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NASA finally admits what everyone already knows: SLS is unaffordable

arstechnica.com

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Re: NASA finally admits what everyone already knows: SLS is unaffordable

#71

Post by bombolo »

roody15 wrote: post #60
techdragon wrote: post #5

Important context… SLS isn’t the rocket NASA designed or asked for in order to achieve its mission goals… it’s the rocket they were forced into using due to lobbying and senate shenanigans, there’s a reason it has the nickname “senate launch system”. The fact the pork barrel project is so bloated it’s “unaffordable” is irrelevant as far as the senators who are voting for it are concerned. My bet is that the senate wi…

This is a really unfortunate situation with geopolitical consequences. It weakens belief in our system of governance as a whole. The US can spend this kind of money .. with not much progress .. and no real consequences for failure. Adversaries see this as weakness because that is what it is. This has real world consequences … when people see the US spends 10 times more than any other nation on its military and its sp…

[dead]

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#72

Post by peoplearepeople »

throwawaymaths wrote: post #54
mannerheim wrote: post #49

Earlier quoted context omitted.

SLS was already made redundant when the Falcon Heavy flew. 'Let’s be very honest, We don’t have a commercially available heavy-lift vehicle. The Falcon 9 Heavy may some day come about. It’s on the drawing board right now. SLS is real.' - Charles Bolden Note the reason given here isn't that the Falcon Heavy didn't have as large a payload capacity - that excuse came after it started flying years before SLS, because app…

Isn't it the case that f9h's lift capacity has increased over the years due to engine improvements and stage lengthening..? Iirc fairing size is still a major limiting factor.

They have a bigger fairing in dev for the military, and the gateway launch

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#73

Post by kristofferR »

roody15 wrote: post #60
techdragon wrote: post #5

Important context… SLS isn’t the rocket NASA designed or asked for in order to achieve its mission goals… it’s the rocket they were forced into using due to lobbying and senate shenanigans, there’s a reason it has the nickname “senate launch system”. The fact the pork barrel project is so bloated it’s “unaffordable” is irrelevant as far as the senators who are voting for it are concerned. My bet is that the senate wi…

This is a really unfortunate situation with geopolitical consequences. It weakens belief in our system of governance as a whole. The US can spend this kind of money .. with not much progress .. and no real consequences for failure. Adversaries see this as weakness because that is what it is. This has real world consequences … when people see the US spends 10 times more than any other nation on its military and its sp…

It's not like the money spent just disappears, though, someone gets it. The SLS is a huge jobs program.

Me and GPT had a good discussion about it: https://chat.openai.com/share/828cb390-dac0-4f3b-a556-f02972...

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#74

Post by ajross »

GMoromisato wrote: post #56
bnralt wrote: post #14

While true, it's missing the forest for the trees. NASA spends almost half it's budget on human spaceflight, and there doesn't seem to be any particular goal there beyond "send people into space because we want to send people into space." Meanwhile, a measly 3.5% of the NASA budget is spent on aeronautics. Yes, the SLS is an inefficient way of performing a mission that NASA shouldn't be performing in the first place,…

This is a common sentiment, but I don't share it. Crewed spaceflight is no worse and no different than spending money on Hubble, JWST, or the Voyager missions. We pay for those missions because they inspire us. For many, gaining knowledge about the universe is its own reward, even if it doesn't lead to cancer cures or longer-lasting batteries. In the same way, sending people into space connects us to all those namele…

> Crewed spaceflight is no worse and no different than spending money on Hubble, JWST, or the Voyager missions. We pay for those missions because they inspire us.

That's true only in a very strained and tautological sense of "inspire".

Science has quantifiable results. There are facts that we know and theories we've understood (and discarded!) because of telescopes and probes that we would not know had they not flown. Whether that knowledge has value or not is, I guess, subjective. But it's not only "inspiration" except insofar as you declare that the only reason for wanting to know about martian geology or the early universe or whatever is "because it inspires us". Which is to say: you're making a semantic argument, not a profound one.

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#75

Post by woooooo »

rdtsc wrote: post #52
wmf wrote: post #34

Earlier quoted context omitted.

Jobs.

That's the answer. It's keeping the jobs (i.e. voters) in orbit around the senators. They could care less about space, as long as they can say they brought "jobs" to their state. If it does that, it works as designed.

I always hear this and I never hear anyone say they voted for senate based on Abrams tank manufacturing or whatever.

Is it a senate cultural thing that they all tell themselves despite tenuous links to reality?

Is it kickbacks?

Why doesn't the logic apply to infrastructure projects which seem more marketable?

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#76

Post by danpalmer »

justrealist wrote: post #67
danpalmer wrote: post #29

Earlier quoted context omitted.

I think this is a little unfair. SpaceX of 10 years ago didn’t have the same launch capacity and was not human rated, or even close to human rating. Now the trajectory (no pun intended) of SpaceX was good back then and you might have guessed they would grow rapidly in capabilities and capacity, but it wasn’t a done deal. I’m no fan of SLS, but it was a very understandable safe bet 10 years ago.

> and was not human rated The SLS has not launched a human.

No, but that was the plan all along, and it's built out of multiple components that have launched humans. I don't think the plan for F9 was to launch humans for a long time, or at least it didn't appear to be a focus for SpaceX until Commercial Crew came along.

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#77

Post by ClumsyPilot »

bnralt wrote: post #14

While true, it's missing the forest for the trees. NASA spends almost half it's budget on human spaceflight, and there doesn't seem to be any particular goal there beyond "send people into space because we want to send people into space." Meanwhile, a measly 3.5% of the NASA budget is spent on aeronautics. Yes, the SLS is an inefficient way of performing a mission that NASA shouldn't be performing in the first place,…

> there doesn't seem to be any particular goal there beyond "send people into space because we want to send people into space."

No, we are figuring out - how do you survive in space? How do you take a shit in space? Toilets would constantly break on ISS and it was a huge problem.

And people can get shit done. They are designing robots for mining lunar regolith, but they are all less efficient than a guy with a shovel. You could send 10 dudes to the moon with a shovel and a 3D printer, and they could produce aluminium parts on the moon.

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#78

Post by danpalmer »

Rebelgecko wrote: post #43
danpalmer wrote: post #26

Earlier quoted context omitted.

This is a good point, but to extend it a bit, changing the fuel means changing the chemistry of the whole system, changing tradeoffs and thresholds, changing capabilities, all sorts. Rockets very much need to be designed around a particular fuel, it defines so much of the rest of the rocket either directly or indirectly.

I imagine it also impacts all the other infra (eg, what reagents dou need to store at the launchpad, what do you need to store nearby, do you need cryogenic cooling, etc

It does! The take-off temperature is a very big concern, how much chilling of the rocket needs to happen etc. The ground support equipment I gather is also complex, although I think storage and transport of all those sorts of fuels around tank farms is much more of a solved problem, I suspect you could buy much of it off the shelf (not that NASA would, but SpaceX seem to be buying regular commercial equipment for theirs).

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#79

Post by danpalmer »

mcny wrote: post #42
danpalmer wrote: post #26

Earlier quoted context omitted.

This is a good point, but to extend it a bit, changing the fuel means changing the chemistry of the whole system, changing tradeoffs and thresholds, changing capabilities, all sorts. Rockets very much need to be designed around a particular fuel, it defines so much of the rest of the rocket either directly or indirectly.

At a savings of USD 80 million or more per engine, I'd say it is well worth it to push deadlines or whatever we need to do to consider the cheaper options. Right now it looks and smells like corruption.

I think it's a false comparison to say 80m per engine today.

When SLS was being architected 10+ years ago, I believe the idea was that the RS-25 engines would be cheaper, and there were spares around. Also there were no $1m engines, not even close. Perhaps there might have been a competitor for 1/2 the price, but would that be worth it over an engine that you already have flight ad maintenance experience with? Probably not, it's certainly not a convincing argument.

Lastly there weren't any Methane engines – both of the hottest engines in the market now (pardon the pun) are Methane based, the Raptor and BE-4, but the decision to use Hydrogen as the fuel for SLS was set in stone years ago and unrealistic to change.

Basically there weren't convincingly better options at the time the decision was made, and changing that decision now would mean basically going back to the drawing board on the entire rocket.

Re: NASA finally admits what everyone already knows: SLS is unaffordable

#80

Post by woooooo »

hypercube33 wrote: post #48
wkat4242 wrote: post #32

Earlier quoted context omitted.

And the whole reason for the hydrogen burning was to keep the space shuttle contractors jobs. Once again it's not a technical reason but a pork barrel one.

Possibility of corruption aside, these are clones of the Saturn 5 rocket engines and tech just scaled up - the whole thing is built for hydrogen which is clean burning (water is the byproduct) but you'd think SpaceX could take the design and make something for 20mil

SpaceX is on record with not wanting to use hydrogen for the "pain in the ass factor".

It boils at a lower point than oxygen, so you have to insulate the tanks from each other, it's very.. undense (sparse?) per volume so you need bigger tanks, and it's the smallest molecule that exists and makes leaks and shipping harder.

Methane is slightly less efficient but way easier logistically.

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