Author Topic: SLS trades lean towards opening with four RS-25s on the core stage  (Read 94352 times)

Offline Rocket Science

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Great article Chris, loaded with information. I am curious if they will create a mock up of SLS as a design study. Although it is not needed with today’s computer aided design, it would go a long way if placed on display to the public for PR value and future funding. Gives the politicos some nice photo ops ;)

Regards
Robert
"The laws of physics are unforgiving"
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Offline Downix

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Great article Chris, loaded with information. I am curious if they will create a mock up of SLS as a design study. Although it is not needed with today’s computer aided design, it would go a long way if placed on display to the public for PR value and future funding. Gives the politicos some nice photo ops ;)

Regards
Robert

Not needed?  CAD does not give ground crews chance to practice, to test operations.  Only a pathfinder, a full sized mockup, allows for that.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline Chris Bergin

Thanks Uko, Mike, Demo and RS!

This is more technical than the next article - and needed to turn it around, but the next one will be via the wonderful industry presentation (which wasn't released for some reason, but we got it for L2), which includes what they want to do with SLS and lots of pretty pictures :)

That'll be another baseline level article for SLS. Might need to write that over a few days.

Offline Mr. Justice

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This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

Seriously, there is no rational to spending the better part of the next two decades developing and redeveloping the SLS. Particularly when the principle reason for this is to reach the arbitrary 130 ton requirement. At this stage, keep the 5 segment boosters and make a decision if they should be recovered based solely on a cost benefit analysis. The core can be stretch from the start and fly with five RS-25 engines. The upper stage can be developed in parallel with the core. The only thing necessary to determine is the size and how many engines, perhaps the possibility of designing it to fly with one or three engines.

No need to spend time and money on multiple upper stages nor on multiple boosters and, well, we can actually accomplish something other than rocket building.

Offline Lurker Steve

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Did I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ?

After that, ATK has a more "advanced" design, or we switch to LRBs.

So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster.

Who pays for the development of this new ATK design ?

Offline Chris Bergin

This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

It's been noted more times than I can remember that the mission planning is in work, via Mr Shannon :)

Offline Downix

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Did I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ?

After that, ATK has a more "advanced" design, or we switch to LRBs.

So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster.

Who pays for the development of this new ATK design ?
No difference than the 2 and 3 segment SRB's, or the ASRM's, all of which have had ground testing, but none launched.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline marsavian

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Unless this approach is reversed, I don't see how SLS will be able to fit within the given budget. Sigh.

Simple, by deferring Block II to never-never land. After all, the law only requires the rocket to be upgradable to 130 mT, not the 130 mT version actually flying, no? I thought only the 70 mT (Block I) has a law-mandated deadline?

We could already do plenty with Block I SLS alone. And Block IA with a good CPS could cover virtually all our HSF needs for the next 30 years at least, since I can't see any manned Mars mission (which would require Block II) before that time-frame anyway.

That's probably how it will pan out. Lunar and NEO can be done with Block 1A/CPS but any Mars or Martian Moon missions will take Block 2 as the reference hardware and that will be developed along with mission modules in the $3+bn budget. I suppose it's all part of ensuring the use of all the CxP hardware in development, the J-2X will be developed and then parked until the upper stage can be developed in the fixed budget.

The 130mT Block 2 was obviously the line at which Congress, especially the House, drew the line at giving up CxP hardware i.e. we will sacrifice Ares I but we want at least an Ares V Classic class HLV. The politics of compromise ;). Maybe the Lunar drive-by missions will get political/public interest up and additional funds may follow to speed up mission module hardware, perhaps from the ending of ISS involvement. Considering how far apart the politicians and space community were originally this may not a bad compromise for everybody in achieving the final goal of manned Martian exploration but agreed compromises never please everybody entirely just upset them the least ;).

Offline Chris Bergin

Did I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ?

After that, ATK has a more "advanced" design, or we switch to LRBs.

So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster.

Who pays for the development of this new ATK design ?

Yep, at this moment, the Ares Five Seg gets two flights. I know what you're getting at, not great value for a billion dollars of dev, but the alternative was absolutely nothing for a billion dollars of dev, so this is still a better situation. They may yet keep it flying through SLS-3 to 5 whatever, but those "Oh, we have to have a competition" funsters are the reason it may only see two flights.

It's worth noting to people who seem to point at ATK costs for a "new design" (note I've already reported, and it was linked in this article**, about the potential route to improve the ATK booster) that they also need to ask the same questions going to be asked about all that testing and dev of the Liquid boosters?

**
Quote
This example, provided to the RAC Team 1 at Marshall, proposes the change to a HTPB (Hydroxyl-terminated polybutadiene) fueled solid in “composite over wrapped steel cases” to allow higher MEOP (Maximum Expected Operating Pressure) – to as much as 1500 psi.

There are also proposals to use lighter weight nozzles with expansion ratios up to 12:1.....

Offline Rocket Science

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Great article Chris, loaded with information. I am curious if they will create a mock up of SLS as a design study. Although it is not needed with today’s computer aided design, it would go a long way if placed on display to the public for PR value and future funding. Gives the politicos some nice photo ops ;)

Regards
Robert

Not needed?  CAD does not give ground crews chance to practice, to test operations.  Only a pathfinder, a full sized mockup, allows for that.
I'm with you Nate ;) A low fidelity Pathfinder "Battleship" will be used for that. I'm saying a high fidelity mock-up for display. Even though CATIA software is powerful if that is what they may use…
Regards
Robert
« Last Edit: 10/06/2011 12:49 AM by Rocket Science »
"The laws of physics are unforgiving"
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Offline Mr. Justice

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This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

It's been noted more times than I can remember that the mission planning is in work, via Mr Shannon :)

Yes, the problem is it appears it is more of the old "don't call us, will call you line." It is an eternal wait. The real problem is if we keep spending money designing and redesigning the SLS that is money that cannot be spent on an LSAM or crew modules or the actual cost of a mission.

Offline aquanaut99

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That's probably how it will pan out. Lunar and NEO can be done with Block 1A/CPS but any Mars or Martian Moon missions will take Block 2 as the reference hardware and that will be developed along with mission modules in the $3+bn budget. I suppose it's all part of ensuring the use of all the CxP hardware in development, the J-2X will be developed and then parked until the upper stage can be developed in the fixed budget.

Yes.

I predict the Block I will fly more than twice (maybe up to 4 times, since there are apparently about 16 RS-25Ds available, which would allow for 4 flights).

So that already puts us into the 2023 - 2025 timeframe before we get Block IA. Plenty of time for political / mission focus shifts.

As for the block IA, I predict we'll keep that at least until 2035.

Finally, I predict that after the first two Block I flights with the current 5-segs, we will get an evaluation between different "Advanced Booster Options" (as planned), but in the end, they'll most likely stick with the ATK 5 seg boosters, for cost reasons, (unless some very effective and cheap LRBs become available or unless the 5 segs fail completely), with a vague promise of some sort of "improved booster" somewhere down the road. Just like with Shuttle, which was supposed to replace the RSRBs with something new (ASRB, 5-segs, even LRBs) several times during its lifetime...
« Last Edit: 10/05/2011 04:35 PM by aquanaut99 »

Offline Robotbeat

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This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

It's been noted more times than I can remember that the mission planning is in work, via Mr Shannon :)
It shows where the real priorities are when the actual mission planning (and hardware, etc) is practically an afterthought compared to the launch vehicle.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Namechange User

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This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

It's been noted more times than I can remember that the mission planning is in work, via Mr Shannon :)
It shows where the real priorities are when the actual mission planning (and hardware, etc) is practically an afterthought compared to the launch vehicle.

Where were your mission plans (and hardware, etc) for anything without SLS?  They had years.
« Last Edit: 10/05/2011 05:14 PM by Chris Bergin »
Enjoying viewing the forum a little better now by filtering certain users.

Offline Chris Bergin

This is just a great disappointment. There are no missions of any substance in the planning: flying by and waving at the Moon is not a real mission. It is 51 years after the Apollo 8 mission proving that we cannot match that mission's abilities.

It's been noted more times than I can remember that the mission planning is in work, via Mr Shannon :)
It shows where the real priorities are when the actual mission planning (and hardware, etc) is practically an afterthought compared to the launch vehicle.

To be fair they had it, with the flexible path, which replaced the VSE, with a nice amount of flexibility on the LV (I think they mainly used an Ares V for that....and we're not a million miles off with SLS on that score).

I'm as frustrated with the next man on mission content, but I think the big problem is if they had designed the missions say two years ago, then they'd probably be redoing them now based on the latest budget cycles and such. Not sure, but I bet there would be some people saying "HA, you've created missions and you don't even have a LV yet".

We're not launching SLS any time soon, so Mr Shannon has everything he needs, the LV design, the crew capsule design, the latest budget projects and the time to - I'm sure - work his magic, as he's (Dr Evil voice) "a fricking genius" ;D

Offline Lobo

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Maybe the Lunar drive-by missions will get political/public interest up and additional funds may follow to speed up mission module hardware, perhaps from the ending of ISS involvement. Considering how far apart the politicians and space community were originally this may not a bad compromise for everybody in achieving the final goal of manned Martian exploration but agreed compromises never please everybody entirely just upset them the least ;).

Especially if we could do the Apollo 8 redux on the 50th Anneversary of Apollo 8, Dec 2018.

Offline sewand

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The Block 1A upper stage is interesting - is this going to be ACES-like?  Any idea how much 1A can push through TLI?   

Offline ChileVerde

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We're not launching SLS any time soon, so Mr Shannon has everything he needs, the LV design, the crew capsule design, the latest budget projects and the time to - I'm sure - work his magic, as he's (Dr Evil voice) "a fricking genius" ;D

Does Mr. Shannon's remit include defining in some detail what the crew is going to do once it gets wherever the DRMs say they're going? Or is that part to be supplied separately by the National Academies study?  Or (which would seem to make sense) is Mr Shannon going to coordinate with the National Academies in working all this out?

E.g., DRM 13.3 sends four people to Deimos and Phobos where they will stay for X weeks. NA says, "And while they're there, they will conduct studies S1 - S37."
"I can’t tell you which asteroid, but there will be one in 2025," Bolden asserted.

Offline Chris Bergin

Good question, Chile. We did ask Mr Shannon for an interview (main angle reflecting on Shuttle), but he refused....

....well PAO said he did, which is probably more to do with them than anything.

Offline 93143

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It is an eternal wait.

It hasn't even been a month.  Give him some time.
« Last Edit: 10/05/2011 08:21 PM by 93143 »

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