Author Topic: How should NASA evolve the SLS?  (Read 49895 times)

Offline sdsds

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Re: How should NASA evolve the SLS?
« Reply #345 on: 03/24/2013 05:05 AM »
We won't be going to Mars within that time frame. In the meantime, building the rocket such that the core can reach disposal orbit gives maximum versatility to SLS. You can put a chemical EDS atop it for Luna or an EML point. You can assemble components for an asteroid, Phobos rendezvous, or Mars orbit mission and use a chemical EDS. Later, when we want to land on Mars, several assemblies can be put together and flown by SEP tug in sequence. Building the rocket so that it can accommodate all these profiles without the rocket itself needing modifications along the way is the wisest path forward. Payloads change, but the rocket doesn't. Build it once in a manner that will accommodate this full spectrum of missions, then leave the design alone.

I agree with everything you wrote there ... and I believe Boeing does too. They are designing a core that will only be used in a four RS-25 configuration. Configured with 5-seg boosters, a small upper stage (i.e. ICPS) and payload, that core reaches an almost-orbital disposal trajectory and the ICPS sends about 24 tonnes through TLI.

That exact same core, assisted at lift-off by the exact same boosters, but augmented by a larger upper stage, could do much better. With a ~200 tonne upper stage it could put ~45 tonnes through TLI. That's a capability that could be used to great benefit for decades.

When the time comes for a Mars surface mission, one option would be to use the exact same core, maybe with advanced boosters but no upper stage, for an LEOR assembly architecture. But we don't know that will be the architecture chosen. (Just for example, a lunar-derived abundant-chemical architecture with EML assembly might be chosen instead.)

The ~200 tonne upper stage enables a truly flexible path. Advanced boosters ... don't.
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Offline Hyperion5

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Re: How should NASA evolve the SLS?
« Reply #346 on: 03/24/2013 07:10 PM »
We won't be going to Mars within that time frame. In the meantime, building the rocket such that the core can reach disposal orbit gives maximum versatility to SLS. You can put a chemical EDS atop it for Luna or an EML point. You can assemble components for an asteroid, Phobos rendezvous, or Mars orbit mission and use a chemical EDS. Later, when we want to land on Mars, several assemblies can be put together and flown by SEP tug in sequence. Building the rocket so that it can accommodate all these profiles without the rocket itself needing modifications along the way is the wisest path forward. Payloads change, but the rocket doesn't. Build it once in a manner that will accommodate this full spectrum of missions, then leave the design alone.

I agree with everything you wrote there ... and I believe Boeing does too. They are designing a core that will only be used in a four RS-25 configuration. Configured with 5-seg boosters, a small upper stage (i.e. ICPS) and payload, that core reaches an almost-orbital disposal trajectory and the ICPS sends about 24 tonnes through TLI.

That exact same core, assisted at lift-off by the exact same boosters, but augmented by a larger upper stage, could do much better. With a ~200 tonne upper stage it could put ~45 tonnes through TLI. That's a capability that could be used to great benefit for decades.

When the time comes for a Mars surface mission, one option would be to use the exact same core, maybe with advanced boosters but no upper stage, for an LEOR assembly architecture. But we don't know that will be the architecture chosen. (Just for example, a lunar-derived abundant-chemical architecture with EML assembly might be chosen instead.)

The ~200 tonne upper stage enables a truly flexible path. Advanced boosters ... don't.

Just went checking through Chuck Longton's Jupiters and came up with one that would come very close to matching your parameters: http://www.directlauncher.org/documents/Baseball_Cards/J246H-41.5004.08001_EDS_090608.jpg

The Jupiter 246 Heavy is basically the best comparison for your proposal, sdsds.  Its upper stage gross mass is just over 202 mt, and it comes with a fantastic propellant mass fraction of .9324, which tops even that of the S-II on the Saturn V.  I personally think you wouldn't need to have an upper stage quite that heavy to do the job.  The SLS Bloc IB's upper stage, after all, should mass around 120-125 mt, and with the current setup can put at least 43 mt through TLI.  Given the Jupiter 246 Heavy had to make up for 4 engines on a core sized for 3, the elongated SLS core stage should eliminate the need for much of that mass.  I'd guess a maximum size of around 184 mt would do just fine, and with six RL-10B-2 engines should easily top 45 mt through TLI.  I personally though would trim it down to around 160 mt-170 mt to let the core do more of the ascent.  That would be more of an EDS and less of a second stage and should still outperform the Bloc IB to LEO & through TLI. 

---

Fregate and I have been testing engine-out scenarios for engines for another rocket with similar capacity to an SLS Bloc II.  We're pretty sure, given our results, that NASA will not be using RL-10A-4-2 engines on the Bloc IB's upper stage.  Otherwise if they were launching with LRBs and max TLI cargo, losing one of four RL-10A-4-2 engines would see the remainder exceed their maximum burn time.  So in a bit of interesting news, the only RL-10 engine you could currently use on the Bloc IB & Bloc II and have engine-out margin would be the bigger RL-10B-2. 
« Last Edit: 03/24/2013 07:12 PM by Hyperion5 »

Offline Hyperion5

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Re: How should NASA evolve the SLS?
« Reply #347 on: 03/25/2013 03:44 AM »
For Block 1B can the US be 5.5m?

If so then if they choose the LRB's then they could first start them out as the single stick with a (4) RL-10 US ( US to be used then as the SLS US ). Later change the engine mount for a J-2X for greater mass to LEO for the single stick, same tanks for the US.

Btw, I did some checking as to how you could max your LEO figures on a 5.5 meter stage.  Although I profess it would be ridiculously overpowered, you could stuff four J-2S engines, complete with gimbals, into a 5.5 meter stage.  Heck, you might even be able to add a nozzle extension on each one to improve their Isp modestly.  Those engines are only 2.01 meters in diameter after all.  I personally would only use a pair of them to keep things less ridiculous, but they'd give you a huge helping of power out of what is otherwise a modest diameter HLV stage.  A pair or trio of J-2S engines on a super-sized version of the 8.4 m CPS with large nozzle extensions would likely do even better.  It's too bad the J-2S never saw service, because it appears just as well suited, with help from a nozzle extension, as the J-2X. 
« Last Edit: 03/25/2013 03:46 AM by Hyperion5 »

Offline sdsds

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Re: How should NASA evolve the SLS?
« Reply #348 on: 03/25/2013 04:41 AM »
losing one of four RL-10A-4-2 engines would see the remainder exceed their maximum burn time. 

Thank-you for providing your spreadsheet, and for doing the underlying work! Upper stage "engine out" scenarios are clearly important. How NASA will perceive them (if/when SLS gets there) deserves a thread of its own. During portions of the TLI burn where a survivable abort is available, it isn't clear NASA's response to losing thrust from an engine would be to press on with the mission.... That has implications both for the number of engines NASA would want on the SLS upper stage, and also on their thrust, and thus on the propellant capacity of the stage.
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Offline RocketmanUS

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Re: How should NASA evolve the SLS?
« Reply #349 on: 03/25/2013 04:51 AM »
For Block 1B can the US be 5.5m?

If so then if they choose the LRB's then they could first start them out as the single stick with a (4) RL-10 US ( US to be used then as the SLS US ). Later change the engine mount for a J-2X for greater mass to LEO for the single stick, same tanks for the US.

Btw, I did some checking as to how you could max your LEO figures on a 5.5 meter stage.  Although I profess it would be ridiculously overpowered, you could stuff four J-2S engines, complete with gimbals, into a 5.5 meter stage.  Heck, you might even be able to add a nozzle extension on each one to improve their Isp modestly.  Those engines are only 2.01 meters in diameter after all.  I personally would only use a pair of them to keep things less ridiculous, but they'd give you a huge helping of power out of what is otherwise a modest diameter HLV stage.  A pair or trio of J-2S engines on a super-sized version of the 8.4 m CPS with large nozzle extensions would likely do even better.  It's too bad the J-2S never saw service, because it appears just as well suited, with help from a nozzle extension, as the J-2X. 

More than likely they would just go with one J-2X.
If they do go with multiple engines then it might be the NGE.

My point was a possible savings by not launching SLS with 5 seg SRB's if they are not to be used beyond the test flights. Also the boosters could be tested out on the single stick first before having to test them on the SLS with the few RS-25's we have. If a commercial HLV comes about by that time then there could be the human rated single stick to launch the BLEO Orion for a 1.5 launch architecture. This path might offer less waste with a more flexible path forward. By taking advantage of something they are already looking into.

If we don't get the advanced boosters then they will have to look at how they will be able to use the 5 seg SRB SLS blocks for possible Mar mission(s). Also how they will make more 5 seg SRB's.

As we already know, no evolution for SLS until we know what we are planning on launching on it up to 2040 and how many launches are expected up to 2040.
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Offline JohnFornaro

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Re: How should NASA evolve the SLS?
« Reply #350 on: 03/25/2013 11:54 AM »
Hyperion:  Thanks for that spreadsheet.  Special bonus for clear, well paginated formatting.
Sometimes I just flat out don't get it.

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #351 on: 03/25/2013 04:47 PM »
For Block 1B can the US be 5.5m?

If so then if they choose the LRB's then they could first start them out as the single stick with a (4) RL-10 US ( US to be used then as the SLS US ). Later change the engine mount for a J-2X for greater mass to LEO for the single stick, same tanks for the US.

So we could test the boosters out before even launching a SLS.

Would it be possible to use one of the shuttle hangers to process the 1st and 2nd stages of the single core?

So develop the LRB's and US.
Test it out as the single stick.
Then put the boosters on the SLS core for it's first launch.

They say they need seven years to develop the advanced boosters.
That brings us to around 2020. If they delay the first two test flights till 2020 as there does not seem to be any missions for the SLS yet, then they could skip using the 5 segs SRB's that they don't plan on using for the SLS BLEO future missions.

Only an idea.

Edit:
The single stick could test Orion in LEO with a test crew before sending it on later missions BLEO.

Well, SLS Block 1 –will- have a 5m upper stage.  And the core and boosters for Block 1B will be the same as Block 1.  So the answer is “yes”, but then we get into the question about a 5 or 5.5m upper stage of a length to adequately propel the payloads SLS can put into LEO, to BLEO.  The ICPS will obviously be very inadequate for Block 1’s LEO capability.  Much of Block 1’s capability will be wasted on it.  I don’t know how long a 5 or 5.5m upper stage would need to be in order to properly utilize the Block 1 core’s LEO capability, or moreover, the core’s capability with advanced boosters?  If the 5/5.5m upper stage is too long, then the stack ends up being extra long.  And you either will need to encapsulate that payload so it looks like a big version of an Atlas 5xx, or not encapsulate it, and make it structural, so it will look more like the neck-down between the S-II and S-IVB stages on a Saturn V, and keep the PLF to 5/5.5m.  Although you could hammer-head the fairing out so it looks like a scaled up Atlas-4xx. 
Anyway, it will add length to the stack, which means more bending loads, and requiring a stronger core, and PLF or upper stage sidewall. 

But, it might not be too long, I just don’t know.  I’d imagine it’d probably be somewhat undesirable.  I think it would be more feasible on a more medium-heavy sized launcher like J-130.  Something like an ACES-41 would probably have worked pretty good for the J-130, as the J-130 can put the upper stage and payload all the way into disposal sub orbit.
But So, would something like an ACES-71, or ACES-81, or ACES-91, or whatever would be optimized for SLS’s LEO capacity, be too long?

If you were making big LRB’s for SLS with the intention of launching them as stand along LV’s, then I could see the case to be made for a common upper stage core that could have different lengths for SLS vs. booster core, and could mount two or four RL-10’s like ACES.  Might have to go up to RL-60’s depending on how much thrust is needed after the booster 1st stage separation on the stand alone LV.  J2X would be a possibility, but when it’s used on SLS, it wouldn’t need J2X, so designing an MPS that could mount either J2X or RL-10’s would be difficult I think.

I’d probably suggest going with building the Block 1B upper stage now, and launching that 8.4m upper stage on a single booster core (maybe with a partial prop load) and making that your common upper stage.  Especially if there’s no sharing with any other LV other than SLS and the SLS LRB.

But, better than any of that I think, is back to my concept of the FH booster.  Mount two FH’s as SLS boosters.  No need to develop a new upper stage other than the Block 1B stage then.  It can launch and test Orion before putting a crew on the SLS stack.  FH can be a dedicated crew launcher to LEO for Orion as well as being the SLS booster.  (See my other discussion on this.  The FH would act as a single booster even though it has 3 cores.  It’s be treated as a single booster, with the central core interfacing with the SLS core.  The outboard FH boosters would only interface with the FH central core, and thus they wouldn’t know the difference between an SLS launch and a standard FH launch.  The whole FH booster separates from the SLS core together as a single entity.  No crossfeeding obviously). 

And actually something interesting.  If NASA is using FH as an SLS and an Orion crew launcher, FH might be able to get Orion all the way to a Gateway station  by itself.  Not a fully fueled Orion, but Orion doesn’t need to be fully fueled to go to an EMLP.  Because there’s no braking into LLO, or TEI from LLO.  As I understand, breaking a halo orbit at an EMLP requires very little delta V?  If I understand that correctly, the FH could launch a short-fueled Orion to EMLP (there’s about 8mt of SM prop in Orion I believe, so such an Orion might mass as low as around 13mt depending on how much is needed to break halo orbit).  Another option would be to launch fully fueled Orion towards the EMLP Gateway, and let the SM do the rest of the escape burn after the Falcon upper stage has been spent.  Not sure if that would gain anything though, over short fueling Orion and letting the Falcon stage do the whole burn. 

This would be handy for doing other things at the Gateway other than staging for a lunar or NEO mission.  Repairs, refurbishment, extended stays BLEO for research, etc.  A full SLS wouldn’t need to be used to just get a Orion there. 

Offline Hyperion5

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Re: How should NASA evolve the SLS?
« Reply #352 on: 03/25/2013 05:05 PM »

I’d probably suggest going with building the Block 1B upper stage now, and launching that 8.4m upper stage on a single booster core (maybe with a partial prop load) and making that your common upper stage.  Especially if there’s no sharing with any other LV other than SLS and the SLS LRB.

But, better than any of that I think, is back to my concept of the FH booster.  Mount two FH’s as SLS boosters.  No need to develop a new upper stage other than the Block 1B stage then.  It can launch and test Orion before putting a crew on the SLS stack.

Lobo, the engine count we're talking about with two Falcon Heavies mounted onto the side of the SLS is off the charts.  To my knowledge, the highest engine count for simultaneous firing was 30 on the N-1, and that failed spectacularly.  I've seen Mythbusters struggle with simultaneous ignition with just a few dozen fireworks for goodness sakes.  Now imagine trying to fire up some 54 Merlin 1D engines at the same time alongside the four RS-25 engines on the central core.  That's 58 rocket engines going at the same time.  It sounds like an engineering nightmare.  Ed Kyle and Jim are skeptical enough of the Falcon Heavy's design as it is.  Now imagine their reactions if you were their boss and said this was the way forward. 

--

If we're talking a common 8.4 m upper stage for the booster LV & SLS, the RL-10 is not going to be the most ideal.  Even supposing the LRBs had three AJ-1-E6 engines or a pair of RD-170 engines, the booster LV is going to be staging much earlier than the SLS core.  If however we're talking about a quartet of RL-60 engines or NGEs, I'd be more enthusiastic about this common upper stage. 

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #353 on: 03/25/2013 06:14 PM »

I’d probably suggest going with building the Block 1B upper stage now, and launching that 8.4m upper stage on a single booster core (maybe with a partial prop load) and making that your common upper stage.  Especially if there’s no sharing with any other LV other than SLS and the SLS LRB.

But, better than any of that I think, is back to my concept of the FH booster.  Mount two FH’s as SLS boosters.  No need to develop a new upper stage other than the Block 1B stage then.  It can launch and test Orion before putting a crew on the SLS stack.

Lobo, the engine count we're talking about with two Falcon Heavies mounted onto the side of the SLS is off the charts.  To my knowledge, the highest engine count for simultaneous firing was 30 on the N-1, and that failed spectacularly.  I've seen Mythbusters struggle with simultaneous ignition with just a few dozen fireworks for goodness sakes.  Now imagine trying to fire up some 54 Merlin 1D engines at the same time alongside the four RS-25 engines on the central core.  That's 58 rocket engines going at the same time.  It sounds like an engineering nightmare.  Ed Kyle and Jim are skeptical enough of the Falcon Heavy's design as it is.  Now imagine their reactions if you were their boss and said this was the way forward. 


Hyperion,

First, as I understand, none of the N-1’s problems were related to it’s first stage engine ignitions.  If any of the engines had failed to ignite, they all would have been shut down on the pad for an abort.  They all lit, but then developed vibration problems at various points after that which caused engines to fail, shut down, etc.  So I don’t think lighting a large number of engines on the pad is much of a potential problem.  I believe much of the N-1’s problems were because the Soviets couldn’t effectively model the vibration conditions with such a large rocket, or test them comprehensively on stands ahead of time.  And also the N-1 had relatively complex plumbing those 30 engines had that was fragile.  They really just lit their rockets in order to see what they did. 
The FH may have a lot of plumbing, but that will be a proven configuration by the time it would even be considered.

And beyond that, you are looking at this wrong.  You are looking at each engine as it’s own separate rocket.  Like you are building a new monolithic rocket with 58 engines on the first stage.  But instead what you are building is a monolithic core with four engines, and two boosters, each with effectively –one- engine.  As all three cores and all the engines act together as a single booster on a side.  Each engine is no more than a part of that booster just as any other part of that booster is just a part.  A structural element, a panel, a piece of plumbing, etc.  (important pieces, no doublt) 
NASA buys the FH booster because the FH booster has flown X number of times with no major problems and no LOM in 2023 (or whatever time they look at advanced booster).  If the FH has been riddled with problems over many years year, then it wouldn’t be a viable option to even consider.  So this assumes only that if flies, and flies reliable for several years.
You don’t look at the individual engines, or even the individual cores as separate entities.  If an engine doesn’t light on the pad, then the whole stack can be shut down.  If a single engine shuts down in flight, then an engine on the opposite booster is also shut down.  The stack will probably have enough margin that a few engine pairs can go out and still have nominal ascent.   

You look at the tri-core FH booster as a single booster.  It’s reliable, or it’s not.  It can withstand an engine out event, or it can’t.

This is probably better discussed further over here though:

http://forum.nasaspaceflight.com/index.php?topic=31455.0


If we're talking a common 8.4 m upper stage for the booster LV & SLS, the RL-10 is not going to be the most ideal.  Even supposing the LRBs had three AJ-1-E6 engines or a pair of RD-170 engines, the booster LV is going to be staging much earlier than the SLS core.  If however we're talking about a quartet of RL-60 engines or NGEs, I'd be more enthusiastic about this common upper stage. 


Well obviously if the 8.4m upper stage were to be used as a common upper stage, that would be incorporated into it’s design.  Which would include RL-60’s, or NGE’s or whatever, as necessary.  It might even mean that a single J2X is used on both so it could do double duty, even if it isn’t the most ideal for SLS. 
I –think- that’s why the S-IVB had the J2, so that it could do double duty on the Saturn 1B as well.  I don’t think a J2 was necessary for it as the Saturn V’s 3rd stage.  But RL-10’s wouldn’t work on the S-IVB on the Saturn 1B.

Maybe I’m in error on that though. 

RL-60 or MB-60 would probably be the best engine for a double duty 8.4m upper stage though.  As good of ISP as the RL-10, and about the same size, but over twice the thrust.   And that for only double the mass…which is only 0.5mt.  When used as the SLS upper stage, it would only need maybe two RL-60’s.  And then it could mount four when used as a booster upper stage.   It would also mean the booster would launched as a single stick could use the same PLF’s as SLS, as they’d mate with the same upper stage for both LV’s. 

And Maybe with the development of an MB-60 or RL-60, ULA might consider going to it for the EELV’s for cost sharing. 

Offline deltaV

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Re: How should NASA evolve the SLS?
« Reply #354 on: 03/25/2013 08:32 PM »
Let's move discussion of Falcon Heavy as boosters to the thread Lobo just created for that: http://forum.nasaspaceflight.com/index.php?topic=31455.msg0#new .

Offline russianhalo117

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Re: How should NASA evolve the SLS?
« Reply #355 on: 03/25/2013 10:56 PM »
Well obviously if the 8.4m upper stage were to be used as a common upper stage, that would be incorporated into it’s design.  Which would include RL-60’s, or NGE’s or whatever, as necessary.  It might even mean that a single J2X is used on both so it could do double duty, even if it isn’t the most ideal for SLS. 
I –think- that’s why the S-IVB had the J2, so that it could do double duty on the Saturn 1B as well.  I don’t think a J2 was necessary for it as the Saturn V’s 3rd stage.  But RL-10’s wouldn’t work on the S-IVB on the Saturn 1B.
See attached pictures and the included link for detailed information about the three different versions that create the S-IV Stage Family:
Saturn I:
S-IV two versions:
S-IV v1: x6 RL-10-A-1 Flown only on Saturn I Launcher (through flight 3) and Centaur US 15,000 lbf per engine with 425 Isp each
S-IV v1: x6 RL-10-A-3 Flown only on Saturn I Launcher (starting flight 4 through last flight) and Centaur US Thrust was 14,700 lbf per engine with 444 Isp each

Saturn 1A (Designed but never flown):
S-IVA: x4 LR-119 The LR-119 Development Program cancelled in favor of RL-10-A-3. Would have used  LR-119 instead of RL-10-A-1 (Note: LR-115 engine was prototype for original RL-10 and LR-119 engine was a significantly uprated engine and with a complement of four LR-119 engines produced 80,000 pounds of thrust)

Saturn IB/Saturn V:
S-IVB (Saturn 1B): x1 J-2: Stage is nearly identical except for "stage interfaces in different Saturn vehicles required different skirt and interstage designs." Interfaces are completely different, but propellant tanks and engine are the same.

S-IVB (Saturn V): x1 J-2: Stage is nearly identical except for "stage interfaces in different Saturn vehicles required different skirt and interstage designs." Interfaces are completely different, but propellant tanks and engine are the same.

History and the reasoning behind the eventual switch to S-IVB can be found here:
http://history.nasa.gov/SP-4206/ch6.htm

LINK for the entire document can be found here: http://history.nasa.gov/SP-4206/contents.htm

LINK for Chapter 11: Qualifying the Cluster Concept: EARLY BIRDS: BLOCK I AND BLOCK II can be found here: http://history.nasa.gov/SP-4206/ch11.htm

LINK for Chapter 5: Unconventional Cryogenics: RL-10 and J-2 can be found here:
http://history.nasa.gov/SP-4206/ch5.htm

"ORIGINS OF THE J-2 ENGINE
 

Because of the known high-energy qualities of hydrogen as a fuel, modern rocket propulsion engineers manifested a continuing interest in liquid hydrogen as an attractive rocket propellant, able to lift payloads at a very favorable fuel-to-payload ratio. The potential of the liquid hydrogen RL-10 engine was encouraging; nevertheless, designers were thinking ahead of the RL-10's 67 000 newtons (15 000 pounds) of thrust to even heftier propulsion systems. In the fall of 1959, various NASA studies and contracts already included examination of 665 000-newton (150 000-pound) thrust engines, used singly or in clusters, which burned LOX and LH2. When very large space vehicles came into consideration, NASA began to revise its thinking toward even larger LH2-fueled engines for high-energy upper stages-engines rated at 890 000 newtons (200 000 pounds) of thrust. Such a remarkable goal achieved official sanction during the deliberations of the Saturn Vehicle Team, better known as the Silverstein committee, which finished its work and reported its recommendations to NASA on 15 December 1959.23

Following the Silverstein committee's recommendations, a source evaluation board was formed to nominate a contractor. The board included a pair of special teams-a technical evaluation team and a business evaluation team-to examine proposals on two separate levels. [141] Members, who met in Washington for six weeks, were chosen from Marshall, Lewis, and NASA Headquarters. The full board, chaired by MSFC's Hermann Weidner (a Peenemuende veteran and a senior MSFC propulsion engineer), submitted its final recommendation to NASA Administrator Glennan for approval. Glennan made the final announcement. In competition with four other companies, Rocketdyne Division of North American Aviation won NASA's approval on 1 June 1960 to develop a high-energy rocket engine, fueled by liquid oxygen and hydrogen, to be known as the J-2. Specifications for the liquid-hydrogen engine originated at MSFC, and the contractor then went to work on the initial design concepts and hardware. At every step of the way, the contractor and the customer (MSFC) exchanged information and ideas derived from earlier programs, modifying them for the requirements of the LH2 engine technology, and devising new techniques to implement the design goals of the new rocket powerplant.

The final contract, negotiated by Rocketdyne in September 1960, included an especially notable feature. For the first time, a high-energy, high-thrust rocket engine contract specified a design to "insure maximum safety for manned flight." Beginning with the first specifications through the subsequent stages of design, development, and final qualification, planning for manned missions became a mainline theme for Rocketdyne engineers. Other engines in NASA's space program stemmed from propulsion systems engineered for unmanned satellites or ballistic missiles such as the Vanguard, Redstone, Atlas, and Thor. From the start, exceedingly stiff reliability specifications for the J-2 reflected the engine's role in a manned mission. Reliability reviews began at the drawing board stage, and follow-up tests to verify the preceding test and design specifications continued in relentless succession. The technical management organization established to monitor the J-2 development consisted of three major groups. First, the design review board scrutinized each part of the J-2, analyzed it from a technical viewpoint, and investigated all of its design factors. Next, a reliability task force developed statistical methods tailored specifically to proposed test programs for the engine. Finally, all elements dovetailed in the Performance Evaluation and Review Technique (PERT), a reporting system used by the overall program management team.24" (SP-4206 Ch 5)
« Last Edit: 03/26/2013 01:45 AM by russianhalo117 »

Offline HappyMartian

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Re: How should NASA evolve the SLS?
« Reply #356 on: 03/31/2013 01:25 PM »


Well obviously if the 8.4m upper stage were to be used as a common upper stage, that would be incorporated into it’s design.  Which would include RL-60’s, or NGE’s or whatever, as necessary.  It might even mean that a single J2X is used on both so it could do double duty, even if it isn’t the most ideal for SLS. 
I –think- that’s why the S-IVB had the J2, so that it could do double duty on the Saturn 1B as well.  I don’t think a J2 was necessary for it as the Saturn V’s 3rd stage.  But RL-10’s wouldn’t work on the S-IVB on the Saturn 1B.

Maybe I’m in error on that though. 

RL-60 or MB-60 would probably be the best engine for a double duty 8.4m upper stage though.  As good of ISP as the RL-10, and about the same size, but over twice the thrust.   And that for only double the mass…which is only 0.5mt.  When used as the SLS upper stage, it would only need maybe two RL-60’s.  And then it could mount four when used as a booster upper stage.   It would also mean the booster would launched as a single stick could use the same PLF’s as SLS, as they’d mate with the same upper stage for both LV’s. 

And Maybe with the development of an MB-60 or RL-60, ULA might consider going to it for the EELV’s for cost sharing. 




Design the upper stage only one time. Two J-2X engines for the upper stage give engine out capability. 



"While the SLS Block 2 – with advanced Solid Rocket Boosters – is estimated to provide a capability of 130mt to orbit, Dynetics claim that by using the vehicle assumptions for the fully evolved SLS, their proposed booster delivers 150mt, 'providing a 20mt (15 percent) margin, even with a conservative, affordability-focused booster.'"

From: Dynetics and PWR aiming to liquidize SLS booster competition with F-1 power
By Chris Bergin   November 9, 2012
At: http://www.nasaspaceflight.com/2012/11/dynetics-pwr-liquidize-sls-booster-competition-f-1-power/



If you add the margin of "20mt" to the "150mt" "to orbit" you get an SLS with a 170 mt to orbit.

Let's see, that would be about 170,000 kilograms, and that would be about 374,785 pounds or around 187 tons into orbit. 



"Nova's, a group of heavier-than-Saturn V launch vehicles studied by many American aerospace companies and NASA. Some Nova-rockets (most notably Nova C-8, Nova 8L) were intended for direct landing method of lunar exploration like the Saturn C-8, and these rocket-designs were cancelled (like the Saturn C-8) after Saturn V was chosen for the Apollo program. These rockets had payload capacity between 24-75 tons to translunar injection orbit TLI (Saturn V had payload capacity of 45 tons to TLI)."

From: List of space launch system designs
At: http://en.wikipedia.org/wiki/List_of_space_launch_system_designs



The largest Nova rocket noted for Lunar missions:

Saturn V    Encyclopedia Astronautica
At: http://www.astronautix.com/lvs/saturnv.htm 


"Nova N-M1"  with   8 x F-1,   4 x M-1,   1 x J-2        

"180,000" kgs to LEO     "90,000" kgs Escape Payload



The evolved SLS with F-1 powered LRBs could put about 170,000 kgs to LEO and is obviously a powerful Nova class launcher.

As a Nova launcher it might even have more capability to LEO than the "Nova N-M1".

The name Nova sounds good. A Nova launcher could be around for many decades.   


See also:

Nova (rocket)    Wikipedia
At: http://en.wikipedia.org/wiki/Nova_%28rocket%29
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline jamalvender

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Re: How should NASA evolve the SLS?
« Reply #357 on: 04/02/2013 12:32 PM »
According to my information Under NASA, he served as director of the newly formed Marshall Space Flight from the long time. And require far more than applications of the current engineering technology. So I have just enough in my mind.
Have a wonderful day!

Offline Lobo

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Re: How should NASA evolve the SLS?
« Reply #358 on: 04/02/2013 04:35 PM »

"While the SLS Block 2 – with advanced Solid Rocket Boosters – is estimated to provide a capability of 130mt to orbit, Dynetics claim that by using the vehicle assumptions for the fully evolved SLS, their proposed booster delivers 150mt, 'providing a 20mt (15 percent) margin, even with a conservative, affordability-focused booster.'"

From: Dynetics and PWR aiming to liquidize SLS booster competition with F-1 power
By Chris Bergin   November 9, 2012
At: http://www.nasaspaceflight.com/2012/11/dynetics-pwr-liquidize-sls-booster-competition-f-1-power/

If you add the margin of "20mt" to the "150mt" "to orbit" you get an SLS with a 170 mt to orbit.

Let's see, that would be about 170,000 kilograms, and that would be about 374,785 pounds or around 187 tons into orbit. 


I don’t think there’s any doubts that the Dynetics boosters would give more performance than ATK’s advanced boosters.  But careful chasing that pot of gold at the end of the rainbow of the biggest BFR ever. That’s what got NASA into trouble with CxP, and why SLS already is less than economically optimal.

If the ATK advanced boosters get over 130mt, then that will still be the most powerful rocket ever flown, a bit more than the later Saturn V’s.  IT will meet NAA2010 odd and arbritrary mandate, and it –should- much cheaper to develop, build, and implement than the Dynetics booster.  ATK seems to be saying that the advanced boosters will be cheaper to build than the 5-seg booster.  We’ll assume that claim is at least somewhat true, as it’s a newer booster and would be streamlined from the 5-seg’s 40 year old design. 
I don’t know that the design and development would be cheaper than the Dynetics booster, but at least those two should be roughly the same.  And then ATK’s booster will be far cheaper to implement because NASA can use the same SLS ML that Block 1 launches from, where a LRB will likely need a new one.  Also, all of the infrastructure that will already be in place for block 1 should be able to handle the ATK advanced boosters as is, with probably only minor modifications.
All of that makes a pretty strong economics case for the ATK booster, even if it’s not the performer the Dynetics booster is. 






The evolved SLS with F-1 powered LRBs could put about 170,000 kgs to LEO and is obviously a powerful Nova class launcher.

As a Nova launcher it might even have more capability to LEO than the "Nova N-M1".

The name Nova sounds good. A Nova launcher could be around for many decades.   


See also:

Nova (rocket)    Wikipedia
At: http://en.wikipedia.org/wiki/Nova_%28rocket%29

Yea, I always liked “Nova”.  As a Block 2B with ATK advanced boosters would still have capacity in excess of Saturn V, they could call that “Nova” too.  I doubt “SLS” will be trumped by another name, but the Block 2B could get an unofficial nickname of “Nova” or something.

But again, unless the Dynetics booster is going to like replace all of the Atlas and Delta boosters and becomes the USAF/DoD’s sole booster, it will likely only fly on the occasional SLS flight.  Unless NASA were to do [in my opinion] the smart thing and choose SLS advanced booster based on EXISTING and flying booster like the F9, Atlas V, and Delta IV booster threads for shared costs and hardware, then any booster they use will be some expensive, custom, 1-off design with a very low flight rate and high costs.  And if the ATK advanced booster turns out to be a good deal cheaper to produce and implement, then NASA might as well go the “cheapest” expensive custom route. 

Offline RyanC

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Re: How should NASA evolve the SLS?
« Reply #359 on: 04/03/2013 02:16 AM »
Consider that NASA would kind of like to open up space in the VAB again, for all the random stuff that will be using the "21st century spaceport".

Kind of hard to do that with 1,000+ tonnes of explosives in the VAB.

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