What is the best path to a 130 ton (Block II) SLS?

[spectre9]

NASA is being urged to accelerate development of 130 ton configuration.

The 70mt+ SLS will only be used for test flights.

So how should NASA go about this?

Upgrade to 5 engines?

Go with F-1 liquid boosters?

The current plan is 2 flights with 5-seg boosters and 4 flights with the ICPS.

Will NASA have to start work on the upper stage early?

Block 1A/B might not have the performance to meet the mandate.

[MATTBLAK]

NASA should only build either the 70 metric ton version or the full 130 ton version - they shouldn't mess with in-between.

(This could potentially be a very interesting thread! But: I'm really afraid that a few posts after this, someone will be mentioning the 'Elephant in the Room' - this fine website (I believe the best of its type) nonetheless has some very active SLS-haters who will invade every thread about it, push it off course and end up causing it to be locked).
**************************************************************************

I'm certainly willing to stay on topic including - hopefully - the kind of payloads and missions the 130 ton Block II version would be best for.

[MATTBLAK]

I think they'll always keep to a 4 engine Core. Since lightweight Alum/Lith is now out of the question, future upgrades might have to include the RS-25's capable of '114 or 115%' percent thrust and advanced boosters of the ATK all-composite type or the liquid boosters.

The cheapest (there probably is no 'best' - you're asking for an argument around here) way to get close to the 130 ton mark is to use 5 meter Delta IV tooling for the liquid boosters. And the engines? It remains to be seen which would be cheaper, development cost wise: Clustered Aerojet AJ26-500s or pairs of PWR F-1Bs. The cheapest upper stage might be a stretched Delta IV upper stage with 2x RL-10s - the current one only uses 1x engine and other alternatives might be 2x MB-60s instead.

I only didn't mention the J-2X for budgetary reasons - it would require an all-new stage and I doubt that engine could just 'drop in' to another existing stage. If there had to be a budgetary 'sacrificial lamb' for SLS - I vote the J-2X and its unique stage.

Now; I'm not qualified to (accurately) crunch the numbers for the various configs but can anyone else around here do that?

1# - SLS 4x RS-25 corestage with 2x ATK 'black' composite SRBs & twin engined Delta IV upper stage (2x RL-10B2)
2# - As above, but with 2x MB-60s in upper stage.
3# - SLS with 2x liquid boosters; each with 4x AJ26-500 engines and 2x RL-10B2 upper stage.
4# - As above, but upper stage with 2x MB-60s.
5# & 6# - SLS with liquid boosters powered by 2x F-1B and the two upper stage engine options.

'Rocket Lego' - here we go again!!

[Hyperion5]

I think they'll always keep to a 4 engine Core. Since lightweight Alum/Lith is now out of the question, future upgrades might have to include the RS-25's capable of '114 or 115%' percent thrust and advanced boosters of the ATK all-composite type or the liquid boosters.

The cheapest (there probably is no 'best' - you're asking for an argument around here) way to get close to the 130 ton mark is to use 5 meter Delta IV tooling for the liquid boosters and the engines? It remains to be seen which would be cheaper, development cost wise: Clustered Aerojet AJ25-500s or pairs of PWR F-1Bs. The cheapest upper stage might be a stretched Delta IV upper stage with 2x RL-10s - the current one only uses 1x engine and other alternatives might be 2x MB-60s instead.

Cheapest is probably a Bloc IB SLS upgraded with advanced SRBs, though if you're looking for the cheapest long-term operating costs and cost per kg to orbit, you'd be hard-pressed to beat a Bloc IB upgraded to Bloc II with a pair of F-1B boosters.  The stack would be much lighter, it wouldn't require any special handling, and you wouldn't have to worry about the mandate.  A Bloc II like that would put up 155 mt into LEO, and even advanced SRBs should get you to 133 mt into LEO at a minimum.  It looks to me like it will only take NASA a pair of upgrades to meet the mandate, so I'm not too worried.  I'd prefer a pair of LRBs, because that'd give handling and performance bonuses, but you can meet the mandate with only two upgrades even with ATK's composite SRBs (see Chris' story and thread on "Black Knights"). 

I only didn't mention the J-2X for budgetary reasons - it would require an all-new stage and I doubt that engine could just 'drop in' to another existing stage. If there had to be a budgetary 'sacrificial lamb' for SLS - I vote the J-2X and its unique stage.

Already been sacrificed according to another poster and a Boeing report, or at least the two J-2X 2nd stage below the upper stage.  The Bloc II SLS as it stands right now is envisioned as a Bloc IB (four RL-10 engine upper stage upgrade of Bloc I) with more powerful advanced boosters.  Only the Bloc IIA SLS is envisioned with a single J-2X engine upper stage, and with a pair of F-1B engines and the Bloc I SLS core, you can fling up 178 mt into LEO.  The catch is that it isn't as capable in BEO flight compared to a Bloc II SLS with the same boosters and the IB's upper stage.  J-2X only gets you to 58 mt through TLI compared to 61 mt with the other upper stage. 

Now; I'm not qualified to crunch the numbers for the various configs but can anyone else around here do that?

1# - SLS 4x RS-25 corestage with 2x ATK 'black' composite SRBs & twin engined Delta IV upper stage (2x RL-10B2)
2# - As above, but with 2x MB-60s in upper stage.
3# - SLS with 2x liquid boosters; each with 4x AJ26-500 engines and 2x RL-10B2 upper stage.
4# - As above, but upper stage with 2x MB-60s.
5# & 6# - SLS with liquid boosters powered by 2x F-1B and the two upper stage engine options.

'Rocket Lego' - here we go again!!

Boeing's way ahead of you on some of this.  I summed up their report on currently envisioned SLS variants here: http://forum.nasaspaceflight.com/index.php?topic=30554.180

Here's another summary for everyone:

SLS Bloc I
Core Stage (4 SSMEs)+iCPS (Modified Delta IV 2nd stage with 1 RL-10B-2)
Payload to LEO: 70 mt (Ed Kyle's estimate: 90 mt)
BEO Payload: 19 mt
Year available: 2017

SLS Bloc IA
Core Stage+advanced boosters (appears to be LRBs)-upper stage
Payload to LEO: 105 mt
BEO Payload: 0 mt
Year available: 2022 (if advanced booster program is funded)

SLS Bloc IB
Core stage+8.4 m CPS (8.4 m stage with four RL-10 engines)
Payload to LEO: 118 mt
BEO Payload: 43 mt
Year available: 2019 (if upper stage is funded)

SLS Bloc II
Core stage+8.4 m CPS (from Bloc IB)+advanced boosters (LRBs)
Payload to LEO: 155 mt
BEO Payload: 61 mt
Year available: 2022 (if boosters+CPS are funded)

SLS Bloc IIA
Core stage+8.4 m J-2X stage+advanced boosters (LRBs)
Payload to LEO: 178 mt
BEO Payload: 58 mt
Year available: 2027 (if boosters+J-2X stage funded)

[TomH]

I think any upper stage needs to be solely an Earth Departure stage (whose mass is included in the 130 mT "payload"). The core needs to reach a V which requires nothing more of the "payload" than a circularization burn. A 5th RS-25 may burn through the HydroLox too fast and require a US burn to reach LEO. This almost certainly requires use of J-2X. It would seem to this rank amateur that the best way to reach LEO is a 4 engine core with the Dynetics boosters. Now, any US is strictly for Earth departure and can employ an RL-10 variant. With little gravity loss to fight, number of engines (and engine mass) is kept down while ISP is high.

It would seem that any other path is somehow going to require either two upper stages (2nd to reach LEO and 3rd as Earth departure) OR use of a second stage whose 1st burn contributes significant ΔV to reach parking orbit and whose 2nd burn is for Earth departure (much like S-IVB on Saturn V). The thing is, both of these scenarios require J-2X and neither takes full advantage of RS-25's qualities as a sustainer all the way to orbit.

Since advanced boosters are going to be required anyway, it just seems logical to get the maximum total thrust possible out of boosters by going Dynetics 5.49 m dual F-1B, get that 130 mT to LEO with nothing more than boosters and 4 engine core, then have a single US whose sole purpose is as EDS and which can let RL-10 do what it does best-depart LEO yet not have to assist in reaching LEO. J-2X is not used.

If components are to be assembled @ LEOR, the US will not always be part of the stack. Let's say the 1st phase of a Mars mission is being assembled; that unmanned assembly may then be sent on slow departure via SEP, prior to later manned portion of the mission.

[MATTBLAK]

So foregoing an 8.4 meter EDS all together; would a 'Super-stretched' Delta IV upper stage holding 45-50 metric tons of propellant and powered by a pair of RL-10B2 or MB-60 engines be good enough to a 35-40 metric payload BEO?

[93143]

Why RL-10?  By the time CPS flies, won't the Air Force have switched to the NGE?

[MATTBLAK]

Well I really hope so - but with budget cuts and delays, I'm hedging my bets against it not coming to pass. I only mentioned the Mitsubishi MB-60 because it has similar thrust levels, performance and was mostly developed (like the RL-60).

[hkultala]

I think they'll always keep to a 4 engine Core. Since lightweight Alum/Lith is now out of the question, future upgrades might have to include the RS-25's capable of '114 or 115%' percent thrust and advanced boosters of the ATK all-composite type or the liquid boosters.

The cheapest (there probably is no 'best' - you're asking for an argument around here) way to get close to the 130 ton mark is to use 5 meter Delta IV tooling for the liquid boosters. And the engines? It remains to be seen which would be cheaper, development cost wise: Clustered Aerojet AJ26-500s or pairs of PWR F-1Bs. The cheapest upper stage might be a stretched Delta IV upper stage with 2x RL-10s - the current one only uses 1x engine and other alternatives might be 2x MB-60s instead.

'Rocket Lego' - here we go again!!

2 RL-10's is too little thrust to be as an upper stage for reaching orbit for such big rocket.

It the upper stage has to do 2km/s impulse,
accelerating just 130 tonne payload + means it would have to be accelerating for 1182 seconds = 19 minutes just to accelerate the payload. But it also has to accelerate itself and the initial fuel(more than 60 tons to have enough fuel for such long burn), so it becomes something like 27 minutes.

So the gravity losses would be terrible, and might be too bad that it might not reach orbit. Such weak second stages only work for really small orbit circularization burn and as EDS stage.

It the upper stage only had 1km/s job to do, then it would still need something like 13 minutes burn with 2 RL-10's.

[MATTBLAK]

That's all true. So we're back to the MB-60 or RL-60 again. I doubt that 4x RL-10 would fit on the 5 meter Delta IV upper stage without major redesign, taking it into clean-sheet territory.

[Ben the Space Brit]

That's all true. So we're back to the MB-60 or RL-60 again. I doubt that 4x RL-10 would fit on the 5 meter Delta IV upper stage without major redesign, taking it into clean-sheet territory.

Four RL-10B-2s could fit on an 5.4m-diameter ACES stage, so four of the smaller (and crew-rated) A-4s should definitely fit on the 5.1m-diameter DIVHUS.  There would probably have to be a modest tank length stretch, though.

[RotoSequence]

NASA is being urged to accelerate development of 130 ton configuration.

They are? Do you have a link?

[ChileVerde]

NASA is being urged to accelerate development of 130 ton configuration.

They are? Do you have a link?

Not to step in for spectre9, but

http://spaceref.com/news/viewsr.html?pid=43563

Explanatory Statement for the Senate Substitute Continuing Resolution (NASA Excerpts)

    Source: Senate Appropriations Committee
    Posted Tuesday, March 12, 2013

<snip>

SLS vehicle development.-- Support for NASA's evolvable SLS development approach, which will provide a 70 ton SLS configuration by 2017 and build to a 130 ton configuration as work is completed on an upper stage and advanced booster system, is reiterated. However, NASA is urged to identify and implement ways to accelerate the schedule for the attainment of the 130 ton configuration. To enable better congressional oversight of NASA's progress, language from the House report regarding requirements for quarterly SLS funding reports is adopted by reference.

<snip>

Further discussion of this is probably best done on the politics forum, where I think I'll start a thread about it.

[spectre9]

http://forum.nasaspaceflight.com/index.php?topic=28750.msg1025223#msg1025223

It's in the CJS statement. This thread is just to discuss the hardware.

NASA might be forced to redesign their block upgrade path.

I say just go for LRBs from the start but they might want to upgrade to 5 engines early to make sure advanced solids can meet the performance requirements.

Once you start using more and more engines you become less efficient than a RAC2 (Saturn V) style vehicle which is what I don't like.

[Lobo]

NASA is being urged to accelerate development of 130 ton configuration.

The 70mt+ SLS will only be used for test flights.

So how should NASA go about this?

Upgrade to 5 engines?

Go with F-1 liquid boosters?

The current plan is 2 flights with 5-seg boosters and 4 flights with the ICPS.

Will NASA have to start work on the upper stage early?

Block 1A/B might not have the performance to meet the mandate.

Hyperion5 beat me to it and stole my thunder.  But X2 on all he said!  Well said Hyperion.  To the performance options he listed at the bottom, add a Block II with ATK advanced SRB’s at about 133mt to LEO.

Block 1 will be over 90mt, not 70mt like they are “officially saying”.  Take a look at LV26 and LV27 studied under ESAS.  LV26 is the crew+cargo version, and was rated at 91.3mt to 28.5 deg inc.  And LV27 was the cargo only version rated at 96.7mt to 28.5 deg. Inc.  They both have four RS-25’s on stretched cores with 5-seg SRB’s.  Neither has the iCPS though, they basically do the full insertion burn with the core I’m assuming, or they assume the payload does the circ burn. With the ICPS doing a bit of the ascent burn, it might actually improve the full LEO payload closer to the 100mt side of that range.

Because of Block 1’s real performance, I’m assuming that’s why Boeing is stating Block 1B’s real performance will be 118mt.  ATK’s advanced solids supposedly will add about 15mt to the LEO capacity of SLS,  That puts that “Block II” capacity at 133mt at least.  And there you are.

So what will “Block II” look like?  I’m over 90% sure Block II will be Block 1B with the single upgrade of advanced boosters over the defunct 5-seg SRB’s (defunct because the equipment doesn’t exist any more to make more casings.)  This has a lot of advantages I think NASA is realizing over their current PoR Block II, which I think will be axed as soon as NASA gets around to formally announcing their new official plans. 
Four RS-25’s on the stretched core means the core can fly all the way to orbit.  Adding a 5th RS-25 means you need the upper stage to do a large part of the ascent.  Which basically negates the advantage of using a hydrolox sustainer stage, which is to make it basically a ground lit 2nd stage.  Putting too many engines on it and needed a large 2nd stage powered with J2X engines to get to LEO just blows out the advantages of that system.  Might as well scrap the boosters entirely and make the 8.4m core kerolox with new F-1 engines if you are going to have a J2X powered 2nd stage.  Be more simple and probably cheaper than the current PoR Block II.  So use the system as it was meant to be used.  And I think they are seeing that out now.
That means the core MPS doesn’t need redesigned for the 5th RS-25…which is a decent savings.  That also means the J2X powered new large upper stage is deleted completely.  Which is a substantial savings.  It also means the core designed for block 1B loads should be able to handle the block II loads because the stack wont’ be any taller.  I’ve heard they are designing the core from the start with at least the Block 1B loads in mind.  And that, that might be able to handle Block II loads as well, if the stack isn’t any longer.  Which it shouldn’t be…or at least not much.  The PLF might be a little longer.  But who knows?  Maybe NASA it throwing in some margin into Block 1B so that it will also handle the extra loads of Block II payload mass and a little longer PLF.  If they really want to add advanced boosters to Block 1B, that would make sense.

I like LRB’s, but since ATK’s advanced solids will get this “Block II” over 130mt, I really don’t see how they aren’t chosen over brand new LRB’s.  They’ll basically be drop in replacements, so all of the equipment and infrastructure that will be there to handle the 5-segs can stay in place.  They’ll be able to use the existing SLS ML, where LRB’s will require a new ML (so I’ve heard).  So unless ATK just goes nuts on their proposed costs, I don’t see how they don’t get chosen just from the existing infrastructure cost savings.
But who knows.  Certainly a pair of Dynetics boosters bringing back the old F-1’s again get me excited.  I just think they’d have to come in dirt cheap to really look better than advanced solids.  And I don’t know how you can make a brand new 5.49m booster with two quasi-brand new liquid engines each for super cheap.  But I wish them luck.

[newpylong]

Well said!

[RyanC]

I only didn't mention the J-2X for budgetary reasons - it would require an all-new stage and I doubt that engine could just 'drop in' to another existing stage. If there had to be a budgetary 'sacrificial lamb' for SLS - I vote the J-2X and its unique stage.

Not really. We already have a large diameter 8.4m hydrolox stage -- the SLS Core Stage. Design a shortened version that uses J-2X.

Results: we use the SLS CS tooling to produce not one, but two stages. Everyone is happy.

[TomH]

I only didn't mention the J-2X for budgetary reasons - it would require an all-new stage and I doubt that engine could just 'drop in' to another existing stage. If there had to be a budgetary 'sacrificial lamb' for SLS - I vote the J-2X and its unique stage.

Not really. We already have a large diameter 8.4m hydrolox stage -- the SLS Core Stage. Design a shortened version that uses J-2X.

Results: we use the SLS CS tooling to produce not one, but two stages. Everyone is happy.

The question remains whether this 8.4 m US is going to be placed in near LEO by the core or whether a significant burn by this stage is required to reach parking orbit.

If this stage requires a significant first burn to reach parking orbit, that requires J-2X. The RS-25s are not used to their full advantage as sustainers. The second J-2X burn for Earth departure does not have the best ISP and a high mass engine is absorbing more of the thrust than an RL-10 variant.

If this second stage attains significant V from the core, the US engine needs only to do a circularization burn and an Earth departure burn, thus an RL-10 variant is a much better engine.

Any US which by itself is designed to contribute significant ΔV to LEO and then do an Earth Departure burn is an US that is not able to contribute to component assembly via LEOR. The S-IVB version used on Saturn V worked well for the LOR approach. It would not have worked so well in an EOR approach. What do you do with several half fueled H2 upper stages?

The SLS core needs to be able to accelerate everything stacked above that core to almost orbital V; the core falls into the ocean and a small circularization burn stabilizes the payload. This way, a dedicated US with high ISP/low mass (RL-10 variant) engine could provide the ΔV for a single stack lunar mission, while for LEOR component assembly the stage is not utilized.

I am no rocket scientist, yet from my POV, it seems that J-2X provides no utility in a scheme that also involves EOR assembly.

[Lobo]

I only didn't mention the J-2X for budgetary reasons - it would require an all-new stage and I doubt that engine could just 'drop in' to another existing stage. If there had to be a budgetary 'sacrificial lamb' for SLS - I vote the J-2X and its unique stage.

Not really. We already have a large diameter 8.4m hydrolox stage -- the SLS Core Stage. Design a shortened version that uses J-2X.

Results: we use the SLS CS tooling to produce not one, but two stages. Everyone is happy.

The question remains whether this 8.4 m US is going to be placed in near LEO by the core or whether a significant burn by this stage is required to reach parking orbit.

If this stage requires a significant first burn to reach parking orbit, that requires J-2X. The RS-25s are not used to their full advantage as sustainers. The second J-2X burn for Earth departure does not have the best ISP and a high mass engine is absorbing more of the thrust than an RL-10 variant.

If this second stage attains significant V from the core, the US engine needs only to do a circularization burn and an Earth departure burn, thus an RL-10 variant is a much better engine.

Any US which by itself is designed to contribute significant ΔV to LEO and then do an Earth Departure burn is an US that is not able to contribute to component assembly via LEOR. The S-IVB version used on Saturn V worked well for the LOR approach. It would not have worked so well in an EOR approach. What do you do with several half fueled H2 upper stages?

The SLS core needs to be able to accelerate everything stacked above that core to almost orbital V; the core falls into the ocean and a small circularization burn stabilizes the payload. This way, a dedicated US with high ISP/low mass (RL-10 variant) engine could provide the ΔV for a single stack lunar mission, while for LEOR component assembly the stage is not utilized.

I am no rocket scientist, yet from my POV, it seems that J-2X provides no utility in a scheme that also involves EOR assembly.

I think Block 1B is pretty much going with four RL-10’s.  Boeing looked at J2X on the Block 1B stage, but basically made the argument that four RL-10’s was better from pretty much every direction.  Lead time, cost, performance, etc. 

Like you said, the RS-25’s are great engines with great vacuum performance.  Let them do the work for as long as they can.  Just do the last little bit of the ascent with the Block 1B stage after dumping the core is disposal orbit, around the same place the Shuttle dumped the ET.  Four engines are optimal for that with the stretched core, where three engines would have been for an ET-sized core.  That’s how you take advantage of those expensive but high performance RS-25 engines and the whole sustainer stage concept. 
Which is why I never understood Ares V/LV27.3, the official SLS Block II PoR, or anything that doesn’t allow the core to put everything above it into LEO in a sustainer stage type LV using RS-25’s.

[93143]

The question remains whether this 8.4 m US is going to be placed in near LEO by the core or whether a significant burn by this stage is required to reach parking orbit.

Note that the LEO payload of the Block 1B is quoted as 118 tonnes, more than 20 tonnes higher than Block 1.  So evidently the upper stage is at least capable of burning to orbit if the payload on top is heavy enough to warrant it.

DIRECT's JUS was far too heavy for the core to put it in orbit even with nothing on top.  The result was a larger payload through TLI (in DIRECT's two-launch architecture) than could have been achieved with an in-space stage launched on a J-130.

[Lobo]

The question remains whether this 8.4 m US is going to be placed in near LEO by the core or whether a significant burn by this stage is required to reach parking orbit.

Note that the LEO payload of the Block 1B is quoted as 118 tonnes, more than 20 tonnes higher than Block 1.  So evidently the upper stage is at least capable of burning to orbit if the payload on top is heavy enough to warrant it.

DIRECT's JUS was far too heavy for the core to put it in orbit even with nothing on top.  The result was a larger payload through TLI (in DIRECT's two-launch architecture) than could have been achieved with an in-space stage launched on a J-130.

Yea, ultimately, I think I liked that better.  Three RS-25's on the J-130 core means the core could burn all the way to orbit, maximizing the benefit of the sustainer core with higher performance sustainer engines platform.
By putting four RS-25's on it, the core emptied long before it got to orbit, requiring the JUS to need a good deal of thrust.

I think even a better way to go than Direct 3.0, would have been J-130 only, then a CPS/EDS.  Or rather, use an encapsulated 5m common Centaur (ACES/WBC/etc, perhaps stretched to maximize J-130's lift capacity with the shorter version used for the EELV fleet) from ULA for each J-130 launch and go with a two launch LOR architecture.  Probably not quite as efficient as a larger CPS on one launch and the CSM and lander on the other launch for EOR.  But it would save the need for development of a new 8.4m upper stage and create synergy with EELV's.  And I think that's an advantage.
Also, (if I understand comments by the Direct guys correctly) J-130 didn't need any core strengthing from the ET.  Basically it was just an ET with a new LOX dome and MPS.  The rest was the same.  But the J-246 need core strengthening for the greater mass on top than the ET design could support.
Which means the J-130 could have been developed cheaper and faster, with no need for the thicker J-246 core, or the JUS. 

[RocketmanUS]

.
{snip}
Which is why I never understood Ares V/LV27.3, the official SLS Block II PoR, or anything that doesn’t allow the core to put everything above it into LEO in a sustainer stage type LV using RS-25’s.

Interesting.

Core with (3) RS-25's with 130mt payload on top ( no US ).
Boosters to do the extra needed work at launch so the core can take the payload all the way to orbit.

Now if the could have gone that way with LRB's then with throttle engines it could have launched less mass to with low enough g's. Possible the boosters could have launched with less engine on them when the stack was launched with less payload mass.

So with an 8.4m core could they have been able to make boosters that could have done the job and still fit the MLP and VAB?

So for the thread title only.
Block I.
Block IB ( add RL-10 US )
Block IB later with new boosters.

Now that is with the thread title, only if we find that we need the 130mt capacity or greater should we go with the new advanced boosters. The best path to 130mt is only if we needed the capacity.

Edit:
https://info.aiaa.org/Regions/SE/HSV_AIAA/Downloadable%20Items/AIAA-Chilton_18Oct2012_Final2.pdf

page 19.
Quote:
Advanced boosters require significant funding and ~7 years for development (including 30 month study phase)

[Lobo]

.
{snip}
Which is why I never understood Ares V/LV27.3, the official SLS Block II PoR, or anything that doesn’t allow the core to put everything above it into LEO in a sustainer stage type LV using RS-25’s.

Interesting.

Core with (3) RS-25's with 130mt payload on top ( no US ).
Boosters to do the extra needed work at launch so the core can take the payload all the way to orbit.

Now if the could have gone that way with LRB's then with throttle engines it could have launched less mass to with low enough g's. Possible the boosters could have launched with less engine on them when the stack was launched with less payload mass.

So with an 8.4m core could they have been able to make boosters that could have done the job and still fit the MLP and VAB?

So for the thread title only.
Block I.
Block IB ( add RL-10 US )
Block IB later with new boosters.

Now that is with the thread title, only if we find that we need the 130mt capacity or greater should we go with the new advanced boosters. The best path to 130mt is only if we needed the capacity.

Edit:
https://info.aiaa.org/Regions/SE/HSV_AIAA/Downloadable%20Items/AIAA-Chilton_18Oct2012_Final2.pdf

page 19.
Quote:
Advanced boosters require significant funding and ~7 years for development (including 30 month study phase)

yea, an ET/Jupiter sized core with three RS-25's can put a payload in orbit, or rather, in disposal orbit.

The SLS core is stretched so that it can feed four RS-25's to the same disposale orbit.

If an ET/Jupiter sized core were strengthend to support 130mt on top, and have powerful enough boosters, and had three RS-25's, then it should be able to put 130mt into LEO.  Liquid boosters help in this as they burn for longer and have better ISP than solids. 

Three RS-25's produce as much or more thrust and ISP as the five J2's on the S-II stage, and the S-II stage was pushing towards 130mt to LEO. So after booster separation, they should have enough power to push that much payload further up, and then enough ISP later to get to disposal orbit.

The boosters might need to be throttled as well as the RS-25's if there's any g-loading issues.  But most kerolox boosters no can throttle down to at least 70%.

But yea, that configuration could have worked.  AJAX was something like that.  I can't remember if Downix had 3 or 4 RS-25's on the core, but with 8 Atlas V boosters, I believe he said the core could get 130mt into LEO without needing an upper stage.

Two 5.4m wide kerolox boosters with four RD-180's on them each could probably do about the same or a bit better because of the larger single boosters.  Although thrust would be about the same as the Dynetics boosters, they have better ISP.  So they should be able to do about the same even with the non-stretched core.

[JohnFornaro]

There's no question at all that a 130 ton launch vehicle would be more capable than a 70 ton vehicle.

The country, as a family, plans on buying a car and an RV, theoretically to go on a long east coast to west coast vacation.  Dad sez that they're not going to drive down the east coast from DC to Florida, because they went to Disney World forty years ago.   Some of the family members are intent upon getting the biggest RV on the lot; it would require purchasing an F-450 in order to tow it.  There's no money for the RV at all, and they'd have to wait for a decade or morre before the F-450 is actually manufactured and ready to sell.

Some of the younger members of the family think that the family should just purchase an F-150, which will tow a pretty good sized RV itself, and allow a fair amount of money to be left over to spend when they get to the west coast.  The F-150 will be ready to purchase in just a few years, and cost a good bit less.  So would the smaller RV.

The younger members of the family remember how much fun it was going to Disney World the first time, even tho all they had was Chevy station wagon and a pop up camper.  Not only that, but with a new F-150 and a new RV, they could stay in Florida for a while, maybe get jobs picking oranges, and save up the money to pay for the gas to go to the west coast.  They could get two vacations that way.

The older members of the family insist that the younger members just shut up.

[Lobo]

There's no question at all that a 130 ton launch vehicle would be more capable than a 70 ton vehicle.

The country, as a family, plans on buying a car and an RV, theoretically to go on a long east coast to west coast vacation.  Dad sez that they're not going to drive down the east coast from DC to Florida, because they went to Disney World forty years ago.   Some of the family members are intent upon getting the biggest RV on the lot; it would require purchasing an F-450 in order to tow it.  There's no money for the RV at all, and they'd have to wait for a decade or morre before the F-450 is actually manufactured and ready to sell.

Some of the younger members of the family think that the family should just purchase an F-150, which will tow a pretty good sized RV itself, and allow a fair amount of money to be left over to spend when they get to the west coast.  The F-150 will be ready to purchase in just a few years, and cost a good bit less.  So would the smaller RV.

The younger members of the family remember how much fun it was going to Disney World the first time, even tho all they had was Chevy station wagon and a pop up camper.  Not only that, but with a new F-150 and a new RV, they could stay in Florida for a while, maybe get jobs picking oranges, and save up the money to pay for the gas to go to the west coast.  They could get two vacations that way.

The older members of the family insist that the younger members just shut up.

What???

[TomH]

What???

It's an allegory about NASA's previous manned deep space program and our current discussion regarding the same. Every aspect of his allegorical tale has an analogue in the discussions of the path forward re. Manned exploration of deep space.

[llanitedave]

I think the Saturn V was somewhat better than the analogous old Chevy and pop-up camper.

[Lobo]

What???

It's an allegory about NASA's previous manned deep space program and our current discussion regarding the same. Every aspect of his allegorical tale has an analogue in the discussions of the path forward re. Manned exploration of deep space.
[/quote]

I know, he just went so far with it, that I think it lost it's point and sounded like he was actually trying to figure out how to take his family camping...

heheheh

[Robotbeat]

fix quotes

[Lobo]

There's no question at all that a 130 ton launch vehicle would be more capable than a 70 ton vehicle.

The story about you taking your family camping aside...  ;-)

I never said they should or needed to make the more capable 130mt vehicle.  Just that you could with an ET sized core I think.  Which was a reply to Rocketman's post. 

REad back farther, and you'll see where I advocate going with just two J-130's, and skipping the JUS development entirely, and going with a common EELV upper stage (stretched) for them for synergy and cost sharing. 
In a perfect world, I'd go one better.  Replace the SRB's entirely with a pair of Atlas V's on each side.  Similar if not better performance, and more cost sharing and synergy with EELV's.  NASA is only responsible for maintaining the J-130 core itself.  Everything else they just buy as needed.

Or, go with one upgraded core, that could mount 4-8 Atlas V boosters, and still have the three RS-25's on the core.  That could put 70-130mt to LEO depending on what was needed. (AJAX) The core would need to be strengthend for the heavier configurations, but really if that was done up front, it wouldn't cost any more to develop and make than a J-130 core. 

Either option would have been much more flexible and cheaper in the long run than CxP or SLS. 

[Hyperion5]

I think the Saturn V was somewhat better than the analogous old Chevy and pop-up camper.

I would think the Saturn V should have been analogous with a Corvette at the very least, though I think a Ferrari California is the best analogy.  Expensive, beautiful, rare and very high performance, and like the Apollo missions, it even has two modes of transport, top down and top up. 

---

So with an 8.4m core could they have been able to make boosters that could have done the job and still fit the MLP and VAB?

A pair of F-1B boosters some with maximum length & width in dimensions (I believe the figures were 70 meters & 5.5 meters in width) should fit and pretty much have no problem getting the SLS up to 130 mt to LEO.  You'd probably have to do a few modifications to the MLP, but nothing too extraordinary.  I'd be curious if the Air Force might consider those Dynetic boosters for replacing the Delta IV Heavy.  Of course that'd be yet another rocket chasing after the same number of payloads, so that might not pay off.  Anyone know what an F-1B is likely to cost?  I've heard the Russians are selling PWR RD-180 engines at a price of $10,000,000 per, so how would a US-built F-1B compare in price & price per kN? 

So for the thread title only.
Block I.
Block IB ( add RL-10 US )
Block IB later with new boosters.

Now that is with the thread title, only if we find that we need the 130mt capacity or greater should we go with the new advanced boosters. The best path to 130mt is only if we needed the capacity.

Well if the goal is a manned flight to Martian orbit some day, I'd say yes, absolutely we need the new advanced boosters.  If however the goal is flinging people over to an EML-2 space station or down to the lunar surface, I'd say the SLS Bloc IB is up to the task.  If anyone's ever seen the various imagined Mars Transfer Vehicles thought up by NASA, they all have one thing in common: they're enormous.  I believe the last time NASA showed how such a mission might look, it took three Ares V flights just to put the thing into orbit.  But at least an MTV would be reusable, which is more than anyone could say for our Apollo hardware.  The landers for crew and equipment also have to be quite big, given the mission length, Mars having more gravity than the moon, and the need for both propulsion and aero-braking/heat shield elements.  This is why Elon Musk is talking about rockets with a minimum 7 meter core and a capability ranging from 150-200 mt to LEO as being necessary for colonizing Mars. 

[JohnFornaro]

I think the Saturn V was somewhat better than the analogous old Chevy and pop-up camper.

I didn't say it was old.  Was thinking of the 1969 Chevy Impala wagon, which had an "available" 425 hp V-8.  Top o' the line in its class.

I stand by the analogue of the pop up camper and the Apollo lander, even tho the camper did have thicker aluminum...

[JohnFornaro]

There's no question at all that a 130 ton launch vehicle would be more capable than a 70 ton vehicle.

The story about you taking your family camping aside...  ;-)

I never said they should or needed to make the more capable 130mt vehicle.  Just that you could with an ET sized core I think.  Which was a reply to Rocketman's post.  ...

Never said you said anything.  I did read your reply up there, and generally agree.

[RocketmanUS]

.
{snip}
Which is why I never understood Ares V/LV27.3, the official SLS Block II PoR, or anything that doesn’t allow the core to put everything above it into LEO in a sustainer stage type LV using RS-25’s.

Interesting.

Core with (3) RS-25's with 130mt payload on top ( no US ).
Boosters to do the extra needed work at launch so the core can take the payload all the way to orbit.

Now if the could have gone that way with LRB's then with throttle engines it could have launched less mass to with low enough g's. Possible the boosters could have launched with less engine on them when the stack was launched with less payload mass.

So with an 8.4m core could they have been able to make boosters that could have done the job and still fit the MLP and VAB?

So for the thread title only.
Block I.
Block IB ( add RL-10 US )
Block IB later with new boosters.

Now that is with the thread title, only if we find that we need the 130mt capacity or greater should we go with the new advanced boosters. The best path to 130mt is only if we needed the capacity.

Edit:
https://info.aiaa.org/Regions/SE/HSV_AIAA/Downloadable%20Items/AIAA-Chilton_18Oct2012_Final2.pdf

page 19.
Quote:
Advanced boosters require significant funding and ~7 years for development (including 30 month study phase)

yea, an ET/Jupiter sized core with three RS-25's can put a payload in orbit, or rather, in disposal orbit.

The SLS core is stretched so that it can feed four RS-25's to the same disposale orbit.

If an ET/Jupiter sized core were strengthend to support 130mt on top, and have powerful enough boosters, and had three RS-25's, then it should be able to put 130mt into LEO.  Liquid boosters help in this as they burn for longer and have better ISP than solids. 

Three RS-25's produce as much or more thrust and ISP as the five J2's on the S-II stage, and the S-II stage was pushing towards 130mt to LEO. So after booster separation, they should have enough power to push that much payload further up, and then enough ISP later to get to disposal orbit.

The boosters might need to be throttled as well as the RS-25's if there's any g-loading issues.  But most kerolox boosters no can throttle down to at least 70%.

But yea, that configuration could have worked.  AJAX was something like that.  I can't remember if Downix had 3 or 4 RS-25's on the core, but with 8 Atlas V boosters, I believe he said the core could get 130mt into LEO without needing an upper stage.

Two 5.4m wide kerolox boosters with four RD-180's on them each could probably do about the same or a bit better because of the larger single boosters.  Although thrust would be about the same as the Dynetics boosters, they have better ISP.  So they should be able to do about the same even with the non-stretched core.

If they did go with core to LEO with LRB's at 130mt+-
Use the RD-180's for the LRB's.
The LRB's could be a 1st stage with the avionics in the 2nd stage.
1st stage tanks and engine mount made with specs that America, ESA, and Russia all have the ability to make. Make it a universal 1st stage that could be made in America, ESA, and or Russia. The RD-180's could be made in Russia as is or could expand to America if there is a larger demand for them.

America, Russia , and ESA could make their own US for the single stick version. Could possible lower cost for all three partners.

If it could be sized right then the core could lift 130mt+ to a given LEO orbit.

[Lobo]

If they did go with core to LEO with LRB's at 130mt+-
Use the RD-180's for the LRB's.
The LRB's could be a 1st stage with the avionics in the 2nd stage.
1st stage tanks and engine mount made with specs that America, ESA, and Russia all have the ability to make. Make it a universal 1st stage that could be made in America, ESA, and or Russia. The RD-180's could be made in Russia as is or could expand to America if there is a larger demand for them.

America, Russia , and ESA could make their own US for the single stick version. Could possible lower cost for all three partners.

If it could be sized right then the core could lift 130mt+ to a given LEO orbit.

Well, there’s a pretty good chance that the SLS core will keep just four RS-25’s on it, which means it can always make disposal orbit. 

An LRB for SLS using RD-180 engines would need at least 3 of them, and probably four.  Four is close to the Dynetics booster in terms of thrust, but the higher ISP would probably mean more performance than the Dynetics booster.  I don’t know if boosters with three RD-180’s could get 130mt to LEO without a 2nd stage burn.  Maybe…someone with more knowledge than me could probably answer that.  But I’m assuming four RD-180’s per booster to be safe.  That’s basically the equivalent of AJAX will all 8 boosters (but a better mass fraction with two big boosters rather than 8 smaller ones)  That should be a booster with about the same liftoff thrust and same size as the Dynetics booster. 

You could take that booster and short-fill it, and put just two engines on it, and have essentially an Atlas Phase 2 for smaller payloads.  (I’m assuming you can short fill a kerolox booster?)
(You could strap three of them together, put the Block 1B upper stage on top, and basically retire the SLS core and RS-25 engines.  :-)  )

I doubt the Russians or ESA would use it as a “universal boosters” though.  A Nationalistic thing.  Countries don’t want to depend on other countries or orginizations for their national security needs. 
And it’s probably too big of a booster for most international commercial customers who only need something like Atlas V, Falcon 9, Soyuz, Proton, or Araine 5 (dual payloads, not many need the full Araine 5 by themselves).

I think better than all of that…put a modified FH on each booster mount for SLS.  Other than a modified central FH core allowing it to interface with the SLS booster mounts, and probably to handle some lateral loads of that, the FH booster will be a –production- booster of the power range that should get the core to LEO with around 130mt load on top.  It will have about 3.8M lbs of thrust, similar to that of the Dynetics booster.  Actually a little better even than the Dynetics 3.6M lbs thrust.  The entire 3-core booster will behave as a single booster, with the outboard boosters only being attached to the central core, as with a normal FH.  And the entire 3-core booster will be jettisoned as one.  No crossfeed obviously as it would serve no purpose.  Now the SLS booster is based on existing cores and engines that are in production.  Only a new modified central FH core needs to be developed.  It’s all US made, and when used as boosters, the higher performance staged combustion RD-180’s aren’t really much of an advantage over the GG M1d’s or F-1B’s. 
That seems like a far easier development than either a new Dynetics booster, or even a composite ATK SRB, with synergy and cost sharing that the Dynetics booster and ATK SRB won’t have. 

[Lobo]

Well if the goal is a manned flight to Martian orbit some day, I'd say yes, absolutely we need the new advanced boosters.  If however the goal is flinging people over to an EML-2 space station or down to the lunar surface, I'd say the SLS Bloc IB is up to the task.  If anyone's ever seen the various imagined Mars Transfer Vehicles thought up by NASA, they all have one thing in common: they're enormous.  I believe the last time NASA showed how such a mission might look, it took three Ares V flights just to put the thing into orbit.  But at least an MTV would be reusable, which is more than anyone could say for our Apollo hardware.  The landers for crew and equipment also have to be quite big, given the mission length, Mars having more gravity than the moon, and the need for both propulsion and aero-braking/heat shield elements.  This is why Elon Musk is talking about rockets with a minimum 7 meter core and a capability ranging from 150-200 mt to LEO as being necessary for colonizing Mars. 

Boeing’s SEP MTV concept looks like it could launch from a single Block 1B SLS.  So I don’t know that advanced boosters are needed.  I’m really warming up to the concept of that SEP MTV.  Although, something along the lines of Mars Direct, or Mars Semi-Direct could work pretty good too I think, and could all be done with a Block 1B SLS (3 launches ever other year for a sustained plan for Mars Semi-Direct)

Either of those concepts I’d prefer to NASA big DRM 5.0 concepts with NTR’s and lots of LH2.  Mars Direct/Semi-Direct launch directly for Mars, with no in-orbit construction.  Boeing’s SEP concept uses a reusable MTV which needs much less and much easier to handle argon fuel.  There’s a Gateway station to aid in refurb and reuse of the MTV. 

As far as “colonizing” Mars…if you are trying to do that, then you might be launching a larger rocket at a high enough rate to justify bigger rockets.

That said, after 10 flights of 5-seg boosters, -something- needs done.  Going to ATK composite boosters might be cheaper than restarting 5-seg production of casings.  ATK seems to be trying to imply that they will have cost savings vs. the 5-seg boosters.   They should have enough extra capacity to get 130mt to LEO as well. 

[su_liam]

There's no question at all that a 130 ton launch vehicle would be more capable than a 70 ton vehicle.

The country, as a family, plans on buying a car and an RV, theoretically to go on a long east coast to west coast vacation.  Dad sez that they're not going to drive down the east coast from DC to Florida, because they went to Disney World forty years ago.   Some of the family members are intent upon getting the biggest RV on the lot; it would require purchasing an F-450 in order to tow it.  There's no money for the RV at all, and they'd have to wait for a decade or morre before the F-450 is actually manufactured and ready to sell.

Some of the younger members of the family think that the family should just purchase an F-150, which will tow a pretty good sized RV itself, and allow a fair amount of money to be left over to spend when they get to the west coast.  The F-150 will be ready to purchase in just a few years, and cost a good bit less.  So would the smaller RV.

The younger members of the family remember how much fun it was going to Disney World the first time, even tho all they had was Chevy station wagon and a pop up camper.  Not only that, but with a new F-150 and a new RV, they could stay in Florida for a while, maybe get jobs picking oranges, and save up the money to pay for the gas to go to the west coast.  They could get two vacations that way.

The older members of the family insist that the younger members just shut up.

Nice.

Let's go to the Moon, get a job picking oranges, then buy enough gas to drive over to Mars. Sounds like a good plan!

[JohnFornaro]

Nice.

Let's go to the Moon, get a job picking oranges, then buy enough gas to drive over to Mars. Sounds like a good plan!

They've discovered oranges on the Moon?  I had not heard that.  Link please?

[newpylong]

Does that MTV give anyone else a stiffy?

no? hmmmmm

Honestly, humans assembling a massive vehicle in earth orbit to go to Mars and land is amazing to think about.

I'm 31... I hope I get to see it.

[JohnFornaro]

Does that MTV give anyone else ...

Careful there, pardner.

Mars needs women.

[TomH]

They've discovered oranges on the Moon?  I had not heard that.

Oran ja familiar with Helium3 and polar crater ice?

[Vahe231991]

Although the SLS conducted its first successful launch last November, the first flight of the SLS Block 2 almost certainly won't take place until the early 2030s, but with respect to the question posed by the title of this thread, NASA in May 2018 said that any SLS mission beginning with Artemis 9 would have to require new technology solid rocket boosters given the limited supply of sets of SRBs that utilize components of the SRBs used on the Space Shuttle. Thus, Northrop Grumman has already undertaken design of new-technology SRBs for the Block 2, which remain in the design study phase at the current moment.

Link:
https://www.nasaspaceflight.com/2021/07/sls-bole-srbs/

[spacenut]

The only real path to 130 tons is a 5 engine core, and liquid boosters, with a J2X upper stage.  All of that will cost $billions and with the national debt as high as it is, it is not going to happen.  Reusable liquid boosters would be the best answer, but NASA isn't going to spend the money on their development.

One elephant in the room is development costs with the government debt at an all time high. 

Other elephants in the room are Starship, New Glenn, Neutron, and the existing Falcon Heavy.  All will be able to get tonnage to orbit at a much lower cost.  Even if Starship and New Glenn only recover their boosters, they will be much less expensive than any version of SLS.  Solids are expensive, RS-25's are expensive, RL-10's are expensive, and all are expendable.  SLS is already too late and too expensive.  How many billions will Boeing need to develop reusable side boosters or a decent upper stage that is not too high for the VAB. 

[DanClemmensen]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

[JohnFornaro]

Oran ja familiar with Helium3 and polar crater ice?

Dang.  Bumping this thread from 2013.  SLS has come such a long way from back then.

[Zed_Noir]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship Super Heavy.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

Ahem, the "pseudo SLS Block 2" should be a stock Super Heavy with a shorten 7 engine (6xRVac & 1xRSL) expendable Starship variant 2nd stage and a Centaur X upper stage (dual- engine Centaur V with more propellant tankage).

AIUI the Congressional 130 tonne requirement for the SLS Block II is a minimum payload capacity. The contractor can substitute something more capable, as long as the cost is the same or less.

However the mandate to only use Shuttle derived hardware have to be rescinded and alternate PORK programs being implemented in certain Congressional districts. Before re-branding the Starship stack.

[DanClemmensen]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship Super Heavy.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

Ahem, the "pseudo SLS Block 2" should be a stock Super Heavy with a shorten 7 engine (6xRVac & 1xRSL) expendable Starship variant 2nd stage and a Centaur X upper stage (dual- engine Centaur V with more propellant tankage).

AIUI the Congressional 130 tonne requirement for the SLS Block II is a minimum payload capacity. The contractor can substitute something more capable, as long as the cost is the same or less.

However the mandate to only use Shuttle derived hardware have to be rescinded and alternate PORK programs being implemented in certain Congressional districts. Before re-branding the Starship stack.

I forgot about the shuttle reuse mandate. OK, instead of de-rating the thrust to get down from 250 tonne to 130 tonne, we can load 120 tonne of RS-25s and shuttle SRB segments into the "ballast compartment" to provide the required stability. We don't need to mention that this is political stability, not engineering stability.

[TomH]

Best thing is just to cancel SLS. If you insist on having it, you do it like this with a swap of engines and boosters:

Just replace the RS-25s with J-2X. Also replace the boosters with Super Heavy, not on the sides, but underneath the SLS core which becomes an S2. Now you have the mother of all rockets. (Or, to decrease the price of that, you strip down a SS and stretch it as a throw away and use that as your S2.)

Anyway, the 130 tonne LEO requirement no longer exists. Congress replaced it with a requirement for deep space throw ability.

But enough silliness. This thread should be locked.

[Vahe231991]

Best thing is just to cancel SLS. If you insist on having it, you do it like this with a swap of engines and boosters:

Just replace the RS-25s with J-2X. Also replace the boosters with Super Heavy, not on the sides, but underneath the SLS core which becomes an S2. Now you have the mother of all rockets. (Or, to decrease the price of that, you strip down a SS and stretch it as a throw away and use that as your S2.)

Anyway, the 130 tonne LEO requirement no longer exists. Congress replaced it with a requirement for deep space throw ability.

But enough silliness. This thread should be locked.

I'm not sure why Congress issued the 130 tonne LEO requirement, but the fact that they replaced it with a requirement for deep space throw ability shows that there was a general understanding that the Block 2 variant would be a long way off just as design of the Block 2 was getting underway.

[jstrotha0975]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

[Vahe231991]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

If the first Starship launch goes well, then NASA is comfortable waiting a few more years to get ready to manufacture components for the first SLS Block 2 rocket in the event that Congress puts potential funding for the SLS Block 2 on hold.

[TomH]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

If the first Starship launch goes well, then NASA is comfortable waiting a few more years to get ready to manufacture components for the first SLS Block 2 rocket in the event that Congress puts potential funding for the SLS Block 2 on hold.

Yea, well, you never know what a bunch of politicians are going to do. They are always full of hidden motive.

[spacenut]

Yeah, follow the money to the politicians.