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SLS / Orion / Beyond-LEO HSF - Constellation => Heavy Lift Launch Vehicle (HLV/SLS) => Topic started by: Hog on 07/25/2014 01:47 PM

Title: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 07/25/2014 01:47 PM
The unflown ME-0525 test engine has been installed in the A-1 test stand July 10, 2014 at Stennis. 

Any idea when ME-0525 will break its 5 year silence since its last firing in 2009?

Anticipation for the RS-25 testing/operations is growing.


RS-25 testing for SLS - UPDATE - thread is located here:

http://forum.nasaspaceflight.com/index.php?topic=35220.0

Articles on this path:

http://www.nasaspaceflight.com/tag/ssme/ <---pretty much a few years of recent history on the path to testing on that one page.

E0525 is now installed on the A-1 Test Stand. So we're getting close.
http://www.nasaspaceflight.com/2014/07/rs-25-stennis-testing-sls-schedule/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: AnalogMan on 07/25/2014 03:13 PM
Any idea when ME-0525 will break its 5 year silence since its last firing in 2009?

Last public info I saw was this:

Pegasus Barge to begin renovations for SLS core shipping
July 7, 2014 by Chris Bergin

"According to L2 information, Test stand A-1 modifications were completed June 30, with engine E0525 mounted on the stand July 1. E0525 testing is still scheduled to start NET (No Earlier Than) August 20"

http://www.nasaspaceflight.com/2014/07/pegasus-barge-renovations-sls-core-shipping/ (http://www.nasaspaceflight.com/2014/07/pegasus-barge-renovations-sls-core-shipping/)

L2 link:
http://forum.nasaspaceflight.com/index.php?topic=32883.msg1222678#msg1222678 (http://forum.nasaspaceflight.com/index.php?topic=32883.msg1222678#msg1222678)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 08/25/2014 03:01 PM
Remembering a post that Wayne Hale made over in the Q&A section.
http://forum.nasaspaceflight.com/index.php?topic=17437.3210


Quoted in its entirety to avoid snipe quoting, emphasis mine.

"Unfortunately there is a lot of oversimplification going on in this thread which could lead to an inaccurate understanding of several complex subjects regarding the SSME and its upgrade.  The block upgrade (from Phase II+ to Block I to Block II) took almost a decade and cost over $2B.  The intention was to provide a more robust engine, not just because of some pad abort that occurred.  The newer block engine had lower ISP (by about 1.5 sec) which required an increase in thrust from 104% RPL to 104.5%RPL to make up for the performance loss.  Neither engine was certified for 109% operation but that was certainly the intent for the Block II engine.  Both nominal flight and all intact aborts used the 104.5% RPL thrust level.  During testing to certify the 109% for aborts, it was found that there were components in the main propulsion piping in the orbiter which likely could not withstand the higher vibration environment associated with that flow rate.  Cracking of the metallic components could have lead to liberation of metal pieces into the engine inlet which would not have been good at the pumps.  So efforts to certify 109% or 111% were terminated.  109% throttles were authorized only in 'do or die' contingency abort scenarious which were multiple failures deep."


In light of the issues which were proven at the 109% RPL using the existing Shuttle MPS piping. 
1)Does this mean that the MPS piping/valves/hardware removed from the OV's would not be used on the test stand?
2) Was the Shuttle MPS piping/valves etc. removed from the Orbiters just in case the SLS core stage used 3 RS25 engine, and now that 4 engines will be used, that MPS hardware is not able to be used on thetest stand or as flight hardware?

3) Will any 111%RPL be tested, or do abort modes such as an ATO(Abort to Orbit), such as an engine out later in the 2nd stage after the solid boosters have jettisoned, increase the remaining 3 RS25's to 111%RPL to help reach a more desireable velocity, or do these Shuttle'esque off-nominal engine thrust settings/ATO scenarios not apply to SLS?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Steven Pietrobon on 08/27/2014 08:05 AM
My understanding is that the existing RS-25D engines will be flown at 109%. The new RS-25E engines will be flown at 111%. From page 25 of the attached document. The RS-25D has been certified at 109% and also ground tested at 111%.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: QuantumG on 08/27/2014 08:07 AM
My understanding is that the existing RS-25D engines will be flown at 109%. The new RS-25E engines will be flown at 111%. From page 25 of the attached document. The RS-25D has been certified at 109% and also ground tested at 111%.

So.. what they're saying is.. ours go to 11?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Steven Pietrobon on 08/27/2014 08:16 AM
So.. what they're saying is.. ours go to 11?

Although RS-25D has been tested at 111%, that does not mean that it is certified for 111% which I believe requires additional testing or modifications to the engine.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Mark S on 08/27/2014 03:48 PM
I understood that the RS-25E would be a simplified design using modern manufacturing techniques, and a considerably reduced part count. So where does the extra ~300 lbs for the new engine come from?

Is the new channel-wall nozzle that much heavier than the legacy tube-wall version?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 08/27/2014 08:32 PM
So.. what they're saying is.. ours go to 11?

Although RS-25D has been tested at 111%, that does not mean that it is certified for 111% which I believe requires additional testing or modifications to the engine.
That is my understanding of the situation.  Attempts to certify 109% and 111% for nominal flight were squashed, with the 109% option for extreme contingencies.

Source Wayne Hale:
"During testing to certify the 109% for aborts, it was found that there were components in the main propulsion piping in the orbiter which likely could not withstand the higher vibration environment associated with that flow rate.  Cracking of the metallic components could have lead to liberation of metal pieces into the engine inlet which would not have been good at the pumps.  So efforts to certify 109% or 111% were terminated.  109% throttles were authorized only in 'do or die' contingency abort scenarious which were multiple failures deep."
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 08/27/2014 08:48 PM
I understood that the RS-25E would be a simplified design using modern manufacturing techniques, and a considerably reduced part count. So where does the extra ~300 lbs for the new engine come from?

Is the new channel-wall nozzle that much heavier than the legacy tube-wall version?
The legacy tube wall nozzle is 130lbs lighter than the "new" channel-wall nozzle, at least when compared in the Block III SSME proposal. The Block III SSME was projected to be approx. 400lbs heavier than Block II SSME.
Of course there is the question of just how similar will the RS-25E be to the Block III proposals?

The Block III proposal offers greater thrust for contingency aborts than Block II did, sounds like 111% was on the table for contingency aborts for the Block III SSME.

Here is the Block III proposal
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000112952.pdf
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: robertross on 08/27/2014 11:22 PM
I understood that the RS-25E would be a simplified design using modern manufacturing techniques, and a considerably reduced part count. So where does the extra ~300 lbs for the new engine come from?

Is the new channel-wall nozzle that much heavier than the legacy tube-wall version?


And so people know: the reason for channel wall (and the parts count) was for cost considerations.
It takes a long time to braze the tubes into place aroud the engine bell.

(Of course if SLS doesn't fly that many flights, a re-designed engine will end up costing likely alot more. Oh well, different topic of discussion for the other SLS thread.)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 11/30/2014 02:31 PM
Things should be getting ready to fire shortly,  Anyone heard anything?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: russianhalo117 on 12/02/2014 02:54 PM
Things should be getting ready to fire shortly,  Anyone heard anything?
Expect testing around beginning of year on the latest schedule.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Wayne Hale on 12/17/2014 03:33 PM
regarding the new SSME controller - 'if it ain't broke, don't fix it'
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: PahTo on 12/17/2014 04:00 PM

The environment in which these controllers reside must be rather challenging, what with the acoustics/vibration as well as thermal.  Is the idea to replace the software and some of the hardware, but keep the outer casing and interfaces the same?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: rsnellenberger on 12/17/2014 04:36 PM
As I recall, there weren't all that many of the Block II SSME controllers ever built -- on the order of 10 or so.  That's a good plan when you're recovering and re-using the engines, but not so good when you're tossing them in the ocean four at a time.  Since you'd need to build new hardware anyway (even if you used "stock" SSMEs & controllers for the first flights), it makes sense to build newer (hopefully, cheaper) controllers and use them from the start.  Obviously, the new controller needs to interface with the standard with both the stock SSME as well as the new-built RS-25E for this to make sense.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: newpylong on 12/18/2014 04:16 PM
regarding the new SSME controller - 'if it ain't broke, don't fix it'

Except in this case, where it wasn't broken, but inadequate.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 12/21/2014 04:23 PM
IIRC the new RS-25 controller and the new J2X controller are one in the same.  So Block II SLS will use a common controller on bothe the core and the upper stage.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: woods170 on 12/21/2014 10:54 PM
IIRC the new RS-25 controller and the new J2X controller are one in the same.  So Block II SLS will use a common controller on bothe the core and the upper stage.
Unlikely. SLS, as currently envisioned up to the 130 mT version, will never fly J-2X on any upper stage.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 12/21/2014 11:44 PM
IIRC the new RS-25 controller and the new J2X controller are one in the same.  So Block II SLS will use a common controller on bothe the core and the upper stage.
Unlikely. SLS, as currently envisioned up to the 130 mT version, will never fly J-2X on any upper stage.
Including or not including the Block II 130mt SLS?  I understand that anything on the books is not Block II related.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Edit: It appears that the RS-25 "Controller development is based heavily on the recent development experience with the J-2X engine controller".

But then there is this quote "You can't put yesterday's hardware on today's engine, especially since many parts of the shuttle-era engine controller unit aren't even made anymore," said Russ Abrams, avionics subsystem manager in the SLS Liquid Engines Office at NASA's Marshall Space Flight Center in Huntsville, Alabama"
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Steven Pietrobon on 12/22/2014 05:19 AM
IIRC the new RS-25 controller and the new J2X controller are one in the same.  So Block II SLS will use a common controller on bothe the core and the upper stage.
Unlikely. SLS, as currently envisioned up to the 130 mT version, will never fly J-2X on any upper stage.

My simulations show you need a J-2X or four MB-60 second stage engines to get to 130 t, regardless of the boosters used.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: newpylong on 12/25/2014 12:42 AM
Simulations are simulations, not reality. 129 tons or 130 tons, J-2X is not going to happen. If the mandate is not met, so be it. No one will count in 10 years.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Patchouli on 12/25/2014 02:03 AM
IIRC the new RS-25 controller and the new J2X controller are one in the same.  So Block II SLS will use a common controller on bothe the core and the upper stage.
Unlikely. SLS, as currently envisioned up to the 130 mT version, will never fly J-2X on any upper stage.

My simulations show you need a J-2X or four MB-60 second stage engines to get to 130 t, regardless of the boosters used.

The MB-60 stage actually gets a little better TMI performance while the J-2X has better LEO performance.

Though on IMLEO numbers SLS Block 1A supposedly can get 120tons of payload with the liquid  Pyrios boosters.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/05/2015 02:49 PM
Apparently the new RS25 uses about 60% of the tested J2X controller according to Mr Phillip Sloss's article
http://www.nasaspaceflight.com/2015/01/nasa-ready-power-up-rs-25-engine/

From Mr Chris Bergin's post introducing the article.
http://forum.nasaspaceflight.com/index.php?topic=36465.0

ME-0525 on the stand at Stennis could be making H2O (hot firing) in very short order.

I would love to have a video feed onf the test stand.(dreams)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/08/2015 09:41 PM
Still holding for a test, we're on the cusp of the mighty RS-25D roaring to life.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/09/2015 09:31 AM
While we wait:

According to the attached reference from the Block III SSME proposal, there are a total of three Block-III Develoment Engines with Development Units #1(10,000 seconds of run time) and #3(16,000 seconds of run time)  totalling  80 combined starts on the A-1 Test Stand.
Development Unit #2 having 30 starts(12,000 seconds run time) on the A-2 Test Stand.
Combined starts for all 3 Development Block III SSME's is 110, with a combined runtime across both the A-1 and A-2 test stands at 38,000 seconds.

There is also mention of the two Block III SSME Certification Engines referred to as Cert Engine #004 and #005.
Certification Engine #004 had 22 A-2 test stand starts with 11,000 seconds of run time, and Cert. Engine #005 had 22 A-1 Test STand starts and 11,000 seconds of run time.

So with all 5 of these Block III SSME's we have 154 starts, and a total of 60,000 seconds(1000 minutes or 16-1/3 hours) of run time.

So Block III SSME appears, in my common view, to be a viable option for future RS25 maturation(both Block III and Block III-Phase 2(with Advanced Health Management System).

Attachment 1: Test Matrix
Attachment 2: The complete Block III RS25 proposal(please rotate once downloaded)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: AnalogMan on 01/09/2015 10:37 AM
Here's a copy of the Block III SSME Upgrade Project Overview presentation with the pages rotated to the correct orientation.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/09/2015 04:57 PM
Here's a copy of the Block III SSME Upgrade Project Overview presentation with the pages rotated to the correct orientation.
Thank you very much AnalogMan.

I bid the Stennis team all the best for todays hotfire test.
Go RS-25, burn, baby, burn!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: catdlr on 01/10/2015 02:37 AM
Test Video

http://forum.nasaspaceflight.com/index.php?topic=36465.msg1312812#msg1312812
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Ronpur50 on 01/10/2015 05:12 PM
Exciting video!!
Question: I see two vehicles close by the test facility, is there someone inside that thing during the test??
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/11/2015 06:16 PM
Test Video

http://forum.nasaspaceflight.com/index.php?topic=36465.msg1312812#msg1312812
There is a lot going on in that video, and some which has been editted.  A few seconds before shutdown, you can see an instability develop and the video cuts to a wide view of the test stand.

I thank NASA and Aerojet/Rocketdyne for allowing these videos to be released.  Hugely interesting.  I'm sure all the people who work/have worked with these thoroughbreds are proud of their accomplishments. Amazing hardware!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: MarkM on 01/22/2015 07:10 PM

In the article posted on Jan 2 it is mentioned that the head pressures for the fuel and oxidisers will be greater for SLS as opposed to the shuttle.  I am just wondering how that would affect the performance of the engines?  Increase/decrease thrust or ISP?  And will it be a greater or less stress on the turbine pumps?

I guess the reason for the tests are two determine the outcomes but if anyone wanted to make an informed guess I would very much appreciate it!

Thanks
Mark
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Steven Pietrobon on 01/23/2015 06:18 AM
I don't think there will be any significant change in performance. A higher head pressure implies that the boost pumps would need slightly less work to perform in order to get the output pressure to be the same, so there might be a very small, perhaps negligible, increase in performance. In any case, the engines are going to be operated at a higher thrust level compared to shuttle, at 109% (111% for new RS-25s) compared to 104% for the Space Shuttle.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: MarkM on 01/23/2015 12:57 PM
Thanks Steven!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 01/27/2015 04:27 PM

In the article posted on Jan 2 it is mentioned that the head pressures for the fuel and oxidisers will be greater for SLS as opposed to the shuttle.  I am just wondering how that would affect the performance of the engines?  Increase/decrease thrust or ISP?  And will it be a greater or less stress on the turbine pumps?

I guess the reason for the tests are two determine the outcomes but if anyone wanted to make an informed guess I would very much appreciate it!

Thanks
Mark
SLS also be experiencing greater G loading(3.3g) during ascent than STS(3 g) did, which in effect increases head pressure even more.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: newpylong on 05/28/2015 08:09 PM
http://www.nasa.gov/exploration/systems/sls/some-assembly-required-the-newest-rs-25-joins-the-space-launch-system-family.html

16th RS-25 completed.

I believe there also was an engine test today.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 05/29/2015 03:10 AM
http://www.nasa.gov/exploration/systems/sls/some-assembly-required-the-newest-rs-25-joins-the-space-launch-system-family.html

16th RS-25 completed.

I believe there also was an engine test today.
Yes, 2063 is the 16th engine completed, and according to NASA there are 2 RS-25D engines that have no flight experience. Once acceptance testing of 2063 is complete, it will join the other 14 veterans and the other rookie engine(which is E2062).

Waiting for the test video, should be cool as always.




Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 05/29/2015 03:12 AM
Block II/RS25D Engines with flight experience (listed with last mission flown)
1)  2044  STS-133
2)  2045  STS-135
3)  2047  STS-135
4)  2048  STS-133
5)  2050  STS-120
6)  2051  STS-132
7)  2052  STS-132
8)  2054  STS-131
9)  2056  STS-121
10) 2057 STS-134
11) 2058 STS-133
12) 2059 STS-134
13) 2060 STS-135
14) 2061 STS-134

Unflown Block II/RS25D engines
15) 2062 (circa 2010 build)
16) 2063 (2015 build)

E2049, 2053 & 2055 were lost on STS-107
E2043 was a flown Block IIA engine/RS25C but was never flown in a full Block II configuration
E2046 is not listed as a flown or unflown engine or if even existed
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: OnWithTheShow on 05/29/2015 03:32 AM
Quote
The RS-25 is unique among many engines in that it automatically runs through its cycles and programs.
from http://www.nasa.gov/image-feature/steamy-summer-begins-for-sls-with-rs-25-test

What?!?!?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Welsh Dragon on 05/29/2015 08:20 AM
What's the engine standing nozzle up in the background from 0:20 or so in the video above? The one with the dark nozzle extension? RL-10?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: German Space Fan on 05/29/2015 01:08 PM
I´m not entirely sure, but I think it´s a J2-X. :o
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: okan170 on 05/29/2015 05:10 PM
Video of the test:
https://www.youtube.com/watch?v=Xz1L2-CjsIo
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 05/31/2015 05:29 AM
Thanks for posting OKAN.

There is a marked throttle up at 1:50 of the video timer and stays upthrottled until 7:20 which is a runtime of 5 mins 30 secs (330 seconds) at this elevated power level.

I wonder what this elevated power level was? The new 109% RPL?

6 more tests for development engine 0525 before being swapped out for DE-0528 for a series of 10 more hotfire tests.

Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: psloss on 05/31/2015 03:15 PM
There is a marked throttle up at 1:50 of the video timer and stays upthrottled until 7:20 which is a runtime of 5 mins 30 secs (330 seconds) at this elevated power level.
The basics looked similar to Shuttle; the engine is throttled down from "full power" shortly after "liftoff" and then again to something like minimum power level at the end of the test to set up for shutdown.

Maybe we'll get to see some detailed test objectives on L2 at some point in the development series.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: DaveS on 05/31/2015 03:49 PM
There is a marked throttle up at 1:50 of the video timer and stays upthrottled until 7:20 which is a runtime of 5 mins 30 secs (330 seconds) at this elevated power level.
The basics looked similar to Shuttle; the engine is throttled down from "full power" shortly after "liftoff" and then again to something like minimum power level at the end of the test to set up for shutdown.

Maybe we'll get to see some detailed test objectives on L2 at some point in the development series.

Actually, the engines was not at Rated Power Level (RPL) at lift-off (104.5%) but rather at 100%. Only at tower clear was the engines throttled up to 104.5%. Then for the throttle bucket, the engines throttled down (72%) and then back up to RPL. Then there was two more throttle downs, one for 3G-limiting (usually around 7:30) and then down again for shut down.

But for this test, they did throttle up the engine at the 1:50 mark as evident by the blue mach diamond moving away from the nozzle. If they throttled down, the diamond would have moved closer to the nozzle. This could be indicative of the RS-25 throttle profile for at least EM-1, where lift-off happens at a reduced power level (100%?) and then at tower clear it's throttled up to Full Power Level (FPL, 109%).
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: psloss on 05/31/2015 04:10 PM
There is a marked throttle up at 1:50 of the video timer and stays upthrottled until 7:20 which is a runtime of 5 mins 30 secs (330 seconds) at this elevated power level.
The basics looked similar to Shuttle; the engine is throttled down from "full power" shortly after "liftoff" and then again to something like minimum power level at the end of the test to set up for shutdown.

Maybe we'll get to see some detailed test objectives on L2 at some point in the development series.

Actually, the engines was not at Rated Power Level (RPL) at lift-off (104.5%) but rather at 100%.
Yes, hence the double-quotes for "full power" and "liftoff."  I probably should have added Dr. Evil "laser" tags to make it more obvious. :P
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 06/01/2015 05:35 PM
Interesting tidbits.

Minimum Power Level (MPL)=67% 316,100 lbs.
Rated Power Level (RPL)=100% 470,800 lbs.
Nominal Power Level (NPL)=104.5%=491,900 lbs.
Full Power Level (FPL)=109%=512,900 lbs

Each Percent of throttle= approx. 4,700lbs
Throttle range 67%-109%
Chamber pressure at 109%=3008 psi
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 07/15/2015 01:54 AM
Tomorrow should bring us yet another test of RS-25 test engine 0525..

I'm wondering if the following technologies are being tested in the current run of RS-25 tests of E0525 or if they will be incorporated in the new build "expendable" engines?

Here are a couple pics of some Z-baffles for a RS-25 engine.  These parts were manufactured using "Selective Laser Melting" which fuses metal dust with a high powered laser housed in the machine in the background(1st pic).

2nd pic: pogo z-baffle is being inspected with a structured light scan.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Danny Dot on 08/12/2015 02:38 PM
Do you mean the test will use the new controller?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: robertross on 08/12/2015 04:32 PM
Do you mean the test will use the new controller?

They have been using the new controller for a while now (based on the J-2X design).

Obviously tweaking it along the way.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 08/13/2015 11:14 AM
A NASA release:

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

NASA TV to Air Test of Space Launch System Engine

NASA Television will broadcast live coverage Thursday, Aug. 13 of the penultimate hot fire test of an RS-25 engine. This is one of four engines that will power the core stage of NASA’s new Space Launch System (SLS), and carry the agency’s Orion crew capsule as part of the journey to Mars and other deep space destinations.

From 11 a.m. to 12:30 p.m. EDT, NASA TV will broadcast a series of conversations at Stennis among media, social media followers, engineers and managers discussing the SLS rocket, Orion, ground systems, and the RS-25 engine. Viewers can ask questions via social media using the hashtag #askNASA.

Coverage of the 5 p.m. engine test will begin at 4:30 p.m. The test will last 535 seconds, the amount of time the engines will fire during an actual launch. Both programs can be viewed on NASA TV-1, the public channel for the space agency, and NASA TV-2, the education channel.

The test will take place on the historic A-1 test stand at NASA’s Stennis Space Center in Mississippi and is part of a series designed to put the upgraded former space shuttle main engines through the rigorous temperature and pressure conditions they will experience during a launch.

The tests also support the development of a new controller, or “brain,” for the engine, which monitors engine status and communicates between the vehicle and the engine, relaying commands to the engine and transmitting data back to the vehicle. The controller also provides closed-loop management of the engine by regulating the thrust and fuel mixture ratio while monitoring the engine's health and status.

For NASA TV streaming video, downlink and scheduling information, visit:

http://www.nasa.gov/nasatv

For more information about NASA’s Space Launch System, visit:

http://www.nasa.gov/exploration/systems/sls/rocket.html

-end-

http://www.nasa.gov/press-release/nasa-tv-to-air-test-of-space-launch-system-engine

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

A small correction for NASA.  The engine being used in todays test is E0525 which is a development/test engine.  It is NOT one of the 4 engines which will power SLS during EM-1 which is scheduled NLT(No Later Than) November 2018.


Very nice article Mr Sloss, it's nice to get some details about what is actually happening during these tests.
Link to article I am referring to.
http://www.nasaspaceflight.com/2015/08/sls-test-stennis-team-overview-rs25-ignition/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: John44 on 08/13/2015 05:35 PM
NASA RS-25 Test Social.
http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=9555
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Rocket Science on 08/13/2015 11:21 PM
http://www.nasaspaceflight.com/2015/08/sls-test-stennis-team-overview-rs25-ignition/

Thanks for the great article Philip of which I like to refer to as "The music of the Shuttles"... ;D
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Endeavour_01 on 08/14/2015 05:08 PM
Video of the test.

https://www.youtube.com/watch?v=nAIZKX9wcqc (https://www.youtube.com/watch?v=nAIZKX9wcqc)

http://www.nasaspaceflight.com/2015/08/sls-test-stennis-team-overview-rs25-ignition/

Thanks for the great article Philip of which I like to refer to as "The music of the Shuttles"... ;D

Amen. It makes me feel so good to see them up and burning again.  ;D
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: sdsds on 08/14/2015 05:28 PM
Given the more or less precise nominal burn time of 535 seconds, and that the flight engines will be disposed of along with the core, planners must have a pretty good sense of where the final resting place of the EM-1 engines will be. Is the impact point in the Indian Ocean? Or the Pacific?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Martin FL on 08/27/2015 11:42 PM
Great articles for this test series rounded off by this one!

Test complete!

Here's Philip's article to mark the series and preview the next - plus more on the turnaround of the engine between test six and seven. Top work by Philip with the access and quotes.

http://www.nasaspaceflight.com/2015/08/rs-25-completes-test-series-next-engine/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 09/03/2015 03:28 AM

Test complete!

Here's Philip's article to mark the series and preview the next - plus more on the turnaround of the engine between test six and seven. Top work by Philip with the access and quotes.

http://www.nasaspaceflight.com/2015/08/rs-25-completes-test-series-next-engine/
Very nice article!

So we have DE-0525 which currently just finished its duty on the test stand for this current round of tests. DE-0525 will now be swapped out for the 2nd Development Engine-DE-0528 for another battery of tests for SLS usage. 16 Main Engines and 2 Development Engines for a total of 18 RS-25s in NASA's current inventory.

Block II/RS25D Engines with flight experience (listed with last mission flown)
1)  2044  STS-133
2)  2045  STS-135
3)  2047  STS-135
4)  2048  STS-133
5)  2050  STS-120
6)  2051  STS-132
7)  2052  STS-132
8)  2054  STS-131
9)  2056  STS-121
10) 2057 STS-134
11) 2058 STS-133
12) 2059 STS-134
13) 2060 STS-135
14) 2061 STS-134

Unflown Block II/RS25D engines
15) 2062 (circa 2010 build)
16) 2063 (2015 build)

Development Engines Block II/RS25D
17) 0525
18) 0528

According to the supplied excerpt from the 2000 Block III SSME Upgrades Project Overview which states that there are three-Block III Development Engines and two-Block III Certification Engines with a total of 154 starts and 60,000 seconds (16.6 hours)of hotfire runtime that were in existence at some time.
001-Development Engine
002-Development Engine
003-Development Engine
004-Certification Engine
005-Certification Engine

I wonder what became of these Block III RS-25 engines?

Heres a link to the 2000 Block III SSME proposal for those who haven't seen it.
http://archive.org/stream/nasa_techdoc_20000112952/20000112952#page/n0/mode/2up


Hopefully the next round of testing using DE-0528 goes as well as testing with DE-0525 did.



Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: russianhalo117 on 09/03/2015 04:47 AM

Test complete!

Here's Philip's article to mark the series and preview the next - plus more on the turnaround of the engine between test six and seven. Top work by Philip with the access and quotes.

http://www.nasaspaceflight.com/2015/08/rs-25-completes-test-series-next-engine/
Very nice article!

So we have DE-0525 which currently just finished its duty on the test stand for this current round of tests. DE-0525 will now be swapped out for the 2nd Development Engine-DE-0528 for another battery of tests for SLS usage. 16 Main Engines and 2 Development Engines for a total of 18 RS-25s in NASA's current inventory.

Block II/RS25D Engines with flight experience (listed with last mission flown)
1)  2044  STS-133
2)  2045  STS-135
3)  2047  STS-135
4)  2048  STS-133
5)  2050  STS-120
6)  2051  STS-132
7)  2052  STS-132
8)  2054  STS-131
9)  2056  STS-121
10) 2057 STS-134
11) 2058 STS-133
12) 2059 STS-134
13) 2060 STS-135
14) 2061 STS-134

Unflown Block II/RS25D engines
15) 2062 (circa 2010 build)
16) 2063 (2015 build)

Development Engines Block II/RS25D
17) 0525
18) 0528

According to the supplied excerpt from the 2000 Block III SSME Upgrades Project Overview which states that there are three-Block III Development Engines and two-Block III Certification Engines with a total of 154 starts and 60,000 seconds (16.6 hours)of hotfire runtime that were in existence at some time.
001-Development Engine
002-Development Engine
003-Development Engine
004-Certification Engine
005-Certification Engine

I wonder what became of these Block III RS-25 engines?

Heres a link to the 2000 Block III SSME proposal for those who haven't seen it.
http://archive.org/stream/nasa_techdoc_20000112952/20000112952#page/n0/mode/2up


Hopefully the next round of testing using DE-0528 goes as well as testing with DE-0525 did.




Last I heard was they were placed into indefinite storage at Rocketdyne and procurement leads for flight engines was halted after STS-107 and cancelled shortly after shuttle retirement was announced by the President and NASA. I have no clue where they are since Boeing sold Rocketdyne.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: sghill on 11/24/2015 12:41 PM
And in other news, Aerojet-Rocketdyne was just awarded their contract to reopen the RS-25 production line.

http://www.satprnews.com/2015/11/24/nasa-and-aerojet-rocketdyne-to-restart-production-of-the-rs-25-engine-for-the-space-launch-system/

Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Todd Martin on 11/24/2015 01:25 PM
The press release does not indicate how many RS-25 engines will be manufactured under the $1.16 Billion dollar contract.  Anyone know?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: woods170 on 11/24/2015 01:34 PM
The press release does not indicate how many RS-25 engines will be manufactured under the $1.16 Billion dollar contract.  Anyone know?
This contract is for re-developing the RS-25 to suit the SLS requirements beyond the 16 re-purposed STS SSME's. The contract can be modified to include the construction of 6 new engines.
The purchase of additional production RS-25's, based on the work done under this contract, will require a new contract (and thus additional money).
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: AnalogMan on 11/24/2015 01:35 PM
The press release does not indicate how many RS-25 engines will be manufactured under the $1.16 Billion dollar contract.  Anyone know?

In NASA's press release it says:

"The contract also allows for a potential future modification that would enable NASA to order six flight engines."

See: http://forum.nasaspaceflight.com/index.php?topic=31740.msg1448620#msg1448620 (http://forum.nasaspaceflight.com/index.php?topic=31740.msg1448620#msg1448620)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Khadgars on 11/24/2015 05:13 PM
And in other news, Aerojet-Rocketdyne was just awarded their contract to reopen the RS-25 production line.

http://www.satprnews.com/2015/11/24/nasa-and-aerojet-rocketdyne-to-restart-production-of-the-rs-25-engine-for-the-space-launch-system/

Exciting news!  Good to see them restarting production at an early stage.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Lars-J on 11/24/2015 05:15 PM
The press release does not indicate how many RS-25 engines will be manufactured under the $1.16 Billion dollar contract.  Anyone know?
This contract is for re-developing the RS-25 to suit the SLS requirements beyond the 16 re-purposed STS SSME's. The contract can be modified to include the construction of 6 new engines.

Ah lovely, a billion dollars for no flying hardware. This is the kind of contract that Aerojet Rocketdyne dreams of. Right up their alley, now they can kick the can down the road for a few more years until they close up shop.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: RocketGoBoom on 11/25/2015 01:25 AM

Ah lovely, a billion dollars for no flying hardware. This is the kind of contract that Aerojet Rocketdyne dreams of. Right up their alley, now they can kick the can down the road for a few more years until they close up shop.

I can't help but think that most of these new engines will end up parked in front of various museums around the USA after the SLS program is cancelled due to unsustainable costs.

(http://cdn.c.photoshelter.com/img-get/I0000AF.Nww.EVfg/s/650/Alamogordo-Space-Museum-Rocket-Engine-MANN-8669.jpg)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Lars-J on 11/25/2015 01:37 AM

Ah lovely, a billion dollars for no flying hardware. This is the kind of contract that Aerojet Rocketdyne dreams of. Right up their alley, now they can kick the can down the road for a few more years until they close up shop.

I can't help but think that most of these new engines will end up parked in front of various museums around the USA after the SLS program is cancelled due to unsustainable costs.

(http://cdn.c.photoshelter.com/img-get/I0000AF.Nww.EVfg/s/650/Alamogordo-Space-Museum-Rocket-Engine-MANN-8669.jpg)

But this contract doesn't even produce any engines at all, that's my issue. SLS would have to go really well for them to issue a follow-up contract to actually build the engines that might one day end up as museum pieces.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Khadgars on 11/25/2015 01:54 AM

Ah lovely, a billion dollars for no flying hardware. This is the kind of contract that Aerojet Rocketdyne dreams of. Right up their alley, now they can kick the can down the road for a few more years until they close up shop.

I can't help but think that most of these new engines will end up parked in front of various museums around the USA after the SLS program is cancelled due to unsustainable costs.

(http://cdn.c.photoshelter.com/img-get/I0000AF.Nww.EVfg/s/650/Alamogordo-Space-Museum-Rocket-Engine-MANN-8669.jpg)

But this contract doesn't even produce any engines at all, that's my issue. SLS would have to go really well for them to issue a follow-up contract to actually build the engines that might one day end up as museum pieces.

Do we really need this kind blabber in every SLS thread?  SLS has progressed farther than opponents were saying even just couple years ago.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: woods170 on 11/25/2015 12:02 PM

Ah lovely, a billion dollars for no flying hardware. This is the kind of contract that Aerojet Rocketdyne dreams of. Right up their alley, now they can kick the can down the road for a few more years until they close up shop.

I can't help but think that most of these new engines will end up parked in front of various museums around the USA after the SLS program is cancelled due to unsustainable costs.

(http://cdn.c.photoshelter.com/img-get/I0000AF.Nww.EVfg/s/650/Alamogordo-Space-Museum-Rocket-Engine-MANN-8669.jpg)

But this contract doesn't even produce any engines at all, that's my issue. SLS would have to go really well for them to issue a follow-up contract to actually build the engines that might one day end up as museum pieces.

Do we really need this kind blabber in every SLS thread?  SLS has progressed farther than opponents were saying even just couple years ago.
Exactly. The next president will not take office until early 2017. By which time SLS has progressed to the point where flight-hardware is being tested prior to first flight. If that next president decides to kill SLS that late in the game it will be the biggest waste of money, on an unflown program for NASA, ever. Much worse in fact than the killing of Constellation.
CxP was killed-off long before any of the proposed vehicles even got close to CDR. Both SLS and Orion have passed that point.
CxP was killed-off long before any flight-hardware was being manufactured. Both SLS and Orion have passed that point.
Etc, etc.
The way I see it SLS will not be killed off until after (at least) EM-1. By that time it will be similar to prematurely ending Apollo or STS.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Space Invaders on 12/23/2015 06:48 PM
A few years ago, Ross said the following:

Most prominent of all the possible upgrades is the Brazed Tube Nozzle.   That is currently the most time-consuming and expensive element in the SSME.   It consists of 1080 separate tubes, each carefully formed with continually changing diameter and circular/elliptical shape along its entire length.   These tubes are then brazed together into the shape we all know, and a jacket is then mounted around them for support, plus forward and aft ducts and other tubing.   The whole operation involves intensive human touch-labour throughout, so this is an extremely expensive and inefficient way of making things.   The Brazed Tube Nozzle approach is the reason for the current production "bottleneck" which restricts production to a maximum of 12 units per year.

If the Nozzle were replaced with a Channel Wall Nozzle, the part count and the touch labor would be *massively* reduced and the production bottleneck effectively removed -- with just one change.

This change alone, while certainly not a trivial change, should reduce the cost of the SSME by about ~20%.   It is therefore one of the most significant single upgrades under consideration.

Has there been any progress on this front?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 12/23/2015 07:52 PM
I'm shocked to the core to see negative posts about SLS! Shocked I tell you ;)

But seriously, let's not get dragged into this "It's L- one day but I still say SLS will never fly. OK, they've launched, but like I said, SLS will NEVER FLY!!!" ;D
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: russianhalo117 on 12/23/2015 10:55 PM
A few years ago, Ross said the following:

Most prominent of all the possible upgrades is the Brazed Tube Nozzle.   That is currently the most time-consuming and expensive element in the SSME.   It consists of 1080 separate tubes, each carefully formed with continually changing diameter and circular/elliptical shape along its entire length.   These tubes are then brazed together into the shape we all know, and a jacket is then mounted around them for support, plus forward and aft ducts and other tubing.   The whole operation involves intensive human touch-labour throughout, so this is an extremely expensive and inefficient way of making things.   The Brazed Tube Nozzle approach is the reason for the current production "bottleneck" which restricts production to a maximum of 12 units per year.

If the Nozzle were replaced with a Channel Wall Nozzle, the part count and the touch labor would be *massively* reduced and the production bottleneck effectively removed -- with just one change.

This change alone, while certainly not a trivial change, should reduce the cost of the SSME by about ~20%.   It is therefore one of the most significant single upgrades under consideration.

Has there been any progress on this front?
Im aware of talk a while back of develop the capability to 3D print most or all of the nozzle for either tube or channel design. AR is currently working on it as part of project within production restart contract. we should get more info as this contract kicks off next year
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 08/07/2016 08:47 PM
Looks like DE-0528 lit off nicely.  Anyone have interesting developments they wish to share?  Please, discuss.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 03/13/2017 06:58 PM
Upcoming hotfire test green running flight hardware(engine controller) IIRC it should be FM2(March), then FM3(April), then FM4 to be tested on good old Qualification Engine E-0528 (which continues on in active qualification service with her sister E-0525).

Then come Summer time we get into some flight engine acceptance testing with E-2063, then early Autumn E-2062.
The Summer/Fall testing of 2017 at Stennis will see E-2063, which was built in 2014, and E-2062, which was the last RS-25D engine that was built a year before the SSP was stood down. These 2 flight engines, that are awaiting certification, will get their "green runs" during these 2017 sessions.  If all goes well, NASA will then have 16 fully functioning and hotfired pieces of flight hardware and will further increase the over 1 million seconds, or over 280 hours of hotfire experience that RS-25 has gathered.

 We have these 2 engines which along with E-2047 and E-2059 are scheduled to be primary flight engines on EM2, and are scheduled as contingency engines for EM-1, in case the Primary EM-1 flight set consisting of engines: 2045, 2056, 2058, 2060 must be removed and replaced prior to the launch of EM-1.

The 16 flight engines, who are they? where they been? where they from? burning more than hydrogen on your tongue. (a small tribute to Metallica-Holier than Thou)

Exploration Mission–1 (ready for launch in 2018)
• Engine 2045, STS–95 – John Glenn’s return to space
• Engine 2056, STS–109 – Hubble Space Telescope
   servicing mission
• Engine 2058, STS–133 – Last flight of orbiter Discovery
• Engine 2060, STS–135 – Final flight of the Space Shuttle Program

Exploration Mission–2 (slated for 2021)
• Engine 2047, STS–98 – Delivered Destiny lab module
   to the International Space Station (ISS)
• Engine 2059, STS–117 – Longest mission for the
   orbiter Atlantis
• Engine 2062, New engine never flown
• Engine 2063, New engine never flown

Exploration Mission–3
• Engine 2048, STS–92 – 100th mission of the Space Shuttle
• Engine 2054, STS–126 – Most supplies and equipment ever on
   a single mission
• Engine 2057, STS–125 – Final servicing mission of Hubble
   Space Telescope
• Engine 2061, STS–130 – Delivered the Tranquility node and
its 7-window cupola to ISS

Exploration Mission–4
• Engine 2044, STS–88 – First mission to ISS
• Engine 2050, STS–108 – Delivered U.S. Harmony module to ISS
• Engine 2051, STS–128 – Delivered Quest airlock module to ISS
• Engine 2052, STS–99 – Longest mission for Atlantis, lasting
  more than 13 days and 20 hours


Just in case you missed it, here is the assembly of E2063 in late 2014 condensed down into a 2 minute clip. This is NASA's newest RS-25, and completes the "sweet sixteen" number of flight engines for 4 SLS missions.
http://www.youtube.com/watch?v=HtE_61ZR67Y


Excellent article by Phillip Sloss, from Feb 22/17.
https://www.nasaspaceflight.com/2017/02/rs-25-test-sls-team-waits-new-controllers/

Lots of excitement in store from Stennis this year.  RS25's are my favourite Hydrogen combustion devices.

Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 10/01/2017 03:22 PM
Over on the Update thread, PSLOSS fills us in that the new terminology for the RS25 is Heritage, Adaptation, Restart.
http://forum.nasaspaceflight.com/index.php?topic=34671.140

Heritage-the old school SSME with the original SSME controllers-14 flight veterans and 2 engines which still require "green runs" at Stennis- ME-2062 (circa2010) and ME-2063(circa 2014)
Adaptation- the same 16 engines after hotfiring in an SLS environment with SLS equipment incl. SLS controllers
Restart-new build specifically designed for SLS, not yet in existence (what us oldschoolers would rather call RS25-"E") ideally to be used post EM-4, provided all 16 "ADAPTATION" engines test and operate nominally in preflight.

IMO, RS25-D(SSME), RS-25D+(SLSME), RS-25E(SLSME) would work, but no matter.

The new "RESTART" engines only will run at 111%RPL no doubt to overcome the extra mass of the new engines. She only has a service life of 4 starts and 1700 seconds, much different than the reusable "HERITAGE" units.  Just like what occurred when the Block-II-A RS25 came into usage for STS (STS-89)
which required a bump from 104% to 104.5% to compensate for the new Block-II-A and eventual Block-II RS-25-D masses.

Engine durability can be traded for increased thrust, no need for such extreme costs for low weight in a SLS spec engine. The new nozzle is a perfect example of this.

Hopefully we get a 4 engine core stage "greenrun" before the end of the decade.


I've included the graphic supplied by PSLOSS just for quick reference.  Thanks Phillip!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Khadgars on 10/03/2017 06:22 PM
Very cool thank you Hog.  I never quite understood peoples obsession with RS-25 being a bottleneck for SLS. 
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 10/08/2017 02:47 PM
NASA has ME-2063 mounted up in the test stand at Stennis.  It should be noted that ME-2063 is the 16th Main Engine of 16 currently available for SLS usage and is currently scheduled for flight duty in the next decade during EM-2.
ME-2063 was built in 2014 is only 1 of 2 ME's that have never been hot fired, so new that she doesn't appear in the oft seen SSME History Diagram(4th picture bellow- 15 of the 16 current 16 RS-25s have asterisks below them on the diagram-on the lower right of the diagram).
 Her sister ME-2062 was built back in 2010 when the STS program was still operational.

Here is ME-2063 being assembled is a couple posts up.

ME-2063 is to be tested during a public display on October 19, so long as you are a USA citizen.  I guess I'll watch from home.  2063 is the 2nd flight engine to be tested after ME-2059 was fired.

(First picture, you can see why modifications to the test stand we required as the engines are roughly the same size as the test stand. joke)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 10/19/2017 01:31 AM
New test, this time with Engine 2063 - which has never been tested before.

Awesome feature article from Philip Sloss:
https://www.nasaspaceflight.com/2017/10/stennis-fire-up-untested-rs-25-engine/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 10/19/2017 07:45 PM
T-15 mins. Test should be on NASA TV:
http://www.ustream.tv/NASAHDTV
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 10/19/2017 07:55 PM
T-5 minutes. Sirens sounding. Those cars are going to get a free wash.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 10/19/2017 07:59 PM
Epic view.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Joffan on 10/19/2017 08:04 PM
Epic, certainly, but why on Earth are they firing this thing for so long? It will never approach this in flight - will it?

[It certainly feels like an incredibly long test time.... maybe that is an illusion]

Ah finally they are done :)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Chris Bergin on 10/19/2017 08:05 PM
That was super!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: DaveS on 10/19/2017 08:06 PM
Epic, certainly, but why on Earth are they firing this thing for so long? It will never approach this in flight.
500 seconds = 8.33 minutes, roughly how long they fired on a nominal shuttle ascent. So it is a perfectly valid test.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Stardust9906 on 10/19/2017 08:14 PM
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: FutureSpaceTourist on 10/20/2017 03:02 PM
https://www.youtube.com/watch?v=lFqfCDEp6iw (https://www.youtube.com/watch?v=lFqfCDEp6iw)

Quote
Published on 19 Oct 2017
Engineers at NASA’s Stennis Space Center in Mississippi on Oct. 19 completed a hot-fire test of RS-25 rocket engine E2063, a flight engine for NASA’s new Space Launch System (SLS) rocket. Engine E2063 is scheduled to help power SLS on its Exploration Mission-2 (EM-2), the first flight of the new rocket to carry humans.

This video is available for download from NASA's Image and Video Library: https://images.nasa.gov/#/details-NAS...
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Hog on 06/20/2018 01:06 PM
I just rewatched STS-31 Discover-HST on Youtube and I noticed something about the TAL abort calls.
https://www.youtube.com/watch?v=CFaaaC-D3RQ

At 35:35 of the video we get the "Droop Banjul-109" call meaning that Discovery could reach it's TAL site under 2 engine out conditions with a single SSME thrusting at 109%.
Then 40 seconds later, at about 36:15  we get the "Single engine Banjul 104" call, meaning that Discovery could now reach the Banjul TAL site in a 2 out case with a single engine thrusting at 104%.

I find it fascinating that a mere 5% of extra throttle, on a single RS-25 engine, can buy a crew/payload an extra 40 seconds of margin in reaching a Trans Atlantic Landing site back in the "Shuttle days".

Though this extra "throttle" won't be used to reach "Abort Sites" just imagine what a constant 109% throttle x 4 engines will do for SLS?  Extra push, when called for is never a bad thing.

Let's not forget the recent 113%RPL that one of the workhorse Development Engines- DE-0528 was tested at for 50 seconds of the 260 second test at Stennis back in Feb.

Article by Phillip Sloss about the test
https://www.nasaspaceflight.com/2018/02/rs-25-hot-fire-sls-engine-113-percent/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: johnfwhitesell on 06/21/2018 04:21 AM
If the engine goes up to 109% thrust, why dont they make that 100% thrust?  And why dont they just make 10 louder instead of adding 11?  And why wont these kids get off my lawn?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: hopalong on 06/21/2018 05:14 AM
If the engine goes up to 109% thrust, why dont they make that 100% thrust?  And why dont they just make 10 louder instead of adding 11?  And why wont these kids get off my lawn?

Short answer - Mission Planning.
The SSME increased in thrust after its introduction into service, but the missions were based on the baseline thrust (100%), so to avoid confusion about which '100%' the engines were rated at, they kept the same baseline thrust rate as 100% and the up rated engines ran at 104% on the normal missions and 109% on an abort.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: daveklingler on 07/10/2018 02:39 PM
There's something I've wondered about for the past 10- or 15-odd years, and maybe someone here knows the answer.

The SSME underwent many years of development, some of it at the hands of Pratt engineers who were asked to come in and quietly fix Rocketdyne's design issues, and some of it by engineers who came well after.  The AR-22 seems to provide evidence that the RS-25 is a much better engine than the one that first flew in 1981.

IIRC, the downcomer was next on the redesign list when SSME production was discontinued. Does someone know whether PWR just picked up where they'd left off?  I know it's far more reliable now, but how much? How close is the RS-25 to its original reuseability design goals?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: whitelancer64 on 07/10/2018 03:28 PM
There's something I've wondered about for the past 10- or 15-odd years, and maybe someone here knows the answer.

The SSME underwent many years of development, some of it at the hands of Pratt engineers who were asked to come in and quietly fix Rocketdyne's design issues, and some of it by engineers who came well after.  The AR-22 seems to provide evidence that the RS-25 is a much better engine than the one that first flew in 1981.

IIRC, the downcomer was next on the redesign list when SSME production was discontinued. Does someone know whether PWR just picked up where they'd left off?  I know it's far more reliable now, but how much? How close is the RS-25 to its original reuseability design goals?

The SSME went through several iterations. FMOF [First Manned Orbital Flight] (1981), Phase I (1983), Phase II (1988), Block I (July 1995), Block IA (Oct. 1995), Block IIA (1998), and Block II (2001).

I'm of the understanding, but someone else will probably correct me, that all SSMEs Block I and later could be full-duration fired multiple times with little more than borescope inspections.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: russianhalo117 on 07/10/2018 03:30 PM
There's something I've wondered about for the past 10- or 15-odd years, and maybe someone here knows the answer.

The SSME underwent many years of development, some of it at the hands of Pratt engineers who were asked to come in and quietly fix Rocketdyne's design issues, and some of it by engineers who came well after.  The AR-22 seems to provide evidence that the RS-25 is a much better engine than the one that first flew in 1981.

IIRC, the downcomer was next on the redesign list when SSME production was discontinued. Does someone know whether PWR just picked up where they'd left off?  I know it's far more reliable now, but how much? How close is the RS-25 to its original reuseability design goals?
The RS-24 demonstrator engine served as the basis for the operational RS-25. It was originally conceived as expendable but switched to reusable design for the STS programme.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: AncientU on 07/11/2018 12:39 AM
Great engine... huge effort to make it truly resuable. 
So, could someone explain to me again why we are throwing four of them away each flight?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: ulm_atms on 07/11/2018 01:22 AM
Great engine... huge effort to make it truly resuable. 
So, could someone explain to me again why we are throwing four of them away each flight?

To funnel more money to AR?  8)

I kid but it is because this engine was/is the most powerful engine they had at the time when designing SLS and they were trying to do it on the "cheap"....so no engine development money was available.  I do hate seeing that beautiful engine being thrown away though.

I know you knew the answer when you asked however... ;)

Edit: Forgot words...Twice...I'm tired... :-[
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: johnfwhitesell on 07/11/2018 03:18 AM
I do hate seeing that beautiful engine being thrown away though.

I wonder how much it would cost to develop a SMART system (like Vulcan) to recover them.  They shouldn't even wait for SLS to start trying.  Just make some dummies and put the dummies on a Vega as the payload then try to parachute the dummies.  Vega's only cost 37 million so it should be a lot cheaper then throwing away 4 of those beauties.

But more seriously, it's pretty damn infuriating that they are yanking bits out of the old space shuttles for the SLS.  It's like looting the Parthenon for marble.  If they are going to throw away RS-25s, they should throw away the ones that are made for a single use.  They've had plenty of time to get them ready.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: daveklingler on 07/12/2018 10:49 PM
I do hate seeing that beautiful engine being thrown away though.

I wonder how much it would cost to develop a SMART system (like Vulcan) to recover them. 

It may be that Phantom Express will prove to be as helpful to the RS-25's continued existence as SLS. If Phantom Express proves the engine's a safe design choice for reusable vehicles with rapid turnaround, it may pick up other design wins.

Maybe Phantom Express is a smarter recovery system than SMART.  :)

Quote
They shouldn't even wait for SLS to start trying.  Just make some dummies and put the dummies on a Vega as the payload then try to parachute the dummies.  Vega's only cost 37 million so it should be a lot cheaper then throwing away 4 of those beauties.

I confess that I have the attitude toward SMART that many people have after watching a whole bunch of F9 landings: "Huh?"

Quote
But more seriously, it's pretty damn infuriating that they are yanking bits out of the old space shuttles for the SLS.  It's like looting the Parthenon for marble.  If they are going to throw away RS-25s, they should throw away the ones that are made for a single use.  They've had plenty of time to get them ready.

I go back and forth. On the one hand, those are museum pieces.  On the other hand, they're rocket engines, and deserve to be pushing payloads.  On the gripping hand, they're being thrown away????!!!!!!
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: daveklingler on 07/12/2018 11:01 PM
There's something I've wondered about for the past 10- or 15-odd years, and maybe someone here knows the answer.

The SSME underwent many years of development, some of it at the hands of Pratt engineers who were asked to come in and quietly fix Rocketdyne's design issues, and some of it by engineers who came well after.  The AR-22 seems to provide evidence that the RS-25 is a much better engine than the one that first flew in 1981.

IIRC, the downcomer was next on the redesign list when SSME production was discontinued. Does someone know whether PWR just picked up where they'd left off?  I know it's far more reliable now, but how much? How close is the RS-25 to its original reuseability design goals?

The SSME went through several iterations. FMOF [First Manned Orbital Flight] (1981), Phase I (1983), Phase II (1988), Block I (July 1995), Block IA (Oct. 1995), Block IIA (1998), and Block II (2001).

I'm of the understanding, but someone else will probably correct me, that all SSMEs Block I and later could be full-duration fired multiple times with little more than borescope inspections.

Thanks to you and RussianHalo117.  If that's the case, which is certainly implied by its use in Phantom Express, I'm really looking forward to watching it finally do what it's capable of doing, sigh...even though it's an expensive alternative to a BE-4 or maybe even an AR-1.  In a way, Phantom Express is somewhat like a Shuttle 2.0, a little more-so than Dream Chaser or X-37b.  RS-25 is the late-blooming, somewhat homelier half-sister to the high-pressure hydrolox engines that Pratt developed during the 1960's for passenger use.

Maybe there will be a cost-competitive, scaled-up version of Phantom Express some day with a reusable first stage, designed to be a "space truck".  :)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: wannamoonbase on 07/16/2018 03:00 AM
Great engine... huge effort to make it truly resuable. 
So, could someone explain to me again why we are throwing four of them away each flight?

To funnel more money to AR?  8)

I kid but it is because this engine was/is the most powerful engine they had at the time when designing SLS and they were trying to do it on the "cheap"....so no engine development money was available.  I do hate seeing that beautiful engine being thrown away though.

I know you knew the answer when you asked however... ;)

Edit: Forgot words...Twice...I'm tired... :-[

The RS-25 is an incredible engine with a long history and great performance stats.  But it is 40+ year old technology at this time.

Throwing away 4 of these expensive wonder machine with each SLS launch is an expensive endeavor.

However, SLS has such a slow and long manifest there won't be too many flights.  (Until the public forces congress to adopt cheaper commercial alternatives.)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: johnfwhitesell on 07/16/2018 03:30 AM
I confess that I have the attitude toward SMART that many people have after watching a whole bunch of F9 landings: "Huh?"

Vertical landing is the best solution... if you are landing 20 times a year.  The SLS wont be anywhere close to that.

Also for Falcon 9 vertical landing makes more sense because of how early the separation is.  Falcon 9 has a heavy second stage with RP-1 instead of the LH2.  SLS has LH2 in the first stage as well as the second stage plus it has those massive boosters.  All that adds up to the SLS first stage needs to be going pretty darn fast to do it's job so a vertical landing would be tough.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Coastal Ron on 07/17/2018 02:31 AM
I do hate seeing that beautiful engine being thrown away though.

I wonder how much it would cost to develop a SMART system (like Vulcan) to recover them.

More than it costs to buy the engines. But more importantly, it was not a requirement from Congress.

You do understand how products are designed, right? They start with a list of requirements, and if reusability is not part of the requirements, then they don't design for it. The SLS was not designed, in any way, for reusability or recovery of it's components.

Quote
They shouldn't even wait for SLS to start trying.

Sure, they are already spending $30B for the SLS, what another couple of $Billion?   ;)

Also for Falcon 9 vertical landing makes more sense because of how early the separation is.  Falcon 9 has a heavy second stage with RP-1 instead of the LH2.  SLS has LH2 in the first stage as well as the second stage plus it has those massive boosters.  All that adds up to the SLS first stage needs to be going pretty darn fast to do it's job so a vertical landing would be tough.

The Falcon 9 stages low because of the need to recover the 1st stage, and also because the 2nd stage has the ability to take the payload the rest of the way.

The SLS has to stage higher and faster because of the EDS. Which also means if you were to detach the engine compartment it would be traveling through space for a while before entering Earth's atmosphere at a heck of a velocity. Did you anticipate that?   ;)
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: johnfwhitesell on 07/17/2018 03:36 AM
More than it costs to buy the engines.

This says the engines cost 50 million a pop on top of the 1.1 billion in startup costs. (https://spaceflightnow.com/2015/11/27/aerojet-rocketdyne-wins-propulsion-contracts-worth-nearly-1-4-billion/)  Has that information been superseded?  If not those engines are costing 200-240 million a flight.

I'm having a hard time seeing SMART costing more to develop then that.

You do understand how products are designed, right?

No, I'm a moron who you should lecture in a tone of poorly concealed contempt.

what another couple of $Billion?   ;)

Well, at 37 million a Vega launch a couple billion would be about 50 launches.

The SLS has to stage higher and faster because of the EDS. Which also means if you were to detach the engine compartment it would be traveling through space for a while before entering Earth's atmosphere at a heck of a velocity. Did you anticipate that?   ;)

Yes.  Hence why I thought SMART might be applicable to the situation.

Good talk.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: envy887 on 07/17/2018 03:44 AM
I do hate seeing that beautiful engine being thrown away though.

I wonder how much it would cost to develop a SMART system (like Vulcan) to recover them.

More than it costs to buy the engines. But more importantly, it was not a requirement from Congress.

You do understand how products are designed, right? They start with a list of requirements, and if reusability is not part of the requirements, then they don't design for it. The SLS was not designed, in any way, for reusability or recovery of it's components.
...

The requirements were vague enough that reuse could have been included if NASA thought it worthwhile.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: eeergo on 09/06/2018 05:45 PM
Question about the scheduling and objectives:

I understand the Retrofit 1A test series is complete and all heritage engines and ECUs with 109% RPL settings are certified for SLS (so I assume 8 successful tests were performed in that series), and now the Retrofit 1B 9-test series has started with the declared objective of certifying new components for the production restart RS-25s, along with continuing ECU certification for the next two SLS flights (still with heritage 109%RPL engines).

Now, will the RS-25s for the third and fourth SLS flights incorporate the improved components (RS-68-derived processes, 3D printing...) or will they be replaced with the heritage ones?
Is the extra (9th) test intended to provide a spare ECU apart from the 8 needed for SLSs 3 and 4?
Is there a plan/schedule already in place for subsequent testing (Retrofit 1C / Retrofit 2 / something else), I guess starting to certify newly-built RS-25s for the fifth SLS?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: psloss on 09/06/2018 08:17 PM
Is there a plan/schedule already in place for subsequent testing (Retrofit 1C / Retrofit 2 / something else), I guess starting to certify newly-built RS-25s for the fifth SLS?
A lot of that is covered in our summer two parter.

Part 1:
https://www.nasaspaceflight.com/2018/07/rs-25-program-production-restart-test-series/

Part 2:
https://www.nasaspaceflight.com/2018/07/aerojet-rocketdyne-six-engine-rs-25-run/
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: eeergo on 09/07/2018 09:18 AM
Is there a plan/schedule already in place for subsequent testing (Retrofit 1C / Retrofit 2 / something else), I guess starting to certify newly-built RS-25s for the fifth SLS?
A lot of that is covered in our summer two parter.

Part 1:
https://www.nasaspaceflight.com/2018/07/rs-25-program-production-restart-test-series/

Part 2:
https://www.nasaspaceflight.com/2018/07/aerojet-rocketdyne-six-engine-rs-25-run/


Thanks, I had missed reading those earlier in the summer, indeed many questions are answered there, especially on the long-term planning.

I may have missed it, but I didn't see stated what's the purpose of the 9th test in the Retrofit 1B series (unless there were 7 tests in 1A), although I guess having a spare ECU is quite probable? And concerning the old SSMEs to be used in the first SLSs, will they keep their new components (POGO accumulator etc) they hot-fired them with, or are they just certifying those designs, but the actual flight configuration will be with the heritage ones?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: psloss on 09/07/2018 02:23 PM
I may have missed it, but I didn't see stated what's the purpose of the 9th test in the Retrofit 1B series (unless there were 7 tests in 1A), although I guess having a spare ECU is quite probable?
The overall objectives of the tests (and the number of tests in these particular series) have mostly to do with the production restart design so they can start building new engines for flight #5 and beyond. 

But they'll take the opportunity like yesterday to acceptance test parts for the overall inventory, like new ECUs.

They will have more than enough of the controllers to support the first vehicle activities before this test series ends.

And concerning the old SSMEs to be used in the first SLSs, will they keep their new components (POGO accumulator etc) they hot-fired them with, or are they just certifying those designs, but the actual flight configuration will be with the heritage ones?
The flight engines (the old SSMEs) kept all of their parts and are mostly left alone; they replaced the ECUs and they retained some parts inventory from Shuttle with the engines for things that time out.

The adaptation design using the leftover SSMEs with new ECUs is more or less ready to fly.

With few exceptions, flight engines are not repeatedly ground tested.  Just like yesterday, the two development engines left over from Shuttle are used for almost all ground tests. 

None of engines that will go in the first Core Stage have been started since their last Shuttle launch.  Flight engines get a single ground acceptance test when they are new and that's usually it.  For example, E2063 was assembled from Shuttle inventory a few years ago and acceptance tested last year:
https://www.nasaspaceflight.com/2017/10/stennis-fire-up-untested-rs-25-engine/

New flight parts are acceptance tested on the ground by installing and running them on those two development engines, just like the ECU yesterday.

The first two sets of leftover SSMEs will be used in the Stage Green Run hot-fires, but that's testing just about everything *except* the engines.  For that test, the engines are being run to test the Core Stage.
Title: RS-25 testing/development at Stennis for SLS - 16:30 Today, 26 September
Post by: Aurora on 09/26/2018 06:37 PM
https://www.nasa.gov/nasalive

RS-25 test firing to be broadcast live at 16:30 today, 26 September
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: DaveS on 09/26/2018 06:43 PM
https://www.nasa.gov/nasalive

RS-25 test firing to be broadcast live at 16:30 today, 26 September
That's a remnant from yesterday. The page was last updated then.
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: Aurora on 09/26/2018 08:41 PM
Sorry, my mistake everyone
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: MattBaker on 10/11/2018 07:13 PM
3:12 PM and all I've got on NASA TV is a replay of the press conference of the Soyuz, is the test today not happening (which doesn't make any sense, totally unrelated program to the ISS, right?) or is it just not shown?
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: catdlr on 10/12/2018 03:19 AM
3:12 PM and all I've got on NASA TV is a replay of the press conference of the Soyuz, is the test today not happening (which doesn't make any sense, totally unrelated program to the ISS, right?) or is it just not shown?

watch here:  https://forum.nasaspaceflight.com/index.php?topic=35220.msg1866709#msg1866709
Title: Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
Post by: MattBaker on 10/12/2018 07:58 AM
Yeah, I got it live yesterday, it was scheduled for 3:00 but then didn't happen until 3:45 and I didn't see a notice so I was confused!