Author Topic: How should NASA evolve the SLS?  (Read 178693 times)

Offline RocketmanUS

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Re: How should NASA evolve the SLS?
« Reply #300 on: 03/20/2013 01:27 am »
Use RD-180's.

That's called Atlas Phase 2, and it's nowhere near as powerful.
(4) RD-180's with a 5.4m diameter stage.

And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?
I'm looking at less development cost and less time till a possible first flight.
Yes I would have preferred an American made engine.

Offline newpylong

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Re: How should NASA evolve the SLS?
« Reply #301 on: 03/20/2013 02:06 am »

No, your point is baseless.

RS-68 manrating mods are known and were going to be used for SLS
It doesn't take much to manrate the vehicle
Delta launch site only needs a crew access tower
P.S. Delta doesn't have a mobile launcher

Don't take it personally big guy, it's okay to disagree.

-We all know the RS68 was going to be manrated for Ares V but whats your source that they were seriously considered for SLS? Secondly, we all know it can be done, but at what cost?

-"only needs a crew access tower"? It's not as simple as throwing a rope bucket seat over.

From ULA: "First, our existing launch pads will require accommodations to allow for ingress and egress to and from a crewed spacecraft. Second, we require the addition of an Emergency Detection System (EDS) to monitor the health of the launch vehicle, detect anonomolous conditions, safe the launch vehicle, and to trigger an abort."

Then you need emergency ground services. It won't help to get people off the tower if they can't go anywhere.

All of these things cost $$ to design and develop when they already have been for SLS. Like I said, I am all for it, but not if it removes the option for crewed SLS.
« Last Edit: 03/20/2013 02:10 am by newpylong »

Offline llanitedave

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Re: How should NASA evolve the SLS?
« Reply #302 on: 03/20/2013 02:42 am »
Use RD-180's.

That's called Atlas Phase 2, and it's nowhere near as powerful.
(4) RD-180's with a 5.4m diameter stage.

And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?
I'm looking at less development cost and less time till a possible first flight.
Yes I would have preferred an American made engine.

How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?
"I've just abducted an alien -- now what?"

Offline RocketmanUS

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Re: How should NASA evolve the SLS?
« Reply #303 on: 03/20/2013 04:46 am »
Use RD-180's.

That's called Atlas Phase 2, and it's nowhere near as powerful.
(4) RD-180's with a 5.4m diameter stage.

And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?
I'm looking at less development cost and less time till a possible first flight.
Yes I would have preferred an American made engine.

How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?
No, and you didn't answer the question ( What engines in production that do not need to be modified? ).

If they are going to have the LRB's , then let's have them now and not use the 5 seg SRB's. And if they do go with the LRB's then commercial could use it as a 1st stage for a single stick. If for some reason SLS were canceled then the single stick with common core ( tri-core ) could be a HLV ( back up plan and would not have to restart production of the costly SSME's ).

With the already in production and well proven with great specs RD-180's four of them on each booster would get us at least the 130mt that is required for block II. They could be ready by the wanted 2017 launch and the core made for them.

Offline davey142

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Re: How should NASA evolve the SLS?
« Reply #304 on: 03/20/2013 10:55 am »
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?

Offline Proponent

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Re: How should NASA evolve the SLS?
« Reply #305 on: 03/20/2013 11:43 am »
And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?

Yes, the US abandoned hydrocarbon-engine technology after the F-1, whereas the Soviets stuck with it.  There is no US engine today that matches the power and efficiency of the RD-180.  The one American entity that has seriously invested in hydrocarbon engines, SpaceX, presently has only a much smaller engine.

Offline tnphysics

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Re: How should NASA evolve the SLS?
« Reply #306 on: 03/20/2013 02:24 pm »
Though you could use Falcon 9 cores as boosters.

Offline deltaV

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Re: How should NASA evolve the SLS?
« Reply #307 on: 03/20/2013 02:28 pm »
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?

Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?

Offline llanitedave

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Re: How should NASA evolve the SLS?
« Reply #308 on: 03/20/2013 02:38 pm »
Use RD-180's.

That's called Atlas Phase 2, and it's nowhere near as powerful.
(4) RD-180's with a 5.4m diameter stage.

And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?
I'm looking at less development cost and less time till a possible first flight.
Yes I would have preferred an American made engine.

How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?
No, and you didn't answer the question ( What engines in production that do not need to be modified? ).

If they are going to have the LRB's , then let's have them now and not use the 5 seg SRB's. And if they do go with the LRB's then commercial could use it as a 1st stage for a single stick. If for some reason SLS were canceled then the single stick with common core ( tri-core ) could be a HLV ( back up plan and would not have to restart production of the costly SSME's ).

With the already in production and well proven with great specs RD-180's four of them on each booster would get us at least the 130mt that is required for block II. They could be ready by the wanted 2017 launch and the core made for them.

We already have RS25D's in stock, ready to go.  That's what the core is already designed around, and that's what will work.  That gives us plenty of time to complete follow-on engines if we wish, whether J2-X, which is essentially complete, F1B, which has had the bulk of development work already done via previous iterations, or the RS25-E, which is a fairly minor modification to the current version.

If all you're talking about is replacing the SRB's with RD-180 LRB's, there's no need for that "right now".  We wouldn't be saving any money by tossing out the SRB segments we already have, nor for making a crash program to go to 130 tons of lift when payload development has barely even been considered.

The key word of this thread is "evolve".  Let's get the basic system going, spend the money to make the core operational, and then start shunting money into payload development that will justify the 130 ton vehicle.  That way the true heavy lift capacity and the truly heavy payloads will both be ready in closer to the same time frame.
"I've just abducted an alien -- now what?"

Offline TomH

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Re: How should NASA evolve the SLS?
« Reply #309 on: 03/20/2013 02:48 pm »

No, your point is baseless.

RS-68 manrating mods are known and were going to be used for SLS
It doesn't take much to manrate the vehicle
Delta launch site only needs a crew access tower
P.S. Delta doesn't have a mobile launcher

Don't take it personally big guy, it's okay to disagree.

...whats your source...

Don't take him personally either. He comes across that way to everybody. He's to the point and does not use any extra words.

He is a source. He works for NASA. He is a rocket scientist. He is smarter than most of us put together. He's virtually never wrong.
« Last Edit: 03/20/2013 02:49 pm by TomH »

Offline deltaV

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Re: How should NASA evolve the SLS?
« Reply #310 on: 03/20/2013 03:19 pm »
If the RD-180 were US-built would Energomash make any profit on those engines? Depending on how the contracts were written this might happen via royalties paid to Energomash or via Energomash's partial ownership of RD AMROSS. If so I could see a nationalism problem for US-built RD-180s.

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #311 on: 03/20/2013 04:49 pm »


Don't take him personally either. He comes across that way to everybody. He's to the point and does not use any extra words.

He is a source. He works for NASA. He is a rocket scientist. He is smarter than most of us put together. He's virtually never wrong.

Oh man....there will be no living with Jim now that you've said all of that....

;-)

« Last Edit: 03/20/2013 05:21 pm by Lobo »

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #312 on: 03/20/2013 05:09 pm »
Though you could use Falcon 9 cores as boosters.

The problem with using F9 as SLS boosters is NASA doesn't seem to want more than two boosters.  That's basically why they tossed out the 4-booster Atlas V Phase 3a in the ESAS study.  And my guess is that's why nothing like AJAX ever got evaluated in ESAS.  They looked at an SLS like core with two Atlas V boosters, and two Delta 4 boosters (neither of which had very good performance obviously) But they didn't look at that with four or more AA or D4 boosters. 

Two F9 1.1 cores on each side would probably give SLS performance in the rage of the 5-seg booster.  With 3 on each side, you'd get Advanced booster performance.  I've actually thought that if you took a FH and put that on each side, you'd have a pretty good SLS.  AS in, only the central core of the FH would be connected to the SLS core, and would be modified to do so.  The two outboard FH boosters would only be connected to the central core as they would be for a FH launch.  Then the central FH core could be attached to the upper thrust beam on SLS, adn the 3 cores of the FH together woudl act as a single booster.  So in effect, SLS would still have only two boosters.  And other than the FH central core mods to allow it to interface with the SLS core it would really still be a production LV flying by itself, which would have cost sharing and should keep costs down.  Each FH would not be cross fed, as there's no reason to with the sustainer core of SLS.  They'd just be dumb boosters, with only two separation elements, as the FH outboard boosters won't separate from the central core, all three will be jettisoned as a single booster. 

Seems like that would be a great cost saving option.  Then Orion could also launch on FH for a more "1.5" architecture. 

A great option, so it will probably never be considered by NASA...  :-(

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #313 on: 03/20/2013 05:13 pm »
We already have RS25D's in stock, ready to go.  That's what the core is already designed around, and that's what will work.  That gives us plenty of time to complete follow-on engines if we wish, whether J2-X, which is essentially complete, F1B, which has had the bulk of development work already done via previous iterations, or the RS25-E, which is a fairly minor modification to the current version.

If all you're talking about is replacing the SRB's with RD-180 LRB's, there's no need for that "right now".  We wouldn't be saving any money by tossing out the SRB segments we already have, nor for making a crash program to go to 130 tons of lift when payload development has barely even been considered.

The key word of this thread is "evolve".  Let's get the basic system going, spend the money to make the core operational, and then start shunting money into payload development that will justify the 130 ton vehicle.  That way the true heavy lift capacity and the truly heavy payloads will both be ready in closer to the same time frame.

Agreed.

A tri-core scaled up Atlas Phase 2, could be looked at down the road when ADvanced boosters are being considered for SLS.  But right now, I don't think that helps us much vs Block 1 SLS for those reasons.

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #314 on: 03/20/2013 05:20 pm »
If the RD-180 were US-built would Energomash make any profit on those engines? Depending on how the contracts were written this might happen via royalties paid to Energomash or via Energomash's partial ownership of RD AMROSS. If so I could see a nationalism problem for US-built RD-180s.

I think it depends on how it's done.  Top secret US government satillites are launched on Russian engines with Atlas.  But that's the LV ULA provides, so it's seen as a government payload launching on a commercial rocket. 
If NASA builds the rocket with Russian engines, then maybe there's a perception problem.  But if NASA buys rocket boosters from some company, and they have RD-180's on them, is the "NASA launching on Russian engines"?  Or NASA launching on a ULA made "Super-Atlas V" rocket?

And PWR can always transition to making the RD-180's themselvs if there was a business case to do so.  I believe they bought the liscence to do that.  And make other engines in the family, like the RD-171. 
 

Offline Hyperion5

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Re: How should NASA evolve the SLS?
« Reply #315 on: 03/20/2013 05:52 pm »
If the RD-180 were US-built would Energomash make any profit on those engines? Depending on how the contracts were written this might happen via royalties paid to Energomash or via Energomash's partial ownership of RD AMROSS. If so I could see a nationalism problem for US-built RD-180s.

I think it depends on how it's done.  Top secret US government satillites are launched on Russian engines with Atlas.  But that's the LV ULA provides, so it's seen as a government payload launching on a commercial rocket. 
If NASA builds the rocket with Russian engines, then maybe there's a perception problem.  But if NASA buys rocket boosters from some company, and they have RD-180's on them, is the "NASA launching on Russian engines"?  Or NASA launching on a ULA made "Super-Atlas V" rocket?

And PWR can always transition to making the RD-180's themselvs if there was a business case to do so.  I believe they bought the liscence to do that.  And make other engines in the family, like the RD-171. 

I'm a much bigger fan of powering the boosters with a trio of Aerojet AJ-1-E6 engines.  I just read that an AJ-500 would have some 550,000 lbs of thrust (249,476 kgf), which should see the AJ-1-E6 hit 1.1 million lbs of thrust (498,952 kgf).  Given the increased chamber pressure and decent expansion ratios, such an engine would be nearly as efficient as an RD-180 but have roughly a quarter more thrust at liftoff.  It should also be noted the RD-180 would still have higher chamber pressures (3,868 Psi (266.8 bar) )than its AJ-1-E6 cousin (roughly 3000 Psi (206.8 bar).  I know the RD-180 has proved very reliable, but if I'm NASA, surely a trio of AJ-1 engines per LRB looks safer than a quartet of RD-180 engines. 

If the SLS Bloc II were to use LRBs, I would think the favorite would be the F-1B (due to sheer thrust and reliability), with the RD-180 and AJ-1-E6 coming in behind.  However, if PWR were to create a quad-chamber equivalent to the RD-171M, that might even the odds.  It would have nearly as much lifting power as with the F-1B engines but would be much more efficient, so the payload to LEO would be fantastic.  The only catch is the incredible chamber pressures involved, but if RD Amross can make the RD-180 incredibly reliable, why can't PWR make an RD-171 equivalent reliable?  I'd still go with a pair of F-1B engines, but at least that option wouldn't lose on performance. 

If NASA were to go with F-1B powered LRBs, I think at least a minor renaming would be in order.  I'd at least call it the Saturn Launch System Bloc II, given the use of evolved Saturn V main engines. 
« Last Edit: 03/20/2013 05:53 pm by Hyperion5 »

Offline MP99

Re: How should NASA evolve the SLS?
« Reply #316 on: 03/20/2013 08:23 pm »
RS-68 manrating mods are known and were going to be used for SLS

RS-68 was baselined for Ares V - did you mean that?

I believe the language in PL111-267 pretty much set RS-25 as SLS's engine from the start?

cheers, Martin

Offline RocketmanUS

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Re: How should NASA evolve the SLS?
« Reply #317 on: 03/20/2013 10:19 pm »
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?

Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?
Antares.

Use RD-180's.

That's called Atlas Phase 2, and it's nowhere near as powerful.
(4) RD-180's with a 5.4m diameter stage.

And why should we use Russian engines when we have several perfectly good ones of our own?
What engines in production that do not need to be modified?
I'm looking at less development cost and less time till a possible first flight.
Yes I would have preferred an American made engine.

How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?
No, and you didn't answer the question ( What engines in production that do not need to be modified? ).

If they are going to have the LRB's , then let's have them now and not use the 5 seg SRB's. And if they do go with the LRB's then commercial could use it as a 1st stage for a single stick. If for some reason SLS were canceled then the single stick with common core ( tri-core ) could be a HLV ( back up plan and would not have to restart production of the costly SSME's ).

With the already in production and well proven with great specs RD-180's four of them on each booster would get us at least the 130mt that is required for block II. They could be ready by the wanted 2017 launch and the core made for them.

We already have RS25D's in stock, ready to go.  That's what the core is already designed around, and that's what will work.  That gives us plenty of time to complete follow-on engines if we wish, whether J2-X, which is essentially complete, F1B, which has had the bulk of development work already done via previous iterations, or the RS25-E, which is a fairly minor modification to the current version.

If all you're talking about is replacing the SRB's with RD-180 LRB's, there's no need for that "right now".  We wouldn't be saving any money by tossing out the SRB segments we already have, nor for making a crash program to go to 130 tons of lift when payload development has barely even been considered.

The key word of this thread is "evolve".  Let's get the basic system going, spend the money to make the core operational, and then start shunting money into payload development that will justify the 130 ton vehicle.  That way the true heavy lift capacity and the truly heavy payloads will both be ready in closer to the same time frame.
Limited amount of RS-25D's, will need more for missions if SLS goes past the test flights. Or will have to spend more on developing the RS-25E's.

The boosters and core with RD-180's would be all the same. They are already in production and can always be made in America later if there is a high enough demand for them.

Keep in mind that this is only if they go with the LRB's.

If we stick with the 5 seg SRB's then there is now reason for the advanced boosters, just make more of them. However if they do plan on going to the advanced boosters then let's not waste time with what will not be used for the most part of the possible future mission for SLS. If we switch later then SLS will have to be requalified.

SLS does not need to be evolved, just add the US to it when needed like Direct v3. It needs missions to justify it's development and existence. Block I and block IB can do the job. This 130mt+ just takes the launcher out of reach of the payloads the would fly on a HLV. There is no reason to spend money to make payloads to justify 130mt payloads. There is a limit to the size a launcher can be ( sound, more thrust, more sound, greater distance from populated areas including wild life ).

Offline davey142

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Re: How should NASA evolve the SLS?
« Reply #318 on: 03/20/2013 10:46 pm »
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?

Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?
Wouldn't that negate any cost savings for the RD-180? SLS can't afford any increased cost, especially changing an engine midway through the design. Using them for LRBs could work if an American company modifies them just enough to make it an American derivative, but that means more money!

Offline RocketmanUS

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Re: How should NASA evolve the SLS?
« Reply #319 on: 03/20/2013 10:52 pm »
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?

Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?
Wouldn't that negate any cost savings for the RD-180? SLS can't afford any increased cost, especially changing an engine midway through the design. Using them for LRBs could work if an American company modifies them just enough to make it an American derivative, but that means more money!
Atlas V uses the RD-180's so could LRB's for SLS.

Edit:
Keep in mind I'm only looking at going to the LRB's now if that is what they are going to do later.

I don't believe they can make the advanced SRB's cheaper than the 5 seg SRB's based on history. For LRB's it does have the advantage of engine throttle for lighter payloads , better rides up, ect. over SRB's.

I prefer to just keep the design we have and not go to the so called advanced boosters, just add in the US when needed. between now and 2040 no matter how much funding they could throw at BLEO possible future missions there would only be a few SLS launches that carry crew and they will have an escape system. The rest of the launches would be cargo. Between now and 2040 I don't see NASA sending more than 4 to 6 crewed missions to Mars and perhaps the same for the moon if they go there to test out equipment.
« Last Edit: 03/20/2013 11:01 pm by RocketmanUS »

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