Posted on 09/06/2022 5:02:31 PM PDT by BenLurkin
Hydrogen is extremely useful as a rocket fuel. It’s readily available, clean, lightweight, and, when combined with liquid oxygen, burns with extreme intensity.
To keep it from evaporating or boiling off, rockets fueled with liquid hydrogen must be carefully insulated from all sources of heat...venting is necessary to prevent the tank from exploding..liquid hydrogen can leak through minute pores in welded seams.
When tanking SLS, the sudden influx of cryogenic hydrogen causes significant changes to the rocket’s physical structure. The 130-foot-tall (40-meter-tall) hydrogen tank shrinks about 6 inches (152 mm) in length and about 1 inch (25.4 mm) in diameter when filled with the ultra-cold liquid, according to NASA. Components attached to the tank, such as ducts, vent lines, and brackets, must compensate for this sudden contraction. To achieve this, NASA uses connectors with accordion-like bellows, slotted joints, telescoping sections, and ball joint hinges.
But hydrogen—the smallest molecule in the universe—often finds its way through even the tiniest of openings. The fuel lines are particularly problematic, as they cannot be hard-bolted to the rocket. As their name suggests, the quick disconnects, while providing a tight seal, are designed to break free from the rocket during launch. This seal must prevent leakage under high pressures and ultra-cold temperatures, but it also needs to let go as the rocket takes flight. On Saturday, a leak in the vicinity of the quick disconnect reached concentrations well beyond the 4% constraint, exceeding NASA’s flammability limits. Unable to resolve the leak, NASA called the scrub.
That NASA has yet to fully fuel the first and second stages and get deep into the countdown is a genuine cause for concern. The space agency has dealt with hydrogen leaks before, so hopefully its engineers will once again devise a solution to move the project forward.
(Excerpt) Read more at gizmodo.com ...
The Engineers who designed/built the Apollo rockets did it with sliderules.
They should fuel the rockets with helium instead of hydrogen. Much safer.
valuing diversity over merit
Designed with slide rules
Drawn on vellum with pencil
Fabricated by high school graduates on manually operated machine tools
Good Lord, how did they ever do it /sarc
“60 years later and we’re still using rockets”
What do you suggest?
Don't say it.
There is no connections for hydrogen that are 100% free of leakage. So what does SpaceX do?
NASA handled LH2 just fine for Saturn V upper stages.
NASA handled LH2 just fine for STS.
Euros handle LH2 just fine for Ariane 5 and Ariane 6
ULA handles LH2 just fine for Delta IV and Delta IV heavy
ULA handles LH2 just fine for Atlas V upper stage
It’s not like LH2 is some kind of new, untested fuel that nobody is really familiar with ...
I wonder how much continuity there is in organizations like this. Do “lessons learned” have to be re-learned decades later?
Hydrogen is racist!
SpaceX uses RP1/LOX in Falcon 9 rocket and CH4/LOX in the Starship rocket.
Quite possibly the stupidest comment ever.
Exactly, safer and easier to handle.
Lemme guess - gaskets and / or sealant materials must be green / earth friendly
As an engineer, I really want to see the system work ... too many good people have put too much work into it ... OTOH, it really is a mess ... a worse mess than the STS ... and needs to be scrapped/replaced ASAP. And NASA should publish performance specs and let industry design and build the thing. Sort of like they did with the 1960s space program.
Maybe then it would actually work.
Back when this fiasco got started, they had a team study the old F-1 engine and design a new "F-1B" engine that would have had better performance, while being compatible with the US industrial base ca 2013. Congress nixed it in favor of reusing Shuttle stuff. ARGGH!
They need a rocket scientist to deal with that.
The Saturn V was fueled by kerosene and liquid oxygen.
LH2 blew up the Challenger.
This is going to prove to be a diversity-fueled fiasco that we will be lucky to ever fly. When I saw they had incorporated SRBs I almost threw up.
See #29 ... LH2 is a fine fuel, widely used for decades without any real trouble. The problem isn’t LH2, the problem is a fxxxed up culture at NASA and a fxxxed up culture in Congress.
Monomethylhydrazine (not simple hydrogen) and nitrogen tetroxide (powerful oxidizer) are the normal rocket fuels.
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