Author Topic: Space Launch System (SLS) Q&A  (Read 49968 times)

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #60 on: 06/28/2018 03:12 pm »
Thanks Dave S, when you said that Pathfinder was used for VAB checkout operations, I thought you were inferring that there was never a fit-check of any type that occurred out at the pad.  I then came across the pic of Enterprise being checked out at 39-A and it didn't compute for me.

SO the "The core stage pathfinder demo in the VAB will not involve stacking it on the ML or going out to the pad." and "It (referring to the core stage pathfinder) will pretty much do what the orbiter mock-up Pathfinder did when it was at KSC, check out the facilities but not go to the pad."

So, is there any SLS program components, other than the core stage pathfinder or the SLS Core Stage-1 (C/S-1) that will be stacked on ML-1 and taken to 39-B for any sort of a test, be it a Crawler Transport test, or any sort of Pad based fit-check test?

My apologies for the difficult conversation via written text. An in person conversation whilst enjoying a beverage would be far more cogent.
Paul

Online DaveS

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Re: Space Launch System (SLS) Q&A
« Reply #61 on: 06/28/2018 03:24 pm »
Thanks Dave S, when you said that Pathfinder was used for VAB checkout operations, I thought you were inferring that there was never a fit-check of any type that occurred out at the pad.  I then came across the pic of Enterprise being checked out at 39-A and it didn't compute for me.

SO the "The core stage pathfinder demo in the VAB will not involve stacking it on the ML or going out to the pad." and "It (referring to the core stage pathfinder) will pretty much do what the orbiter mock-up Pathfinder did when it was at KSC, check out the facilities but not go to the pad."

So, is there any SLS program components, other than the core stage pathfinder or the SLS Core Stage-1 (C/S-1) that will be stacked on ML-1 and taken to 39-B for any sort of a test, be it a Crawler Transport test, or any sort of Pad based fit-check test?

My apologies for the difficult conversation via written text. An in person conversation whilst enjoying a beverage would be far more cogent.
Pathfinder was never stacked, just like the SLS core stage pathfinder won't be. The VAB wasn't ready at that time to support any stacking operations. The EM-1 SLS will be the first time a full SLS stack will be at the pad. The Core stage pathfinder will just check out the VAB from a crane operations stand point.

Nothing else will be done. Nothing will be stacked on ML-1 for these operations. They'll take ML-1 to the pad in Augusthopefully for a more comprehensive fit check than what was done back 2011. Then it will go to VAB High Bay 3to complete the GSE outfitting and Validation&Verification (V&V) testing. Then it will simply wait until it's time to start EM-1 stacking operations.
"For Sardines, space is no problem!"
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Offline Jim

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Re: Space Launch System (SLS) Q&A
« Reply #62 on: 06/28/2018 04:26 pm »

The Saturn-V used a "Fixed Service Structure"(FSS) aka "Launch Tower", formally aka the "Launch Umbilical Tower"(LUT) and a Mobile Service Structure(MSS) as pictured below in picture #2.
The Saturn-V FSS is attached to the stack in the VAB atop a Mobile Launcher, and a Crawler Transporter(C/T) carries the stack to the pad, sets it down atop the holddown posts and then retreats. The MSS is then positioned directly across from the FSS thus encapsulating the stack, the MSS is withdrawn prior to launch.

The Saturn-V used a Mobile Launcher that had a Launch Umbilical Tower (LUT) on it. ;-).  It was permanent. 

Shuttle made a made a mistake by calling it an FSS, it was a FUT like every other pad.

The SLS conops is for minimal access at pad so no MSS
« Last Edit: 06/28/2018 04:30 pm by Jim »

Offline se jones

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Re: Space Launch System (SLS) Q&A
« Reply #63 on: 12/17/2018 07:20 am »
What are these techs doing in this image from SRB casting Promontory? What is the function of the hundreds of translucent plastic (I assume) tubes?

Thanks in advance



 
« Last Edit: 12/20/2019 05:12 am by se jones »

Offline Jim

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Re: Space Launch System (SLS) Q&A
« Reply #64 on: 12/17/2018 05:53 pm »

(my SWAG: some sort of acoustic damper system) 

Those are not part of the motor

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #65 on: 12/18/2018 03:53 pm »
Will we ever see a pair of 5 segment SLS SRBs atop a Mobile Launcher just as we see a pair of 4 segment boosters in this picture?   


There is a piece of hardware that consists of a white cross beam that was placed in between both SRBs.  There was a picture here at NSF of this cross beam both installed atop a pair of SRBs on a Shuttle MLP and pictured on teh floor beside a wall.  Ive searched and cant find the pic of thi beam.

Pic#2 just a quick pic of the cross section of a Solid Rocket Motors propellant casting shape.
Paul

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #66 on: 06/24/2019 06:22 pm »
As STS-135 landed thus concluding STS operations there were 15 RS-25D SSME's in inventory.  The newest of the 15 was ME-2062 that was assembled in 2010, a year before the Shuttle program was ended. This engine was never hot fired.  It was discovered that there was enough spare parts to construct a further RS-25D/SSME for a full compliment of 4 Exploration Missions using 4 engines per flight.  This RS-25D engine, ME-2063 was assembled in late 2014/early 2015.


RS-25 engines for
EM-1 ME-2045, ME-2056, ME-2058, ME-2060

EM-2 ME-2047, ME-2059, ME-2062, ME-2063

EM-3 ME-2048, ME-2054, ME-2057, ME-2061

EM-4 ME-2044, ME-2050, EM-2051, EM-2052

These 16 RS-25D/Space Shuttle Main Engine as part of the Space Shuttle Program(SSP) came off the pad at 100% RPL(rated power level) and except for Max Q and 3 G throttling, nominally stayed at 104.5% RPL.  They were designed with a service life of 55 starts and 27,000 seconds(450minutes or 7.5 hours) of runtime.  These RS-25D/SSME are now referred to by NASA as "HERITAGE" engines.

Along comes SLS and the decision to use STS assets for SLS.  For SLS the RS-25 engine will be expendable, yet will continue on as a Sustainer engine though will nominally provide thrust at the 109% RPL. New requirements make its design service life of just 6 starts and 2500 seconds(41.6 minutes) of runtime.  These RS-25 engines ready for use in the Core Stage of SLS are now referred to as "ADAPTATION" engines.

The "new build" RS-25 engines of which 6 flight engines and one new Certification/Development Engine have been ordered and their production is already underway, will be used for all SLS missions after EM-4, after which all the "ADAPTATION" RS-25s will have been expended.  These new build engines will again be expendable, and nominally run at 111% RPL, have a service life of 4 starts and 1700 seconds or 28 minutes in duration.  TRhese new build engines are now referred to as "RESTART" engines as these are the engines that are part of the new effort of Aerojet/RocketDyne to restarts the RS-25 assembly lines and supply NASA with 6 new flight engines and 1 Certification/Development engines.  Whatever you call this "RESTART" certification/development RS-25, it will never fly in space, though it has all the same components that the other 6 flight engines will.  The cert./dev "RESTART" engine will join Development Engine-0525 and DE-0528, which are the current workhorses on the test stands at Stennis.

They will feature many new less expensive methods of manufacture/assembly including additive manufacturing.  As of right now, they will still feature the 1080 stainless steel tubes which lines the inside wall of the nozzle, which carries liquid hydrogen from the manifold at the end of the nozzle, to the upper inside portion of the nozzle thus providing regenerative cooling of the nozzle.  As part of the RS-25 Block III study, from the year 2000, a new design "Channel Wall" nozzle design eliminated the 1080 SS lines and its labour intensive brazing-similar to the Soviet designed RD-0120 engine that was used as a Sustainer engine in the Energia Super heavy lifter that hoisted the Soviet Buran into space.  The brazed Stainless steel design is lighter, as seen in the Block III proposal, and the Soviet RD-0120, but it is considerably more economical.  This Channel Wall nozzle would also allow a full 2 pass flow of hydrogen through the nozzle thus eliminating the feedlines to aft of the nozzle as in the current design.  The Channel Wall nozzle MAY be addressed in further Block IV versions of the RS-25 engine.

My question. 
As we can see Exploration Mission #1 is the uncrewed "test" flight of Orion and ME-2045, ME-2056, ME-2058, ME-2060 will power the Core Stage.
For EM #2 which will be the first crewed mission for Orion/SLS ME-2047, ME-2059, ME-2062, ME-2063 will be used.  The bolded engine numbers are the 2 engines built in 2010 and 2014 respectively.  ME-2047 has 8 STS missions under its belt( in the newest Block II version, known as RS-25D: STS-112,115,118,123, 126, 128, 132 and 134) and ME-2059 has 5 STS missions (this engine only flew in the most current Block II iteration of the RS-25, the RS-25D: STS-117, 122, 125, 130 and STS-134)
We have 2 Core Stage engines with a proven flight history, right beside 2 engines which were the last two Rs-25s ever built with one of those being built in 2014 years after the RS-25 assembly line was closed, both of which have only been hotfired at Stennis.
Does anyone have any idea what the decision process is/was in regards to the selection of which Core Stage engine to fly on what mission and which engines to "cluster" together?  Any and all input is welcome.

I really hope we get to hear the PAO phrase
"Coming out of the bucket, 4 at One Eleven. Orion #5 is go at throttle up!" 
That means we have flown through the 16 Adaptation engines, IOW SLS has flown 4 times and that for the 5th SLS mission, we are now using 4 brand spanking new SLS Core Stage RS-25 RESTART engines and we only have 3 more sets of 5 segment steel casing SRBs left in inventory with the need for the Advanced Boosters being required for SLS-9 and beyond.
Here's to hoping.

Thanks!


pics
1 through 3 NASA presentation slides from NTRS(NASA Technical Reports Server)
#4 RS-25 Block III presentation from 2000
5) List of past and current Rs-25 engines, what form they took and what missions they were flown on.(the 2014 build RS-25 ME-2063 is absent from this diagram)
Paul

Offline Fequalsma

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Re: Space Launch System (SLS) Q&A
« Reply #67 on: 06/25/2019 11:33 am »
https://www.semanticscholar.org/paper/Operating-Deflection-Shapes-for-the-Space-Shuttle-Buehrle-Kappus/d70d351a376eca8949e33c2d9626694e792a39de

https://www.nasa.gov/missions/shuttle/f_vibetest.html


There is a piece of hardware that consists of a white cross beam that was placed in between both SRBs.  There was a picture here at NSF of this cross beam both installed atop a pair of SRBs on a Shuttle MLP and pictured on teh floor beside a wall.  Ive searched and cant find the pic of thi beam.


Edit - finally found the photo of the SRB crossbeam:

http://www.capcomespace.net/dossiers/espace_US/shuttle/ksc/VAB/VAB%20ET%20Cross%20Beam%201.JPG
« Last Edit: 06/26/2019 04:17 am by Fequalsma »

Offline brickmack

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Re: Space Launch System (SLS) Q&A
« Reply #68 on: 06/27/2019 01:04 am »
https://www.semanticscholar.org/paper/Operating-Deflection-Shapes-for-the-Space-Shuttle-Buehrle-Kappus/d70d351a376eca8949e33c2d9626694e792a39de

https://www.nasa.gov/missions/shuttle/f_vibetest.html


There is a piece of hardware that consists of a white cross beam that was placed in between both SRBs.  There was a picture here at NSF of this cross beam both installed atop a pair of SRBs on a Shuttle MLP and pictured on teh floor beside a wall.  Ive searched and cant find the pic of thi beam.


Edit - finally found the photo of the SRB crossbeam:

http://www.capcomespace.net/dossiers/espace_US/shuttle/ksc/VAB/VAB%20ET%20Cross%20Beam%201.JPG

Theres a number of photos from in the ET intertank that show this piece, eg https://www.nasa.gov/images/content/511977main_mendoza_twotanks.jpg

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #69 on: 06/27/2019 03:41 pm »
https://www.semanticscholar.org/paper/Operating-Deflection-Shapes-for-the-Space-Shuttle-Buehrle-Kappus/d70d351a376eca8949e33c2d9626694e792a39de

https://www.nasa.gov/missions/shuttle/f_vibetest.html


There is a piece of hardware that consists of a white cross beam that was placed in between both SRBs.  There was a picture here at NSF of this cross beam both installed atop a pair of SRBs on a Shuttle MLP and pictured on teh floor beside a wall.  Ive searched and cant find the pic of thi beam.


Edit - finally found the photo of the SRB crossbeam:

http://www.capcomespace.net/dossiers/espace_US/shuttle/ksc/VAB/VAB%20ET%20Cross%20Beam%201.JPG
Thank you.  Those are the exact pics I was looking for.  I didn't realize that the pics were part of the 2nd NASA STS RTF effort.  "Partial Stack Rollout Test".
IIRC the picture of the green SRB beam beside the wall was used in a NSF.com article.

Thanks again.
Paul

Offline jd2017

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Re: Space Launch System (SLS) Q&A
« Reply #70 on: 10/08/2019 03:48 pm »
I'm looking for some good Schematics and animations or blueprints of the RS-25, I'm an L2 subscriber, but I'm new so the Setup is still a little confusing for me. Thanks!

Offline SWGlassPit

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Re: Space Launch System (SLS) Q&A
« Reply #71 on: 10/14/2019 03:39 pm »
I'm looking for some good Schematics and animations or blueprints of the RS-25, I'm an L2 subscriber, but I'm new so the Setup is still a little confusing for me. Thanks!

Look for "SSME Bible".  That'll get you a huge amount of what you want.

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #72 on: 10/16/2020 02:46 pm »
Regarding the upcoming Wet Dress Rehearsal (WDR) for the Artemis-1 Core Stage.

Will this be the first time that an SLS core stage has been completely filled with LOx and LH2? 

700,000 gallons of propellant is 2,649,788 litres which will be burned in just over 8 minutes.  Simply amazing.  Apparently the hydrogen tank is the largest cryogenic tank for flight at 130 feet(39.6 meters) x 27.6 ft. (8.4 m).
Paul

Offline woods170

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Re: Space Launch System (SLS) Q&A
« Reply #73 on: 10/16/2020 07:57 pm »
Regarding the upcoming Wet Dress Rehearsal (WDR) for the Artemis-1 Core Stage.

Will this be the first time that an SLS core stage has been completely filled with LOx and LH2?

700,000 gallons of propellant is 2,649,788 litres which will be burned in just over 8 minutes.  Simply amazing.  Apparently the hydrogen tank is the largest cryogenic tank for flight at 130 feet(39.6 meters) x 27.6 ft. (8.4 m).

Emphasis mine.

The answer is Yes. First time this stage will be filled with LOX and LH2.

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #74 on: 10/22/2020 01:58 pm »
 Has any of the test/development LH2 tanks for SLS ever been filled with LH2?  I'm pretty sure  LNG has been used, but I cant find details about actual LH2 testing.
TIA
Paul

Offline John Kerslake

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Re: Space Launch System (SLS) Q&A
« Reply #75 on: 10/22/2020 02:17 pm »
Re the amount of propellant's. What is that in Kg or tones?
thanks

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #76 on: 10/27/2020 06:55 pm »
Re the amount of propellant's. What is that in Kg or tones?
thanks
Core Stage weights 85,270 kg (187,990 lb)
Core Stage full 979,452 kg (2,159,322 lb)

894,182 kg or 894.182 tonnes of propellants

Using vehicle weights from here https://en.wikipedia.org/wiki/Space_Launch_System

The RS-25 engines use propellants at the ratio of 6:1 fuel/oxidizer ratio()by mass) if you wish to go further.
Paul

Offline Remes

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Re: Space Launch System (SLS) Q&A
« Reply #77 on: 08/31/2022 08:03 am »
Why are the panels of the intertank of the core stage bolted and not welded?

https://www.nasa.gov/exploration/systems/sls/multimedia/sls-intertank

it says the ribs need to be bolted, so was the production simplified and one connection process used rather than bolting + friction stir welding?

Offline Hog

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Re: Space Launch System (SLS) Q&A
« Reply #78 on: 08/31/2022 05:17 pm »
Why are the panels of the intertank of the core stage bolted and not welded?

https://www.nasa.gov/exploration/systems/sls/multimedia/sls-intertank

it says the ribs need to be bolted, so was the production simplified and one connection process used rather than bolting + friction stir welding?
the answer is located within the link you provided.

"Connecting the liquid hydrogen and liquid oxygen tanks, the intertank is built differently from the rest of the core stage. It is bolted together, not welded, with ribs on the outside for strength. The added strength is required because the intertank is a connection point for the rocket's twin solid rocket boosters. The intertank also houses avionics and electronics"
Paul

Offline laszlo

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Re: Space Launch System (SLS) Q&A
« Reply #79 on: 08/31/2022 06:57 pm »
Why are the panels of the intertank of the core stage bolted and not welded?

https://www.nasa.gov/exploration/systems/sls/multimedia/sls-intertank

it says the ribs need to be bolted, so was the production simplified and one connection process used rather than bolting + friction stir welding?
the answer is located within the link you provided.

"Connecting the liquid hydrogen and liquid oxygen tanks, the intertank is built differently from the rest of the core stage. It is bolted together, not welded, with ribs on the outside for strength. The added strength is required because the intertank is a connection point for the rocket's twin solid rocket boosters. The intertank also houses avionics and electronics"

That doesn't explain why it was bolted rather than welded, just that the ribs are there for the extra strength.

I'm thinking that Remes is on the right track. Since the intertank doesn't contain pressurized cryogenic liquids, welding wasn't needed and they stuck to the simpler process. Depending on how it's done, bolts can be lighter, cheaper and less cost than welding. They can also handle flexing better since a bolted joint doesn't propagate a crack the way a welded one does.

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