Author Topic: RS-68 CLV First Stage  (Read 61787 times)

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #60 on: 07/19/2006 06:13 AM »
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edkyle99 - 18/7/2006  4:58 PM
One alternative ESAS option, for example, called for the development of only one, "mid-size" launch vehicle (90-100 tonnes to LEO).  The study found that a lunar mission performed with two such launchers would cost less than the current "1.5 Launch" mission.  

 - Ed Kyle

That option has me curious.

Pure hypothetical:   Two 4-seg SRB's plus three 500,000lb thrust engines (Shuttle) today is enough to launch 116mT to ISS.

Replace the three SSME's with two RS-68's and you'd get very similar performance, but you can do so in a simpler in-line arrangement, and spend less cash.

The Payload would require an OMS system to performa the final circularisation burn, but the ol' space tug idea would seem to suit that role nicely.   The two Shuttle's OMS Pods mass a total of about 20mT, including the integral RCS systems, so my guess would be you could launch 100mT of useful payload on each flight.

NASA wouldn't need to pay for 5-segs (yet, although they'd be nice as an upgrade later), wouldn't need to plan extensive changes to the MLP's or Pad Structures and could retain much of the current infrastructure for both SRB's and ET processing.

Depending on it's expected LOC figures, it might be a realistic, less costly and quicker system to get operational.

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

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Re: RS-68 CLV First Stage
« Reply #61 on: 07/20/2006 07:50 AM »
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JIS - 18/7/2006  6:18 AM

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lmike - 18/7/2006  7:25 AM

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JIS - 18/7/2006  5:19 AM
...When you want to go to Moon or Mars you need super heavy lift vehicle. ...

First of all what is exactly a "super heavy lift vehicle"?

The haavier the better.
In reality landing 20t at Moon in one shoot is enough.
Landing less is not enough for manned missions. More shoots are too complex.

I'm sorry but "the heavier the better" is not something one can put in a technical design definition.  Otherwise we'd be waiting for the Sea Dragon.  And then we'd be waiting for something else.  There is no single technical justification for a single number that's "good enough".  

Why exactly is 20t at the Moon is enough?!  Why not 35t?  Is that based on a study (not ESAS I hope), or a crystal ball?  Note, I'm not arguing for "landing less on the Moon".  I'm actually arguing for landing "more on the Moon" with the "existing" launchers.  "More shots are too complex"?  Not so.  If we can't put together 2 modules in space we are better off not venturing to the Moon (or Mars) at all.  But once we can, and I believe we can, we are up to any task with any existing launcher.  Not just the Ares V.  Granularity is a long since proved point of a delivery service (both on Earth and in space)

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #62 on: 07/20/2006 09:49 AM »
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lmike - 20/7/2006  2:37 AM

Why exactly is 20t at the Moon is enough?!  Why not 35t?  Is that based on a study (not ESAS I hope), or a crystal ball?  

One doesn’t need to be Nasa expert to find out that 4 people staying 7 days on the Moon need some infrastructure. What is the minimum?
What is the minimum for the Mars mission?
I said 20t. It can be 15 or 25t. It’s hardly 5t. ESAS has some hints inside.

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"More shots are too complex"?  Not so.  If we can't put together 2 modules in space we are better off not venturing to the Moon (or Mars) at all.  But once we can, and I believe we can, we are up to any task with any existing launcher.  Not just the Ares V.  Granularity is a long since proved point of a delivery service (both on Earth and in space)

The problem is that it never worked before and there is no infrastructure yet.
Some similarity is in rendezvous of Apollo LM with CM+SM, ISS and MIR construction.
Even rendezvous of CEV with EDS+LSAM will be a big step. I can’t imagine that more complex construction would work (after what I saw at ISS).
And it would have to happen every time you want to travel somewhere. Two times a year – mission impossible!
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline lmike

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Re: RS-68 CLV First Stage
« Reply #63 on: 07/20/2006 09:58 AM »
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JIS - 20/7/2006  2:36 AM

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lmike - 20/7/2006  2:37 AM

Why exactly is 20t at the Moon is enough?!  Why not 35t?  Is that based on a study (not ESAS I hope), or a crystal ball?  

One doesn’t need to be Nasa expert to find out that 4 people staying 7 days on the Moon need some infrastructure. What is the minimum?
What is the minimum for the Mars mission?
I said 20t. It can be 15 or 25t. It’s hardly 5t. ESAS has some hints inside.


I said "why not 35t?".  But in multiple, much cheaper launches.  35 is greater than 20?  No?

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"More shots are too complex"?  Not so.  If we can't put together 2 modules in space we are better off not venturing to the Moon (or Mars) at all.  But once we can, and I believe we can, we are up to any task with any existing launcher.  Not just the Ares V.  Granularity is a long since proved point of a delivery service (both on Earth and in space)

The problem is that it never worked before and there is no infrastructure yet.
Some similarity is in rendezvous of Apollo LM with CM+SM, ISS and MIR construction.
Even rendezvous of CEV with EDS+LSAM will be a big step. I can’t imagine that more complex construction would work (after what I saw at ISS).
And it would have to happen every time you want to travel somewhere. Two times a year – mission impossible!
[/quote]

If we can do 2 dockings of modules, we can do 2*n dockings.  Period.  Mathematics.

Two times a year - mission impossible?!  You just doomed the entire ESAS study, you know ;)

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #64 on: 07/20/2006 12:01 PM »
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lmike - 20/7/2006  4:45 AM

I said "why not 35t?".  But in multiple, much cheaper launches.  35 is greater than 20?  No?

35t is better than 20t. 50t is better than 35t. But don't push too hard. I just said that we should be happy with 20t in one shoot which defines "super heavy lift" in my eyes.


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If we can do 2 dockings of modules, we can do 2*n dockings.  Period.  Mathematics.

Derive by time...
ESAS uses two pads so two launches at once seems OK to me. More complex vehicle first, less complex and more reliable second.

This gives one manned randezvous at LEO each time. No randezvous would be easier but NASA is more skilled than decades ago.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #65 on: 07/20/2006 05:09 PM »
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kraisee - 19/7/2006  1:00 AM

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edkyle99 - 18/7/2006  4:58 PM
One alternative ESAS option, for example, called for the development of only one, "mid-size" launch vehicle (90-100 tonnes to LEO).  The study found that a lunar mission performed with two such launchers would cost less than the current "1.5 Launch" mission.  

 - Ed Kyle

That option has me curious.

Pure hypothetical:   Two 4-seg SRB's plus three 500,000lb thrust engines (Shuttle) today is enough to launch 116mT to ISS.

One ESAS option used exactly this launch vechicle (an in-line version), but listed the payload as only 74 tonnes.  Three launches would be needed to do a lunar mission, but the per-mission cost was still only "0.78", compared to the 1.5 launch mission's "1.0" cost.  Loss of crew odds were given as 1 in 1,170.

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Replace the three SSME's with two RS-68's and you'd get very similar performance, but you can do so in a simpler in-line arrangement, and spend less cash.

The Payload would require an OMS system to performa the final circularisation burn, but the ol' space tug idea would seem to suit that role nicely.   The two Shuttle's OMS Pods mass a total of about 20mT, including the integral RCS systems, so my guess would be you could launch 100mT of useful payload on each flight.

The CEV would fly itself after separation from this launch vehicle.  The LSAM could too, as could the Earth Departure Stage.

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NASA wouldn't need to pay for 5-segs (yet, although they'd be nice as an upgrade later), wouldn't need to plan extensive changes to the MLP's or Pad Structures and could retain much of the current infrastructure for both SRB's and ET processing.

Depending on it's expected LOC figures, it might be a realistic, less costly and quicker system to get operational.

Ross.

It sure looks that way to me.

 - Ed Kyle

Offline Norm Hartnett

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Re: RS-68 CLV First Stage
« Reply #66 on: 07/20/2006 05:38 PM »
Would using the RS-68's improve the LOC figure?
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #67 on: 07/20/2006 05:44 PM »
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Norm Hartnett - 20/7/2006  1:25 PM

Would using the RS-68's improve the LOC figure?

It would go in the other direction since they are not manrated yet

Offline gladiator1332

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Re: RS-68 CLV First Stage
« Reply #68 on: 09/19/2007 06:07 PM »
If there were a switch to an all liquid CLV, obviously ULA is in the lead for the first stage. But what if Falcon 9 ends up being as successful as SpaceX claims it will be. I like the idea of how Falcon has engine ignition, they check all of the systems, and then it lifts off.

Barring any more technical issues, and assuming that all goes to plan with the Falcon 9, aka "in a perfect world" what would the LOC numbers be for a Falcon 9 launching the CEV? I'm assuming the large amount of engines will scare NASA away. However, Musk is talking of developing a larger engine to lessen the number of engine clusters.

Still 2 x RD-180 may still be the best bet if there is a switch to EELV.

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #69 on: 09/19/2007 06:55 PM »
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gladiator1332 - 19/9/2007  2:07 PM

 I like the idea of how Falcon has engine ignition, they check all of the systems, and then it lifts off.

.

Most launch vehicles do this.  This is just marketing BS

Titan with solids didn't have holddowns, it didn't need them.   It just sat on the pad and lifted off when the solids lit

Atlas I, II, III & V had/have holddown arms or bolts
Delta IV  holddown bolts
Delta II, just sat on the pad.  The RS-27A can't lift it, so it has a "holddown" system.  The SRM's aren't lit until the RS-27 burns through a wire

Offline luke strawwalker

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RE: RS-68 CLV First Stage
« Reply #70 on: 09/19/2007 08:07 PM »
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edkyle99 - 13/7/2006  10:17 AM

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bad_astra - 13/7/2006  9:22 AM

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Not if you listen to anyone on this forum.

I'm given to understand that the shuttle SRM's lack of emergency cut-out makes it more dangerous than a liquid engine. Does everyone still agree?

I don't know anyone who watches a Shuttle launch that doesn't breathe a huge sigh of release at SRB sep.


I don't breath until wheels stop on the runway.  Fair to mention, by the way, that liquid boosters fail more often than solids.  Just look at the recent GSLV failure from India, for one example.  GSLV has a powerful solid booster core with four strap-on liquid boosters.  The solid worked fine.  One of the liquids failed.  

There have been three launch failures this year so far, in 31 attempts.  All of the failures involved liquid propulsion systems.  Last year there were three failures in 55 attempts.  All of the failures were liquids.  Three of the four failures in 2004 were liquids.  The solid rocket failure (Shavit) involved a failed stage separation.  Etc.

 - Ed Kyle

Do you have any specs on the reliability of ALL solids since the beginning of the space program?   I would be interested in knowing how many ullage motors or seperation motors failed to light,  or failed in any other way due to the motor itself.  Interesting stuff... OL JR :)
NO plan IS the plan...

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Offline gladiator1332

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Re: RS-68 CLV First Stage
« Reply #71 on: 09/19/2007 09:19 PM »
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Jim - 19/9/2007  2:55 PM

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gladiator1332 - 19/9/2007  2:07 PM

 I like the idea of how Falcon has engine ignition, they check all of the systems, and then it lifts off.

.

Most launch vehicles do this.  This is just marketing BS

Titan with solids didn't have holddowns, it didn't need them.   It just sat on the pad and lifted off when the solids lit

Atlas I, II, III & V had/have holddown arms or bolts
Delta IV  holddown bolts
Delta II, just sat on the pad.  The RS-27A can't lift it, so it has a "holddown" system.  The SRM's aren't lit until the RS-27 burns through a wire

You learn something new every day. Even though I knew other vehicles are held down before lift-off, SpaceX makes it sound as if they are the first and only vehicle to have this capability.
Thanks for clearing that up Jim


Offline Jim

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Re: RS-68 CLV First Stage
« Reply #72 on: 09/19/2007 10:30 PM »
Saturn I, IB, & V, Atlas A, B, C, D, and H, Titan I & II  also

Thor didn't

Offline simonbp

Re: RS-68 CLV First Stage
« Reply #73 on: 09/20/2007 12:53 AM »
Witness Ye The Birth of a Forum Legend!

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kraisee - 18/7/2006  11:13 PM
Pure hypothetical:   Two 4-seg SRB's plus three 500,000lb thrust engines (Shuttle) today is enough to launch 116mT to ISS. Replace the three SSME's with two RS-68's and you'd get very similar performance, but you can do so in a simpler in-line arrangement, and spend less cash.
...
Depending on it's expected LOC figures, it might be a realistic, less costly and quicker system to get operational.

That said, I think I still prefer the 1.5 architecture (much less orbital complexity than 2 Direct launches), and so the RS-68-ified Ares I.

I wonder if Atlas-style drop-off engines would work (2 booster, 1 sustainer)...

Simon ;)

Offline Norm Hartnett

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Re: RS-68 CLV First Stage
« Reply #74 on: 09/20/2007 01:57 AM »
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simonbp - 19/9/2007  5:53 PM

Witness Ye The Birth of a Forum Legend!

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kraisee - 18/7/2006  11:13 PM
Pure hypothetical:   Two 4-seg SRB's plus three 500,000lb thrust engines (Shuttle) today is enough to launch 116mT to ISS. Replace the three SSME's with two RS-68's and you'd get very similar performance, but you can do so in a simpler in-line arrangement, and spend less cash.
...
Depending on it's expected LOC figures, it might be a realistic, less costly and quicker system to get operational.

-snip-
Simon ;)

Huh, 1 year 2 months from first inception to AIAA presentation.

And if rumors be true it could well be a legend that extends beyond the Forum and into the realms of reality.

Norm ;)
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline gladiator1332

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Re: RS-68 CLV First Stage
« Reply #75 on: 09/20/2007 01:37 PM »
Wow, I never realized that that was in this thread. Keep a close watch on this one for when the history books are being written.

Offline kkattula2

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Re: RS-68 CLV First Stage
« Reply #76 on: 09/21/2007 04:56 AM »
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simonbp - 20/9/2007  12:53 PM
...
That said, I think I still prefer the 1.5 architecture (much less orbital complexity than 2 Direct launches), and so the RS-68-ified Ares I.

I wonder if Atlas-style drop-off engines would work (2 booster, 1 sustainer)...

Simon ;)

The "1.5 architecture" nomenclature is just PR BS to make it sound better.  There are 2 launches with 2 different launch vehicles! It's "asymetrical dual launch".

2 launches on the same, or very similar, vehicle makes much more sense.

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #77 on: 09/21/2007 10:42 AM »
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kkattula2 - 21/9/2007  5:56 AM

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simonbp - 20/9/2007  12:53 PM
...
That said, I think I still prefer the 1.5 architecture (much less orbital complexity than 2 Direct launches), and so the RS-68-ified Ares I.

I wonder if Atlas-style drop-off engines would work (2 booster, 1 sustainer)...

Simon ;)

The "1.5 architecture" nomenclature is just PR BS to make it sound better.  There are 2 launches with 2 different launch vehicles! It's "asymetrical dual launch".

2 launches on the same, or very similar, vehicle makes much more sense.

It's certainly not PR. 1.5 architecture simply means that there is one smaller launch vehicle and another much bigger one. 2 launch architecture means two same (or similar) size rockets. Is it difficult to understand?
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline rumble

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Re: RS-68 CLV First Stage
« Reply #78 on: 09/21/2007 01:02 PM »
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JIS - 21/9/2007  5:42 AM

It's certainly not PR. 1.5 architecture simply means that there is one smaller launch vehicle and another much bigger one. 2 launch architecture means two same (or similar) size rockets. Is it difficult to understand?
Ok...call it MARKETING then.  But the fact remains that two launches are going to take place.  Saying otherwise doesn't make it so.

If you're trying to use the relative (publicly projected) capacities of the Ares-I/V vehicles, you'd be more accurate to call it a 1.2 launch.  Or if you measure it by number of 1st stage engines, it's a 1.15 launch.

"1.5 architecture" is using words in a non-literal fashion to drive a change in perception.  As an engineer, I call that "marketing fluff" or "creative lying" (or other less generous terms).  

I understand it's being used as a term to describe large + small, but it was deliberately chosen so that even the "1.5 launch" phrase has an advantage over "2-launch," because when the human mind reads that, it means something...even though it's just marketing BS.  Similar to $19.99 feeling materially cheaper than $20.00.

It is your first sentence I'm taking exception with.

Offline TrueBlueWitt

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Re: RS-68 CLV First Stage
« Reply #79 on: 09/21/2007 01:53 PM »
As much as I like the Direct concept, I think having a more capable liquid fueled(EELV or Direct) Orion launch vehicle along with a super heavy lifter(either Ares-V or Evolved Direct) makes sense now.

You really do need a super heavy lifter if you're going to take up the large pressurised housing modules that have recently been spec'd instead of modular design with assembly. Look how much of ISS time is wasted on assembly(I love watching assembly flights, but they are a waste of time). If the hab modules go up whole, I'm guessing at least 50% more time is available on the moon to do real research and exploration.  Not to mention hauling the big pressurized rovers they'r talking about.  We must have heavy lift!

I'd happily dump Ares-I for EELV or Direct and have NASA start working on more capable Ares-V(or Heavy DIRECT Varient) NOW!!!!!

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