Author Topic: RS-68 CLV First Stage  (Read 61788 times)

Offline simonbp

RS-68 CLV First Stage
« on: 07/13/2006 01:43 AM »
I got thinking the other day (dangerous, I know), about how you could replace the (soild) first stage of the Ares I with a drop-in liquid replacement. Most of the criticism I've heard WRT the CLV pertains to the first, rather than the second stage (with the exception of RL-10s vs. J-2s, and there's 40+ years of trades on that). Considering the RS-68 is going to be "NASA-ized" for the Ares V, it seems like a reasonable engine to use. Likewise, the diameter of the CLV upper stage is 5.5 meters and the Delta IV core diameter is 5.1 meters, and so a vertical scaling of it seems logical.

With that all in mind, I started running the numbers for a scaled Delta IV with the same net delta V as the SRB stage. Accounting for fuel necessary and the volumes of LH2 and LOX, I found that the tank would need to be lengthened by about 6 meters (for a total length of 46 meters). In order to have a t/w greater than 1, two RS-68s were required (though the t/w is still 76% of the SRB); also, the lower thurst lengthens the burn time by 56%.

Advantages:
  • Half the liftoff gross mass

  • Easier TVC (would single-axis gimbals and throttle vectoring work?)

  • It's not a solid :)


Disadvantages:
  • Twice the amount of engines to fail

  • Integrating two engines on a Delta IV-ish core could be difficult

  • Not recoverable, so potentially higher operational costs (though that's rather nebulous either way)



So what did I do wrong? :)

Simon ;)

Offline hyper_snyper

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Re: RS-68 CLV First Stage
« Reply #1 on: 07/13/2006 01:48 AM »
I think the SRBs were one of the main drivers to the architecture we have today.  Whether thats a good thing or bad thing I don't know.  If you're going to have a RS-68 first stage you might as well just mod a Delta IV to do the job, IMO.

Online hop

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RE: RS-68 CLV First Stage
« Reply #2 on: 07/13/2006 02:27 AM »
Quote
simonbp - 12/7/2006  6:30 PM
Not recoverable, so potentially higher operational costs (though that's rather nebulous either way)
I thought they weren't going to recover the SRB from the CLV anyway ?

The other factor is that according to the ESAS study, a single stick SRM is vastly safer than any of the alternatives.  :o

Offline mike robel

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RE: RS-68 CLV First Stage
« Reply #3 on: 07/13/2006 02:37 AM »
Instead of developing a two RS-68 version of the Delta IV, you could either (1) just the Delta IV Heavy or maybe (2) use the Delta IV Medium with 4 of its smaller SRBs.  I don't that my second suggestion would handle the load, but the Heavy version sure  would...

Offline zinfab

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RE: RS-68 CLV First Stage
« Reply #4 on: 07/13/2006 03:09 AM »
Quote
hop - 12/7/2006  10:14 PM
The other factor is that according to the ESAS study, a single stick SRM is vastly safer than any of the alternatives.  :o

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?

Offline yinzer

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Re: RS-68 CLV First Stage
« Reply #5 on: 07/13/2006 04:16 AM »
The lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events.  The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.

In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage.  And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV.  If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available.  NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.
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Online hop

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RE: RS-68 CLV First Stage
« Reply #6 on: 07/13/2006 04:16 AM »
Quote
zinfab - 12/7/2006  7:56 PM
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 wasn't commenting on the merits of that claim one way or the other, just pointing out that it is part of NASAs justification for sticking with the stick :)

For a single SRB, not being able to shut down may make the escape system requirements harder to meet, but otherwise doesn't seem like a big deal.  As long as you can get a little ways away from it, range safty can shut it down.  It's a problem for the shuttle because it has two of the things (with any significant imbalance being fatal), and no escape system.

I suspect that the safety argument has some merit. All else being equal, simpler is better...  but the devil is in the details.

Offline bad_astra

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RE: RS-68 CLV First Stage
« Reply #7 on: 07/13/2006 02:35 PM »
Quote
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.
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Offline gladiator1332

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Re: RS-68 CLV First Stage
« Reply #8 on: 07/13/2006 02:57 PM »
I like your idea for the CLV, and it reminds me a bit of the Titan-2. I jsut read the NASA Watch post and it does seem there is a distinct possibility we will be hearing about a switch soon. As much as I like the SDLVs it just appears that they will take the whole program down with them.

Since NASA Watch was about the RD-180 and an Atlas Derived CLV, could you run the same numbers on that and maybe make us a render. It would be ncie to see the current CLV, the Delta CLV and the Atlas CLV next to eachother.

And I know what you mean bad astra...watching the launch the other day, the firs thing that came to my mind at SRB sep was "are we really going to launch a crew on one of those things?"

Offline edkyle99

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RE: RS-68 CLV First Stage
« Reply #9 on: 07/13/2006 03:17 PM »
Quote
bad_astra - 13/7/2006  9:22 AM

Quote
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

Offline rumble

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Re: RS-68 CLV First Stage
« Reply #10 on: 07/13/2006 03:24 PM »
Quote
yinzer - 12/7/2006  11:03 PM

In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage.  And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV.  If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available.  NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.

How serious is this "chatter?"  Based on what I understand (which could be incorrect), I would assume a kerosene 1st stage (RD-180) for the core stage would need a beefy second stage.  The current plan for the 2nd stage/EDS doesn't seem to be this.

Could an RD-180 based 1st stage truly be a replacement for the capability of the RS-68 CaLV core stage, or would other vehicle changes be necessary to accompany this?

RD-180 for the 1st stage of the CLV makes good sense to me.

Quote
edkyle99 - 13/7/2006 10:04 AM

Fair to mention, by the way, that liquid boosters fail more often than solids.

...but AFAIK the only failure of a manned launch in the U.S. was due to a solid failure (Challenger).

Offline Jim

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RE: RS-68 CLV First Stage
« Reply #11 on: 07/13/2006 03:41 PM »
Quote
edkyle99 - 13/7/2006  11:04 AM

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

the liquied failures are surivable.  The rest of the world is not a good database.  Spacex and India are not in the same population as the US and Russia wrt spacelaunch

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #12 on: 07/13/2006 03:43 PM »
Quote
rumble - 13/7/2006  10:11 AM

Quote
edkyle99 - 13/7/2006 10:04 AM

Fair to mention, by the way, that liquid boosters fail more often than solids.

...but AFAIK the only failure of a manned launch in the U.S. was due to a solid failure (Challenger).


The Challenger failure could have been survivable on a launcher with an escape system.  

The other manned U.S. failure (Columbia) was due to a problem with insulation on the *liquid* propulsion system tank during the launch phase.  No escape system for that one.

 - Ed Kyle

Offline rumble

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Re: RS-68 CLV First Stage
« Reply #13 on: 07/13/2006 04:23 PM »
Quote
edkyle99 - 13/7/2006  10:30 AM

The Challenger failure could have been survivable on a launcher with an escape system.  

Agreed.  Especially if the SRB could have shut down when it started detecting problems.

Quote

The other manned U.S. failure (Columbia) was due to a problem with insulation on the *liquid* propulsion system tank during the launch phase.  No escape system for that one.

 - Ed Kyle

Well...  That's a stretch.  It DOES speak to the danger of putting the re-entry vehicle where falling ice/debris can strike it, so if the crew re-entry vehicle had been above the booster, that wouldn't have happened.


And, as for the Challenger disaster, I think it would have required a launch escape system AND having the crew above the launch vehicle for that to have been survivable.

Offline yinzer

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Re: RS-68 CLV First Stage
« Reply #14 on: 07/13/2006 04:34 PM »
With an escape system, a Challenger-style hardware failure could have been escaped from.  However, the escape system would have to be fairly robust as solids can't be shut down gracefully enough for a system designed around a 3G limit.  The Columbia failure was more or less independent of propulsion mode, and was in fact more related to the total vehicle design.  After all, the foam fell off of the upper stage, and I haven't seen anyone propose an all-solid LV of more than about 5 tons capacity.

Then you start looking at catastrophic failures during first stage flight; the Titan IV that pitched over and blew up (avionics), the Delta III that ran out of stored hydraulic system energy (design/solids), the Delta II that had a solid motor blow up (solids), the X-43 Pegasus (design/structural failure), the first LMLV/Athena (avionics), the Atlas II that got hit by lightning (avionics), the Titan 34D that blew up (solids), the Conestoga that also ran out of stored hydraulic system energy (design/solids), and the SpaceX Falcon (operational/liquid).

Which brings you back to the point that there's no incredible advantage either way, just that you want people and preferably a team who have been around the block with launch vehicle design and operation.  Which is not MSFC.
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Offline Jim

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Re: RS-68 CLV First Stage
« Reply #15 on: 07/13/2006 04:52 PM »
Quote
edkyle99 - 13/7/2006  11:30 AM

Quote
rumble - 13/7/2006  10:11 AM

Quote
edkyle99 - 13/7/2006 10:04 AM

Fair to mention, by the way, that liquid boosters fail more often than solids.

...but AFAIK the only failure of a manned launch in the U.S. was due to a solid failure (Challenger).


The Challenger failure could have been survivable on a launcher with an escape system.  

The other manned U.S. failure (Columbia) was due to a problem with insulation on the *liquid* propulsion system tank during the launch phase.  No escape system for that one.

 - Ed Kyle

Columbia is not a launch failure.  No where near one.  It is a entry failure.  It doesn't matte what caused the damage

Offline edkyle99

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RE: RS-68 CLV First Stage
« Reply #16 on: 07/13/2006 05:09 PM »
Quote
Jim - 13/7/2006  10:28 AM

Quote
edkyle99 - 13/7/2006  11:04 AM

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

the liquied failures are surivable.  The rest of the world is not a good database.  Spacex and India are not in the same population as the US and Russia wrt spacelaunch

If we only look at US launch vehicles since 1980 (including all shuttle launches), there have been 605 by my count with 36 launch vehicle failures.  Of these, I can only identify four that were clearly solid rocket motor failures:  STS-51L, Delta 241, Titan 4 K-11, and Titan 34D-9.  I count at least nine that were clearly liquid propulsion system failures:  AC-62, AC-70, AC-71, AC-74, Atlas 19F, Delta 178, Delta 269, Titan 34D-7, and Titan 34D-3.  There may have been others, as a few of the DoD launches are listed cryptically as "failed to orbit" on my list.

 - Ed Kyle

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #17 on: 07/13/2006 05:11 PM »
Quote
Jim - 13/7/2006  11:39 AM

Columbia is not a launch failure.  No where near one.  It is a entry failure.  It doesn't matte what caused the damage

The root cause occurred during the launch phase.  Columbia's crew were as good as dead when the bipod ramp hit the wing less than two minutes into the flight.

 - Ed Kyle

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #18 on: 07/13/2006 05:14 PM »
It was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #19 on: 07/13/2006 05:18 PM »
Quote
rumble - 13/7/2006  11:10 AM

And, as for the Challenger disaster, I think it would have required a launch escape system AND having the crew above the launch vehicle for that to have been survivable.

I've always wondered about that, since the crew module and crew did survive the initial breakup.  The crew may have been alive, if not conscious, right down to impact with the ocean.  I've always wondered what might have happened if they had had pressure suits and parachutes, but a true rocket-propelled escape module would have provided the only real chance.

 - Ed Kyle

Offline zinfab

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Re: RS-68 CLV First Stage
« Reply #20 on: 07/13/2006 05:20 PM »
Would this group agree that the ATK solid rocket boosters are the most reliable rockets currently available?

If we switch to EELV, will they cut the size/mass of the CEV EVEN MORE, or redesign them to carry more (MORE development costs)?

Offline Jim

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RE: RS-68 CLV First Stage
« Reply #21 on: 07/13/2006 05:24 PM »
Quote
edkyle99 - 13/7/2006  12:56 PM

Quote
Jim - 13/7/2006  10:28 AM

Quote
edkyle99 - 13/7/2006  11:04 AM

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

the liquied failures are surivable.  The rest of the world is not a good database.  Spacex and India are not in the same population as the US and Russia wrt spacelaunch

If we only look at US launch vehicles since 1980 (including all shuttle launches), there have been 605 by my count with 36 launch vehicle failures.  Of these, I can only identify four that were clearly solid rocket motor failures:  STS-51L, Delta 241, Titan 4 K-11, and Titan 34D-9.  I count at least nine that were clearly liquid propulsion system failures:  AC-62, AC-70, AC-71, AC-74, Atlas 19F, Delta 178, Delta 269, Titan 34D-7, and Titan 34D-3.  There may have been others, as a few of the DoD launches are listed cryptically as "failed to orbit" on my list.

 - Ed Kyle

Altas 76E,  liquid, loss of thrust

Delta 228 hanging solid,

D259 was a solid tvc issue.

3 of the solid failures would have been not survivable but all of the liquids were.

There are no failed DOD launches that aren't acknowldged



Offline Jim

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Re: RS-68 CLV First Stage
« Reply #22 on: 07/13/2006 05:25 PM »
Quote
zinfab - 13/7/2006  1:07 PM

Would this group agree that the ATK solid rocket boosters are the most reliable rockets currently available?

If we switch to EELV, will they cut the size/mass of the CEV EVEN MORE, or redesign them to carry more (MORE development costs)?

NO

And no, EELV development would be cheaper than for the Stick

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #23 on: 07/13/2006 05:28 PM »
Quote
Jim - 13/7/2006  12:01 PM

It was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.


Official ruling?  There are officials?  :-)

Whatever it was "ruled", it didn't look like a good launch to me.  

 - Ed Kyle

Offline bad_astra

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Re: RS-68 CLV First Stage
« Reply #24 on: 07/13/2006 05:44 PM »
Ed, if the columbia stack had been a sidemounted cargo pod a-la Polyus, the payload would have survived, therefore it was a good launch.
"Contact Light" -Buzz Aldrin

Offline rumble

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Re: RS-68 CLV First Stage
« Reply #25 on: 07/13/2006 06:18 PM »
Quote
rumble - 13/7/2006  10:11 AM

How serious is this "chatter?"  Based on what I understand (which could be incorrect), I would assume a kerosene 1st stage (RD-180) for the core stage would need a beefy second stage.  The current plan for the 2nd stage/EDS doesn't seem to be this.

Could an RD-180 based 1st stage truly be a replacement for the capability of the RS-68 CaLV core stage, or would other vehicle changes be necessary to accompany this?

Dang...didn't put all of my thought here.  It would have made more sense if I had done that??

I mentioned a beefy second stage, because I'm not sure an RD-180 based 1st stage is appropriate for taking a payload nearly as close to orbit as the currently spec'd RS-68 stage with its substantially higher vacuum isp.  What I was assuming is that we might want an RP-1 stage to "pass the baton" to a higher isp stage earlier in the flight than we would with an LH2 1st stage.

Am I thinking correctly on this?

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Re: RS-68 CLV First Stage
« Reply #26 on: 07/13/2006 06:31 PM »
Quote
edkyle99 - 13/7/2006  1:15 PM

Quote
Jim - 13/7/2006  12:01 PM

It was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.


Official ruling?  There are officials?  :-)

Whatever it was "ruled", it didn't look like a good launch to me.  

 - Ed Kyle

Stuff comes off every launch vehicle.

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #27 on: 07/13/2006 06:58 PM »
Quote
Jim - 13/7/2006  1:18 PM

Quote
edkyle99 - 13/7/2006  1:15 PM

Quote
Jim - 13/7/2006  12:01 PM

It was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.


Official ruling?  There are officials?  :-)

Whatever it was "ruled", it didn't look like a good launch to me.  

 - Ed Kyle

Stuff comes off every launch vehicle.


I look at the issue from an insurance adjustor's point of view.  A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit.  The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed.  STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit.  If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed.

 - Ed Kyle

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #28 on: 07/13/2006 07:03 PM »
Quote
bad_astra - 13/7/2006  12:31 PM

Ed, if the columbia stack had been a sidemounted cargo pod a-la Polyus, the payload would have survived, therefore it was a good launch.


STS-107/Columbia was not Energia/Polyus.  Two different animals.  The orbiter has to be delivered undamaged into orbit.  It is not OK for the launch system to deliver it with a hole in its wing.

See my thoughts on this in message #48987.

 - Ed Kyle  


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Re: RS-68 CLV First Stage
« Reply #29 on: 07/13/2006 07:26 PM »
Quote
edkyle99 - 13/7/2006  2:45 PM

Quote
Jim - 13/7/2006  1:18 PM

Quote
edkyle99 - 13/7/2006  1:15 PM

Quote
Jim - 13/7/2006  12:01 PM

It was a successful launch and the mission was completed as far as a launch vehicle. And that is the official ruling.


Official ruling?  There are officials?  :-)

Whatever it was "ruled", it didn't look like a good launch to me.  

 - Ed Kyle

Stuff comes off every launch vehicle.

The orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics) .  Any payload that would have deployed form the shuttle, would have done so and with success.  The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw).  Foam coming off the ET is not flaw, it is happens with all vehicle that use foam.

NASA and the USAF classify it as a entry failure


I look at the issue from an insurance adjustor's point of view.  A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit.  The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed.  STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit.  If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed.

 - Ed Kyle

The orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics). It isn't the payload.  Any payload that would have deployed form the shuttle, would have done so and with success.  The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw).  Foam coming off the ET is not flaw, it is happens with all vehicle that use foam, trying to fix it is a crutch (that's why there will always be post flight inspections).  the orbiter wasn't properly designed for the flight environment    Harsh as it sounds this was a reuse issue.

NASA and the USAF classify it as a entry failure

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #30 on: 07/13/2006 07:31 PM »
Quote
edkyle99 - 13/7/2006  2:50 PM

Quote
bad_astra - 13/7/2006  12:31 PM

Ed, if the columbia stack had been a sidemounted cargo pod a-la Polyus, the payload would have survived, therefore it was a good launch.


STS-107/Columbia was not Energia/Polyus.  Two different animals.  

 - Ed Kyle  


wrong.  the Energia/Polyus was not an LV failure but a spacecraft failure, which was the same as OV-102

Offline pierogoletto

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Re: RS-68 CLV First Stage
« Reply #31 on: 07/13/2006 07:39 PM »
Quote
hyper_snyper - 13/7/2006  3:35 AM

I think the SRBs were one of the main drivers to the architecture we have today.  Whether thats a good thing or bad thing I don't know.  If you're going to have a RS-68 first stage you might as well just mod a Delta IV to do the job, IMO.

I agree; more, it seems to me that the first concern is to have a man-rated architecture, which the SRBs grant since they are used for the Space Shuttle. I don't know, really, if the RS-68 engine has been man-rated.
Piero Giuseppe Goletto

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Re: RS-68 CLV First Stage
« Reply #32 on: 07/13/2006 07:44 PM »
Quote
Jim - 13/7/2006  9:13 PM


The orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics). It isn't the payload.  Any payload that would have deployed form the shuttle, would have done so and with success.  The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw).  Foam coming off the ET is not flaw, it is happens with all vehicle that use foam, trying to fix it is a crutch (that's why there will always be post flight inspections).  the orbiter wasn't properly designed for the flight environment    Harsh as it sounds this was a reuse issue.

NASA and the USAF classify it as a entry failure

Jim, I agree.
The Orbiter is a part of the launch vehicle since during the ascent phase the SSME's are used (and all the avionics which controls the ascent and reentry phase is in the General Purpose Computers.
In my very humble opinion, the Orbiter design flaw is to have put the Orbiter on the ET instead of on the top of it.
Piero Giuseppe Goletto

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #33 on: 07/13/2006 08:26 PM »
Quote
Jim - 13/7/2006  2:13 PM

Quote
edkyle99 - 13/7/2006  2:45 PM

I look at the issue from an insurance adjustor's point of view.  A successful launch is one that delivers a payload, *unscathed*, to the contracted orbit.  The shuttle launch stack successfully delivered its orbiter "payload" to the proper orbit, but it was most certainly not unscathed.  STS-107 delivered damaged goods (the orbiter Columbia with a fatal hole in its wing's leading edge) to orbit.  If this were a commerical type launch, with one company owning the launch vehicle and another owning the orbiter (as payload), an adjustor would ascribe the failure to the launch vehicle, and a claim would be promptly filed.

 - Ed Kyle

The orbiter is the part fo the LV and it performed its part of launch (SSME's, avionics). It isn't the payload.  Any payload that would have deployed form the shuttle, would have done so and with success.  The orbiter failed as a reentry vehicle because it's TPS wasn't robust enough (a design flaw).  Foam coming off the ET is not flaw, it is happens with all vehicle that use foam, trying to fix it is a crutch (that's why there will always be post flight inspections).  the orbiter wasn't properly designed for the flight environment    Harsh as it sounds this was a reuse issue.

NASA and the USAF classify it as a entry failure


Interesting points.  

Regardless of where the design flaw was (ET or orbiter), stuff (the relatively heavy bipod ramp) still came off the ET that wasn't supposed to come off.  That's different than the usual popcorning or smaller particle shedding.  

NASA has always defined payload as stuff carried in the orbiter's payload bay.  The truth is that space shuttle orbiters themselves are really part launch vehicle and part "payload".  The traditional description of "payload" is  orbited, separated mass that continues to function after the launch vehicle completes its job.  The delivered "payload" portion of the orbiter should, in my opinion, include the TPS and the wings (among other parts), because they are functional hardware delivered to orbit for later use.  They are similar, in my opinion, to the aeroshells and parachute systems delivered to orbit as part of the MER or Viking "payloads", etc.  

 - Ed Kyle

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Re: RS-68 CLV First Stage
« Reply #34 on: 07/13/2006 09:36 PM »
Landing of an orbiter has nothing to do with the delivery of a satellite.  I am going to harsh again, but it is the same as the failure of the SRB parachutes on STS-4.  The SRB's were not recovered.  Is this a mission failure.

"The traditional description of "payload" is orbited, separated mass" is wrong.  Payload adapters, spintables, dual payload adapter assemblies are payload mass and not separated.  The cradles of the spacecraft that used to fly on the shuttle were not separated.   If the cradle was a damaged........  aeroshells and parachute are part of the spacecraft and not equivilent to the shuttle orbiter.

Offline R&R

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Re: RS-68 CLV First Stage
« Reply #35 on: 07/13/2006 10:04 PM »
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yinzer - 13/7/2006  10:03 PM

The lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events.  The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.

In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage.  And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV.  If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available.  NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.

Did you find something more than the "hallway chatter" that I see described on NASA Watch?

I have a hard time believing NASA would make another significant design change like they did going from Revised Shuttle to RS68 engines, especially going to RD180's.  Since PW&Rocketdyne are very far from building them in the US if ever I wonder if NASA can avoid the political backlash of once again relying on the Russians as significantly as they have been with Soyuz flights to ISS.

Offline general

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Re: RS-68 CLV First Stage
« Reply #36 on: 07/13/2006 10:40 PM »
Seems that if the RD-180 provides better performance than RS68, thus allowing fewer engines, it should be considered.  Fewer engines means fewer chances for failure.  The reduced tank diameter is a bonus, too.  

And it seems that NASA hasn't been adverse to changing ESAS.

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RE: RS-68 CLV First Stage
« Reply #37 on: 07/13/2006 11:01 PM »
Arguing about whether Columbia was an LV failure seems like pointless pedantry to me. The actual failure mechanism isn't in doubt, and what column you want to put it in depends on your choice of criteria. Just because NASA classifies it one way doesn't make it the only valid classification. There is no doubt that Columbia broke up on re-entry, and there is also no doubt that an off-nominal event during launch was the cause of this. Trying to stuff it in one tidy category doesn't really gain you anything.

The real question to me is, is it significant in the debate over CLV booster ? The answer seems to be an emphatic NO since the failure mechanism isn't possible for a top mounted payload. Of course, that reasoning applies to any number of the other failures you might want to use in this kind of statistical guesstimate. Every failure is unique, and only has limited applicability to other LVs. Combine that with the small sample size, and it's clear you can only get a very general trend from them.

Accepting these limits, it still seems that mature solid systems fail less often than mature liquid systems. How much this relates to the reliability of any particular system isn't nearly as a clear. The shuttle SRM is different from most other solid systems, and the actual failure rates of individual systems are all over the map.

Offline Avron

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Re: RS-68 CLV First Stage
« Reply #38 on: 07/14/2006 04:34 AM »
Solids vs "mature liquid systems" ( LOX driven systems - assumption)... lets up the statistical numbers... if x is the number of STS flights, then 2x is the number of SRB's used in the real world, but in the same time there are 3X SSME in these flights, with one failure to one SRB failure... based on this for US based manrated LV's in the last quarter century..

Clearly the "mature liquid systems" are ahead of the game.. and if you add in the time of operation, under flight load conditions... SRB just don't come close in that numbers game...its all MTFB.. reliability numbers are as a WAG an order of magnitude higher...

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #39 on: 07/14/2006 02:31 PM »
Quote
Avron - 13/7/2006  11:21 PM

Solids vs "mature liquid systems" ( LOX driven systems - assumption)... lets up the statistical numbers... if x is the number of STS flights, then 2x is the number of SRB's used in the real world, but in the same time there are 3X SSME in these flights, with one failure to one SRB failure... based on this for US based manrated LV's in the last quarter century..

Clearly the "mature liquid systems" are ahead of the game.. and if you add in the time of operation, under flight load conditions... SRB just don't come close in that numbers game...its all MTFB.. reliability numbers are as a WAG an order of magnitude higher...


An engine is not a liquid propulsion system, it is only an engine.  The fair comparison against a solid rocket motor is to look at an entire equivalent liquid propulsion stage, which includes not only the engines but also the pressurization systems, etc.  To be even more fair, the entire comparison should be normalized to total impulse or some such.  

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Offline Avron

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Re: RS-68 CLV First Stage
« Reply #40 on: 07/14/2006 02:36 PM »
Granted... on total impulse normalized ... do the numbers change? still an order of magnitute?

Offline edkyle99

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RE: RS-68 CLV First Stage
« Reply #41 on: 07/14/2006 03:35 PM »
Quote
I got thinking the other day (dangerous, I know), about how you could replace the (soild) first stage of the Ares I with a drop-in liquid replacement.

This works, but it would probably be less expensive to simply put a new upper stage on top of an existing Delta IV Heavy 3xCBC cluster (with reduced propellant loading in the CBCs).  The latter approach, unlike NASA's current Ares I plan, could be accomplished with a first stage that already exists, saving billions of development dollars.  The Heavy approach would also mitigate the main weakness of a 2xRS-68 design, which is low liftoff thrust-to-weight ratio.  

 - Ed Kyle

Offline Smatcha

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Re: RS-68 CLV First Stage
« Reply #42 on: 07/14/2006 03:50 PM »
Quote
R&R - 13/7/2006  2:51 PM

Quote
yinzer - 13/7/2006  10:03 PM

The lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events.  The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.

In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage.  And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV.  If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available.  NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.

Did you find something more than the "hallway chatter" that I see described on NASA Watch?

I have a hard time believing NASA would make another significant design change like they did going from Revised Shuttle to RS68 engines, especially going to RD180's.  Since PW&Rocketdyne are very far from building them in the US if ever I wonder if NASA can avoid the political backlash of once again relying on the Russians as significantly as they have been with Soyuz flights to ISS.

Not withstanding the Russian source of the RD180 it’s important to remember while LOX/Kerosene is a good first stage choice the current Shuttle configuration of using SRB’s in combination with low thrust LOX/LH2 is fairly equivalent.  Effectively, while the LOX/LH2 engines are burning from launch they are really part of an equivalent upperstage after the SRB are jettisoned.  LOX/LH2 is really the best choice for upper stages.  The fact that they also burn thru some of the fuel prior to SRB jettison just means a little larger tank than if the engines fired up as a true second stage.  When you consider the weight of inter tanks and lower stage jettison, structure and engines plus tank, it kind of washes out in the end.

The RD180 would essentially get rid of ATK and Boeing at the same time in favor of Lock/Mart.  Not going to happen.  There is a better way that works both technically and politically, with significant amounts of future work focused on the particular areas of expertise for all three.
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Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #43 on: 07/14/2006 04:11 PM »
Quote
SMetch - 14/7/2006  10:37 AM

The RD180 would essentially get rid of ATK and Boeing at the same time in favor of Lock/Mart.  

Assuming we are talking about the Crew Launch Vehicle here, wouldn't NASA split the work regardless of main engine?  For example, Energomash/Pratt&Whitney Rockedyne (PWR) would do the RD-180s, PWR would do the J-2X, Lockheed might do the first stage and Boeing the upper stage, or vice-versa.  ATK would still have escape rockets, separation rockets, etc., though an admitedly much smaller piece of the pie but pie nonetheless.  On top of these, of course are the lucrative CEV contracts to be awarded.

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Offline Avron

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Re: RS-68 CLV First Stage
« Reply #44 on: 07/14/2006 04:48 PM »
Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #45 on: 07/14/2006 07:21 PM »
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Jim - 13/7/2006  4:23 PM

Landing of an orbiter has nothing to do with the delivery of a satellite.  I am going to harsh again, but it is the same as the failure of the SRB parachutes on STS-4.  The SRB's were not recovered.  Is this a mission failure.

"The traditional description of "payload" is orbited, separated mass" is wrong.  Payload adapters, spintables, dual payload adapter assemblies are payload mass and not separated.  The cradles of the spacecraft that used to fly on the shuttle were not separated.   If the cradle was a damaged........  aeroshells and parachute are part of the spacecraft and not equivilent to the shuttle orbiter.

I have more thoughts on this, but they seem to belong in a different thread, so I will post them in the General Discussion area.

 - Ed Kyle

Offline general

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Re: RS-68 CLV First Stage
« Reply #46 on: 07/15/2006 12:24 AM »
I fear the "division of work".  This is not the best way to design, develop and field a new launch vehicle.  Looking at recent failure reports, they ALWAYS point out a lack of Systems Engineering and Integration.  Unless you have a strong SE&I, most programs are doomed to delays, cost escalation, or failures.

This is the problem with "divsion of work".  Work is parsed out for political reasons, then NASA is left trying to integrate the whole thing.  Their SE&I experience for LV development is rooted in Saturn, which is certainly not current.  

Why not simply put out an RFP and let the best company (ones with recent LV development experience) win?  Clearly Boeing and LockMart have the necessary experience for successful LV development.  NASA (and their toady ATK) clearly do not.

Offline quark

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Re: RS-68 CLV First Stage
« Reply #47 on: 07/18/2006 04:34 AM »
Quote
Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The 2X RD-180 booster works at the 5m diameter.  LM did a lot of work on it.  On the other hand, 2 RS-68's will not fit within a 5m diameter.  Not sure what diameter it takes, probably 6 or 7m.

The 2X RD-180 booster delivers substantially more energy than the 5-seg SRB.  So much more that you don't need the J-2x any more and can deliver 25mT with 4 RL-10's.  So two major propulsion development programs obviated and 25mT performance resotored.

Offline meiza

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Re: RS-68 CLV First Stage
« Reply #48 on: 07/18/2006 11:11 AM »
What about an ULAriane: two Atlas V first stages with shortedened tank around a widened or lengthened RS-68-powered delta4ish stage (nozzle extension?). Top off with an appropriate number of RL10:s, although it can probably orbit some stuff without any upper stage. :)
All liquid, possible to shutdown on pad if the readings are not good for liftoff. And easy abort always possible. Drawback is at least weird load paths and vehicle dynamics. Is the staging too hard on the fragile Atlas first stages? (Compared to the rugged shuttle srb:s?)

Just a thought excercise.

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Re: RS-68 CLV First Stage
« Reply #49 on: 07/18/2006 12:32 PM »
Quote
quark - 17/7/2006  11:21 PM

Quote
Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The point is:
When you want to go to Moon or Mars you need super heavy lift vehicle. And there is already one – STS (thanks to SRB). You would need around 10 x RD-180 to match Saturn V first stage. So the choice is:

1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V
'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 #50 on: 07/18/2006 12:38 PM »
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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. ...

Well, that doesn't seem to be the point.  First of all what is exactly a "super heavy lift vehicle"?  15tonnes?  How about 50 tonnes?  500 metric tonns?  Which one and why exactly?  And why do we want it?  I mean, really?

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Re: RS-68 CLV First Stage
« Reply #51 on: 07/18/2006 12:52 PM »
Quote
JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #52 on: 07/18/2006 01:21 PM »
Quote
Jim - 18/7/2006  7:39 AM

Quote
JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

But it's needed for Ares V.
Or do you think that there will be enough resources to develop and prepare Moon stuff for Ares V before 2018?
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #53 on: 07/18/2006 01:31 PM »
Quote
lmike - 18/7/2006  7:25 AM

Quote
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.
'Old age and treachery will overcome youth and skill' - Old Greek experience

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Re: RS-68 CLV First Stage
« Reply #54 on: 07/18/2006 01:53 PM »
Quote
JIS - 18/7/2006  9:08 AM

Quote
Jim - 18/7/2006  7:39 AM

Quote
JIS - 18/7/2006  8:19 AM


1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

It's not either/or.  The stick is not need for the CaLV.

But it's needed for Ares V.
Or do you think that there will be enough resources to develop and prepare Moon stuff for Ares V before 2018?

CaLV is Ares V.

Yes, If you eliminate all the Ares I changes and go with cheaper EELV derivitives

Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #55 on: 07/18/2006 09:11 PM »
Quote
JIS - 18/7/2006  7:19 AM

Quote
quark - 17/7/2006  11:21 PM

Quote
Avron - 14/7/2006  10:35 AM

Maybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking

At some point, you have to quit the political engineering and find a technical solution that works.  So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch.  Why?  Did ATK win a competition?  When they had to compete at the beginning of the EELV competition, they lost first round.  

The point is:
When you want to go to Moon or Mars you need super heavy lift vehicle. And there is already one – STS (thanks to SRB). You would need around 10 x RD-180 to match Saturn V first stage. So the choice is:

1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)

2. go with Ares 1 and Ares V

As Jim said, it doesn't have to be either/or.  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

Offline josh_simonson

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Re: RS-68 CLV First Stage
« Reply #56 on: 07/19/2006 12:23 AM »
The core stage of the Aries V with RS-68s and 10m tank has enough fuel fraction to send CEV to ISS in a single stage that NASA intends to build anyway.  Launching crew on the Aries V core would double it's economies of scale because crew/cargo LVs roll off the exact same assembly line, and developing the CLV will get halfway to having an HLV.  This would put NASA's ducks in a row instead of scattered willy-nilly tinkering with ELVs or designing dead-end rockets with components that don't exist yet.  No other CLV option also serves to make the HLV significantly cheaper.

Offline HailColumbia

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Re: RS-68 CLV First Stage
« Reply #57 on: 07/19/2006 01:06 AM »
wouldent the Ares V core be overkill?

How much can the core lift alone? Plus, wouldent an ares V core cost more then the Ares I ?
-Steve

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #58 on: 07/19/2006 01:09 AM »
Quote
josh_simonson - 18/7/2006  8:10 PM

The core stage of the Aries V with RS-68s and 10m tank has enough fuel fraction to send CEV to ISS in a single stage that NASA intends to build anyway.  Launching crew on the Aries V core would double it's economies of scale because crew/cargo LVs roll off the exact same assembly line, and developing the CLV will get halfway to having an HLV.  This would put NASA's ducks in a row instead of scattered willy-nilly tinkering with ELVs or designing dead-end rockets with components that don't exist yet.  No other CLV option also serves to make the HLV significantly cheaper.

This won't work.  It was shown in another thread.  Anyways can't use the SM as a 2nd stage because it wouldn't be able to complete its lunar mission.

Offline kraisee

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RE: RS-68 CLV First Stage
« Reply #59 on: 07/19/2006 05:34 AM »
Sadly it is an either/or situation guys.   It's not the technology which is the limit, but the political and economic realities of the USA today in the mid 2000's:-

We all know and accept that the Ares-V won't fly until 7 years after STS has been retired.

If there isn't *something* to keep all the ET manufacturing staff at Michoud, the SRB manufaturing staff in Utah, and the thousands of staff at the various NASA center busy during that seven year gap, there would be zero reason to keep that huge workforce employed just twiddling their thumbs while they wait half a decade to do something useful.

Current staff would be released at the end of the Shuttle pProgram and they'd try re-hiring afresh about five years later, two years before the new vehicle is ready, so we would just have an identical repeat of the post-Apollo era.

The EELV guys are already staffed, so would not be in a position to hire thousands of extra workers, so the result would be thousands of aerospace engineers and administrators from around the country all looking for work in an already depressed aerospace industry.

That's a political and economic nightmare scenario.

People waaaaaaay above Griffin on the foodchain have already made that decision and have directed NASA as to how to proceed.   This reality is the only reason why we're finishing ISS with the Shuttle instead of with another launcher - because it saves jobs.   It's why the SDLV's will be chosen for both new vehicles - unless another vehicle could offer massively higher safety margins or and hugely beneficial economic benefits - and I'm sorry to say, but the alternatives out there just can't offer huge advantages in either field, so they never stood a chance.

While the technology would allow for the Crew launcher to come from one family of LV's, and the Cargo lifter to come from a separate family, the political and economic realities of the nation will preclude such a thing from ever actually happening.   Whichever the first comes from, the second is assured to follow directly from the same lineage.

All IMHO.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #60 on: 07/19/2006 06:13 AM »
Quote
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"
-Robert A. Heinlein

Offline lmike

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

Quote
lmike - 18/7/2006  7:25 AM

Quote
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 »
Quote
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.

Quote
"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 »
Quote
JIS - 20/7/2006  2:36 AM

Quote
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?

Quote
Quote
"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 »
Quote
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.


Quote
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 »
Quote
kraisee - 19/7/2006  1:00 AM

Quote
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.

Quote
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.

Quote
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 »
Quote
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 »
Quote
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 »
Quote
edkyle99 - 13/7/2006  10:17 AM

Quote
bad_astra - 13/7/2006  9:22 AM

Quote
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...

"His plan had no goals, no timeline, and no budgetary guidelines. Just maybe's, pretty speeches, and smokescreens."

Offline gladiator1332

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

Quote
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!

Quote
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 »
Quote
simonbp - 19/9/2007  5:53 PM

Witness Ye The Birth of a Forum Legend!

Quote
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 »
Quote
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 »
Quote
kkattula2 - 21/9/2007  5:56 AM

Quote
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 »
Quote
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!!!!!

Offline CFE

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Re: RS-68 CLV First Stage
« Reply #80 on: 09/23/2007 02:33 AM »
"1.5 launches" reminds me of a saying that a wise professor of mine had: "You can't be half-pregnant."

I guess that a "half launch" would be one that fails to achieve orbit.  Ouch!  Let's hope for no half-launches.

I understand NASA's logic about the Ares I being "half an Ares V."  The cost of producing the Ares I will be less than half of what it will cost to produce an Ares V.  But that ignores the reality of fixed costs, which have destroyed the shuttle cost model (and will destroy the Ares cost model.)  In the Ares architecture, you need a standing army that can handle two very different vehicles with different sets of launch pads and different types of ground support equipment.  I would expect the commonality between Jupiter 232 and Jupiter 120 to reduce the standing army costs when compared to Ares.

Besides, if you've read the TeamVision paper presented at AIAA Space 2007, you'll see that the Jupiter 120 no longer plays a role in the lunar mission baseline.  The preferred architecture uses two J-232's.  Presumably, Jupiter 120 is phased out once the ISS is shut down.
"Black Zones" never stopped NASA from flying the shuttle.

Offline bad_astra

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Re: RS-68 CLV First Stage
« Reply #81 on: 09/23/2007 04:28 AM »
Ares IV sans srb's..
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Offline A_M_Swallow

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Re: RS-68 CLV First Stage
« Reply #82 on: 09/23/2007 07:21 AM »
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CFE - 23/9/2007  3:33 AM
Besides, if you've read the TeamVision paper presented at AIAA Space 2007, you'll see that the Jupiter 120 no longer plays a role in the lunar mission baseline.  The preferred architecture uses two J-232's.  Presumably, Jupiter 120 is phased out once the ISS is shut down.

Someone somewhere will want to put a 40 mT satellite in LEO or possibly 30 mT plus astronauts.

Offline sticksux

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Re: RS-68 CLV First Stage
« Reply #83 on: 09/23/2007 02:51 PM »
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gladiator1332 - 19/9/2007  7:07 PM
Still 2 x RD-180 may still be the best bet if there is a switch to EELV.

Note: Russian engineers are not very happy with RD-170/180/190 family of engines. There is a concern that they are "overstressed".

Basically, oxidizer-rich hot turbine gases are too hot and too high pressure. They tend to ignite piping they are flowing through. The biggest difficulty of R&D of these engines was to prevent this. There should be no foreign particles, even minute ones (<0.1 mm). No particles should be generated by O turbine while it operates (you can imagine how hard is to achieve that with 100s of atmospheric pressure and flow speeds of nearly speed of sound). There are special coatings on turbine blades and piping.

And yet, this engine still sometimes has fires in O turbine at ignition. Latest Zenith failure. There are opinions among engineers that there was no foreign particle, that this is just a convenient excuse.

If RD-180 will ever be americanized, I think it makes sense to sacrifice a bit of Isp, but get those pressures down.

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Re: RS-68 CLV First Stage
« Reply #84 on: 09/23/2007 03:07 PM »
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sticksux - 23/9/2007  10:51 AM

If RD-180 will ever be americanized, I think it makes sense to sacrifice a bit of Isp, but get those pressures down.

It doesn't need to be changed.  The engine is fine.  There is just a difference in cleaning practices between users

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #85 on: 09/23/2007 07:31 PM »
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CFE - 22/9/2007  10:33 PM
Besides, if you've read the TeamVision paper presented at AIAA Space 2007, you'll see that the Jupiter 120 no longer plays a role in the lunar mission baseline.  The preferred architecture uses two J-232's.  Presumably, Jupiter 120 is phased out once the ISS is shut down.

CFE,
There is no particular reason to phase out the Jupiter-120.   The only practical differences between J-120 the J-232 Core vehicle is simply software control and having the ability in the VAB to remove/fit the central main engine.   That's almost negligible in cost and manpower terms, so you can continue to fly the J-120 whenever you need it and never have to officially phase anything out.

We have to remember that while Lunar missions (and Mars eventualy) are certainly the real "meat" of the new program, LEO can't be ignored.   ISS and Hubble are not going to be the only requirements we will have for LEO access over the next 30 years, so having J-120 "online" whenever required would be very sensible IMHO providing very efficient (~$3,000 per kg to LEO) man-rated lift capability.   I can certainly imagine a lot of uses for that without spending all the money for full J-232 flights.

Ross.
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Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #86 on: 09/23/2007 07:32 PM »
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A_M_Swallow - 23/9/2007  3:21 AM

Someone somewhere will want to put a 40 mT satellite in LEO or possibly 30 mT plus astronauts.

I *know* the NRO would already love to be able to do something like that today - but simply can't right now.

Ross.
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Offline Integrator

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Re: RS-68 CLV First Stage
« Reply #87 on: 09/29/2007 02:03 AM »
AW&ST reports DoD is stockpiling RD180s for some heavy lift vehicle, possibly for NRO.
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Offline Peter NASA

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Re: RS-68 CLV First Stage
« Reply #88 on: 09/29/2007 02:21 AM »
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Integrator - 28/9/2007  9:03 PM

AW&ST reports DoD is stockpiling RD180s for some heavy lift vehicle, possibly for NRO.

I'd wait for industry confirmation. AW have gotten some things wrong lately.

Offline MKremer

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Re: RS-68 CLV First Stage
« Reply #89 on: 09/29/2007 02:23 AM »
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Integrator - 28/9/2007  9:03 PM

AW&ST reports DoD is stockpiling RD180s for some heavy lift vehicle, possibly for NRO.

DoD doesn't buy and store engines, its contractors do. Sounds like someone may have read a memo or heard a rumor about the Atlas VH concept and started making assumptions.

Offline CFE

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Re: RS-68 CLV First Stage
« Reply #90 on: 09/29/2007 05:27 AM »
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Integrator - 28/9/2007  8:03 PM

AW&ST reports DoD is stockpiling RD180s for some heavy lift vehicle, possibly for NRO.

AW&ST can say a lot of things, but that doesn't always mean they're correct.  I'd chalk this one up alongside Soviet nuclear-powered bombers, Tesla Death Rays, and Blackstar (some of AW&ST's other "shining moments.")
"Black Zones" never stopped NASA from flying the shuttle.

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Re: RS-68 CLV First Stage
« Reply #91 on: 09/30/2007 02:00 AM »
There is some interest in DoD at very high levels for developing a new heavy lifter -- I know: "we've heard that before..." but I have an inside source who I know personally and trust.  Meanwhile, work in NASA on Ares V has come to a virtual standstill.  Do you think some sort of collaborative DoD-NASA effort is being discussed?

Offline CFE

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Re: RS-68 CLV First Stage
« Reply #92 on: 09/30/2007 02:40 AM »
There's always going to be some degree of high-level DoD interest in certain concepts.  The challenge is to turn that high-level interest into Congressional funding.  There are certain people within DoD who want a military space-plane, but that's not going to happen anytime soon.
"Black Zones" never stopped NASA from flying the shuttle.

Offline Jim

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Re: RS-68 CLV First Stage
« Reply #93 on: 09/30/2007 03:22 AM »
Quote
- 29/9/2007  10:00 PM

There is some interest in DoD at very high levels for developing a new heavy lifter -- I know: "we've heard that before..." but I have an inside source who I know personally and trust.  Meanwhile, work in NASA on Ares V has come to a virtual standstill.  Do you think some sort of collaborative DoD-NASA effort is being discussed?

Your source isn't really so "inside".   The "real" DOD doesn't need anymore lift than the current fleet which includes upgrades in work.

Ares V hasn't come to a stand still, it just is being work according to its need date

The DOD will never get in bed with NASA wrt launchers again.  Also the DOD "heavy" lifters are used on the west coast which doesn't have any pads for SRB based boosters

Offline tnphysics

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Re: RS-68 CLV First Stage
« Reply #94 on: 09/30/2007 03:48 AM »
If the DoD wants a military space plane, they should pay NASA to give them one.

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Re: RS-68 CLV First Stage
« Reply #95 on: 09/30/2007 03:50 AM »
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tnphysics - 29/9/2007  11:48 PM

If the DoD wants a military space plane, they should pay NASA to give them one.

It is not NASA's job to develop and procure hardware for the DOD.  The DOD can do it on its own, they have the expertise

Offline simonbp

Re: RS-68 CLV First Stage
« Reply #96 on: 10/06/2007 11:30 PM »
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Jim - 29/9/2007  8:50 PM

Quote
tnphysics - 29/9/2007  11:48 PM

If the DoD wants a military space plane, they should pay NASA to give them one.

It is not NASA's job to develop and procure hardware for the DOD.  The DOD can do it on its own, they have the expertise

And a much, much larger budget.

The mutually beneficial cooperation between DoD and NASA on upgrading the RS-68 is a better example of how it should work...

Simon ;)

Offline publiusr

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Re: RS-68 CLV First Stage
« Reply #97 on: 10/26/2007 05:17 PM »
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TrueBlueWitt - 21/9/2007  8:53 AM

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!!!!!

Agreed. I will say this much. Had Atlas V used RD-170 and not RD-180--it would have been a great contenter for CLV. An Americanized Zenit with smaller strap-ons would look rather like a scaled up Delta II.

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Re: RS-68 CLV First Stage
« Reply #98 on: 10/26/2007 05:40 PM »
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publiusr - 26/10/2007  1:17 PM

 Had Atlas V used RD-170 and not RD-180--it would have been a great contenter for CLV. An Americanized Zenit with smaller strap-ons would look rather like a scaled up Delta II.

That has no bearing.  2 RD-180's could be used

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #99 on: 10/26/2007 05:55 PM »
LM actually did an analysis on that a while back - for their Phase 2 vehicle - and found that there were better engine-out options if two RD-180's were used instead of a single RD-171 (BTW, needs to be the 171 variant because 170 hasn't got full-range gimbal control).

Of course, Congress seem to be strongly against using a Russian engine.   I'm not sure how to persuade them otherwise given the deteriorating political climate with Russia these days, and PWR say that they'll have to do some seriously expensive reverse engineering of the RD-180, even with the plans in-hand, that they aren't bothering too.   They'd probably be better off building the RS-84 instead.

Ross.
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Re: RS-68 CLV First Stage
« Reply #100 on: 10/26/2007 05:56 PM »
But that would be a fresh start now. If it had used two RD-180's from the beginning...

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Re: RS-68 CLV First Stage
« Reply #101 on: 10/26/2007 06:05 PM »
There's a lot to be said for having a common core for both CLV and CaLV, whether that be Direct or Atlas Phase whatever.

With lack of an American-made kero-lox engine, it's fortunate there was a -68 to turn to.

Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #102 on: 10/26/2007 07:59 PM »
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Jim - 26/10/2007  10:40 AM

Quote
publiusr - 26/10/2007  1:17 PM

 Had Atlas V used RD-170 and not RD-180--it would have been a great contenter for CLV. An Americanized Zenit with smaller strap-ons would look rather like a scaled up Delta II.

That has no bearing.  2 RD-180's could be used

RD-170 is much simpler integration.

Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #103 on: 10/26/2007 08:05 PM »
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kraisee - 26/10/2007  10:55 AM

LM actually did an analysis on that a while back - for their Phase 2 vehicle - and found that there were better engine-out options if two RD-180's were used instead of a single RD-171 (BTW, needs to be the 171 variant because 170 hasn't got full-range gimbal control).

Ross.


Let's just entertain this scenario a bit.  At lift off, most LV has a T/W ratio between 1.1 to 1.4.  All of sudden you have an "engine out scenario" with ONE of the RD-180.  Now you have a T/W ratio of 0.5 to 0.7.  No matter how you cut it, you do not have enough lift to keep that vehicle IN the air and OFF the ground.  Also, the other RD-180's thrust is now off-center thereby tilting the vehicle over and heading directly INTO the ground with its FULL POWER!!  Now how does that help mission reliability?

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #104 on: 10/26/2007 08:29 PM »
The engine out was available later in the first stage flight, not at liftoff.   I forget precisely where it became a possibility, but probably somewhere about half way to tow-thirds of the way through the first stage burn.

I'm not sure there has ever been a successful rocket designed to be able to cope with an engine out around T+1s.   N-1 might have been, but it was never successful.

Ross.
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Offline edkyle99

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Re: RS-68 CLV First Stage
« Reply #105 on: 10/26/2007 09:56 PM »
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kraisee - 26/10/2007  3:29 PM

I'm not sure there has ever been a successful rocket designed to be able to cope with an engine out around T+1s.  

I think that Space Shuttle can suffer an SSME failure, assuming that it shuts down nice, right off the pad and make an RTLS abort.  

 - Ed Kyle

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #106 on: 10/26/2007 10:10 PM »
Good point, but I was really talking about a mission which still proceeds to successful orbital insertion.

Ross.
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Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #107 on: 10/26/2007 11:57 PM »
Quote
edkyle99 - 26/10/2007  2:56 PM

Quote
kraisee - 26/10/2007  3:29 PM

I'm not sure there has ever been a successful rocket designed to be able to cope with an engine out around T+1s.  

I think that Space Shuttle can suffer an SSME failure, assuming that it shuts down nice, right off the pad and make an RTLS abort.  

 - Ed Kyle


That's because it still has that 2 MILLION pound thrust going full blast during the initial ascent.  After that, then it can still ascent with only 2 engines.  



Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #108 on: 10/27/2007 12:12 AM »
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kraisee - 26/10/2007  1:29 PM

The engine out was available later in the first stage flight, not at liftoff.   I forget precisely where it became a possibility, but probably somewhere about half way to tow-thirds of the way through the first stage burn.

Ross.

That's a valid point.  However; history has shown that when liquid rocket engines fail, they fail in the first few second of start (thus the hold-down bolts, etc.).  I don't think using the last 1/3 of boost phase as "engine-out" justification for multiple engines is a good one.  If they admit that they can only buy the RD-180 engines, then perhap that's a more reasonable explanation.





Offline tnphysics

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Re: RS-68 CLV First Stage
« Reply #109 on: 10/27/2007 05:23 PM »
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kraisee - 26/10/2007  4:29 PM

The engine out was available later in the first stage flight, not at liftoff.   I forget precisely where it became a possibility, but probably somewhere about half way to tow-thirds of the way through the first stage burn.

I'm not sure there has ever been a successful rocket designed to be able to cope with an engine out around T+1s.   N-1 might have been, but it was never successful.

Ross.

Falcon 9. But it has never flown.

Offline JIS

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Re: RS-68 CLV First Stage
« Reply #110 on: 10/31/2007 08:33 AM »
Are there any news about humanrating RS-68? How long would it take? How much is the estimated cost? The original development took 4 and half year and cost about $500mil.
I think that the specs of new engine is pretty nailed down by AF and NASA requirements. I expect that it will be again certified for up to 350s burn. As the certification for human rating is very expensive proces I would expect the develpment cost and time to be very similar to the orginal $500mil and 4 and half year. I suppose that the real development will start only after STS retirement.
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Offline TrueGrit

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Re: RS-68 CLV First Stage
« Reply #111 on: 10/31/2007 08:05 PM »
Lets just say your $500mil is off base...  Boeing wrote off nearly $2bil on Delta IV development losses and government only kicked in $500mil...

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Re: RS-68 CLV First Stage
« Reply #112 on: 10/31/2007 08:45 PM »
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TrueGrit - 31/10/2007  5:05 PM

Lets just say your $500mil is off base...  Boeing wrote off nearly $2bil on Delta IV development losses and government only kicked in $500mil...

Offbase high.  He was only talking RS-68 and not the whole Delta IV development

Offline kraisee

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Re: RS-68 CLV First Stage
« Reply #113 on: 10/31/2007 09:06 PM »
RS-68 remained on-budget AFAIK.

Rocketdyne's own documentation claims the entire development program cost ~$500m through to first flight.

Ross.
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Offline TrueGrit

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Re: RS-68 CLV First Stage
« Reply #114 on: 10/31/2007 09:06 PM »
Understood...  Yet I remember quite a few engien testing incidences and a particular redesign activity that would dispute the "on cost" claim.

As for manrating...  Total Delta IV manrating was priced around $500mil during the OSP days, and only a portion was engine related.  NASA will likely be able to develop the RS-68B for Ares V for less than half what the Delta IV manrating would have been.

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Re: RS-68 CLV First Stage
« Reply #115 on: 10/31/2007 09:20 PM »
Quote
TrueGrit - 31/10/2007  6:06 PM

As for manrating...  Total Delta IV manrating was priced around $500mil during the OSP days, and only a portion was engine related.  NASA will likely be able to develop the RS-68B for Ares V for less than half what the Delta IV manrating would have been.

It was much less than $500mil.  A new crew access tower was $500mil

Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #116 on: 10/31/2007 09:31 PM »
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kraisee - 31/10/2007  3:06 PM

RS-68 remained on-budget AFAIK.

Rocketdyne's own documentation claims the entire development program cost ~$500m through to first flight.

Ross.

Since this was an internally funded program, nobody really knows what it cost.


Offline TrueGrit

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Re: RS-68 CLV First Stage
« Reply #117 on: 10/31/2007 10:41 PM »
As for "manrating"...  The real question comes to what needds to be changed?  And then how many engines need to be tested to establish confidence?  The number of engines is the biggest factor in the costs.  In general the minimum amount of engines is 3 (1 development and 2 certification), for a significant engine upgrade.  A component certification, valves or controller, might be accomplished with only 1 engine test series.  And in general you test each engine ~2x life, which is normaly ~4x flight time.  So your talking about ~8x flight time.  It really depends on the change.

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Re: RS-68 CLV First Stage
« Reply #118 on: 11/01/2007 02:30 AM »
It's not as much the amount of test time as it is the design standards.  Go through all of the standards that SSME meets or is supposed to but waives.  Check if -68 meets 'em.  Fracture control and trey-redundant controller come to mind.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline TrueGrit

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Re: RS-68 CLV First Stage
« Reply #119 on: 11/01/2007 04:55 PM »
RS-68 was designed the same PWR and military standards that were used on SSME...  The big difference in SSME and RS-68 development is the number of engines tested prior to first flight, not the design standards.  The exceptions are in the controller design which lacks triple redundancy, no in-flight redline shutdown capability, and the main valves which lacked the SSME pneumatic backup.

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Re: RS-68 CLV First Stage
« Reply #120 on: 11/01/2007 05:06 PM »
It's the NASA standards that EELV did not use that are the gap, not the PWR and military standards.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #121 on: 11/01/2007 08:31 PM »
Quote
TrueGrit - 1/11/2007  10:55 AM

RS-68 was designed the same PWR and military standards that were used on SSME...  The big difference in SSME and RS-68 development is the number of engines tested prior to first flight, not the design standards.  The exceptions are in the controller design which lacks triple redundancy, no in-flight redline shutdown capability, and the main valves which lacked the SSME pneumatic backup.


I am sorry but I could not keep a straight face reading this statement.

 They are not the same.  RS-68 is a COST-DRIVEN design, e.g., design it to the lowest cost (i.e., cheap), while the SSME was a PERFORMANCE-DRIVEN design.

You could say that they may use the same MIL "standards" but they certainly did not have the same design "REQUIREMENTS".



Offline Propforce

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Re: RS-68 CLV First Stage
« Reply #122 on: 11/01/2007 08:35 PM »
Quote
Antares - 1/11/2007  11:06 AM

It's the NASA standards that EELV did not use that are the gap, not the PWR and military standards.

Did you just say that NASA has a deisgn standard for liquid rocket engines?  

Is that like the NASA-SP's?  or is it more like "ummm... Marshall, what do you think?...  how about you, Langely?.... Glenn, why are you so quiet? ....  OK, we'll have to get back to you on this, when we figure out what's going on internally first.... "


Offline Antares

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Re: RS-68 CLV First Stage
« Reply #123 on: 11/02/2007 04:15 AM »
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Propforce - 1/11/2007  4:35 PM
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Antares - 1/11/2007  11:06 AM
It's the NASA standards that EELV did not use that are the gap, not the PWR and military standards.
Did you just say that NASA has a deisgn standard for liquid rocket engines?
No.  There are plenty of NASA Standards that RS-68 was not required to follow since it was a commercial development with some funding from DoD.  Of course, Rocketdyne's experience on NASA engines informed the design.  Use the standards where cost effective.  IMO, that's enough for ANY payload as long as the top of the stack has an abort mode.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

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