Author Topic: Schedule for First SLS Core Stage Still Sliding  (Read 35332 times)

Offline TomH

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #80 on: 05/19/2018 11:46 pm »
Unless you have documentation showing otherwise, I don't think that was the calculus used.

It's in the old threads and was written by a person of authority. It may have been posted before you joined the board, but I'm not going to take the time to look it up for you. You are free to believe it or not.
« Last Edit: 05/20/2018 01:05 am by TomH »

Offline spacenut

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #81 on: 05/20/2018 01:25 am »
I too remember how many core they could produce in a year.  It was at least two or three per month with multiple shifts and enough people.  This was brought up in the Direct threads.  If Direct was selected, multiple launches could be made for more payload to LEO.  The more cores manufactured, the lower the cost per each.  This was at least 10 years ago or more. 

Offline TomH

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #82 on: 05/20/2018 06:35 am »
I too remember how many core they could produce in a year.  It was at least two or three per month with multiple shifts and enough people.  This was brought up in the Direct threads.  If Direct was selected, multiple launches could be made for more payload to LEO.  The more cores manufactured, the lower the cost per each.  This was at least 10 years ago or more.

That may have been possible with one of the Jupiter proposals and plenty of money. If you have not yet set up a production line, you can plan to optimize it as you so choose, but this discussion is centered specifically on how they actually did choose to optimize the line for SLS. They chose to optimize it for one core per year. Could it go faster? Yes. But it would not be operating at its optimum efficiency in relation to the way it was originally set up. In order to speed up, they'd need to bring in temporary laborers who are not skilled in the task at hand. They'd have to ask suppliers for increased deliveries, and those suppliers would have to make similar adjustments for labor, raw materials, etc. Now if a flood of new money became available, sure, you could re-optimize your materials and labor arrangements. You renegotiate the amount of materials you want delivered and on what schedule. You train new line workers and bring them up to speed on what they are to do. Re-optimizing requires some adjustment.

In relation to SLS, not Direct, they optimized the run for one core per year. They could change that if they wanted to, but it would require adjustments as described above.
« Last Edit: 05/20/2018 06:50 am by TomH »

Offline Coastal Ron

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #83 on: 05/20/2018 04:35 pm »
Unless you have documentation showing otherwise, I don't think that was the calculus used.

It's in the old threads and was written by a person of authority. It may have been posted before you joined the board, but I'm not going to take the time to look it up for you. You are free to believe it or not.

You think you remember something, but you're not sure when or where it was? And it was a NSF post, not a public document outlining official actions of our government?

Not sure how this answered my question...  ;)
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Coastal Ron

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #84 on: 05/20/2018 04:53 pm »
They chose to optimize it for one core per year. Could it go faster? Yes. But it would not be operating at its optimum efficiency in relation to the way it was originally set up.

When you are only producing one unit per year, "optimum efficiency" is not valid metric.

Quote
In order to speed up, they'd need to bring in temporary laborers who are not skilled in the task at hand.

The production folks will have years of notice that a production rate change is coming, so I don't see any scenario where they would need to bring in unskilled temporary workers.

Quote
They'd have to ask suppliers for increased deliveries, and those suppliers would have to make similar adjustments for labor, raw materials, etc.

The biggest problem with the SLS is that it has no dedicated supply chain outside of the SLS factory. Everything is built at such a low volume that the suppliers are moving their personnel and tooling around to work on other customer orders in between SLS needs.

And for critical components the U.S. Government would have to pay to stockpile unique parts so that they won't run out of them, so in reality there are planned engineering changes in the future that they will have to deal with re-qualification again for critical items because of obsolescence.

I've had to deal with this with a number of different types of products, including restarting product lines that were shut down.

Quote
Now if a flood of new money became available, sure, you could re-optimize your materials and labor arrangements. You renegotiate the amount of materials you want delivered and on what schedule. You train new line workers and bring them up to speed on what they are to do. Re-optimizing requires some adjustment.

As long as the production rate is one per year there is no "optimizing" that can be done. Increase it to 2-3 per year and then you can start operating as a production line instead of a job shop, but there is no indication that will ever happen.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline AncientU

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #85 on: 05/20/2018 05:36 pm »
The program is actually designed to be perpetually in development mode (20-25 years... IOW, forever).  With no program budget and nothing that resembles a schedule, they can grind along forever without getting into the nastiness of 'production' or 'optimizing.'  Just how 'we' like our government programs.
« Last Edit: 05/20/2018 05:37 pm by AncientU »
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Offline John Santos

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #86 on: 05/20/2018 06:20 pm »

...
And don't get too hung up on this production capability, there are likely no real barriers for ramping up to 3-4 per year. But talking about more than one/year is fantasy at this point anyways...   ;)

There is no way that 16 RS-25Es will be made in a year. 
Current plan is for 2 engines per year.

Mobile launcher and pad can maybe stretched to handle two per year, as probable four boosters can be prepared(till they run out of casings).  At the moment, these seem to be the only pieces capable of supporting better than one flight per year.
People (not just you) appear to be confusing "production rate" with "production time".  It is perfectly possible to configure operations such that 16 (or more) RS25Es or 1.5 (or more) SLS rockects can be rolled off the factory floor in a year, while each takes much longer than a year to produce.  This is normally the way assembly lines work.  You just need to have the floor space and access to the jigs to start work on the 2nd (and 3rd and maybe the 4th) core stage or engine while the 1st core stage (or engine) is still being assembled.

Also, the first few engines (or core stages) are produced at a much lower rate than possible because the manufacturer is still refining procedures and because they don't want to get too far ahead and then discover through testing that they need to go back and redo parts of the 2nd and 3rd item that have already been completed.  It's more efficient to wait until they've made a few and fixed all the problems than to start stamping them out as fast as possible and then go back and rework the defects.

In another comment (can't find it now) someone said there was no reason to start work on the next core stage now because they can build more than one a year, but the next flight is so many years off.  A production rate of 1+ a year definitely DOES NOT imply that it takes less than a year to build one.

Edit: I think I was mis-remembering Ron's comment #67, about not starting on a flight unit for 2022-3 yet, because they still need to iron out a lot of wrinkles.  I think he understands both the scheduling and development issues and wasn't implying they could start in 2021-2022 for a core stage planned to fly just one year later.
« Last Edit: 05/20/2018 06:31 pm by John Santos »

Offline AncientU

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #87 on: 05/20/2018 06:35 pm »
There were less than 48 RS-25s built in a 30-year Shuttle program... so around 10% of the production rate.  Certainly given a huge amount of money, and a huge lead time AJR could get 'production' running for 16 RS-25s per year -- all of which would be thrown away after a single use.  Most of the SLS budget might do it by 2030 or so. (Recall that it took $1.15B and eight years to get a 'production' line running for 2 per year.)

So no, it cannot happen, at least not in this universe.
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Offline Coastal Ron

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #88 on: 05/20/2018 07:56 pm »
People (not just you) appear to be confusing "production rate" with "production time".  It is perfectly possible to configure operations such that 16 (or more) RS25Es or 1.5 (or more) SLS rockects can be rolled off the factory floor in a year, while each takes much longer than a year to produce.

Well said, and I think what people are forgetting is that Boeing and NASA know what the lead time is in case Congress plans to authorize enough activity in space that more than one flight per year is needed.

For instance the SLS factory can ramp up to two rockets per year fairly quickly (tooling already supports that), but the supply chain would likely need a couple of years to get ready for that on a sustaining basis. Going above two flights per year may not take much longer to prepare for, but the key thing is that you don't want to be jerking the supply chain around by increasing, decreasing, then increasing again. Every change in production rate costs money that the taxpayer has to fund.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Hog

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #89 on: 05/24/2018 01:06 pm »
Good move retiring STS.

I'd rather be stuck in LEO, than stuck on the ground.
Paul

Offline AncientU

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #90 on: 05/24/2018 08:09 pm »
Good move retiring STS.

I'd rather be stuck in LEO, than stuck on the ground.

Get used to it. 
We're only half way there (seven years down, seven years to go), if you are waiting for SLS/Orion.
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Offline speedevil

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #91 on: 05/24/2018 08:14 pm »
Good move retiring STS.

I'd rather be stuck in LEO, than stuck on the ground.

Get used to it. 
We're only half way there (seven years down, seven years to go), if you are waiting for SLS/Orion.
EM-2 (manned lunar flyby) is still officially scheduled at 5 years out I thought?

Offline spacenut

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #92 on: 05/24/2018 08:21 pm »
One flight per year is no good for any kind of Moon or Mars permanent manned activity.  Mars alone will take about 6 SLS flights to assemble a Mars craft capable of going to and from Mars with a small lander.  At this rate the SLS program is just a money pit.  Either ramp production up or cut the budget and build something useful for Mars or the with the money and let commercial launch it. 

Offline AncientU

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #93 on: 05/24/2018 11:02 pm »
Good move retiring STS.

I'd rather be stuck in LEO, than stuck on the ground.

Get used to it. 
We're only half way there (seven years down, seven years to go), if you are waiting for SLS/Orion.
EM-2 (manned lunar flyby) is still officially scheduled at 5 years out I thought?

And EM-1 is officially scheduled in late 2019.

I expect EM-1 to happen in 2021, second SLS launch to be NET 2022-2023 with SM-1, and then 1-2 years later, EM-2 in 2024-2025* (all assuming SLS is still alive at those points -- not even a 50-50 proposition IMO).

2025 is seven years away.


* Note that when I suggested first crew flight in 2024-2025 about a year or two ago, several responses on this thread were aghast that such a thing could be possible.  Looking not-so-unlikely these days, even with a second mobile launcher.  In another year or two, it may be considered optimistic.

Edit: added quote below with emphasis added:
This really locks them into a three-year or so gap between EM-1 and the subsequent launch.  Can't start modifying the ML until EM-1 flies, no matter how late it slides into 2019 or 2020.  (Once you start the mods, a 'cargo' launch can't fly using a second ICPS -- don't know if that was the plan, though.)  Probably pushes the first manned flight to 2024/2025.  There was talk of compressing the big interval between EM-1 and EM-2 (so that the manned flight -- EM-3 -- wouldn't also slip), but now that seems unlikely.

Where do you get this non-sense?  I have never seen any documentation that shows 2024/2025 as EM-2.  In fact, most documentation shows 2021, which exactly corresponds to the 36 months it will take to modify the ML for EUS after EM-1.
« Last Edit: 05/25/2018 12:06 am by AncientU »
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Offline MATTBLAK

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #94 on: 05/24/2018 11:11 pm »
This whole situation is one big cluster-frakk! :(  How long will it be until this is universally acknowledged and dealt to?
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Offline spacenut

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #95 on: 05/24/2018 11:29 pm »
I don't think anything will be done until SpaceX launches a BFR/BFS successfully.  Not only this, but when Vulcan w/ACES launches, and when New Glenn launches, it makes no sense for NASA to even build SLS.  With 40-60 tons to LEO with three available launch companies, they can spend the money on assembly of a large Nautilus X exploration craft.  Nautilus X was designed for 20 ton launches and in space assembly.  With 40-60 ton parts, instead of 20 ton parts, fewer launches could be make for quicker assembly.  The Nautilus parts could be contracted out to the same contractors making SLS so they can keep their work force busy.  Maybe NASA couldn't botch that.   

Offline woods170

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #96 on: 05/25/2018 09:36 am »
This whole situation is one big cluster-frakk! :(  How long will it be until this is universally acknowledged and dealt to?

When the next President takes office and has the balls to install a next Augustine Committee.

Offline hektor

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #97 on: 05/25/2018 10:58 am »
This article from the Verge

The first three missions of NASA’s next big rocket will have to settle for a less-powerful ride

provides this link

ESD-DM-13030

which says

Quote
Mid-2022 is the target date for the next SLS Block 1 launch using ML-1

Offline Hog

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #98 on: 06/02/2018 03:29 pm »
From the Verge article.

"Block 1B is designed with a much more powerful upper stage, allowing it to carry about 287,000 pounds (130 metric tons)."

Is that statement true?  I thought Block-II was good for 130 tonnes?  Is their graphic(below) obsolete?
Paul

Offline Sknowball

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Re: Schedule for First SLS Core Stage Still Sliding
« Reply #99 on: 06/02/2018 06:50 pm »
From the Verge article.

"Block 1B is designed with a much more powerful upper stage, allowing it to carry about 287,000 pounds (130 metric tons)."

Is that statement true?  I thought Block-II was good for 130 tonnes?  Is their graphic(below) obsolete?

In early May NASA released updated performance numbersl for Block 1 putting it at 95 metric tonnes (there was an excellent article on the NSF front page about the status of SLS which talked about this as well), so the graphic is at least out of date for Block 1 numbers.   It wouldn't surprise me if Block 1b numbers are also being adjusted upwards as the Block 1 performance gains are from the core stage.


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