SpaceX's Crew Dragon Spacecraft Exploded Because of 'Corrosive Bullets' and Leaky Valves

Pubblicato il 16 lug 2019
Yesterday SpaceX released a report on their analysis of the '4/20' Anomaly that destroyed their Crew Dragon spacecraft during a ground tests. It was the result of oxidizer leaking into the wrong part of the plumbing and then being propelled through the system as fast as a bullet.
www.spacex.com/news/2019/07/15/update-flight-abort-static-fire-anomaly-investigation
Raptor Engine images by Jack Beyer
www.jackbeyer.com/print

Commenti

  • Spacex sucks, but at least the taxpayer doesn't have to waste money on space crap anymore.

  • SpaceX dodged a bullet with this one.

  • We had a catastrophic failure would have destroyed the rocket and killed all the crew. We installed 60$ burst disc were sure that is our only problem. Ok who wants to ride into orbit 😁👍

  • Looks like someone didn’t fly safe.

  • The technical term for pushing the fuel through the piping into the check valve is fluid hammer. This can cause a piping failure at a valve or at an inadequately supported piping elbow. In my professional life I have seen piping move several feet due to fluid hammer, only the piping was supported to take the hammering.

  • Say it with me ALUM IN UM

  • ..... Ms paint 😂😂😂

  • Baddaboom!

  • So what are the benefits of using burst discs instead of check valves?

  • It would seem having a valve that opens rapidly instead of modulating was the main culprit but not even mentioned. Maybe the engineers there should have asked their local plumber about rapidly opening/closing shutoff valves and the pitfalls of check valves!

    • @Scott Manley G'day @Scott Manley Yes that's a good point, but we're not talking about the Janitor finishing his hamburger and then wandering out with a Stillson wrench to turn the valve on. A valve that "gradually" opens means milliseconds in order to control the pressure wave front. From your report, the NASA recommendation was for burst valves to be used, and at least that indicated they were considering the shock wave (indeed used that property to perform a function). It seemed by their design, the implications of the pressure wave weren't even considered by the designers, and the proof was in the pudding. ... In this case the pudding exploded. Not exactly a handy design feature for something intended to save the crew! How fast do you want your crew fried as both the "rescue system" and the rocket are exploding? After any accident there are always people like me who will come out with "Coulda ... Woulda .... Shoulda"; those of us in the aviation industry deal with it constantly. That may grate the current generation where everything is always "awesome", but I feel that's the price to pay when dealing with other people's lives/money. I sometimes get the impression the team there are making it up as they're going along. That's fine when building video game; how many there are putting their hand up to sit on top of the candle when they light it? Would you? Obviously all just my personal opinion.

    • @Pete F OK, so how slowly do you want an emergency escape system to operate when your rocket is exploding?

    • @Scott Manley Scott thanks for replying, but from what you mentioned it was the OPENING of the valve in the pressurising gas that caused the "obstruction" to be propelled along the fuel line, causing the damage. This is a very basic and known problem and a first year apprentice plumber would be aware of that issue (as would any home owner dealing with "water hammer"). Obviously I know nothing more about the system than what you described (very well incidentally), but it appeared there was no good reason to have the pressurising system's valve operate so quickly. Pressure shock waves in hydraulic systems is nothing new, neither is the fact that check valves leak. Fluid Dynamics is a first year engineering subject, at least down here in Oz. I thought this failure was a face-palm moment and I'm literally embarrassed for the engineers involved.

    • Do you have time for a slow opening valve if your rocket is exploding?

  • psi really? Use real units man.

  • There is a mystery on the 600 psi disappeared from the He tank. It has been tremendously compensated by the perfect quality of the graphics.

  • Its Tony Bruno

  • corporations can only afford to deliver profit..

  • I believe they haven't killed anyone on their tests yet. but some have

  • I would love to see a video what would happen if a rocket just ascended vertically. Straight up no trajectory

  • Can the pressure system not be brought up to operational pressure slowly so the N2O4 in the lines doesn’t arrive like a bullet?

    • Scott Manley ah, yes well there’s that point. I’d forgotten this was for an escape system. Can the plumbing not be prefilled with an inert buffer? Wouldn’t that prevent the bullet effect of leaked oxidizer without having the untestable burst disk be a part of the mechanism?

    • How long do you want to wait in an emergency abort?

  • I would think the psi in the Helium tank would be higher. ie: my air tank (scuba) holds 3k psi. (not to compare per use)

  • Nope...it exploded because of lack of foresight. Blame it on a valve like an oil rig? No purge valve, no trap in piping, no sensors behind or after valve to test pressures, detect oxidizers in helium? Plz Even a hobbiest at the drag strip installs a purge valve on their NOS system for safety.

  • What about doubling up the check values? Having 1 Check value, then another right after it? You could even add a sensor of some kind in-between the check values and before it. A sensor type that can emit a scanning signal of some kind that is non-reactive to the materials used. If a leak is occurring in one check value, hopefully the second check value can ensure that it wont get very far and the sensors can detect the problem long before device activation.

  • Thank you Scott Manley!!

  • So, Scott, why are the valves replaced by the burst disks, and not supplemented by them by, for example, placing the burst disks between the LF/O tanks and the check valves? These are both relatively low-cost parts, in the context of a rocket engine, but each protects from different kinds of failures, and importantly, these different kinds of failures occur at different times.

  • Great news! The silence was worrying me.

  • 1080p, full HD resolution in MS Paint...lol, you killed it Scott! The best!

  • im impressed with the super draco bell you managed to make in paint. lol

  • Hmmm... So titanium under the right circumstances can act as catalyst? Actually this accident can open new avenues.

    • Not a catalyst; a fuel.

  • The one way valves go back to default closed position to stop fluids going back down the pipe, they are usually spring loaded to auto shut when the pressure drops to below spring force etc, but of course can be motorised

  • Come on it was 4/20 they were all smoking that maryjane. This is just a coverup. But great breakdown, it really helps when everything is simplified down like this.

  • The sooner Spacex gets rid of the helium pressurization systems with Starship the better. It has caused so many headaches.

  • As usual, a quality video (even with MS Paint) full of great info, and explained in a way that everyone can understand. Thank you Scott.

  • Why not keep a bit of helium pressure in the lines at all times?

  • Lucid Explanation. Thank You.

  • by adding bust disk spacex will be making the thrusters a one time use right? one time per flight till the disk can be replaced?

    • No but it was originally designed to propulsive landing and what not just a escape system the system can leave orbit and reenter the atmosphere if the second staged malfunctioned in orbit the draco thruster can do alot more just be used for escape system

    • because you're planning to use the escape system multiple times in the same mission?

  • Most importantly, we now know that there is a spy inside spaceX

  • Well, seems like The old school engineering firms such as Boeing , Lockheed and Northrop know something after all.

  • As stressful a job as it would be to try and figure this out, it's gotta be incredibly rewarding to piece it together and find the answer. Never doubted the SuperDracos for a moment.

  • Wait a minute? Aren't the superdracos supposed to be in-flight restartable?

  • This has been documented for decades. It’s known as the “Taco Bell Effect.” When high pressure gas accelerates a soft blob of material directly through a one-way check-valve apparatus, causing an unexpected blowout. Every taco tuesday, someone experiences this effect.

  • 02:34 ,,something werent quite right'' you told at the start on the video they know exactly what went wrong... seems to me they actually dont now anything^^ in my opinion this ,,something werent quite right'' should be the main thing to look after or am i wrong??

  • so it is Space X causing the helium shortages in the US.

    • Nah, it’s economics. In the 90’s politicians started selling off the strategic helium reserve, that meant it wasn’t profitable to harvest helium. Now supply can’t match demand.