Author Topic: SLS General Discussion Thread 8  (Read 158542 times)

Offline laszlo

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Re: SLS General Discussion Thread 8
« Reply #620 on: 10/03/2022 09:36 am »
Is there anyway to send a camera inside of the solid boosters to check the condition of the solid material?  This would tell if they need to restack and repair or replace the solid material.

No. Segment delamination since initial stacking that is sufficient to damage the propellant cohesion is not visible to the naked eye.
X-ray, ultrasonic and other non-invasive, non-destructive methods should be able to detect invisible changes,

Offline JohnFornaro

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Re: SLS General Discussion Thread 8
« Reply #621 on: 10/03/2022 12:57 pm »
Too much focus on analysis and process above building and getting things done. Also, the tech we had then with rocketry was close to the optimal already (for expendables). And they had more money and wages were lower.

"The tech we had then with rocketry was close to the optimal already"

In this day and age, there's no excuse for the stagnation in rocketry.  I want to say; "Don't break it if it's already fixed.  And SLS is an expendable.  Plus, they redefine "innovation", which is supposed to be synonymous with the common aphorism,  "work harder, not smarter".  Oh wait.  Did I get that one wrong?  One thing the PAO always stresses is how the *cough* team *cough* is working harder every day.  This two decade long narrative makes no logical sense.
« Last Edit: 10/04/2022 10:47 am by JohnFornaro »
Sometimes I just flat out don't get it.

Offline DanClemmensen

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Re: SLS General Discussion Thread 8
« Reply #622 on: 10/03/2022 03:32 pm »
Is there anyway to send a camera inside of the solid boosters to check the condition of the solid material?  This would tell if they need to restack and repair or replace the solid material.

No. Segment delamination since initial stacking that is sufficient to damage the propellant cohesion is not visible to the naked eye.
X-ray, ultrasonic and other non-invasive, non-destructive methods should be able to detect invisible changes,
I don't know the details of such techniques, but  I suspect that determining whether or not the PSA is still sticky on all ten joints, each more than ten meters in circumference, would be an "interesting" exersize. This article has diagrams:
   https://www.nasaspaceflight.com/2020/12/artemis-1-schedule-uncertainty-sls-booster-stacking/2/

Offline laszlo

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Re: SLS General Discussion Thread 8
« Reply #623 on: 10/03/2022 06:39 pm »
Is there anyway to send a camera inside of the solid boosters to check the condition of the solid material?  This would tell if they need to restack and repair or replace the solid material.

No. Segment delamination since initial stacking that is sufficient to damage the propellant cohesion is not visible to the naked eye.
X-ray, ultrasonic and other non-invasive, non-destructive methods should be able to detect invisible changes,
I don't know the details of such techniques, but  I suspect that determining whether or not the PSA is still sticky on all ten joints, each more than ten meters in circumference, would be an "interesting" exersize. This article has diagrams:
   https://www.nasaspaceflight.com/2020/12/artemis-1-schedule-uncertainty-sls-booster-stacking/2/
It certainly would be labor intensive, but what isn't on SLS?

Note that the joints contain leak check ports so that visualization may be entirely unnecessary. They are visible in diagram 1  just to the right of the arrow labeled "Heater".



Offline Hog

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Re: SLS General Discussion Thread 8
« Reply #624 on: 10/04/2022 02:38 pm »
Is there anyway to send a camera inside of the solid boosters to check the condition of the solid material?  This would tell if they need to restack and repair or replace the solid material.

No. Segment delamination since initial stacking that is sufficient to damage the propellant cohesion is not visible to the naked eye.
I thought the SRB age limit related to the segment joints, specifically the adhesion of the PSA and the flexibility of the J-legs. I would have thought that the bulk propellant would last a longer time, based on the lifetime of other solid rocket motors like those in SLBMs.  Based solely on the diagrams, I speculate that your main point is still valid and that it is unlikely that anything is visible to show deterioration.
Will point out that the solid rocket motors in strategic ballistic missiles are monolithic. AFAIK no strategic ballistic missile use segmented solid rocket motors.
I am aware of this. I took clongton's comment as referring to the bulk propellant in each segment, which I thought was roughly equivalent to the propellant in an unsegmented solid booster. The J-legs and PSA are elements of the intersegment seals, and are the only parts of the SRBs that I have seen described when the age limit was being discussed.
emphasis mine
Following media questions in reference to the booster stacked time factors, I do remember clearly that propellant "slumping" was discussed during the post-launch briefing after the first launch attempt. J-legs and Pressure Sensitive Adhesives were not discussed at that briefing. 
AIUI The issues with the field joint time limits are small and there is RSRMV horizontal firings with purposeful "defects" installed in the field joint for the firing test.
I can't see a destack of the SLS due to SRB Field Joint J-leg uncertainty.  That doesn't give NASA a pass for the premature IMO consummation of the first SRM field joints between the nozzle/aft segment and the first propellant only segments(aft center segments) of the motors.

Any chance that some portion of these RSRMV could be salvaged? Not for re-use but for examination?  Booster recovery following STS-51L Challenger was fruitful. I remember that "torch-hole" through the D6AC steel cases.  the RSRMV sees combustion chamber pressures just under 1000 psi whilst the 4 segment units saw just over 900psi moments after ignition when pressures  are the greatest.  Thrust is greatest approx. 15 seconds MET(Mission Elapsed Time=T+15 seconds). Very roughly the same time that the Core Stage Main Engines throttle up from 100%RPL to 109%RPL. (this mini-upthrottle was from 100% to 104.5% for STS missions using full Block-II SSME)



 
Paul

Offline Hog

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Re: SLS General Discussion Thread 8
« Reply #625 on: 10/04/2022 02:45 pm »
Is there anyway to send a camera inside of the solid boosters to check the condition of the solid material?  This would tell if they need to restack and repair or replace the solid material.

No. Segment delamination since initial stacking that is sufficient to damage the propellant cohesion is not visible to the naked eye.
X-ray, ultrasonic and other non-invasive, non-destructive methods should be able to detect invisible changes,
I don't know the details of such techniques, but  I suspect that determining whether or not the PSA is still sticky on all ten joints, each more than ten meters in circumference, would be an "interesting" exersize. This article has diagrams:
   https://www.nasaspaceflight.com/2020/12/artemis-1-schedule-uncertainty-sls-booster-stacking/2/
It certainly would be labor intensive, but what isn't on SLS?

Note that the joints contain leak check ports so that visualization may be entirely unnecessary. They are visible in diagram 1  just to the right of the arrow labeled "Heater".



Propellant delamination and field joint issues are being mixed up here.  Unless you can visualize "stickiness" it would be difficult or almost impossible to determine if the PSA will "stick" following ignition.
It's akin to determining if a Post-It note will stick, without being able to touch it because the simple act of "touching" becomes destructive testing and if the adhesive IS touched, its "stickability" is even more greatly unassured.
Paul

Offline Jim

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Re: SLS General Discussion Thread 8
« Reply #626 on: 10/04/2022 04:42 pm »

Yes as of now.  But there are other blocks for SLS.

Still only for Orion

Offline Jim

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Re: SLS General Discussion Thread 8
« Reply #627 on: 10/04/2022 04:43 pm »

Id love to see a concept of SRBs strapped onto a modified stretched out Starship.


not possible

Offline Robotbeat

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Re: SLS General Discussion Thread 8
« Reply #628 on: 10/04/2022 04:53 pm »
...  Again hypothetically, what if Orion was on top of a Super Heavy Booster? 😱. That would likely be a pretty awful sight.
 
Be very careful what you wish for!
There is a guy on Twitter called 'The Cursed Rockets Guy'. He does what it says on the tin.
[Orion and ICPS on Superheavy]

Alternative rides for Orion was the subject of the most recent video from Apogee (Ken Kirtland): Are Rockets Like Legos?, with four Superheavy relate versions (Superheavy/ICPS; Superheavy/Centaur V; Superheavy/EUS; Superheavy/Simplified Expendable Starship) discussed starting at 17:12.  (Starting at 09:03 he discussed 3 Stage New Glenn; New Glenn/Centaur V; Falcon Heavy/Centaur V.)

Id love to see a concept of SRBs strapped onto a modified stretched out Starship.

On one side of a playing card, what you have ultimately is that this SLS/Orion flight is simply a test.  They have minimal objectives to demonstrate what capabilities they think they have.

On the other side of the playing card, you have every concept including somehow going to Mars.

The first side only validates the test of very minimal set of objectives.  The scope creep occurs with each ante.  By flipping the card over and doing the test, you will see the face value on the card. 

The card value is currently unknown for SLS/Orion.  So a poker bluff is likely being played.  Currently all in with SLS/Orion. 

Starship/SH is just another card.  Need to see if Starship is even being considered realistically for deep space missions. This is a high stakes stare down at this time.  Nobody folds after going all in.

Rockets are as old as steam locomotives. 

Mark Twain (and others) have said every fool must be released of their money.
There's no reason to strap SRBs to Starship.

Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS. Let me repeat that:
Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline clongton

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Re: SLS General Discussion Thread 8
« Reply #629 on: 10/04/2022 05:21 pm »
Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS. Let me repeat that:
Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS.

Emphasis mine
And at an order of magnitude less expensive, ESPECIALLY if it's a vehicle that has already flown several times.
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I started my career on the Saturn-V F-1A engine

Offline DanClemmensen

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Re: SLS General Discussion Thread 8
« Reply #630 on: 10/04/2022 05:40 pm »
Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS. Let me repeat that:
Fully expendable Starship (including a jettisonable fairing) can do direct launch deep space missions just as well as SLS can, certainly Block I SLS.

Emphasis mine
And at an order of magnitude less expensive, ESPECIALLY if it's a vehicle that has already flown several times.
Since neither Starship nor SLS/Orion have actually flown, we are comparing projected capabilities, not proven capabilities. That said, you need to pick a time in the future for your comparison. Let's pick Artemis III. for that mission, I think Crewed Starship could replace SLS/Orion, not just SLS. Nothing fancy, just a straight-up replacement. Crewed SS could meet HLS in NRHO to handle both outbound and return legs of the trip.

Offline Mackilroy

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Re: SLS General Discussion Thread 8
« Reply #631 on: 10/04/2022 09:20 pm »
This thread is about the SLS, not Starship.

Offline sdsds

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Re: SLS General Discussion Thread 8
« Reply #632 on: 10/05/2022 01:58 am »
I want to quickly jump in to share how in my thinking I place huge importance on distinguishing between SLS and Artemis. For emphasis I attach a graphic from a NASA document (admittedly years old) showing SLS used for a Mars mission that was being studied.
https://ntrs.nasa.gov/api/citations/20150001240/downloads/20150001240.pdf

NASA leadership isn't talking much about humans to Mars right now. And the main corps of engineers and technicians are following that leadership. But there exists within NASA a cadre of talented people who haven't forgotten their favorite Mars mission concepts.
𝐬𝐝𝐒𝐝𝐬

Offline kevinof

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Re: SLS General Discussion Thread 8
« Reply #633 on: 10/05/2022 07:41 pm »
Maybe I missed one but was there ever a poll on how many flights SLS will eventually make in it's lifetime? I'm thinking low single digits!


Offline su27k

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Re: SLS General Discussion Thread 8
« Reply #634 on: 10/06/2022 01:52 am »
I want to quickly jump in to share how in my thinking I place huge importance on distinguishing between SLS and Artemis. For emphasis I attach a graphic from a NASA document (admittedly years old) showing SLS used for a Mars mission that was being studied.
https://ntrs.nasa.gov/api/citations/20150001240/downloads/20150001240.pdf

NASA leadership isn't talking much about humans to Mars right now. And the main corps of engineers and technicians are following that leadership. But there exists within NASA a cadre of talented people who haven't forgotten their favorite Mars mission concepts.

I agree that there is a huge difference between SLS and Artemis, in that Artemis can easily continue without SLS. But I don't understand why the document about Mars mission supports this distinction. Please note Artemis is not limited to the Moon, it covers Mars too, it's right there on https://www.nasa.gov/specials/artemis/: "Then, we will use what we learn on and around the Moon to take the next giant leap: sending the first astronauts to Mars." And they even designed the logo to include Mars' color.

Offline tea monster

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Re: SLS General Discussion Thread 8
« Reply #635 on: 10/06/2022 12:23 pm »
The reason that there should be a clear distinction between SLS and Artemis is that Artemis is a program to visit the Moon and the SLS is a rocket. There should be a distinction there. If for some reason SLS fails, we don't want to throw the entire lunar program out the window and start again from scratch (again).

Going on to Mars is a notional goal of Artemis, but AFAIK, no funding has been allocated and no official plans exist at all. Without either of those two, it's just talk. As half a century of power point presentations have taught us, having detailed plans of how to get there isn't any good without the cash to pay for the hardware and support systems. It's tired, and it's cliche, but it's true: 'No bucks, no Buck Rogers.'

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 8
« Reply #636 on: 10/06/2022 03:29 pm »
The current list of when the Artemis early missions have been badly affected because of SLS availability to launch the missions:

Artemis I - Nov/Dec 2022 (I am optimistic with SLS having 2 Launch Periods to try launching that it would likely launch during sometime in these two periods which cover a total of 42 days with which 20+ of them have viable launch windows.)

Artemis II - ~20 months from launch of Artemis I ~Q3 2024.

Artemis III - ~18 months from launch of Artemis II due to the advanced number of detailed evaluations of Artemis II mission ~ Q1 2026

Artemis IV - delayed to 2028 because of the ML2 and EUS schedules ~ Q3 2028

Artemis V - may be the first without much delays at 12 months after Artemis IV ~ Q3 2029. (Last of the Artemis/SLS missions of the 2020s. The next after this will be a year later if a SLS launch does occur in ~H2 2030.)

The out flights of SLS probably has more to do with success of Starship reaching many of it's performance goals than much about SLS. As mentioned above Artemis program does not equal SLS launch vehicle. But something has to be capable of taking over from it else it would continue.
« Last Edit: 10/06/2022 04:46 pm by oldAtlas_Eguy »

Re: SLS General Discussion Thread 8
« Reply #637 on: 10/08/2022 12:45 am »
I wish Artemis II could be that close to Artemis I. Unfortunately, in a GAO report from the beginning of September, they reported that NASA thinks that they will require 27 months between Artemis I and II, and even this schedule is still at risk of delays.  Based on this, Artemis II wont happen until 2025 at the earliest. 

Offline yg1968

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Re: SLS General Discussion Thread 8
« Reply #638 on: 10/16/2022 04:47 pm »
The reason that there should be a clear distinction between SLS and Artemis is that Artemis is a program to visit the Moon and the SLS is a rocket. There should be a distinction there. If for some reason SLS fails, we don't want to throw the entire lunar program out the window and start again from scratch (again).

Going on to Mars is a notional goal of Artemis, but AFAIK, no funding has been allocated and no official plans exist at all. Without either of those two, it's just talk. As half a century of power point presentations have taught us, having detailed plans of how to get there isn't any good without the cash to pay for the hardware and support systems. It's tired, and it's cliche, but it's true: 'No bucks, no Buck Rogers.'

There are plans for Mars. See pages 37-44 of this document:
https://ntrs.nasa.gov/api/citations/20210022080/downloads/HEOMD-007%20HEO%20SCOPE%20-%2009-28-2021%20NTRS.pdf

Offline Coastal Ron

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Re: SLS General Discussion Thread 8
« Reply #639 on: 10/16/2022 05:01 pm »
The reason that there should be a clear distinction between SLS and Artemis is that Artemis is a program to visit the Moon and the SLS is a rocket. There should be a distinction there. If for some reason SLS fails, we don't want to throw the entire lunar program out the window and start again from scratch (again).

Going on to Mars is a notional goal of Artemis, but AFAIK, no funding has been allocated and no official plans exist at all. Without either of those two, it's just talk. As half a century of power point presentations have taught us, having detailed plans of how to get there isn't any good without the cash to pay for the hardware and support systems. It's tired, and it's cliche, but it's true: 'No bucks, no Buck Rogers.'

There are plans for Mars. See pages 37-44 of this document:
https://ntrs.nasa.gov/api/citations/20210022080/downloads/HEOMD-007%20HEO%20SCOPE%20-%2009-28-2021%20NTRS.pdf

Oh please. Just because someone at NASA writes a paper that says that Mars is a goal does not make it a REALISTIC goal for NASA, especially if they have to use the SLS.

As a reminder, for the lunar-oriented Artemis program the SLS is only needed for launching the Orion MPCV, and the Orion MPCV is not designed for going to Mars. So for the purposes of this thread, the SLS is not needed for any effort to go to Mars.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

 

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