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Government Watchdog Says SpaceX Falcon 9s Are Prone To Cracks (engadget.com)
An anonymous reader shares an Engadget article: SpaceX's Falcon 9 rockets apparently have a serious issue that could delay the company's manned missions. According to the Wall Street Journal, the Government Accountability Office investigated both Boeing and SpaceX -- the corporations that won NASA's space taxi contracts -- and found that Falcon 9's turbine blades suffer from persistent cracks. GAO's preliminary report says these turboblades' tendency to crack is a "major threat to rocket safety," since they pump fuel into Falcon 9's rocket engines. NASA's acting administrator Robert Lightfoot told the WSJ that government officials have known about the issue for months or even years. The agency even told SpaceX that the cracks are too much risk for manned flights. A spokesperson said SpaceX has "qualified [its] engines to be robust" to cracks, but it's now "modifying the design to avoid them altogether."
Falcon 9 and the space shuttle are the only rockets whose engines have survived the launch so that they could have been inspected. And similar cracks have been found on shuttle engines too. Many other rocket engines very probbly have generated similar cracks during their burn, but those have not been inspected because the engines have gone to the bottom of the ocean.
There have been 28 launches of falcon. During those 28 launches, 279 Merlin 1-series engines have been used, with only 1 major engine problem. And even in that case, the rocket delivered the primary payload to the desired orbit; Each falcon 9 has 10 engines and only on of those 10 engines is critical whose failure leads to mission failure.
So, until now, the engines have had 99.64% reliability, and due the engine redundancy, only 10% of engine failures means mission failure on most launches(upper stage engine may not fail), meaning mission failure probability of 0.04% due failing engine if the engines keep working equally well in the future than they previously have been working.
No, the this turbine thing is not a big problem. Bigger problems are elsewhere, and spaceX is improving the turbine blades. They will continue launching the version with the weak turbine blanes for some time, and it's very unlikely it will cause ANY problems at all, and then later the will release the block 5 model of the rocket with more robust turbine blades.
It seem that the whole issue is "leaked" by some guy who is pissed to spaceX/Elon for something and the media is always eager to post this kind of "leaks" without really understanding what it is all about.
Autopilot is half baked. I don't think he's even looking into the fact that humans cannot safely 'take over' from autopilot. This from a person who is apparently so afraid of how AI will be dangerous for people, he makes no effort to make it as safe as possible in his own products.
Laws are rules for the court, but merely a bottom bar to hit for life. Think beyond laws in your actions always.
Humans may not be able to "take over" but accidents were reduced according to the NHTSA investigation. So... that would mean humans being able to take over aren't necessary.
That being said, there are plenty of videos online of humans taking over so you're claim is patently false. Maybe they can't take over while watching Harry Potter but that's not the intended use.
It's a fuel pump. Unlike a reciprocating engine, where you can inject the fuel at low pressure and then compress it, a rocket engine has to inject the propellant at the same pressure it's burned at, and thermodynamics wants that pressure to be as high as possible in order to get maximum efficiency (imagine a car engine that injected fuel at the top of the cylinder stroke instead of the bottom). Combined with the sheer amount of propellant being used, that means you need an absolutely insane amount of power in your fuel and oxidizer pumps.
So they use a turbopump. A small amount of fuel and oxidizer are tapped off and burned. The resulting hot CO2 and H2O are used to run a turbine, which drives the pump. In the Merlin engines, and in many other engines, it ends up just exhausting, generating no additional thrust. Other designs, including Raptor, find ways to re-use that exhaust to generate a bit more power.