SpaceX Starship upper stage explodes during ramp-up to expected engine test firing

[Cheezoholic]

24. It's amazing to me that SpaceX engineers are re-learning all of the lessons NASA testing has already gone through

One of the biggest issues with very large rockets is "POGO", a harmonic vibration issue that rips very large rockets apart under acceleration. NASA pretty much solved (though not 100%) this issue 60 years ago with the way the different stages were attached to each other (ripping off a Russian design on the original Soyuz. SpaceX thought they were smarter but guess what, hey are now implementing those design characteristics.

Another is "sloshing" of the massive amounts of fuel in the tanks during acceleration, deceleration and maneuvering. If a powerful rocket engine which pumps 1k's of pounds of fuel per second into its ignition chamber is deprived of either the oxidizer and/or the fuel being burned for even a millisecond because the fuel is "sloshing" around in the pressurized tanks it will melt and explode. NASA solved this problem 60 years ago including doing something called "hot staging" that allows the second stage to ignite while the first stage is still accelerating bot at an ever decreasing rate. SpaceX lost 2 boosters due to this now they are "hot staging".

This "ship" has a new version of their very impressive Raptor engine however they are tackling issues with fuel leaks and transport to these engines. These engines are some of the most powerful and efficient rocket engines yet designed but without being too nerdy there are some lessons once again from the Apollo F1 they could learn from and possibly prevent the issues they
are having with leaks etc. (Btw, the engineers during the Gemini/Apollo program were dealing with Hydrogen to mix with O2 and burn in their engines, a fuel that is 1000 times more complex to work with that the Methane SpaceX uses. Should be a hint right there of how good they were back then)

There are several other things from the 60's SpaceX has ignored as "old thinking" , "just a bunch of nerds with slide rules and pocket protector" rocket scientists and engineers when in fact they should've taken the engineering prowess from that period and used it as a foundation instead of shrugging it off. It's one of the reasons SpaceX's legendary engine designer Tom Mueller left the company many years ago. There was too much resistance by Musk mainly to apply what Musk thought was ancient technology.

I will confess I have been a rocket/space nerd all my life and am fairly well versed in a lot of aspects (rocket scientist I am not lol) and I love what SpaceX is trying to achieve. Not so much the Mars colony fantasy in 5 years ( we have to go back to the moon first period) but they are the ones pushing the envelope in rocket design and efficiency. Contrary to what people may think the engineers and for that matter everyone who works for SpaceX are not a bunch of Eloon fanboys. I personally know a couple. These are very smart young people with vision and drive to do the undoable in their minds. The same vision and drive of the "slide rule" folks back in the 50's and 60's. The sad part is our government space and engineering program has been thrown onto the trash heap so these kids have nowhere to go but someplace like SpaceX. The asshole literally has all the money in the world to throw at this so it's where these bright minds land. There's a reason Eloon doesn't "run" the company. There's actually a contract that keeps him from totally wrecking it, which he would if he had free-range.

And I think, from what I'm hearing and seeing, they are cracking open some notebooks from the 60's because they've already changed many facets of their design using the knowledge from some amazing engineers 60 years ago. They are "hot staging" now, they've incorporated water suppression and flame trench's on the pad, they've re-designed pad fueling connecters to nearly Apollo specs, and tons of other things. They're a year or 2 away still from getting this thing flight ready so expect more "RUD's". They could be 5 years ahead from where they are now if they'd have done that in the first place IMHO.