttle-stack-sized" vehicle thing very well.
Sorry, I was being sarcastic. And I didn't mean NASA (well, a little, maybe), it was mostly aimed at politicians in the House playing rocket designer (since I expect the end result to be somewhere in between the Senate and House proposals and there is some pretty bad stuff in the House version).
Feel free to delete. -
#14 by MP99 on 29 Jul, 2010 16:04
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You know, I really don't think the "NASA will do it differently, just to spite DIRECT" talk is helpful. JSC's recent HLLV document shows that some in NASA get the "Shuttle-stack-sized" vehicle thing very well.
Sorry, I was being sarcastic. And I didn't mean NASA (well, a little, maybe), it was mostly aimed at politicians in the House playing rocket designer (since I expect the end result to be somewhere in between the Senate and House proposals and there is some pretty bad stuff in the House version).
Feel free to delete.
Sorry, too. I obviously jumped to a conclusion that was aimed at NASA rather than the House, which you'd mentioned. And the House bill does show we're not out of the woods yet.
cheers, Martin -
#15 by Ben the Space Brit on 29 Jul, 2010 16:42
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Quote from: Nathan
not good if living on the surface at the time. Need propellant depots to fuel spacecraft that aren't designed to fall apart.
That's why the drop tanks would contain enough propellant to do de-orbit, with still more delta-v needed to be expended to complete the de-orbit and land. The drop tanks would overshoot the landing site by a very long way, perhaps a couple of hundred miles.
If dropping into a base of some sort, whether permanent or only a semi-permanent staging area, the "drop zone" for the expendable tanks could serve as a tank collection area to be used as a future material source.
Purely FWIW, I dislike the idea of an uncontrolled de-orbit, even onto the Moon. My drop tank/stage idea includes solid fuel retros to drop the stage down onto a selected part of lunar real estate. Ultimately, all drop stages would end up there, creating a lunar junk yard that, I suppose, could eventually be recycled once there is infrastructure in place to collect the junk and do so.
[edit]
Oops! Can you tell that I was tired when I posted this? -
#16 by Drkskywxlt on 29 Jul, 2010 17:30
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Yes, because it was beyond 2014 I was talking about. If NASA can't ever execute a project close to budget or schedule, and this project has a lot of margin by Direct reckoning, then there is no hope, and we should all just give up.
Those who plan to fail... plan to fail.
Ok, I didn't understand that in your original post. I'm not planning to fail, but I'm definitely not optimistic. I don't expect that NASA will select DIRECT, although the final product may bear similarities. I hope I'm wrong and some of NASA management can wake up to reality. -
#17 by kraisee on 29 Jul, 2010 18:50
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Just letting everyone know, we are putting out an important formal Press Release today, something we've only ever done twice before.
There is a copy in the News section of this forum, and also on our website: www.directlauncher.com
Ross. -
#18 by FinalFrontier on 29 Jul, 2010 23:54
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Glad to see that there is a thread 5! And glad to be on it. Bravo Direct
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#19 by FinalFrontier on 30 Jul, 2010 00:06
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Per the senate bill the only thing that can meet their requirments is DIRECT. And the 5 seg j2x "SH" versions are close enoughis there that much confidence that some form of Direct has been selected for SLS to warrent the thread title?
As I understand it, the new launcher architecture proposed by the Senate bill will be called SLS. Be it DIRECT, DIRECT-derived or something different entirely.
but the title seems to imply that direct was officially selected. I would be happy with that, just saying the title is miss leading
