Author Topic: CEV HLV Upper Stage Engine  (Read 15788 times)

Offline AndyMc

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CEV HLV Upper Stage Engine
« on: 11/26/2005 01:20 PM »
Source: http://www.usspacenews.com/index.html

The CEV Heavy Lift Launch Vehicle (HLV) upper stage engine will be an updated version of the J-2 (a J-2S to be exact) from the Apollo program. Rocketdyne has about 9 J-2's developed for Apollo in engineering storage in California and excellent condition.  These would be used as starting points for the J-2S.
I wonder what other delights they have tucked away in their basement - an F1 or two perhaps ;)




Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #1 on: 11/26/2005 07:01 PM »
Quote
AndyMc - 26/11/2005  9:20 AM

Source: http://www.usspacenews.com/index.html

The CEV Heavy Lift Launch Vehicle (HLV) upper stage engine will be an updated version of the J-2 (a J-2S to be exact) from the Apollo program. Rocketdyne has about 9 J-2's developed for Apollo in engineering storage in California and excellent condition.  These would be used as starting points for the J-2S.
I wonder what other delights they have tucked away in their basement - an F1 or two perhaps ;)


Anyone know where they got that information from?

Last time I heard, the SSME had been chosen already - mainly because its performance was far better, and it was already in production.

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

Offline AndyMc

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RE: CEV HLV Upper Stage Engine
« Reply #2 on: 11/26/2005 08:58 PM »
I think they mean 'The Big One' SDHLV. The upper stage is to have two of them, last time I checked. Single SSME is for the upper stage of 'The Stick' ;)

Strange site that, they give no sources, yet appear to accept paid advertising??

Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #3 on: 11/27/2005 08:23 PM »
Quote
AndyMc - 26/11/2005  4:58 PM

I think they mean 'The Big One' SDHLV. The upper stage is to have two of them, last time I checked. Single SSME is for the upper stage of 'The Stick' ;)

Yeah, that's what I figured too.

While the power profile for two J-2's is sufficient for the upper stage of Magnum SDLV, I worry that the J-2 engine does have a failure rate a lot higher than SSME.

Two J-2's failed on the S-II second stage of Apollo-6 flight, and one failed to restart on the upper S-IV stage on that flight too.   One failed on Apollo-13's S-II second stage also.

So, out of 87 flown J-2's, there were 4 mechanical failures.   That's a 4.6% mechanical failure rate, which is pretty high compared to SSME's 0.6% failure rate - especially so considering that both SSME flight failures on record were actually both sensor equipment malfunctions and were not caused by mechanical failures with the engine itself.

I hope they don't lose sight of those facts in making this decision.

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

Offline Spacely

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RE: CEV HLV Upper Stage Engine
« Reply #4 on: 11/27/2005 11:20 PM »
The SSMEs are a fairly amazing model of consistency considering their piecemeal design, testing, etc. If history ultimately remembers the STS kindly, the genius of the SSMEs will be a primary cause.

Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #5 on: 11/28/2005 04:43 AM »
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Spacely - 27/11/2005  7:20 PM

The SSMEs are a fairly amazing model of consistency considering their piecemeal design, testing, etc. If history ultimately remembers the STS kindly, the genius of the SSMEs will be a primary cause.

I also think the SSME's are the jems which glitter brightest for the entire project.

I don't think STS will be remembered badly though.   Sure, it had a goodly number of problems, but the Shuttle was a glorious looking vehicle, and will probably always hold a soft spot in the hearts of the American psyche.

STS brought a gamut of new scientific understanding about everything from building structures in space, to repairing satellites. It performed unprecedented scientific research in orbit for decades and taught us many lessons in the process.

Shuttle may have been a detour off of the true path NASA should have been walking, but it was necessary at the time, or there would not today be any US presence in space at all.

And it certainly has been an interesting adventure all of its own.

I think anyone directly associated with the Shuttle can stand proud of their efforts.

And the STS infrastructure is now going to be a brilliant torch for blazing our way back to our true path again.

If the King dies, his successor will reign on.

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

Offline CuddlyRocket

RE: CEV HLV Upper Stage Engine
« Reply #6 on: 11/28/2005 12:47 PM »
There has been 30+ years of manufacturing methodology improvements since the J-2 was last used, which should have an impact on their reliability.  But yes, I would expect them to take into account the SSMEs reliability, but this may be a question of cost v reliability.

Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #7 on: 11/28/2005 06:48 PM »
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CuddlyRocket - 28/11/2005  8:47 AM

There has been 30+ years of manufacturing methodology improvements since the J-2 was last used, which should have an impact on their reliability.  But yes, I would expect them to take into account the SSMEs reliability, but this may be a question of cost v reliability.

Yes, and that's another reason why I'd prefer SSME, especially an 'S' variant of the SSME, on the Upper stage of SDLV.

We're going to need an air-startable SSME-S for the upper stage of the CLV ultimately, because SSME Block-II is quite expensive.

So why not use the same engine for this too and thus save having to have multiple production lines, with multiple staff etc.

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

Offline HailColumbia

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RE: CEV HLV Upper Stage Engine
« Reply #8 on: 11/29/2005 12:59 AM »
what exactly does the "S" signify?
-Steve

Online MKremer

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RE: CEV HLV Upper Stage Engine
« Reply #9 on: 11/29/2005 01:10 AM »
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HailColumbia - 28/11/2005  7:59 PM

what exactly does the "S" signify?
Designed for single use, I would guess.
(Parts and subsystems of the Shuttle SSMEs are 'overbuilt' to last through multiple launches and overhauls.)

Offline HailColumbia

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RE: CEV HLV Upper Stage Engine
« Reply #10 on: 11/29/2005 03:09 AM »
well what about the J-2S? its not as if the J-2 was reusable.
-Steve

Offline RedSky

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RE: CEV HLV Upper Stage Engine
« Reply #11 on: 11/29/2005 03:45 AM »
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HailColumbia - 28/11/2005  7:59 PM

what exactly does the "S" signify?

Stands for "simplified".  See....

http://www.astronautix.com/engines/j2s.htm


Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #12 on: 11/29/2005 05:37 AM »
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HailColumbia - 28/11/2005  11:09 PM

well what about the J-2S? its not as if the J-2 was reusable.

That's the one they'll use if the go with the J-2 family.

Mind you, another factor should be that there's almost nobody still working at Stennis, Marshall, KSC or Rocketdyne who can remember ever working on the J-2 engine itself.

Right now, there's thousands of engineers already fully familiar with SSME.

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

Offline AndyMc

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RE: CEV HLV Upper Stage Engine
« Reply #13 on: 11/29/2005 12:10 PM »
Reading from Astronautix and elsewhere, the J-2S engine operates at lower a chamber pressure of 30 bar as opposed to 204 bar for the SSME, and has a low thrust feature "for propellant tank settling, on-orbit maneuvering, and rapid engine chill down prior to firing."

Two J-2S engines give the same thrust as one SSME (2x116 kgf - J-2s / 232 kgf - SSME), plus this offers a back-up should one fail. Is one J-2S engine powerful enough to complete the TLI burn though?

Astronautix has the ISP for the J-2S as being 426s as opposed to 453s for the SSME, though elsewhere http://yarchive.net/space/shuttle/j2s.html this guy states that the J-2S ISP is 455s. This may be possible, as a couple of other engines the HG-3 & HG-3-SL derived from the J2 achieved a higher ISP (452s) and higher thrust (142 kgf) using a high pressure combustion chamber.
http://www.astronautix.com/engines/hg3.htm
http://www.astronautix.com/engines/hg3sl.htm

So maybe the J2 and its derivatives still have some potential for development by feeding back knowledge gained from building and operating SSMEs over the last 25 years.




Offline kraisee

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RE: CEV HLV Upper Stage Engine
« Reply #14 on: 12/02/2005 06:52 AM »
Quote
AndyMc - 29/11/2005  8:10 AM

Reading from Astronautix and elsewhere, the J-2S engine operates at lower a chamber pressure of 30 bar as opposed to 204 bar for the SSME, and has a low thrust feature "for propellant tank settling, on-orbit maneuvering, and rapid engine chill down prior to firing."

Two J-2S engines give the same thrust as one SSME (2x116 kgf - J-2s / 232 kgf - SSME), plus this offers a back-up should one fail. Is one J-2S engine powerful enough to complete the TLI burn though?

Astronautix has the ISP for the J-2S as being 426s as opposed to 453s for the SSME, though elsewhere http://yarchive.net/space/shuttle/j2s.html this guy states that the J-2S ISP is 455s. This may be possible, as a couple of other engines the HG-3 & HG-3-SL derived from the J2 achieved a higher ISP (452s) and higher thrust (142 kgf) using a high pressure combustion chamber.
http://www.astronautix.com/engines/hg3.htm
http://www.astronautix.com/engines/hg3sl.htm

So maybe the J2 and its derivatives still have some potential for development by feeding back knowledge gained from building and operating SSMEs over the last 25 years.

A single J-2S should certainly be capable of doing a TLI burn for the new program.   The J-2 in Apollo was over-qualified for the TLI burn. One J-2 was used to send about 60MT to the moon then.   The new program will send about 80-90MT per flight, so if one engine failed, a single-engine burn would have to be longer, but should still be achievable.

As for Isp, the best figure I'd use for a modern J-2S would be 439sec.

That figure actually derives from the XRS-220, more commonly refered to as the "LASRE Linear Aerospike" engine which was being developed for the X-33 program.   One of its other names is "J-2S Linear Aerospike".   Obviously, is was very heavily based on J-2S engine parts and shows the "modern" specification achievable in that basic design.

The J-2S is not a bad engine, but I still think SSME is better.

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

Offline simonbp

RE: CEV HLV Upper Stage Engine
« Reply #15 on: 12/25/2005 02:34 PM »
I've heard that the J-4 altitude test cell at Arnold AFB in Tennessee (which was built in support of the RL-10 and J-2 programs in the 1960's) is being reactivated for CLV/HLLV-related SSME low-pressure testing...

Simon ;)

Online Chris Bergin

RE: CEV HLV Upper Stage Engine
« Reply #16 on: 12/25/2005 11:38 PM »

Offline simonbp

RE: CEV HLV Upper Stage Engine
« Reply #17 on: 12/26/2005 01:30 PM »
Glenn has a high-alititude test cell, B2, but it can only handle 400K lbf thrust (SSME is 500k lbf): https://rockettest.ssc.nasa.gov/nrpta/plmbrk_spacecraft_propulsion_test_facility.asp

The Air Force J-4, though, can handle up to 1,500 K lbf of thrust (meaning the entire HLLV upper stage thrust structure): https://rockettest.ssc.nasa.gov/nrpta/aedc_j4_test_stand.asp

So, NASA is building a new test stand at Glenn, but I doubt it will duplicate J-4 (noone else is using it, so NASA has free reign), so it's either a replacement for B-2, or a smaller stand...

Simon ;)

Online Chris Bergin

RE: CEV HLV Upper Stage Engine
« Reply #18 on: 12/26/2005 07:59 PM »
Impressive images on those links, thanks.

Offline AndyMc

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RE: CEV HLV Upper Stage Engine
« Reply #19 on: 12/27/2005 11:10 PM »
The reason for the choice of 2 x J2-S engines for the EDS is described in Part 13 of the ESAS Final Report, 13.3.4 Recommendation 4 -
Quote:

"The SSME is not considered a viable candidate for powering the EDS due to its inability to be restarted without extensive preparation, which is essentially impossible to do during flight."

Ref: http://images.spaceref.com/news/2005/ESAS.REPORT.13.PDF


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