SLS Falcon heavy configuration.

[Comrade Jenkens]

After seeing how Space X are using what is essentially 3 falcon 9s taped together to make the falcon heavy, I'm wondering if the same would be possible for the SLS in the future?

Would there ever be a need for such a rocket?

Thoughts?

[TechnicalK3rbal]

I doesn't think they could or would. The flacon 9 was partially designed for that. By the way, hoes the kraken research going?

[SargeRho]

It would probably be easier to do it Delta IV Heavy style (no fuel crossfeed). The thing about the Falcon Heavy is that fuel is not only pumped to the booster's engines, but also to the core engines, so you end up with basically launching a fully fueled Falcon 9 from pretty close to Space. Wheras the D4H doesn't do that, instead the core is throttled down. It would be an enormous engineering challenge to cross feed the fuel for multiple SSMEs.

[Comrade Jenkens]

I doesn't think they could or would. The falcon 9 was partially designed for that. By the way, hoes the kraken research going?

Nemrav just made a partial breakthrough in that he can trigger ftl travel but it destroys the solar system.

If they could use the same technique as the Falcon heavy I wonder how much it could lift to LEO?

[Canopus]

I think they planned to have a booster system that uses the F1 engine but i'm not sure if they are still going to do that.

[sgt_flyer]

one problem you will have of stacking the core stage, is that the 4 SSME's of the core stage has nowhere near the thrust of the SLS boosters... it's designed to burn a big chunk of it's fuel before the core stage has a positive TWR

block I SLS has only 7,4 MN of thrust for the core stage - and 16 MN of thrust per booster you'll have more power by just stacking 3 boosters together than stacking 3 SLS core stages together

@canopus

the pyrios booster is the planned rocketdyne/dynetics booster with twin F-1B engines - planned to be at least as powerful as the SLS SRB's.

(also, they think they can have 20 more tons to LKO with a block II SLS with pyrios than a Block II SLS with SRB's )

and pyrios would be able to be throttled / shutdown in case of problem

Edited March 7, 2014 by sgt_flyer

[Nibb31]

They already can't find payloads for SLS, so there really is no need for a multi-billion dollar super-heavy triple-core SLS.

[maccollo]

one problem you will have of stacking the core stage, is that the 4 SSME's of the core stage has nowhere near the thrust of the SLS boosters... it's designed to burn a big chunk of it's fuel before the core stage has a positive TWR

For complete madness, radially stack 2 additional SLS cores + solid boosters. With 118 million newtons of force I think that might just destroy the launch platform.

I will totally do this when we get the SLS in KSP.

Anyway, there's just no room for such an expansion. There would be so much rocket it would hang over the edges of the crawler.

Edited March 7, 2014 by maccollo

[Comrade Jenkens]

They already can't find payloads for SLS, so there really is no need for a multi-billion dollar super-heavy triple-core SLS.

Well if they ever need an ISS replacement they could put it up in a single launch...

Can't really think of any other use for it though.

[rhoark]

They already can't find payloads for SLS, so there really is no need for a multi-billion dollar super-heavy triple-core SLS.

That's simply false. SLS is the launcher around which NASA's plans for the moon, Mars, asteroids, Europa, outer planet probes, and exoplanet imaging are built. It is also the only thing that can launch the Bigelow 2100, and the National Reconnaissance Office is interested (though its classified exactly how interested).

Edited March 7, 2014 by rhoark

[SargeRho]

Also aren't there ideas for a SLS version with strap-on F1B boosters, each of which would have 2 F1-B engines?

[Kryten]

That's simply false. SLS is the launcher around which NASA's plans for the moon, Mars, asteroids, Europa, outer planet probes, and exoplanet imaging are built. It is also the only thing that can launch the Bigelow 2100, and the National Reconnaissance Office is interested (though its classified exactly how interested).

(Some of) NASA's plans, yes. NASA's funded plans, no. The only payload on a funded SLS mission is Orion.

[rhoark]

There is (funded) work happening on science instruments for Europa Clipper and a deep-throttling methane RL10 variant that would be applied to a moon or mars lander. As SLS passes peak expenditure, payloads will come into their own so long as congress doesn't slash and burn. The upgrade path for SLS is planned in two stages: after the initial Block 1 tests, the Block 1b will enlarge the second stage with 4 RL10s and fuel capacity to match. Later would come the Block 2 which would have a J2X upper stage and replace the 5-segment SRBs with new boosters that have yet to be designed. Dynetics and ATK are competing for this opportunity, with the F1B and new SRB chemistry respectively. It's reasonable to doubt whether the Block 2 will come to fruition, as it implies putting very heavy things near Earth, which is not a prominent idea in mission planning right now. The lower Isp of the J2X causes Block 2 to reach a breakeven point with Block 1B's cargo capacity somewhere between a direct Mars and direct Jupiter flight. The "flexible path" concept means maximizing overlap between moon and mars hardware, so we can dance to whatever tune congress directs. This is likely to include a single-stage methane lunar lander that becomes a Mars lander with the addition of drop tanks, and an electric propulsion L2<->Moon tug that becomes an L2->Mars departure stage with enlargement of its solar panels.

[Comrade Jenkens]

*sighs* Should have known that this would rapidly deteriorate into a for and against SLS argument. Any mention of it does.

Slightly more on topic what would ppl do with a 500ton to LEO launcher if they had the option? I'm guessing that is what it could lift assuming the block II version. (In the configuration I'm talking about of course)

[Kryten]

There is (funded) work happening on science instruments for Europa Clipper...

Which doesn't have the slightest chance of going on SLS, like every other probe at any level of development. Every single reference design assumes an EELV class launcher for that reason.

)(snip stuff about powerpoint upgrade paths)

Powerpoints are cheap, upgrades aren't. None of these have any kind of current funding.

[Rakaydos]

Slightly more on topic what would ppl do with a 500ton to LEO launcher if they had the option? I'm guessing that is what it could lift assuming the block II version. (In the configuration I'm talking about of course)

Tokomak reactor components, for assembily in orbit? Those things are HUGE.

[mdatspace]

There is (funded) work happening on science instruments for Europa Clipper and a deep-throttling methane RL10 variant that would be applied to a moon or mars lander.

Why put Europa clipper on SLS? The Rocket is overpowered for that and it is not cheap as a launcher. A Delta IV heavy would do.

[rhoark]

It would reduce the transit time by 4.5 years. The option remains for it to go on an Atlas V.

[shynung]

Slightly more on topic what would ppl do with a 500ton to LEO launcher if they had the option? I'm guessing that is what it could lift assuming the block II version. (In the configuration I'm talking about of course)

Launch an entire space station to orbit?

I did it in KSP once, at least.

[NASAFanboy]

Which doesn't have the slightest chance of going on SLS, like every other probe at any level of development. Every single reference design assumes an EELV class launcher for that reason.

Powerpoints are cheap, upgrades aren't. None of these have any kind of current funding.

Come on man, give it some hope. Stop being so cynical

Cassini started out as a concept with less funding, and now it's reality. So did Curiosity, and New Horizons. NASA is interested in Europa, and so is the United States Congress. With Cassini going out of action around 2016, NASA feels the heat to have another probe heading to the outer planets. Europa Clipper may very well be the successor to Cassini.

However, on the other hand, these are the only SLS payloads that will very likely receive funding.

- Orion MPCV

- NRO/DoD Satellites

- Cislunar Gateway

- Mars Mission (Several payloads over multiple launches)

Bigelow might see some action, if it's willing to fork out the funds. But as for now, funding is only limited to these four components in space.

But for now, these, and only these, will receive funding in the foreseeable future. And with Congress clamping down hard on Presidental powers to cancel the SLS by placing it into an protected class of programs and giving it another 300 million in funding, the SLS is here to stay.

[Skyler4856]

I would develop a completely self-sustaining lunar base, that has the capacity to launch interplanetary flights.

[bs1110101]

Does the SLS core even have the thrust to lift off without boosters? And for that matter, i think that a slightly heavier SLS could be better done with 2 more boosters way cheaper.

[NASAFanboy]

Does the SLS core even have the thrust to lift off without boosters? And for that matter, i think that a slightly heavier SLS could be better done with 2 more boosters way cheaper.

I believe it does. The boosters are there to give it a better payload capacity.

[sgt_flyer]

well, if the numbers in wikipedia are roughly the good ones for SLS, the core stage + upper stage weight approximately 1000 tons fueled on launch, while the four SSME's gives out around 7440 kN of thrust at sea level.

which gives a fueled TWR of around 0.75 for just the core stage + upper stage with no payload.

a space shuttle 4-segment SRB weights around 590 tons fueled (91 tons unfueled) - so with the additional segment of the SLS SRB's, we are looking at around 730 tons for each booster.

in the end, we are looking at a fueled weight for the full SLS of around 2560 tons - for a 100 tons payload. each srb gives around 16000kN of thrust, + the SSME's we are looking at nearly 40000kN of thrust at liftoff

- it gives the fully fueled SLS around 1.5 / 1.6 TWR at liftoff.

so no based on the known numbers, the SLS could not liftoff only on it's core stage thrust (even with no upperstage, it would not be able to liftoff, as the upper stage is extremely light compared to the rest of the rocket - the upper stage would only serve for circularization anyway, with it's 30 tons... )

Edited March 12, 2014 by sgt_flyer

[bs1110101]

Thank you for doing the math i couldn't be bothered to do!

Anyway, i've made many rockets like that in ksp, the upper stage is mostly because the core is too big and heavy to turn and/or i don't want junk in orbit.

Sorta relatedly, why not contract spacex to make huge flyback boosters for it?

Kinda like the plan to use F1 based boosters, but without the problems of having to redeign it to be reusable and give spacex a reason to make a bigger engine.