Starship explodes, but why?

so amazing this video of Elon Musk's latest spaceship the the starship blowing out blast fueling I was testing its oxygen tank so why did that happen well Rockets traditionally two giant fuel tanks some very powerful pumps that pump that fuel over the period of about two minutes into the engines which then takes you up into orbit those tanks one of them usually contains a powerful oxidant like liquid oxygen and liquid oxygen obviously a cryogenic liquid boils at about minus 170 that sort of thing but there is a colossal amount of it in there so if you pump it in at minus 170 180 that sort of thing then the vapor pressure above the liquid will be one atmosphere that means that you don't need a pressure vessel to store it in which are probably what all those tanks in the foreground are actually they're cryogenic storage containers now when a rocket sparks itself up and starts pumping that fuel from the giant tanks into the engines of course a hit sucks a vacuum into these giant fuel tanks and if you didn't compensate for that somehow the vacuum would cause those tank or the parasol vacuum would cause those tanks to collapse you'd lose the rocket yet have a bad day so what typically is done before the launch of the rocket issue pressurized the headspace of the rocket of the fuel tank with something that won't liquefy the liquid oxygen type temperatures which is you usually helium helium would is what is used so with all the big rockets that I know of you want that pressure to be as low as possible because that means the tanks can be as light as possible ba ya wanted to be strong enough to survive so with the shuttle tanks and with the Saturn 5 tanks they were pressurized to about you know two atmospheres to bar to launch the thing is here Terrace obviously a colossal amount of pressure in there you know my reckoning is you ballpark figures you couldn't know what the volume is prior to the actual explosion but if you say that these year tanks are like half-full and they expand to ten times that size that means there was 10 atmospheres of pressure in there which would be insane now it turns out that SpaceX have been trying to do something clever which is fine you might remember that they had a rocket that blew up sometime again and what caused that was a rupture of one of the high pressure helium tanks those the exact same helium tanks that are used to fill up the headspace of the rocket such that you don't pull a partial vacuum in your fuel tanks and destroy the rocket now spacex wants to get rid of those with some civil automatic system the repressurized the tanks using some clever mechanism from the exhaust or something you'll be very careful with this because if you're gonna pump any gas in there the gas if most gases will simply condense or shrink you contract the second they hit the cryogenic liquid so you really need a gas that won't liquefy and like I was saying I mean they'd it's basically here it's light and it doesn't liquefy so how do hell did they pressurize this thing up to getting on for 10 atmospheres this I just don't have a decent answer for and if you wanted to pressure a test these things here and there's numerous ways you could do it if you just wanted to test the pressure yo and you fill it up with water and then just inject a bit of gas into the top that would pressure test you for the pressure you might want to pressure test it at cryogenic temperatures in which case you don't need to actually completely fill the thing with cryogenic liquids which it looks from the way this thing blew up it is mostly full of cryogenic liquid so this is another thing that gets me right you can actually look up the vapor pressure of the liquid oxygen at various temperatures so you know you start off with liquid oxygen and one atmosphere boils at about minus 270 that sort of thing you've got to heat all of the liquid oxygen in that tank up something like 20 degrees which will take you an awful long time to conduct in the energy to heat up tons of liquid oxygen by that sort of temperature you would have lots of warning to do this so I mean my suspicion is twofold the first one is something very very simple that they have an overpressure valve asked and very often happen when you're dealing with large-scale cryogenic liquids he just condensed a load of water froze up once the relief valve is frozen up the temperature just goes up and up and up until the thing explodes option number one option number two they were trying to do some smart test with repressurizing the tank I mean it to me this seems way too early to be doing that sort of things I'm for me the my gut reaction is there were safety relief else there but they were just frozen up and yeah once he got up to about 10 atmospheres or something it went boom cuz yeah it's difficult to see why you would test something to destruction like this I mean that sort of pressure would be way beyond anything that the tank would normally be expected to run under like I was saying I mean you typically the tanks run and is slightly more than ambient pressure the turbo pumps at the bottom take the pressure up to about a hundred atmospheres that sort of thing so yeah I've just got no idea the pressure was so high in their tanks and no explanation has come forth from SpaceX just like when their whatever their Dragon capsule blow up so I'm going to go with it was probably a simple up I mean the problem is once your safety valve frozen shut it becomes almost suicidal fully fueled rockets are exceptionally dangerous now it's just one of the things always got me with Elon Musk's you know yeah we're just going to use them like airplanes but I'm gonna fly them 10 times as often per day to make them economically viable the longest part of that flight is actually the boat out and back I mean when come on this this this is awesome but it's crazy right like this is never going to actually happen oh no it's definitely gonna happen no no it's not going to happen and there's a very good reason for that um and let's talk a little bit about the business everyone thinks Rockets are really expensive and to a large degree they are yes they are expensive which is why this is a really stupid idea if only there was some sort of dumb justification would somehow make this dumb idea even dumber how could we possibly compete with airline tickets here but if you think about it if I can do this trip in half an hour to an hour I can do dozens of these a day right and yet a long-haul aircraft can only make one of those flights a day well yes and if I had transonic solar-powered planes I could do it even quicker and even cheaper so even if my rocket was slightly more expensive and the fuel is a little bit more expensive I can run 10x at least what they're running in a day and really make the revenue that I need to out of that system and clearly these oddly preposterous doesn't even hold up the most superficial of inspections but God the Elon Musk fans hate it when you point it out to them and if ya still believe that things like this are gonna be flying 10 is often this airplanes remember the more you hit the like button the quicker this will happen however for everyone else yeah sure why not if you enjoyed the video drop a like on it and they hit the notification belt to make sure you don't miss out on new content [Music]

Channel: undefined

Views: 55,499

Rating: 4.8879271 out of 5

Keywords: elon, musk, starship, space, spacex, explosion, boom, oxygen, tank, liquid, o2, pressure, frozen, valve, helium, rocket, tesla, apollo, nasa, shuttle

Id: rfVXFo6JMtI

Length: 9min 24sec (564 seconds)

Published: Tue Nov 26 2019

Reddit Comments

[u/UristMcKerman]

Agree with his version about frozen safety valve. It is the most likely the cause. But holy shit how did this genius of rocket science, a visionary had managed to explode a rocket because of it in 2019!? It would've been okay in 1960s, but in 21th century this is unexcusable

[u/Ulrichvon_Jungingen]

Saturn 5 rockets pumped 12 tonnes of fuel A SECOND for the 5 x F1 engines i.e. 1/4 the bull**** coming out of Musk's mouth a second.

[u/lithiumdeuteride]

It's not too complicated. A low-quality weld failed during a test which intentionally pressurized the tank beyond its maximum expected operating pressure.

[u/nyolci]

I like Thunderf00t, and he's mostly correct, but now he is mistaken about the pressurization gas. LOX is pressurized with heated oxygen, LH is pressurized with heated hydrogen. They use helium for kerozene. But anyway, his overall argument, especially his overpressure estimation is good as always.