Author Topic: SLS General Discussion Thread 8  (Read 96596 times)

Offline whitelancer64

Re: SLS General Discussion Thread 8
« Reply #440 on: 09/22/2022 10:29 pm »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.
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Offline ZachS09

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Re: SLS General Discussion Thread 8
« Reply #441 on: 09/23/2022 12:22 am »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.

Is it true that people confuse GSE equipment with the rocket itself?
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Re: SLS General Discussion Thread 8
« Reply #442 on: 09/23/2022 12:32 am »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.
T-29 seconds, but they didn't test the engine bleed because....reasons. And there's still several milestone yet to be achieved between T-29 s & T-9 s

They wish they can test the engine bleed at the latest WDR, but again they didn't & just masked it
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Offline DanClemmensen

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Re: SLS General Discussion Thread 8
« Reply #443 on: 09/23/2022 12:34 am »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.

Is it true that people confuse GSE equipment with the rocket itself?
What are the potential consequences of a serious leak at the QD plate during a launch? if there are serious consequences, it does not matter which part of the system failed. If there are no potential consequences, why is NASA bothering with this?

Offline mn

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Re: SLS General Discussion Thread 8
« Reply #444 on: 09/23/2022 12:41 am »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.

I imagine that the QD plate is designed together with the rocket, for purposes of discussing any possible design problems the QD plate is very much part of the rocket.

Offline Hog

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Re: SLS General Discussion Thread 8
« Reply #445 on: 09/23/2022 01:48 am »
The tanking test was successful, the KSC crews are putting in the work, it will fly when the vehicle is ready AND when the planets align.  It's so easy to moan out of frustration(I have MANY times)-classic cases of "launchus-interuptis", esp. when it "appears" to be something as simple as a leak.  Well it's far from simple and the Artemis-2 stack will hopefully be carrying humans and fragging the Arty-1 stack due to a fuel leak MUST be avoided. It's the first time the stack has been at the pad for launch, which happens to be the only configuration where these systems can be tested.  The physics alone is extreme the temps, volumes, weights, pressures are impressive.  It's easy to be critical when we aren't the ones in the hotseat.

Meanwhile 2 of the largest and most powerful flight motors ever, patiently wait for the most efficient liquid engines get their chance to fire.  It's what the USA decided for it's 1-1/2 stage to orbit Space Shuttle(sustainers and External Tank disposal) and what the SLS inherited(sustainers + Core Stage disposal), save for an extra segment, an extra RS25, with the quartet running at an extra 9% Rated Power Level compared to STS-1 through STS-5 RS25.

NASA didn't want the huge shuttle and didn't want the SLS, but we are where we are.  When when the liquids stabilize at 100% and the solids light at T minus zero, we'll know the leak was fixed.   

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Offline woods170

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Re: SLS General Discussion Thread 8
« Reply #446 on: 09/23/2022 08:50 am »
How utterly original and not at all a tired joke.
I'd have to agree.

Alabamatross is more on the nose.

Brilliant. Could be straight out of South Park.

Compared to what? 
Multiple things wrong with your post, and I will break it down for you:

The other two PRIVATE space programs?
SLS is not a space program. Artemis is, but SLS in itself is not. SLS is a rocket development program, funded completely with US taxpayer's dollars.

Weren't those big rockets supposed to launch.....2 years ago?
You may have missed this but SLS was supposed to launch no later than December 2017. In fact: if we go back to the text of the NASA 2010 Authorization Act, which first authorized SLS, than that date is actually a year earlier: December 2016.
It is now late September 2022, just a hair away of being 5 years late from the 2017 date, and almost 6 years late from the date enacted in the 2010 NASA Authorization Act.
Compared to SLS the delay of the two commercial rockets is not even close to being of SLS-levels of delay (yet). So yeah, right now SLS is the Albatross of rocket delays.

Lit 7 out of 33 engines and then had to swap them out!  Whoohoo! Then there's the other one with, no engines?
Contrary to SLS the development of engines for the two private rocket systems has not been completed yet. Main engine development for SLS was completed in the 1990's, when NASA finished development of the current block series of RS-25. You know: the ones hanging from the aft end of SLS right now.
NASA subsequently spent over $100M for each one of those engines to store them and attach them to the aft end of SLS. That is a heck of a lot of money to spend on an existing engine which completed development 20 years ago. Sounds very much like an Albatross to me.

But hey nice launch towers/pads and great inflight abort test!  We don't know much more because they're PRIVATE.  ::)
But hey nice SLS ML and Orion inflight abort test. We don't know much more because NASA, unlike it is obliged to do as a US government agency, did not provide full transparency to the US taxpayers. Particularly not when it comes to planning and funding of SLS and Orion. Plenty of examples here:
https://oig.nasa.gov/docs/IG-19-001.pdf
https://oig.nasa.gov/docs/IG-20-012.pdf
https://oig.nasa.gov/docs/IG-22-012.pdf
https://www.gao.gov/assets/gao-19-377.pdf
https://www.gao.gov/assets/gao-21-105.pdf


The picture with regards to SLS is this:
It took NASA 15 years and a grand total of $27.5B in taxpayer's dollars, to reach the point where it can actually launch something into orbit.  That is very much an Albatross in both time and money spent.
(And yes, that is right: money was being spent on SLS contracts five years before it was named SLS. That's what you get when you don't cancel CxP contracts for 5-segment SRBs but extend them to become part of a renamed Ares V).

Other private rocket number 1 will eventually launch something into orbit in 2023, just 7 years after work on it started, and having spent less than $3.5B in taxpayer's dollars.
Other private rocket number 2 will eventually launch something into orbit at some undisclosed time, many years late, but having spent just $0.5B in taxpayer's dollars.

So, which one of those three is the actual Albatross? It should be abundantly clear to all, including you, that the Albatross is SLS.
« Last Edit: 09/23/2022 08:54 am by woods170 »

Offline Proponent

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Re: SLS General Discussion Thread 8
« Reply #447 on: 09/23/2022 11:34 am »
NASA didn't want the huge shuttle and didn't want the SLS, but we are where we are.

Some parts of NASA wanted them. Then MSFC director Lightfoot, for example was definitely keen on SLS (though I don't know whether he preferred Ares V).
« Last Edit: 09/23/2022 11:35 am by Proponent »

Offline rdale

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Re: SLS General Discussion Thread 8
« Reply #448 on: 09/23/2022 12:15 pm »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

Because that's not necessarily a requirement. Or even a strong need?

Offline yg1968

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Re: SLS General Discussion Thread 8
« Reply #449 on: 09/23/2022 12:57 pm »
SLS is still better than Ares I/V, tho, its earlier iteration.

Ares I was unnecessary but why is SLS better than Ares V?
« Last Edit: 09/23/2022 01:18 pm by yg1968 »

Offline yg1968

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Re: SLS General Discussion Thread 8
« Reply #450 on: 09/23/2022 01:10 pm »
Article today:

NASA's Artemis Delays Fuel Controversy over Rocket Design - Scientific American

From that article:
Quote
“I don’t think there’s an appreciation for how some of the early decisions that were made and constrained by budget are actually manifesting themselves today,” Dumbacher says.

Wow, $30+ billion spent on SLS, the whole point of which was that it was going to be cheap and easy, and Dumbacher is complaining about penny pinching. Talk about a sense of entitlement....

EDIT:  Added missing "point" and changed "if" to "of" in final sentence.

He is not complaining about SLS's budget, he is reminding people that SLS was chosen because of its Shuttle heritage. It was felt at the time that this would reduce development costs over Ares V. As Wayne Hale pointed out, if you build a Shuttle derived HLV, you also inherit some of the Shuttle's problems.

Offline Robotbeat

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Re: SLS General Discussion Thread 8
« Reply #451 on: 09/23/2022 01:47 pm »
SLS is still better than Ares I/V, tho, its earlier iteration.

Ares I was unnecessary but why is SLS better than Ares V?
That’s not what I claimed. (And SLS essentially is Ares V, just one of the earlier variants and with one fewer SSMEs… and having 4 engines is easier to get to work than 5, plus the limited number of SSMEs will last longer. Also, SLS uses an existing, proven upper stage. SLS needs no new engine development. Any of the Ares V variants likely would have taken even longer.)

And Ares I had more problems than just being unnecessary. It was an affront to God lol
« Last Edit: 09/23/2022 01:56 pm by Robotbeat »
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Offline Eric Hedman

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Re: SLS General Discussion Thread 8
« Reply #452 on: 09/23/2022 03:08 pm »
And Ares I had more problems than just being unnecessary. It was an affront to God lol
Chris, tell us what you really think about Ares I.  Don't hold back.  Are you telling us that a rocket with 5000 slinkys between the first and second stage to handle thrust oscillations wasn't the finest piece of engineering you have ever seen? :) :) :) :)

Offline mandrewa

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Re: SLS General Discussion Thread 8
« Reply #453 on: 09/23/2022 03:48 pm »
Other private rocket number 1 will eventually launch something into orbit in 2023, just 7 years after work on it started, and having spent less than $3.5B in taxpayer's dollars.

I agree with the sentiment in your post, Woods170, but I puzzled by a few details.  Where does $3.5 billion come from?

Here are the amounts that I'm aware of.

(a) $33.6 million from a Air Force development contract for a much earlier and different version of the Raptor engine. This was awarded back in 2016 and arguably that contract was fulfilled a long time ago.  There is now and has been for some time a basically functional Raptor engine and that more than fulfilled what the Air Force was looking for.  So should that be included in the tally for the government's investment in the Starship?  Well, it's not worth arguing about.  So we will include it.

And if Starship does its first orbital launch in the next few months or in 2023, well that's it.  There isn't much more than that that the federal government will have invested in Starship by that point.

Now some people will think that we should also include the $2.9 billion contract for designing and building a Moon lander, and landing twice on the Moon.  Now only a small portion of that $2.9 billion has so far been received by SpaceX and I imagine that the small amount has been spent on the development of the Starship Lunar Lander and not the Starship in general.

And the second thing I would quibble with is when we should start the clock in evaluating whether a program is late or not.  As far as the US taxpayer is concerned, the clock started in April 2021, just over a year ago.
« Last Edit: 09/23/2022 03:49 pm by mandrewa »

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Re: SLS General Discussion Thread 8
« Reply #454 on: 09/23/2022 04:25 pm »
From that article:
Quote
“I don’t think there’s an appreciation for how some of the early decisions that were made and constrained by budget are actually manifesting themselves today,” Dumbacher says.

Wow, $30+ billion spent on SLS, the whole point of which was that it was going to be cheap and easy, and Dumbacher is complaining about penny pinching. Talk about a sense of entitlement....

EDIT:  Added missing "point" and changed "if" to "of" in final sentence.
He is not complaining about SLS's budget, he is reminding people that SLS was chosen because of its Shuttle heritage. It was felt at the time that this would reduce development costs over Ares V. As Wayne Hale pointed out, if you build a Shuttle derived HLV, you also inherit some of the Shuttle's problems.

No, it is clear from when he says "early decisions that were made and constrained by budget" that he was meaning the SLS budget was not enough early on to mitigate issues we are seeing today. Which is frightening to think about considering how much money and how many years the SLS program has had to mitigate issues BEFORE getting to the launch pad. That really shows how bad the SLS design is.

As to your comment about "Shuttle heritage", the only heritage that really mattered was the companies involved, NOT the hardware. Keeping the same companies that were already working on the Constellation program (i.e. inheriting them) was the goal.
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Offline whitelancer64

Re: SLS General Discussion Thread 8
« Reply #455 on: 09/23/2022 04:34 pm »
What I don't understand is how they can be thinking about launching when they have not yet managed to make a clean wet dress rehearsal from start to finish.

They got to T-29 seconds, which is reasonably close. The engine start sequence begins at about T-9 seconds, which is where the countdown would have been stopped otherwise.

If they know they've fixed the things they know would have halted the launch up to that point, then there's a fair shot at getting through to T-0 for a real launch.

The main issue now is the persistent leaks at the QD plate, which is not a problem with the rocket itself.

Is it true that people confuse GSE equipment with the rocket itself?
What are the potential consequences of a serious leak at the QD plate during a launch? if there are serious consequences, it does not matter which part of the system failed. If there are no potential consequences, why is NASA bothering with this?

Hydrogen will ignite (burn) at concentrations from 4% to 74%. At over 18%, it will explode. The fuel loading is halted at concentrations over 4% for this reason. They allowed the fueling test to proceed when this threshold was exceeded, but they won't risk a fire for an actual launch attempt.

Worst case scenario is a fire that breaches the fuel line, which could cause an explosion that destroys the launch pad and the rocket.
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Offline woods170

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Re: SLS General Discussion Thread 8
« Reply #456 on: 09/23/2022 05:20 pm »
Other private rocket number 1 will eventually launch something into orbit in 2023, just 7 years after work on it started, and having spent less than $3.5B in taxpayer's dollars.

I agree with the sentiment in your post, Woods170, but I puzzled by a few details.  Where does $3.5 billion come from?

Here are the amounts that I'm aware of.

(a) $33.6 million from a Air Force development contract for a much earlier and different version of the Raptor engine. This was awarded back in 2016 and arguably that contract was fulfilled a long time ago.  There is now and has been for some time a basically functional Raptor engine and that more than fulfilled what the Air Force was looking for.  So should that be included in the tally for the government's investment in the Starship?  Well, it's not worth arguing about.  So we will include it.

And if Starship does its first orbital launch in the next few months or in 2023, well that's it.  There isn't much more than that that the federal government will have invested in Starship by that point.

Now some people will think that we should also include the $2.9 billion contract for designing and building a Moon lander, and landing twice on the Moon.  Now only a small portion of that $2.9 billion has so far been received by SpaceX and I imagine that the small amount has been spent on the development of the Starship Lunar Lander and not the Starship in general.

And the second thing I would quibble with is when we should start the clock in evaluating whether a program is late or not.  As far as the US taxpayer is concerned, the clock started in April 2021, just over a year ago.

The "less than $3.5B" is built up from this:

- $2.9B from HLS award. I am very much aware that not all of this will have been awarded in 2023. Hence my "less than".
- What is less known is that DoD funding for Raptor was extended not once, but several times. What originally started as a contract with a value of "up to $122M" eventually went beyond $200M.
- And then there is the $102M Space Force contract for using Starship in the Rocket Cargo Program. I am aware that not all of this has been paid to SpaceX so, once again, my caveat of "less than".
« Last Edit: 09/24/2022 10:10 am by woods170 »

Offline woods170

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Re: SLS General Discussion Thread 8
« Reply #457 on: 09/23/2022 05:24 pm »
From that article:
Quote
“I don’t think there’s an appreciation for how some of the early decisions that were made and constrained by budget are actually manifesting themselves today,” Dumbacher says.

Wow, $30+ billion spent on SLS, the whole point of which was that it was going to be cheap and easy, and Dumbacher is complaining about penny pinching. Talk about a sense of entitlement....

EDIT:  Added missing "point" and changed "if" to "of" in final sentence.
He is not complaining about SLS's budget, he is reminding people that SLS was chosen because of its Shuttle heritage. It was felt at the time that this would reduce development costs over Ares V. As Wayne Hale pointed out, if you build a Shuttle derived HLV, you also inherit some of the Shuttle's problems.

No, it is clear from when he says "early decisions that were made and constrained by budget" that he was meaning the SLS budget was not enough early on to mitigate issues we are seeing today. Which is frightening to think about considering how much money and how many years the SLS program has had to mitigate issues BEFORE getting to the launch pad. That really shows how bad the SLS design is.

As to your comment about "Shuttle heritage", the only heritage that really mattered was the companies involved, NOT the hardware. Keeping the same companies that were already working on the Constellation program (i.e. inheriting them) was the goal.

Emphasis mine.

That is not entirely correct. The stipulations in the NASA Authorization Act of 2010 specifically point to keeping the hardware development contract from Constellation. That is how the 5-segment SRBs got ported to SLS one-on-one. It is also how Orion managed to find its way on SLS. Only Boeing's Ares I upper stage contract was morphed to provide a ground-started upper stage, aka a sustainer stage, aka what we now know as the Core Stage.
« Last Edit: 09/26/2022 11:19 am by woods170 »

Offline yg1968

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Re: SLS General Discussion Thread 8
« Reply #458 on: 09/23/2022 06:03 pm »
From that article:
Quote
“I don’t think there’s an appreciation for how some of the early decisions that were made and constrained by budget are actually manifesting themselves today,” Dumbacher says.

Wow, $30+ billion spent on SLS, the whole point of which was that it was going to be cheap and easy, and Dumbacher is complaining about penny pinching. Talk about a sense of entitlement....

EDIT:  Added missing "point" and changed "if" to "of" in final sentence.
He is not complaining about SLS's budget, he is reminding people that SLS was chosen because of its Shuttle heritage. It was felt at the time that this would reduce development costs over Ares V. As Wayne Hale pointed out, if you build a Shuttle derived HLV, you also inherit some of the Shuttle's problems.

No, it is clear from when he says "early decisions that were made and constrained by budget" that he was meaning the SLS budget was not enough early on to mitigate issues we are seeing today. Which is frightening to think about considering how much money and how many years the SLS program has had to mitigate issues BEFORE getting to the launch pad. That really shows how bad the SLS design is.

As to your comment about "Shuttle heritage", the only heritage that really mattered was the companies involved, NOT the hardware. Keeping the same companies that were already working on the Constellation program (i.e. inheriting them) was the goal.

I don't agree. Dumbacher mentioned cryofuels (i.e., meaning the choice of using liquid hydrogen for SLS) and the pared down launch (i.e., the clean pad and mobile launcher decisions) as examples of the early decisions that were made that have an impact today (see the full quote from the article below). That is what he is referring to in the article. At the time, these decisions were made with the expectation that they would save money. The use of liquid hydrogen was based on the decision to have Shuttle heritage (see section 304 of the 2010 NASA Authorization bill). The clean pad decision was based on the decision that 39B would become a commercial multi-user pad (which never panned out). The multi-user/clean pad decision comes from the direction provided in section 305 of the 2010 NASA Authorization bill.

https://www.congress.gov/111/plaws/publ267/PLAW-111publ267.pdf

Quote from: the Scientific American article
“I don’t think there’s an appreciation for how some of the early decisions that were made and constrained by budget are actually manifesting themselves today,” Dumbacher says. In particular, he points to the pared down launch and the selection of cryofuels.
« Last Edit: 09/23/2022 06:35 pm by yg1968 »

Offline Robotbeat

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Re: SLS General Discussion Thread 8
« Reply #459 on: 09/23/2022 06:39 pm »
Not a direct quote.
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