The Official SLS Sucks Challenge

[sevenperforce]

SLS will be the most powerful launch vehicle in history. It will also be very stupid. SLS is not powerful enough to do anything useful beyond low earth orbit and it is far too powerful to do anything useful in low earth orbit. Orion was designed to be ferried into low lunar orbit by Altair, making it too heavy and too underpowered to act as a proper command module. 

Nevertheless, it is what we are working with. So, your challenge is to use KSP to design a capsule and launch vehicle exactly as bad as SLS and Orion.

Requirements:

• Your capsule must carry four Kerbals
• Your capsule must have 0-0 abort capacity with splashdown.
• You need an upper stage with one engine, a core with four engines that is too weak to take off under its own power, and two solid boosters.
• Your core stage should not reach orbit.
• All propellant tanks should be full.
• The closer in size and shape to SLS, the better.
• Your upper stage should provide orbital insertion. After this, your spacecraft should deploy its solar panels before the translunar injection burn, also from the upper stage.
• Your spacecraft should be able to do an eccentric Munar orbit insertion and return, but not much more.
• Bonus for aesthetics!

Edited February 11, 2021 by sevenperforce

[Pds314]

Hmm... So if it's the size and config of a real SLS it's gonna go far past the Mun. Probably Jool or something.

 

My inclination would be to make a mini-SLS scaled small enough that single Clydesdales can serve as the boosters.

Edited February 6, 2021 by Pds314

[ralanboyle]

On 2/6/2021 at 11:04 AM, Pds314 said:

So if it's the size and config of a real SLS it's gonna go far past the Mun.

Or just forget to load most of the fuel and derp the thrust down on your engines. 

[Cant think of a username]

if you really want to push it, use MechJeb, it's super efficient. Only if that's allowed thought.

[jinnantonix]

Artemis 1 in Real Solar System.  Many mods used.
 

 

Edited February 10, 2021 by jinnantonix

[Pds314]

10 hours ago, Cant think of a username said:

if you really want to push it, use MechJeb, it's super efficient. Only if that's allowed thought.

I don't know that Mechjeb ascent profiles are anything special. Especially since the upper stage has such an anemic and efficient TWR (like 0.4 with no payload!!!) that you really can't do a conventional gravity turn into LEO. You need to overshoot, put the Apoapsis really high, and have a significant normal component to the burn. The upper stage for the Block I has a 1125 second burn time. That's 18 minutes and 45 seconds.

That said I don't use Mechjeb so I wouldn't know. But my experience generally is that Mechjeb isn't so OP that a human pilot can't compete.

 

Edited February 10, 2021 by Pds314

[Hypercore]

2 hours ago, Pds314 said:

I don't know that Mechjeb ascent profiles are anything special. Especially since the upper stage has such an anemic and efficient TWR (like 0.4 with no payload!!!) that you really can't do a conventional gravity turn into LEO. You need to overshoot, put the Apoapsis really high, and have a significant normal component to the burn. The upper stage for the Block I has a 1125 second burn time. That's 18 minutes and 45 seconds.

That said I don't use Mechjeb so I wouldn't know. But my experience generally is that Mechjeb isn't so OP that a human pilot can't compete.

 

Mechjeb have a mode called "PEG Guidance" that closely copies real world flight profiles, what you said

[FloppyRocket]

I'm not sure whether I'll try this challenge, but I gotta say it's one of the funniest sets of goals I've seen.  And also sadly all true.

[Pds314]

I wonder if a reuseable lower stage could make the SLS great again (or, great to start with)? Afterall SRBs are relatively cheap and the upper stage is extremely, extremely anemic and based on existing Delta hardware and therefore cheap if sufficiently mass-produced. Burning a couple Five Segs, a pretty small fuel tank, and a single RL10 per launch sounds very cheap to me. Especially for 95 tonne payload to orbit. By comparison, an F9 upper stage weighs slightly more than the ICPS when empty, has triple the fuel, and of course has a Merlin Vacuum engine which is an order of magnitude more powerful than RL10.

It does seem to me like throwing out 5 Merlin Vacs and 18 tonnes of dry stage to get the same mass to orbit is a less efficient use of resources than a single RL10 and 3 tonnes of dry stage. Although whether that justifies throwing out two enormous SRBs is a different question and my initial guess is that no, 2 giant SRBs are probably more expensive than 5 F9 upper stages even at the cost of a Merlin each. That being said a reuseable lower stage version of the SLS might have an advantage in ground handling and might be less likely to make launch sites into a bottleneck?

Edited February 11, 2021 by Pds314

[ralanboyle]

12 hours ago, Pds314 said:

I wonder if a reuseable lower stage could make the SLS great again

I don't think SLS's biggest problem is it's complete lack of reusability. While that is a huge problem; remember, those SRBs were reused during the shuttle era at a cost higher than building them new. The RS-25s from the shuttle were also reused, but at horrifying refurbishment cost. I think SLS's biggest problem is the old Cost+ model which has incentivized Boeing (et al) to make it as expensive and time consuming as possible. However, even if it had been completed on time and on budget, it still would only have been a valid option for a short period of time (if at all) because of that anemia you referred to. At the end of the day, this is 40 year old technology bolted together in a complicated way. While Falcon Heavy certainly has more engines, I'd argue it is much less complicated because it has a much lower number of unique parts, therefore manufacturing and testing is easier/cheaper/quicker. 

I don't hate on SLS because I'm a fan of SpaceX, I hate on SLS because I'm a fan of space exploration and SLS represents the worst aspects of the industry. ULA, Blue Origin, and SpaceX have/will made/make SLS obsolete before it has even come online. 

[Guest]

On 2/4/2021 at 7:20 PM, sevenperforce said:

SLS will be the most powerful launch vehicle in history

Not true. Starship is more powerful, as it can carry 100 tons to Mars/anywhere in the solar system with orbital refueling, and SLS can only carry about 95 tons just to LEO  

On 2/4/2021 at 7:20 PM, sevenperforce said:

It will also be very stupid

Starship is also waaaaaay cheaper and fully reusable, with a launch cost of about $2 million, while the development cost SLS has already been $8.75 billion  

Edited February 11, 2021 by SpaceX_Boi

[sevenperforce]

On 2/9/2021 at 10:10 AM, ralanboyle said:

Or just forget to load most of the fuel and derp the thrust down on your engines. 

Oh, I forgot to put that in the rules. All tanks must be full.

1 hour ago, SpaceX_Boi said:

Not true. Starship is more powerful, as it can carry 100 tons to Mars/anywhere in the solar system with orbital refueling, and SLS can only carry about 95 tons just to LEO  

SLS will be the most powerful launch vehicle in history when it launches, assuming Starship doesn't launch all-up before November. Starship will rapidly outstrip it.

[RealKerbal3x]

4 minutes ago, sevenperforce said:

SLS will be the most powerful launch vehicle in history when it launches, assuming Starship doesn't launch all-up before November. Starship will rapidly outstrip it.

I'm not confident in SLS's chances to launch before November either, to be honest

[kspnerd122]

I honestly feel like SLS is just eating the NASA budget, Omg, just scrap it, we could do a moon mission TODAY, stop waiting for SLS, you can do a decent lunar mission on a falcon 9 launching a crew dragon, and any of the several heavy lift rockets already in service(atlas 5, delta 4 heavy, etc) launching a lander and a transfer stage, just dock the modified crew drag to the lander and transfer stage, and don't say that this increases cost per mission,  1 sls launch will likely cost over a billion, and you need to launch it twice per mission(once for lander+surface hardware, and another time for the crew) that's a cost of 2 billion per mission, MINIMUM, with these, each mission will cost less than a bilion in the launcher dept, and also, another thing,  dont say SLS will be good for a moon/mars base, atlas 5 for example, has proven that with the correct setup, It can hurl about 2 tons to mars, for less than half the cost, SLS would probs only be able to send about 4 tons or so to mars, which means its CHEAPER to use a launcher already available. and for the moon, assuming that you wanted to, you could send about 5 tons to the moon, SLS is only ok for LEO, past that, just eat the cost of the extra rocket, also, HOW MUCH WEIGHT DO YOU NEED ON THE MOON, actually, not a lot, if you wanted to make it semi self sufficient(as in, it can grow some food) assuming ABSURDLY HIGH MASSES(you dont really need shielding, just use moon rock for it) Without shielding, and assuming it was built lightly(inflatable with some struts, easier to launch too), you would only really need about 2 tons anyway, then, just launch the stuff needed to set it up, and power supply(solar panels with RTG for emergency(enough to keep basic LS on)), fuel cells(for power storage) would be about 1 ton, plus any form of rover(about 1 ton) then, last launch is just the supplies to last for a month,  as well as any other LS equipment and other things that are fine with vaccum.

Bam, did a moon mission, in 4 launches, at less cost than 2 SLS launches, which would deliver a similar payload, well actually 6, but still, less cost than the 4 sls launches(they launch the lander on a SLS too) essentially, OVER a billion cheaper

[kylelander]

Why use SLS? The ICPS has an absoloutely HORRIBLE TWR, which was why Boeing didn't use a single engine centaur for Starliner. If the RL-10 fails during ascent, your trajectry would likely be so high that the G-Forces from Re-Entry would either knock you out or outright kill you.

[Lewie]

On 2/4/2021 at 8:20 PM, sevenperforce said:

SLS will be the most powerful launch vehicle in history. It will also be very stupid. SLS is not powerful enough to do anything useful beyond low earth orbit and it is far too powerful to do anything useful in low earth orbit. Orion was designed to be ferried into low lunar orbit by Altair, making it too

Cool Challenge! I'll do this after my head gets better...wait...I thought starship will be more powerful then SLS?

[kspnerd122]

Well, you dont need to use it for crew, Im just talking about cargo on atlas 5, crew could go up on a crew dragon that just got modified.