Author Topic: RS-25 testing/development at Stennis for SLS - DISCUSSION  (Read 109149 times)

Offline theinternetftw

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #120 on: 12/13/2018 08:51 pm »
Northrop also tried reusing 30 year old engines. After that Cygnus flew on Atlas for a bit...

None of the RS-25D engines that are going to be flown on the SLS are that old.

The RS-25D variant's first flight was in 2001. The oldest components retrofitted into an RS-25D look to be ones that first flew in 1995. I *think* that particular one is in the SLS engine stock.
« Last Edit: 12/13/2018 08:53 pm by theinternetftw »

Offline Tuna-Fish

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #121 on: 12/16/2018 01:20 am »
Wonder if any Merlin's come close  ;D

Flight engines are unlikely to rack up that much time, and SpaceX likes to blow up their test articles by ramping up the conditions after sufficient testing at reasonable parameters so none of those are likely to survive that long.

Offline docmordrid

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #122 on: 12/16/2018 04:35 am »
Wonder if any Merlin's come close  ;D
>
SpaceX likes to blow up their test articles by ramping up the conditions
>

Ex

Air & Space...

Quote
Part of the Merlin’s qualification testing involves feeding a stainless steel nut into the fuel and oxidizer lines while the engine is running—a test that would destroy most engines but leaves the Merlin running basically unhindered.
DM

Offline rosbif73

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #123 on: 01/10/2019 06:44 am »
ARTICLE: Government MECO delays RS-25 testing following premature shutdown -

https://www.nasaspaceflight.com/2019/01/government-meco-rs-25-premature-shutdown/

https://twitter.com/NASASpaceflight/status/1083064629364953088

Gotta love that title, Chris! Main Executive Cut-Off, I presume :-)

Offline Hog

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #124 on: 04/28/2019 07:09 pm »
NASA Achieves Testing Milestone with Engines for Initial SLS Missions

NASA conducted a hot fire test of RS-25 flight engine No. 2062 on the A-1 Test Stand at Stennis Space Center on April 4, with a full-duration of 500 seconds. The hot fire caps more than four years of testing for engines that will help power the first four missions of NASA’s new Space Launch System (SLS) rocket. All 16 former space shuttle main engines that will help launch the first four SLS missions have undergone acceptance testing and have completed developmental and acceptance testing for new controllers to be used by the engines. It also concludes a 51-month test series that demonstrated RS-25 engines can perform at the higher power level needed to launch the super heavy-lift SLS rocket.

Does this mean the Retrofit 1b test series is complete, and certification of the new HIP MCC, HPFTP and POGO accumulators is now complete (along with the certification of the ECUs for the first four SLS flights)?

If so, the next RS-25 testing we can expect is within the Retrofit 2 series, to certify the flexible ducting?

How long is that program expected to last before Retrofit 3 is reached? I understand the deadline for finishing all Retrofit series and deliver a non-flight certification engine is the middle of next year, to have six new "production restart" engines delivered 3 years later.
Retrofit 1b testing should now be complete with the 9th test.  POGO accumulator was on DE-0528 for Retrofit 1a and the same POGO assembly was retrofitted on DE-0525 for Retrofit 1b.

Retrofit-2 will use DE-0528 for testing and will include the flex hoses you mentioned, a change from the complicated flex-joints which were used on Shuttle. Going from reusable to expendable plus the reduction in gimbaling requirements allowed for this change. We will see the 2nd MCC and 2nd POGO assemblies along with some gimbaling action using the new  thrust vector control (TVC) assembly added to the A-1 test stand.
The test scheduling on the restart of RS-25 production seems to be on schedule, I'm guessing we'll see E-0528 loaded with the new parts for Retrofit2 testing soon(Summerish??EDIT possibly next year-AR-22 gets another round of tests in addition to last Summers testing at A-1)).

The original 16 "Heritage" engines have now been accepted as "Adaptation Engines" which will run at 109% RPL. Along with the engines 17 new controllers, 4 for each mission, with a single spare controller.

The contract delivery date for those six "new build" engines is July of 2024.  The single "Certification Engine" as they are calling it, is really a Development Engine, regardless it will have all the features of a flight engine, but will never see space. We are to see the new build "Certification Engine" by mid 2021.

pics
1) Testing/Development/Production restart for RS-25 engine program
2) Differences between "Heritage(RS-25D/SSME)" "Adaptation" and "Restart" SR25 engines
« Last Edit: 04/28/2019 07:44 pm by Hog »
Paul

Offline Khadgars

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #125 on: 05/10/2019 05:46 pm »
NASA Achieves Testing Milestone with Engines for Initial SLS Missions

NASA conducted a hot fire test of RS-25 flight engine No. 2062 on the A-1 Test Stand at Stennis Space Center on April 4, with a full-duration of 500 seconds. The hot fire caps more than four years of testing for engines that will help power the first four missions of NASA’s new Space Launch System (SLS) rocket. All 16 former space shuttle main engines that will help launch the first four SLS missions have undergone acceptance testing and have completed developmental and acceptance testing for new controllers to be used by the engines. It also concludes a 51-month test series that demonstrated RS-25 engines can perform at the higher power level needed to launch the super heavy-lift SLS rocket.

Does this mean the Retrofit 1b test series is complete, and certification of the new HIP MCC, HPFTP and POGO accumulators is now complete (along with the certification of the ECUs for the first four SLS flights)?

If so, the next RS-25 testing we can expect is within the Retrofit 2 series, to certify the flexible ducting?

How long is that program expected to last before Retrofit 3 is reached? I understand the deadline for finishing all Retrofit series and deliver a non-flight certification engine is the middle of next year, to have six new "production restart" engines delivered 3 years later.
Retrofit 1b testing should now be complete with the 9th test.  POGO accumulator was on DE-0528 for Retrofit 1a and the same POGO assembly was retrofitted on DE-0525 for Retrofit 1b.

Retrofit-2 will use DE-0528 for testing and will include the flex hoses you mentioned, a change from the complicated flex-joints which were used on Shuttle. Going from reusable to expendable plus the reduction in gimbaling requirements allowed for this change. We will see the 2nd MCC and 2nd POGO assemblies along with some gimbaling action using the new  thrust vector control (TVC) assembly added to the A-1 test stand.
The test scheduling on the restart of RS-25 production seems to be on schedule, I'm guessing we'll see E-0528 loaded with the new parts for Retrofit2 testing soon(Summerish??EDIT possibly next year-AR-22 gets another round of tests in addition to last Summers testing at A-1)).

The original 16 "Heritage" engines have now been accepted as "Adaptation Engines" which will run at 109% RPL. Along with the engines 17 new controllers, 4 for each mission, with a single spare controller.

The contract delivery date for those six "new build" engines is July of 2024.  The single "Certification Engine" as they are calling it, is really a Development Engine, regardless it will have all the features of a flight engine, but will never see space. We are to see the new build "Certification Engine" by mid 2021.

pics
1) Testing/Development/Production restart for RS-25 engine program
2) Differences between "Heritage(RS-25D/SSME)" "Adaptation" and "Restart" SR25 engines

Fantastic breakdown Hog, greatly appreciate the updates.  RS-25 restart looks well positioned to support 5th flight on-wards.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline Hog

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #126 on: 12/17/2019 06:55 pm »
Here is a paper about the 18 "Adaptation" RS-25 hot-fire tests that occurred between Jan, 2015 – Jan,
2018 7 at Stennis.  They used the SLS throttle profile of 80%MinimumPL up to 109%Nominal PL.

The 113% PL tests came in the later test series.
« Last Edit: 12/17/2019 07:36 pm by Hog »
Paul

Offline Hog

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #127 on: 05/12/2023 05:49 pm »
300 day warning acknowledged but I'm cross-posting from the RS-25 testing at Stennis for SLS-UPDATES to avoid further muddling of said UPDATES thread. (plus there is some killer information and links to some AMAZING NSF.com articles contained within this DISCUSSION thread)

From the UPDATES thread-https://forum.nasaspaceflight.com/index.php?topic=35220.460

In the imperial system maybe, but not in the metric system.

1) Typically RS25 hotfire testing is referenced to in seconds alone.
 Eg.  "Prior to the December 2018 hotfire test, Development Engine DE0525 has 87 ground test starts at Stennis in its service for Shuttle and SLS, accumulating 43,133 seconds of run time on its powerhead. Similarly, DE0528 has 109 ground test starts, accumulating 58,842 seconds of run time on its powerhead at Stennis." -NASA

2) 10.5 minutes=10-1/2 minutes=00:10:30(hrs:min:sec)=630 seconds  On Earth, one second is equivalent to "the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9,192,631,770 cycles per second or Hz.  If this is untrue,  please explain as obviously I require a serious Metrology edumacation.
Paul

Offline arthuroMo

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Re: RS-25 testing/development at Stennis for SLS - DISCUSSION
« Reply #128 on: 05/12/2023 06:41 pm »
I was just kiddding as someone you told me that 10.5 minutes were 630s as if I didn't know that.
No hard feelings there mate.

As an aside i'm having a hard time understanding the cross/multi posting policy on NSF.
« Last Edit: 05/12/2023 06:44 pm by arthuroMo »

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