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SpaceX SN9 Explodes on Landing

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Re: SpaceX SN9 Explodes on Landing

#61
post #52
post #28

Love seeing these tests for two reasons: 1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."

On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…

The FAA seems to be concerned with exploded bits falling on innocent people. You are welcome to blow up your rockets all day long if you aren't putting other people at risk.

Re: SpaceX SN9 Explodes on Landing

#62
post #52
post #28

Love seeing these tests for two reasons: 1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."

On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…

Plenty of American rockets failed, especially early on! https://www.youtube.com/watch?v=13qeX98tAS8

Re: SpaceX SN9 Explodes on Landing

#63

Earlier quoted context omitted.

> As of 2020, there have been 15 astronaut and 4 cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three The numbers don't really seem to support your assertion that NASA is generally much safer than Soviet/Russia

At least 126 technicians and cosmonauts were killed by accidents during the Soviet space program. It’s rumored that additional cosmonauts died on missions that the Soviets covered up.

As far as technicians, I've always felt sad for the two Space Shuttle technicians who died in 1981 after entering a nitrogen-filled engine compartment (John Bjornstad and Forrest Cole).

Re: SpaceX SN9 Explodes on Landing

#64

Earlier quoted context omitted.

> As of 2020, there have been 15 astronaut and 4 cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three The numbers don't really seem to support your assertion that NASA is generally much safer than Soviet/Russia

But the U.S. has sent 3x as many citizens into space: https://en.wikipedia.org/wiki/List_of_space_travelers_by_nat... So combining with your statistic the U.S. has a fatality rate of 4.4% versus Russia's 3.3%. Given the low N it's probably within margin of error.

I don’t think it makes an enormous difference, but not all of those US citizens flew in US rockets (nor did all Russian ones)

Also, quite a few of those did multiple flights. Looking at that list, I think that moves the needle in favor of US rocket safety.

Re: SpaceX SN9 Explodes on Landing

#65
post #52
post #28

Love seeing these tests for two reasons: 1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."

On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…

[deleted]

Re: SpaceX SN9 Explodes on Landing

#66
Soon after SN8 Elon tweeted that they knew the problem. So they quickly added Helium to pressurize SN9, which is a bandaid given their deliberate elimination of Helium and the fact there isnt any on Mars. Now we see what looks like even worse relight capability.

I wonder if recent departures are related in some way. They failed plenty before, but this seems different.

Re: SpaceX SN9 Explodes on Landing

#67
post #16

Earlier quoted context omitted.

Honestly, my main takeaway from this testing and Falcon 9 dev has been that we should be doing a whole lot more of that than we have been, at least until there are human passengers. The contrast in rate of progress with eg SLS is stunning.

We knew this since watching how much the Russians got done in the time they had for the resources. Put the engineers together with the manufactures, build often, test more.

just don't sit near the launchpad

Re: SpaceX SN9 Explodes on Landing

#68

For both SN8 and SN9 my brain is screaming at me "surely they need more than 3 engines?!" Is the ultimate expectation that the engines will never fail, because it sure seems like they can't deal with losing even a single engine. I'm sure this is completely incorrect given that the issue for SN8 was tank pressure.

Building anything that can deal with a catastrophic engine failure at powered landing time is probably out of scope for the foreseeable future.

Caveat: Did I mistake the scope here? I’ve not checked to see at what point in the trajectory the engine actually failed as I am at work.

*deal with - meaning land successfully anyway

Re: SpaceX SN9 Explodes on Landing

#69
post #11

Earlier quoted context omitted.

It's funny because the Soviets did it right, in that they funded smart people and gave them control. The Nasa's approach was to have people create proposals and get approval for funds. We have forgotten that the "fund smart people and let them do what they want" is the best approach. Look at Xerox Parc, Bell Labs, etc. Nasa's modern approach with SpaceX and other companies seems to reflect these hard learned lessons.

These smart people did not have any semblance of control in the USSR. The Soviet space program was 95% political, heavily influence by the politburo and Soviet interests. Smart people would not have developed the Buran if all options were on the table

Surely that’s the same with NASA pork barrel politics affecting who gets to build it and therefore the particular companies and manufacturing capabilities the engineers have to work with. The space shuttle wasn’t engineering lead either.

Re: SpaceX SN9 Explodes on Landing

#70
post #62
post #52

Earlier quoted context omitted.

On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…

Plenty of American rockets failed, especially early on! https://www.youtube.com/watch?v=13qeX98tAS8

And SpaceX has blown up ten Falcons on landing attempts.
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