NASA prepares SLS core stage for hot fire test today

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kuririn

BARGeezer
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Screen shots of the firing;

The firing was supposed to last up to 8 minutes but was shut down early.

The shutdown was only 1 minute into a planned 8-minute test.

FredA

Well-Known Member
MCF -- Major Component Failure on engine 4.

Not good....

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dhbarr

Amateur Professional
Weren't these just refurbed SSMEs to be later tossed into the Atlantic?

tOD

Sinking in the quicksand of HPR
TRF Supporter
Weren't these just refurbed SSMEs to be later tossed into the Atlantic?
I think that's what I read. They have a few more they plan to use.

FredA

Well-Known Member
Refurb or not....the Atlantic was where they would be [early] if this had been a real launch.

hobie1dog

Well-Known Member
I still have it on my Bucket List to go to Florida and witness a launch of a big rocket.

Well-Known Member
TRF Supporter
MCF -- Major Component Failure on engine 4.
Not good....
Yep.
Pretty significant set back to an already over-optimistic schedule.
This will push the SLS launch timing further out, likely into 2022, from what already has been a long list of delays:
• The Space Launch System has been repeatedly delayed since the program’s announcement in 2011, missing targets for its debut in 2017, 2018, 2019, and 2020.
• Time is running out for NASA to send the Space Launch System (SLS) megarocket aloft for an uncrewed moon-roundtrip mission by November 2021.
• NASA needs to know when the SLS rocket will be ready for flight to proceed with the next stage of building the Artemis 1 megarocket, which is to add the solid rocket booster segments. The segments are ready at Kennedy, but they have a 12-month stack life. So, NASA needs to have word that the SLS is ready before considering approving stacking the SRBs.
• NASA still wants to send astronauts to the moon's surface by the end of 2024, and to do so requires that the SLS and its associated crew capsule, Orion, be certified for human spaceflight before that date.

125cc

Well-Known Member
Well, that could've went better.

Hope the engineers find out what went wrong and get it fixed. Best finding these things out now rather than at a launch. Starship had had its fair share of catastrophic calamities...

125cc

125cc

Well-Known Member
...Whereas my launch SNAFUs are usually explained by a very frank "Well I completely buggered that up then"

georgegassaway

"NASA still wants to send astronauts to the moon's surface by the end of 2024, and to do so requires that the SLS and its associated crew capsule, Orion, be certified for human spaceflight before that date."

2024 was an unrealistic date the day it was announced. And I'm not talking SLS. I'm talking all the other stuff that has to be in place.

Man-rated Lunar Module, which is STILL not chosen. It took nearly 6 years from Grumman being chosen, for a fully functional Lunar Module to be ready to fly, for Apollo-9. That was with the massive mega-funding that Apollo had, not the relatively meager budget that Artemis has. A lander built to be safe and land on the moon with in less than 4 years? Nah. Science fiction.

Man-rated "Lunar Gateway" that Apollo never needed and seems to me more  being flung at "To the moon again, until we get tired of doing it and paying for it again".

To do one Artemis mission, three totally different launch vehicles need to place three totally different spacecraft in orbit around the moon (and the lander has to dock automatically with the Lunar Gateway). Apollo only needed one rocket, the Saturn-V to do that.

I'd rather see crewed missions going to Mars, anyway. Moon again is a distraction from Mars.

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cbwho

Well-Known Member
The moon is not a distraction from Mars...

It takes 9 months to get to Mars and once there, the planets get out of alignment and you must wait many moons until the next alignment.

We need to learn how to make habitats, make fuel, etc. The moon is the perfect place!

Also, the moon has a lot of mining potential that keeps getting mentioned in a "coded manner" (the NASA administrator mentioned it) that another country is gearing up to grab.

Not to mention the far side of the moon is the best for radio telescopes.

dhbarr

Amateur Professional
It just boggles my mind that we flew rs25s from '81 to '11 but can't sustain a full test, to say nothing of the MIA Integrated Powerhead Demonstrator.

Meanwhile Elon is over here doing full flow gas-gas staged combustion and cranking up the pressure both physically and metaphorically.

Nytrunner

Pop lugs, not drugs
TRF Supporter
It just boggles my mind that we flew rs25s from '81 to '11 but can't sustain a full test, to say nothing of the MIA Integrated Powerhead Demonstrator.
From what Ive heard around town, it wasn't an engine problem, but a nearby (important) component

Antares JS

Well-Known Member
To do one Artemis mission, three totally different launch vehicles need to place three totally different spacecraft in orbit around the moon (and the lander has to dock automatically with the Lunar Gateway). Apollo only needed one rocket, the Saturn-V to do that.
A few points:

-NASA has already said they won't be using the gateway for the first landing.
-Automatic docking has been done by the Russians for years. It's not that big a big deal. Soyuz dockings are hands-off except for emergencies.
-The new LM, no matter which gets chosen, is going to be far heavier than the Apollo LM (It has to sustain a crew of four for weeks), to the point where launching it on the same rocket as the crew module is going to be impractical. Especially the Block 1 SLS, which is considerably LESS capable than the Saturn V.
-Parts of the new LM may be reusable, so we won't need to fly a completely new one with every mission. Blue's national team has the goal of making the transfer stage and ascent stage reusable, only requiring a new descent stage for every mission.

NASA is leaning towards repeating the test. That might take another 3 or 4 weeks.

boatgeek

Well-Known Member
It just boggles my mind that we flew rs25s from '81 to '11 but can't sustain a full test, to say nothing of the MIA Integrated Powerhead Demonstrator.

Meanwhile Elon is over here doing full flow gas-gas staged combustion and cranking up the pressure both physically and metaphorically.

From what Ive heard around town, it wasn't an engine problem, but a nearby (important) component
NASA is leaning towards repeating the test. That might take another 3 or 4 weeks.

Also from the Ars Technica article, it appears that there were three significant issues that need to be addressed:
Too much pressure drop in the gimballing system hydraulics
Sensor failure (this caused the Major Component Failure alarm). The sensor was apparently redundant.
The flash seen in the engine section insulation blankets doesn't seem to have been a big deal, but they'll look closer.

On the whole, that doesn't seem so bad.

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Reinhard

Well-Known Member
TRF Supporter
That might be related to one of the differences between Shuttle and SLS. On the Shuttle, the APUs, that provide power for the TVC system, are driven by Hydrazine, because the same APUs are also required for landing. On SLS, the APUs are driven by hot hydrogen gas from the engine.

Reinhard

Winston

Lorenzo von Matterhorn

"Unlike everything else in the SLS program the test ended ahead of schedule."

"World's most expensive humidifier breaks."
[I like that one - H2+O2 along with deluge water steam]

"The failed Soviet N1 has more flight time than SLS at this time."

"Government cloud machine."

"I haven't seen the SLS, but I've seen many a contractor's mansion and they're lovely. Viva la government gravy train!"

"SLS needs to fail just enough to maintain a credible promise to keep getting funded. It's primary purpose is to keep ex shuttle rocket infrastructure employed, not to provide a competitive launch system."

"All of the SLS related documents have flight heritage. They got it being slung across the room in frustration by the engineers at one point or another."

"Well, looks like they'll need some more money for R+D. Maybe their first launch will be for the Webb Telescope in 2060!"

"Advantage: the only rocket capable of launching Congress on an earth escape trajectory."

"Using RS-25s as disposable engines is such an absolute waste."

"The RS-25s are rebelling. They don't want to be senselessly expended."

Throwing four RS-25's away every launch is bad enough - but throwing them away before launch as well? That's just not sustainable. "

"Starship will be bumpin' tunes on 16 Psyche before that tub of lard gets off the deck."

"SLS Core - powering corruption in US Congress!"

"I couldn't identify the legs the core uses to land, am I just blind?"

"Interesting seeing the infrastructure used to mount the RS-25 starting at 6:53 vs the custom forklift pallet, forklift and scissor truck to mount the Raptor engine."

"11 years of work for a lousy 67 seconds of ground-based test time. Embarrassing. Cancel this boondoggle."

"40 year old tech and they still can't pull it off."

"$17 BILLION dollars." and counting. 2011-2019 SLS + Constellation =$28 billion. "Office of Management and Budget Russell Vought estimated the cost of a single SLS launch at "over \$2 billion per launch" -- and that's excluding "development" costs."

125cc

Well-Known Member
"SLS needs to fail just enough to maintain a credible promise to keep getting funded. It's primary purpose is to keep ex shuttle rocket infrastructure employed, not to provide a competitive launch system."
This quote sums up the entire program pretty well IMO - astounding how NASA has lost its way since the glory days of Apollo/Saturn. SpaceX (and others) do it way more affordably and without the endless delays.

Midnight777

Member
I don’t know why NASA continues to throw money at the SLS. It will never be finished. They might as well dig up the Saturn V and modernize it.

OverTheTop

Well-Known Member
TRF Supporter
I definitely can't figure out why they throw their RS-25 motors away. Such a waste. I guess it is just so they mitigate risk and development time (that hasn't worked!). They were engineered to have a life expectancy of 27000 seconds (that's 7.5 hours of runtime).

These are a couple of my favourites from Winston's list:
"All of the SLS related documents have flight heritage. They got it being slung across the room in frustration by the engineers at one point or another."
"The failed Soviet N1 has more flight time than SLS at this time."

Well-Known Member
TRF Supporter
I definitely can't figure out why they throw their RS-25 motors away. Such a waste. I guess it is just so they mitigate risk and development time (that hasn't worked!). They were engineered to have a life expectancy of 27000 seconds (that's 7.5 hours of runtime).
Basically, because NASA presently doesn't have a plan to reuse any of its rocketry equipment. At least, that is not part of the SLS architecture.
The fact that RS25's could be reused is of little value, since there is no feasible way to take advantage of that capability.
The fact that RS25's were used at all, was probably a mistake, but I am not certain, since the data on cost of a new engine design vs. repurposing RS25's is not publicly available. NASA had them sitting in a warehouse, and people got nostalgic and couldn't simply write them off. Instead, they got fixated on using 4 semi-under-powered RS25's (for the task at hand), and augmented them SRBs.

Oh well, if nothing else, NASA has been paying to preserve the R&D and manufacturing capability to build big rockets. Whether they fly or not, is secondary.
SpaceX's BFR seams to be gaining credibility with each test. It not looks increasingly likely that BFR will be lunar flight ready before SLS.

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Arsenal78

Well-Known Member
Basically, because NASA presently doesn't have a plan to reuse any of its rocketry equipment. At least, that is not part of the SLS architecture.
The fact that RS25's could be reused is of little value, since there is not feasibly way to take advantage of that capability.
The fact that RS25's were used at all, was probably a mistake, but I am not certain, since the data on cost of a new engine design vs. repurposing RS25's is not publicly available. NASA had them sitting in a warehouse, and people got nostalgic and couldn't simply write them off. Instead, they got fixated on using 4 semi-under-powered RS25's (for the task at hand), and augmented them SRBs.

Oh well, if nothing else, NASA has been paying to preserve the R&D and manufacturing capability to build big rockets. Whether they fly or not, is secondary.
SpaceX's BFR seams to be gaining credibility with each test. It not looks increasingly likely that BFR will be lunar flight ready before SLS.
Wasn't the whole original idea of SLS to be a reusable rocket, or mostly like the Falcon 9?

Antares JS

Well-Known Member
Wasn't the whole original idea of SLS to be a reusable rocket, or mostly like the Falcon 9?
No. That was never part of the plan.