NASA finally acknowledges the elephant in the room with the SLS rocket

Autapomorphy

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Anyone still think there's a future in hydrogen cars?
Has any serious fuel cell vehicle proposal ever involved liquid hydrogen? I thought that everything was based either on chemicals from which hydrogen is readily freed or on simple compressed hydrogen gas. Handling the compressed gas isn't a huge problem, as evidenced by the fact that a cylinder of industrial grade hydrogen from Airgas would run me about the same cost as a cylinder of nitrogen.
 
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Wickwick

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Has any serious fuel cell vehicle proposal ever involved liquid hydrogen? I thought that everything was based either on chemicals from which hydrogen is readily freed or on simple compressed hydrogen gas. Handling the compressed gas isn't a huge problem, as evidenced by the fact that a cylinder of industrial grade hydrogen from Airgas would run me about the same cost as a cylinder of nitrogen.
I'm not sure about fuel cells. But when I was a graduate student, there was a group nextdoor working on an internal combustion engine based on a liquid hydrogen tank. By the time it got to the piston it was vapor, of course, but along the way, the cold of the hydrogen reserve was used to separate oxygen from air so as to not create NOx during the combustion. I'm not sure they ever closed the loop on efficiencies needed to accomplish that, however.

Of course, the other option is to simply burn at such a lean premix that one need not worry about NOx. But that reduced the power per engine size. But hydrogen is happy to burn at very lean conditions especially once compressed 10 or 12:1.
 
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wagnerrp

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Wow. It's not every day when you get such a thoughtful, knowledgeable, and polite response in an Internet forum. Obviously an Ars and NSF aficionado. Plus-one points to you!

I think no one could have predicted the success that NASA had with COTS and SpaceX has had with reusability. DIRECT, Ares, SLS, all need to be evaluated in the context of the industry as it was at the time, not with hindsight of what has been accomplished since then.
No they don't. DIRECT, Ares, SLS... all were designed around the concept that you needed a single monolithic launch vehicle for high energy missions, and all were simultaneously intended for missions using distributed lift from multiple launch vehicles. DIRECT would have a Jupiter-246 launch a capsule, and another Jupiter-246 launch a departure stage. Constellation was the same concept with an Ares-1 launching a capsule and Ares-5 launching the Altair lander/tug. SLS gets itself to somewhere in the general vicinity of the Moon, but needs Starship or New Glenn to launch a lander, and they all meet up at a space station deployed by Falcon Heavy.

All of these proposals were self-contradictory from the very start. Once you have distributed lift, you only need to reach LEO, and you can design your missions around the maximum vehicle you can send to LEO. Shelby even knew this and made significant efforts to shoot down any plans by ULA of depots and propellant transfer. The one massive enabling technology for Starship (and Blue Moon for that matter) was the one massive threat to Ares twenty years ago.
 
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Statistical

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Who bought his trip from ... Russia.


Well technically he bought the trip from the for profit Space Adventures, Inc who bought it from Russia.

Edit: and I was born a long time before 2001.

Of course the point was people orbited the earth long before you were born.
 
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Lance Bass from the boy band NSYNC reneged on contracted payments after beginning training for a Soyuz mission to the ISS, and that caused Russia to stop selling seats to private customers.

It wouldn't have lasted anyway, because the Columbia disaster put an end to using Shuttle for ISS crew rotation. Soyuz couldn't just be an emergency lifeboat that gets swapped out for a fresh one every year or so. It had to be the crew rotation vehicle, and in that role it could also be the lifeboat. So no more short-duration "lifeboat rotation" missions for private customers.
 
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Wickwick

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Well technically he bought the trip from the for profit Space Adventures, Inc who bought it from Russia.



Of course the point was people orbited the earth long before you were born.
Yes. As I mentioned above. people orbiting wasn't the exciting part of Inspiration 4 to me at least.
 
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Statistical

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Lance Bass from the boy band NSYNC reneged on contracted payments after beginning training for a Soyuz mission to the ISS, and that caused Russia to stop selling seats to private customers.

That is not correct. Private citizens have flown on Soyuz both before and after Bass scheduled flight.

It wouldn't have lasted anyway, because the Columbia disaster put an end to using Shuttle for ISS crew rotation. Soyuz couldn't just be an emergency lifeboat that gets swapped out for a fresh one every year or so. It had to be the crew rotation vehicle, and in that role it could also be the lifeboat. So no more short-duration "lifeboat rotation" missions for private customers.

Kinda. For a while. However it was simply because NASA needed the seats. The new Soyuz always launches before the old Soyuz returns so for every rotation there is always a period where there are two Soyuz overlap. NASA however needed the seats given the gap between STS ending and CC flying. Russia could charge NASA a lot more than it could private citizens ($90M per seat and a guaranteed 6 per year vs $20M and ? per year).

In 2021 a pair of private citizens flew on Soyuz now that Commercial Crew covers NASA's needed. The end of this is more that there are better safer options. Why fly on Soyuz when you can fly on Dragon?


Also post CC Russia is only using one Soyuz at a time they still briefly overlap but that means Russia only has control of 3 instead of 6 seats. They also cross fly one American (one Russian flies on CC) so that means actually two seats. That really complicates the logistics of a space tourist. Having a space tourist would mean a crew staying twice a slong. When you are down to two slots that is problematic. Also the ROS is falling apart it largely takes all their resources to just keep the station running. They have reached the end of the line. Between Dragon being an option, logistics of Soyuz, and manpower constraints I am going to guess the 2021 flight was the last.
 
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sporkinum

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“You know, you’re right, the flight rate—three years is a long time between the first and second,” NASA’s associate administrator said. “It is going to be experimental, because of going to the Moon in this configuration, with the energies we’re dealing with. And every time we do it these are very bespoke components, they’re in many cases made by incredible craftsmen. … It’s the first time this particular machine has borne witness to cryogens, and how it breathes, and how it vents, and how it wants to leak is something we have to characterize. And so every time we do it, we’re going to have to do that separately.”

So there you have it. Every SLS rocket is a work of art, every launch campaign an adventure, every mission subject to excessive delays. It’s definitely not ideal.

I found that passage depressing because I thought part of the point of trying again today was that, with better technology, we could avoid so much of the bespoke craftsmanship that cause the Apollo problem to be non-scalable. That processes could be more standardized and assembly-line for better reliability and a faster launch cadence.

That actually exists, but not at NASA...it's what SpaceX has achieved, along with reusability. And probably what China is aiming for too.

I am a big fan of the space program and practically worshipful of the Apollo program and the programs leading up to it, I really enjoy Eric Berger's articles, and of course I'd like to see the USA return to the moon, but...so many things about the Artemis/SLS program make me very uncomfortable, like we will spend all this time and money and possibly end up with Challenger-style regrets. I deeply hope to be proven wrong about that.
 
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compgeek89

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I just hope they cancel this piece of garbage before it kills someone, which is all too likely, given the constant excuses for things they could easily have tested and fixed in the past 4 years (what did they spend he last $12B on?).

I can hear the excuses already after the tragedy that "space is hard" and "our simulations didn't show that behavior", etc. all of which is true, but hides the fact that the problems are occuring because it is a tragically flawed rocket with a tragically flawed team building it and should just be put out of its misery.

Fingers crossed that it either goes boom before people get on board or somehow makes it through the few flights through sheer dumb luck.
 
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The Shuttle program averaged about one delay per launch because of propellant transfer issues and it launched 135 times in 30 years. So even with a lot more practice, NASA has always had trouble with these volumes of liquid hydrogen.

When you use hydrolox for your main stage, you are swapping a huge increase in costs/complexity for a minor performance increase.. Huge increases in tank mass/volume and no one has ever stopped the leaks.

When you use hydrolox for your upper stage, you are chasing performance at the cost of economics.

When you use it for deep space, you are fighting against boiloff.

The sole use of hydrogen should be as propellent for nuclear thermal engines, where its basically a requirement to achieve high ISPs.
 
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It'd be super-amazing if Eric Berger applied this same amount of skepticism to SpaceX achievements and proclamations.

ETA: I wrote this on a shelled-out tab, this may have been mentioned about 45 times by now. If it has, I am truly sorry.

Ars coverage of SpaceX activities is incredibly detailed and thorough, and Eric is diligent about covering all perspectives and criticisms.

Your problem, as far as i can see it, is that for every ill-advised test launch without water suppression or test item breakup over a carribean island, SpaceX also does maddening things like

1. Reduce cost per ton of launching payloads to space by 90%.
2. Shatter the consecutive successful launch record by over 200%.
3. Advance the industry by the greatest achievement since the shuttle, mastering booster reuse by being first to master hypersonic relights and flybacks.
4. Build the largest and most successful satellite constellation in history.
5. Shatter records for most launches in a year, and launch close to 90% of all world payload to orbit.
 
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Wickwick

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When you use hydrolox for your main stage, you are swapping a huge increase in costs/complexity for a minor performance increase.. Huge increases in tank mass/volume and no one has ever stopped the leaks.

When you use hydrolox for your upper stage, you are chasing performance at the cost of economics.

When you use it for deep space, you are fighting against boiloff.

The sole use of hydrogen should be as propellent for nuclear thermal engines, where its basically a requirement to achieve high ISPs.
Hydrogen at liftoff is actually a performance hit not a performance gain.

Hydrogen as an upper-stage fuel has been fine. Atlas V has managed it well enough.

The important thing is not to try to prevent leaks. It's to mitigate and/or deal with them when they happen. As I observed recently, the Delta IV was designed to belch hydrogen and be engulfed in a hydrogen flame on liftoff.

The really depressing part of the hydrogen leak situation is that from the Shuttle to SLS, there was never an engineering solution to accept the hydrogen leaks. As long as you're not leaking faster than you can refresh, who cares? Just don't let the hydrogen make a fire hazard when it's leaking. That's a very well understood concern among combustion people.
 
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We could’ve launched so many more JWSTs and for that money and learned so much more than we will by sending humans back to the moon.

The SLS and Orion have clearly wasted massive amounts of funding that could have been better spent on actually productive space research. As will the Gateway to Nowhere.

But you are missing the point if you don't see that the actual landings are funding the development of super heavy, super high cadence launch at costs far lower than any before, as well as new in-orbit refueling technologies that open up access to deep space and the solar system we've never had before.

Which means that the next JWST won't need to cost $15B. Instead it will be have a fairing volume many times larger reducing its complexity greatly, and its launch costs will be close to trivial. In fact, it will open the door to mass manufacturing space telescopes at far lower costs to greatly increase the amount of high quality astronomical data humanity can accesss.
And sending probes to the outer planets and Kuiper belt/Oort cloud won't require waiting for rare planetary alignments to boost tiny limited probes on decades long travels, instead we'll be able to launch far more capable and massive probes at high deltaVs directly from low earth orbit to reach destinations far more quickly.

Neither science nor engineering is an island, or are they static. Everything we need to build to ensure that Artemis astronauts on the lunar base can be supplied and relieved regularly and affordably at a high cadence will make it possible to massively increase the numbers and capabilities of solar system robotic probes.
 
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The Chinese lunar program will ironically be the best hope for Nasa turning things around.
Let's cut a deal with the Chinese. We won't race China to the Moon, if China will go at its own pace and land at Tranquility Base....to confirm that Americans were there 60 years ago!
China on Moon.jpg
 
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Jack56

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Yes, hydrogen likes to leak, but …
The US, & NASA, have considerable experience using it. Including:
the Shuttle from which SLS is derived
Centaur III & V
Delta III, IV, IVH
Saturn 1, 1B, V
Elsewhere, there were/are e.g. Japan’s H2 & H3, Europe’s Ariane 5 & 6.
Hydrogen leaks weren't showstoppers for any of these and none of them cost anywhere near what SLS has.
 
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To be fair, this was almost never meant to fly, it was a nice way to funnel money into congressional districts (this is what I get reading past Ars articles on the SLS)
Eric: I think you should use you influence to get the higher-ups at NASA to proactively address the Artemis program failure. The Artemis news is very bad.....and bad news never gets better with time. Blame is on the need to use old hardware. Blame it on Congress. But bite the bullet NOW....before an angry White House slashes your budget so steeply that you become a backwater bureaucracy doing nothing important.
So, I am still asking the same question, years later:
SLS Stop The Madness 2.jpg
 
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Yes, hydrogen likes to leak, but …
The US, & NASA, have considerable experience using it. Including:
the Shuttle from which SLS is derived
Centaur III & V
Delta III, IV, IVH
Saturn 1, 1B, V
Elsewhere, there were/are e.g. Japan’s H2 & H3, Europe’s Ariane 5 & 6.
Hydrogen leaks weren't showstoppers for any of these and none of them cost anywhere near what SLS has.

Hydrogen always leaks, so they just dealt with the delays. I think its been pointed out that upper stages have smaller connectors that make them easier to engineer and fewer leakage problems.

And while none of those rockets cost as much as the SLS, they were all expensive. The blueprint for high cadence lowest cost space launch is currently using a single dense propellent for two stages that share the same engine model using mass engines for the first stage.

Hydrolox will always have the highest ISP (unless you want to get exotic with awful tripropellents and flourine), but its costs, increased dry mass, and launch handling complexities will always kill its economics.
 
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Wolfie2

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No, not “ideal.”

Masterful understatement Eric, the article was (as usual), a joy to read.

“And every time we do it these are very bespoke components, they’re in many cases made by incredible craftsmen…”

… which end up at the bottom of the ocean after one flight. This beautiful handcrafted steam engine isn’t the future of anything.

Hopefully 2026 can be a tipping point where SpaceX and Blue start to show what their launch systems are capable of. Let’s go!
 
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Statistical

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Yes, hydrogen likes to leak, but …
The US, & NASA, have considerable experience using it. Including:
the Shuttle from which SLS is derived
Centaur III & V
Delta III, IV, IVH
Saturn 1, 1B, V
Elsewhere, there were/are e.g. Japan’s H2 & H3, Europe’s Ariane 5 & 6.
Hydrogen leaks weren't showstoppers for any of these and none of them cost anywhere near what SLS has.

The shuttle routinely had delays and cancellations due to hydrogen leaks.
 
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Constellation had a well-defined lunar surface landing mission. The later lack of purpose was a result (not a cause) of the massive launch vehicle budget overruns and schedule delays.
I met with a NASA official on the Ares 1 launcher for Constellation, and he confirmed that NASA wanted to keep quiet the fact that pogo vibrations were predicted to be so huge (+/- 6g at 12-14 hz) that it would likely kill any astronaut. The single unmanned test launch got a "lucky load" on the solids, and NASA saw longitudinal vibrations in the range of "only" +/- 2g, potentially survivable. But it shows that NASA was desperately reaching for ways to keep manned spaceflight alive....in the face of a very obvious end-of-the-line situation.
 
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TheGoodDoctor

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The SLS is the greatest rocket you can make if forced to use the components of the space shuttle. It wasn't just keep funding flowing in general. It was keep funding flowing to the "right" companies namely the companies which built components of the Space Shuttle.
I worked at one of the sub-primes when SLS was being designed and saw it first hand. You could not be more spot on about it.
 
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NetMage

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It's been so hamstrung by Congress that it's incapable of doing its core job function.
As has been pointed out, that is much too charitable to NASA. It was an outside plan brought into NASA and bought into by a lot of NASA personnel that’s brought us to this point.
 
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Stuart Frasier

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Has any serious fuel cell vehicle proposal ever involved liquid hydrogen? I thought that everything was based either on chemicals from which hydrogen is readily freed or on simple compressed hydrogen gas. Handling the compressed gas isn't a huge problem, as evidenced by the fact that a cylinder of industrial grade hydrogen from Airgas would run me about the same cost as a cylinder of nitrogen.
BMW made a small number of 7-Series with a V12 powered by liquid hydrogen. There was apparently a fueling station near me, so I'd see one on the road occasionally.
 
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Humiliatusque59

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It seems to one that the whole Orion project is clearly an "experimental" one. Each is a "one off's" with little to no expectations of "production" or "operationalization". Admittedly compare to the SpaceX program this is a rolling mind numbing experiment in rocketry. It's obviously going to be discontinued like many developmental data collecting X-craft experiments past years for future development, often by NASA. This is what NASA does. It would be useful if folks here looked at where this is most likely going rather than just thowing their Kraft Cheese at the comments section in "cheesy" and predictable comments. LOL. We can do better right?
 
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The really depressing part of the hydrogen leak situation is that from the Shuttle to SLS, there was never an engineering solution to accept the hydrogen leaks. As long as you're not leaking faster than you can refresh, who cares? Just don't let the hydrogen make a fire hazard when it's leaking. That's a very well understood concern among combustion people.
For anyone late to the party, Wickwick is one of the combustion people.

There's even a combustion event named after them!
 
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beb01

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"Dead hardware walking ..." I love it.

A previous post compared the SLS tanking to hydrogen/oxygen upper stages like Delta III/Delta IV, Centaur, and SLS's own upper stage, which is really a version of the Delta IV 5M upper stage. Those typically use smaller umbilicals. Probably a better comparison to getting propellant into the SLS first stage would be the Delta IV first stage. Both O2/H2. Both had "dog houses" on the side of the vehicle. Delta IV had it's issues with leaks, but they figured it out. Point is, some of those same people are still around. And some of them work on SLS. The expertise is there, somewhere.

Is someone not listening to the engineers?
I'm surprised NASA didn't send teams to the Ariana launches to see how they handle fueling their sustainer core rocket.
 
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Wickwick

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I'm surprised NASA didn't send teams to the Ariana launches to see how they handle fueling their sustainer core rocket.
Between Shuttle, Atlas, and Delta launches, I'm betting there have been 4x the number of hydrogen fueling events at the Cape than there have been from Kourou.
 
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