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SpaceX Loses Starship Spaceraft During Test Flight

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Re: SpaceX Loses Starship Spaceraft During Test Flight

#171

Post by 38321003thrw »

alphabettsy wrote: post #169
the_third_wave wrote: post #113

This was mostly a success as far as test flights of experimental rockets go: it left the platform (which remained intact), it cleared the tower, continued on the set course, made it past stage separation and the second stage made it close to orbital speed and as such gave proof of the validity of the concept once the wrinkles have been ironed out. As predictable the news media - most of which seem to have an antipath…

Maybe it’s your own biases at work as well. The major publications I frequent including the NYT talk about it as being progress even with the explosion and seem very neutral if not hopeful and positive. NYT: “The journeys of Starship’s two parts ended in separate explosions. But the engineers at Elon Musk’s spaceflight company overcame problems that marred the rocket’s first flight in April.” https://www.nytimes.com/…

Compare:

Successful test of Starship’s two stages ended in explosions, making progress over the initial test flight in April.

Re: SpaceX Loses Starship Spaceraft During Test Flight

#172

Post by alphabettsy »

38321003thrw wrote: post #171
alphabettsy wrote: post #169

Earlier quoted context omitted.

Maybe it’s your own biases at work as well. The major publications I frequent including the NYT talk about it as being progress even with the explosion and seem very neutral if not hopeful and positive. NYT: “The journeys of Starship’s two parts ended in separate explosions. But the engineers at Elon Musk’s spaceflight company overcame problems that marred the rocket’s first flight in April.” https://www.nytimes.com/…

Compare: Successful test of Starship’s two stages ended in explosions, making progress over the initial test flight in April.

What am I supposed to be seeing?

Re: SpaceX Loses Starship Spaceraft During Test Flight

#173

Post by lamontcg »

gavinray wrote: post #110
parsimo2010 wrote: post #101

Earlier quoted context omitted.

It’s literal rocket science. Liquid fueled rockets have to work in basically the most extreme environments we’ve ever made machines work. Extreme cold temperatures through extreme hot and from extreme high pressures through vacuum. You have to have the best metallurgy and amazing machining tolerances. And then on starship they got it to work more than thirty times simultaneously.

Sure, but if one works, why wouldn't the rest? It's like saying "we built a car engine, but every 33rd car we make the engine doesn't" work. That's not a very good engine. Also, not sure why I am getting downvoted for saying I don't understand something and asking other people how it works.

Things like vibration and Pogo oscillation (https://en.wikipedia.org/wiki/Pogo_oscillation). All the engines collectively have about twice the thrust of a Saturn S-IC first stage (on the Saturn V rocket) and they're all going to be trying to shake the crap out of each other just due to thrust oscillations. If they hit a resonant frequency of the rocket it could shake the rocket apart. So, you can have 33 engines that all individually ignite properly on the pad and are all well-built to tolerances so that they function, but when you put the whole vehicle together and have all 33 of them pushing against the same airframe they could spectacularly fail.

Re: SpaceX Loses Starship Spaceraft During Test Flight

#174

Post by MatthewElvey »

avhon1 wrote: post #143
slenk wrote: post #139

Earlier quoted context omitted.

What bothers me is that they don't even try to succeed. They only want liftoff - they don't seem to care about the ever important orbital aspect

Why don't you think they're trying to succeed? They got very close to orbit today, much closer than many prototype rockets do. Just earlier this year, Japan's new rocket also failed to achieve orbit. Its second stage just didn't ignite at all. Starship got closer to orbit than that today. https://arstechnica.com/science/2023/03/the-launch-of-japans... The Soviet N1 rocket never even got past first stage separation, i…

I think most people don't understand the concept of if you want to succeed, fail faster.

It's valid (and explained well and often) but counterintuitive.

(And with mundane tasks, it's less applicable, as with them, it's reasonable to expect that when competent people attempt them, they generally get done correctly.)

Re: SpaceX Loses Starship Spaceraft During Test Flight

#175

Post by MatthewElvey »

qiine wrote: post #5
valine wrote: post #2

Altogether, it was a terrific flight and a big step forward for the Starship program. The biggest success was the survival of stage zero, which bodes well for a quick turnaround for the next flight. Hot staging was the second big success, and Starship got to space. The flight termination was disappointing, but the actual functioning of the FTS system seems to be fixed. That was a problem with the first flight and sho…

Sad we didn't get any shot from the Starship onboard camera during reentry.

Yeah, me too. There were onboard cameras on Starship and Super Heavy. Hopefully they'll release more footage and info over time.

Even the first launch had some. https://www.reddit.com/r/SpaceXLounge/comments/12claay/the_k.... I recall the during the SpaceX audio commentary of this morning's launch (but perhaps EverydayAstronaut's) it was mentioned that onboard cameras on Starship and Super Heavy would be attempting to communicate via Starlink for the first time.

Re: SpaceX Loses Starship Spaceraft During Test Flight

#176

Post by MatthewElvey »

fragmede wrote: post #125
DoesntMatter22 wrote: post #122

Earlier quoted context omitted.

The early history of rocketry was non stop blowups, I mean hundreds of them. You can watch edits of this on youtube. Rocket science is hard hence "It's not rocket science", except it is. Having money and smart people doesn't ensure success. Bezos started his company before Musk did Space X and they still haven't gotten to space.

And it's science that fails spectacularly. If I utterly fail at a Computer Science, there's no giant explosion.

Depends. Titan 4 test-stand SRB explosion; simulation missed failure mode (S 16 4)

The limits of simulation (From Henry Spencer) The 27May91 Aviation Week, reporting on the April 1 test-stand failure of an upgraded SRB (Solid Rocket Booster) for the Titan 4: Investigators determined that extensive three-dimensional computer simulations of the [motor's] firing dynamics did not reveal subtle factors that they now believe contributed to motor failure. [Program director] Stifling said the full-scale test was essential precisely because computer analyses cannot accurately predict all nuances of solid rocket motor dynamics. "That's why we test", he said. For those who don't follow the space news, a few seconds into the test the motor pressure rose rapidly and exceeded the limits of the casing, the result being a large, spectacular explosion that destroyed the motor and much of the Edwards AFB test stand.

-ACM SIGSOFT SOFTWARE ENGINEERING NOTES vol 16 no 4 Oct 1991 Page 15

Re: SpaceX Loses Starship Spaceraft During Test Flight

#177

Post by Ingaz »

panarky wrote: post #166
hinkley wrote: post #102

Earlier quoted context omitted.

People genuinely don’t understand how statistics work. Which is part of why Vegas still makes so much money. When you put together a bunch of equipment with a small error rate, the time between errors climbs very fast. Build a RAID array with 33 disks and you’d better have a vendor picked out for replacements because you’ll be doing replacements fairly often, instead of every four to ten years with a single disk. And…

> Build a RAID array with 33 disks ... Yes, naturally 33 > 1, so you might expect 33 times as many failures of individual components. But your analogy between arrays of rocket engines and disks is apt, because both have redundancy to survive the failure of individual components. For example, in the high-altitude flight test of the Starship prototype in May 2021, three of the 33 Raptor engines powering the first stage…

The interesting point for me was:

> Every failing hard drive requires a stressful operation on the remaining disks (resilvering) that may push the next drive to failure.

I saw something similar: RAID array with 5 disks and 3 spare disks. One night controller detected failure, ejected one drive and replaced with spare. After rebuild of RAID it ejected another disk and then another. In an hour all spare disks were used and on fourth failure it stopped work

What was probability of such series of failures?

Re: SpaceX Loses Starship Spaceraft During Test Flight

#178

Post by the_third_wave »

alphabettsy wrote: post #172
38321003thrw wrote: post #171

Earlier quoted context omitted.

Compare: Successful test of Starship’s two stages ended in explosions, making progress over the initial test flight in April.

What am I supposed to be seeing?

The thing is called "progress" and is the reason for doing these tests. If you really care about this I suggest looking back in the development history of SpaceX' current cash cow, the Falcon 9. Look for similar explosive events and compare that to the current ease with which they seem to launch and land and relaunch these things now. Now fast-forward another 10 years and imagine the same happening with this new rocket which is poised to bring down the price of launching mass to orbit by another large factor.

Re: SpaceX Loses Starship Spaceraft During Test Flight

#179

Post by alphabettsy »

the_third_wave wrote: post #178
alphabettsy wrote: post #172

Earlier quoted context omitted.

What am I supposed to be seeing?

The thing is called "progress" and is the reason for doing these tests. If you really care about this I suggest looking back in the development history of SpaceX' current cash cow, the Falcon 9. Look for similar explosive events and compare that to the current ease with which they seem to launch and land and relaunch these things now. Now fast-forward another 10 years and imagine the same happening with this new rock…

Yea I already know that and I’ve been following. The articles also say the same thing about progress so what’s the issue?

Re: SpaceX Loses Starship Spaceraft During Test Flight

#180

Post by nilamo »

dylan604 wrote: post #108
nilamo wrote: post #95

Earlier quoted context omitted.

Right but the comment you replied to is just pointing out that there can be multiple winners. Coke and Pepsi both are winning, though your comments sound like you think one is a loser for not being top sales in beverage.

If you ask the reps from Coke/Pepsi if they are losing to the other that has top sales, they will tell you "yes". If you ask someone dealing broadcast TV ratings if they are losing because they are the 2nd rated show, they'd also say yes. I'm not really sure your point. Just because the 2nd placed entity is earning lots of cash means that they are winning? They may be successfully operating their business, but if som…

No, you're using winning in a much more tedious way than most people.

If winning and losing were a spectrum, all those things you listed are very clearly much closer to winning than they are to losing.

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