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.Anyone still think there's a future in hydrogen cars?
When did private citizens buy a trip to orbit?
The orbiting of people wasn't the novel part. It was the economics of the mission.
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.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.
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.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.
Who bought his trip from ... Russia.Dennis Tito in 2001.
Who bought his trip from ... Russia.
Edit: and I was born a long time before 2001.
Yes. As I mentioned above. people orbiting wasn't the exciting part of Inspiration 4 to me at least.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.
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.
From what is been said he got his citizenship through shifty means.So, you're ok with depriving a US citizen of his constitutional rights, just because you don't like him? Do you have orange hair, by any chance?
The sentiment you are expressing there is entirely reprehensible. For shame.
“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.
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.
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.
Hydrogen at liftoff is actually a performance hit not a performance gain.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.
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.
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!The Chinese lunar program will ironically be the best hope for Nasa turning things around.
and....I think Dirksen actually said "million", not billion.A billion here, a billion there, and pretty soon you're talking real money.
- Everett Dirksen - 1896-1969
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.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)
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.
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.
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.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 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.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.
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.It's been so hamstrung by Congress that it's incapable of doing its core job function.
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.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.
For anyone late to the party, Wickwick is one of the combustion people.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.
You left out the High Fructose Corn Syrup.Now imagining a 300 foot tall bottle of flying orange juice....
I'm surprised NASA didn't send teams to the Ariana launches to see how they handle fueling their sustainer core rocket."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?
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.I'm surprised NASA didn't send teams to the Ariana launches to see how they handle fueling their sustainer core rocket.