NASA SPACE SHUTTLE RS-25 SPACE SHUTTLE MAIN ENGINE SSME TESTS & FAILURES FILM XD13604

[@devlinwalters7650]

Love the bell flexing around 20-22mins .Astounding it can move so much without tearing itself to bits.Spectacular video.

[@starshipsn1511]

That’s at 21:21

[@jmmahony]

Some rocket scientist once said: "when you go to launch a rocket, a million things can happen, and only one of them is good".

[@justanotherdrunk]

*the engineers and technicians that image/ design/ develop/ document and troubleshoot are frucking amazing !!!!!*

[@jagboy69]

My step mother worked for Pratt back in the 1970's. I have a photo of her standing next to a main engine. You cannot believe how ENORMOUS these things were. Just the exhaust cone was at least 4 feet taller than her!

[@ashokiimc]

dammm

[@Zoomer30_]

Sadly Pratt&Whittney did not get the SSME contract, instead Rocketdyne did and probably delayed the Shuttle 3 years. Give PnW the contract and shuttle flies in time to save Skylab.

[@ec7888]

I love the notes of all the failures. It takes a lot of broken engines to build a really good one.

[@Zoomer30]

18:49 What could have happened to the Space Shuttle Columbia/Chandra mission if the oxidizer post that dislodged its brass blocking pin had failed. (Most likely would have been a loss of vehicle/crew situation) The pin was put in the post to block it off because it was showing wear. The pin came lose, hit the inside surface of the nozzle and casued a H2 leak which casued other issues. The mission also had a totally unrelated short circuit due to wire chafing and also an unrelated issue with a SRB hydraulics sensor.

[@_mikolaj_]

Wow that's very interesting stuff. Also look at the nozzle shape of early ones, completly different

[@rocketcello5354]

Yep, they were the RS-25-35, which has a smaller nozzle area ratio of 1:35, compared to the RS-25-69 (SSME, the one that flew) which has a nozzle area ratio of 1:69. The smaller area ratio allowed for minimal flow separation at lower throttle, allowing deep throttling to be tested without destroying the engine. There is a massive pipeline of RS-25 derivatives where the only change is the nozzle ratio, it's really cool. My personal favourite is the RS-25-150, which was a massive engine for mars transfer vehicles if nuclear thermal engines didn't work.

[@ivanreis1538]

BEAUTIFUL VÍDEO, THANK YOU!!!

[@uwtitanfan]

I don't know what an "MCC PC LEE JET" is, but that was a heck of an explosion.

[@dsdy1205]

MCC means main combustion chamber I'm reasonably sure PC means pre-combustion if LEE is not an acronym, then it refers to a face which is upwind of the main rocket flow JET probably refers to a jet of fluid that shouldn't be there put together, basically there was a jet of flame impinging on a lee-facing part / component in the main combustion chamber that shouldn't have been there, and that destroyed the engine

[@rocketcello5354]

@@dsdy1205 looks like it caused lower pressure in the nozzle, and the SSME is already very close to flow separation, so that drop probably caused flow separation, which is why the nozzle was wiggling around so much.

[@Ed-yj8ts]

Just spitballing here. MCC is Main Combustion Chamber. PC is really Pc which is Chamber Pressure, the name of the pressure transducer that senses pressure in the MCC roughly 3,000 psi. LEE JET is a small orifice made by the Lee company. Each Chamber pressure transducer had tiny flow of warm hydrogen into the sensor cavity to prevent the combustion gases from freezing near a cryogenic manifold. The flow was controlled by a Lee Jet. The Lee Jet popped out allowing a whole lotta hydrogen into the sense cavity raising the perceived pressure of Pc. The engine incorrectly thought woah, Pc is too high, let's throttle the engine down, but the engine could not operate at that low a throttle.

[@powerfullyacceptabledrafti105]

"Each of the chamber pressure sensors was ported to a small cavity which opened into the MCC Combustion zone just below the injector. The sense port was purged with hydrogen to prevent accumulation and subsequent freezing of the water produced by the combustion process. A very small hydrogen flow rate was provided from the MCC fuel outlet manifold through a tiny orifice contained in a device (Lee Jet) that was pressed into the manifold and retained with a snap ring. The second failure occurred at 3.92 seconds when the channel A Lee Jet was dislodged, which exposed the chamber pressure sensor to the full fuel manifold pressure. Since the manifold pressure was 65 percent higher than the MCC chamber pressure, the engine control system reacted and throttled the engine down to the desired pressure. This resulted in the engine operating at 60 percent power level with a mixture ratio of 3.5. At such a low mixture ratio, the HPOTP turbine gas temperature stabilized at an average temperature of 30 F, which caused the steam to freeze. A gradual ice buildup in the turbine ultimately caused all axial thrust balance capability to be exceeded, which led to internal rubbing and ignition within the LOX pump. Because of the MCC design, it was not possible to use the Lee jet in the preferred installation wherein the pressure differential acts as a holding force rather than a dislodging force. The redesign, however, eliminated the snap ring and incorporated a positive retention feature. As a result of this failure, a permanent minimum redline was established for the HPOTP turbine gas temperature to prevent turbine gas freezing.” Space Shuttle Main Engine: The First Twenty Years and Beyond (ISBN-10: 0877035474) Pg. 29

[@starshipsn1511]

The nossle designs on some of there are crazy

[@Zoomer30]

15:45 What could have happened to the Columbia/CHANDRA mission had the oxidizer post that had been capped had failed (a brass pin flew out of the post and hit the nozzle)

[@ashokiimc]

not brass. it was a gold pin (I think it was used to block injectors)

[@pateva2003]

Yep. The crew almost bought it on that flight. The plug severed 3 coolant lines. 5 severed lines would have produced a burn through in the nozzle.

[@goldgamercommenting2990]

28:40 oof that’s gotta hurt

[@zapfanzapfan]

Good old build, test, blow up, build again-iterative design 🙂

[@nutsackmania]

lots of trouble with fluid flow, that why you see all those annuli in the turbine housings

[@marcocambray7725]

Yes

[@markreeter6227]

"Obviously a major malfunction"

[@PhaQ2]

The Kaiser Hat Nut Failure Sounds like a short story about unplanned pregnancy.

[@e.c.listening326]

Yo, can relate to that

[@lumpyfishgravy]

18 FPS?

[@derby2510]

each one of these engines is about 20 times more powerful then the best Ferari and the power is incredible each one burns over 50 gallons of gas per second that's why the blasts are so strong

[@BlackStarEOP]

20 times? The fuel and oxidizer turbopumps develop 69,000 horsepower and 25,000 horsepower, respectively. That's 69 Bugattis for you for just the fuel turbopump. The output of a single RS-25 engine is 12 million horsepower (!), to this day, it's still unmatched regarding efficiency and it's still the best engine made until this day.

[@jull8600]

154

[@Zoomer30]

Had Pratt and Wittney and not Rocketdyne gotten the SSME contract, this movie would only be 5 mins long. PnW had already done a ton of work on high pressure hydrogen rocket engines. Rocketdyne had to start from square one.

[@incargeek]

MisterMac56 ....and the J-2 ran for eight minutes on the Saturn V S-II just as the RS-25 would in the orbiter.

[@Zoomer30]

At least PnW got their revenge when they bought Rocketdynem

[@satanofficial3902]

Pfffft. They haven't reverse engineered the alien spacecraft at Area 51 yet? Rocket engines are just so primitive and yesterday.

[@allandavis8201]

I only clicked on this for the sound of the engines, the explosions and the technical explanations, so, unfortunately, without the sound or any narration it’s just boring, sorry P.F, this ones a duffer for me. 😔👎🇬🇧🏴󠁧󠁢󠁥󠁮󠁧󠁿

[@nadanada5698]

What a waste of time & money considering that the dome that protects the firmament,cannot be penetrated,so where Does all that money go ? ?

[@satanofficial3902]

I am not now and have never been a teletubbie.

[@RatKeeperDude]

The Stargate program

[@keyweststeve3509]

They actually have discovered the existence of the firmament and impenetrable dome; it lines the skull cavity of flat-Earthers making them impervious to logic and reason!

[@TO-ll4js]

@@keyweststeve3509 lmao good one

[@brokensoap1717]

clown