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Arthur Dent wrote: ↑

April 27 23, 8:45 am

I’m way outside my area here, but I read that it is not compressive stress that’s the issue with the pad concrete. Apparently, the massive amount of gas pressure will make its way through pores and cracks all the way through to the earth, and then produce a huge lifting pressure underneath. The heat loading helps cracks form and more cracks mean more pressure gets through, and you get a run away positive feedback. Though not exactly the kind of concrete physics that goes into your average building design, this is apparently well known, and their engineers were almost certainly aware that this was likely to happen. Musk claims that they they decided it was ok based on the short half throttle static fire test, which sounds exactly like the type management [expletive] I’ve encountered before.

Regarding the fuel tanks close to the pad, that does seem crazy. I would have thought that a the rocket detonating on the pad or only lifting off a short distance before coming crashing back down on the pad would be a more likely failure mode than the one they had. Maybe the theory is that this type of failure would be so bad, that the bit of extra fuel in the tanks is a “who care” afterthought?

Some close up photos of the debris cloud:

Those pictures are amazing.

Hadn't even thought about gasses getting into the pores. Running a static half load test does sound like some gonzo engineering [expletive].

Kind of an inside joke from a company I used to work at where one of the older guys didn't do much engineering and relied on younger people to do all the grunt work including technical design. Time to time, the actual design didn't match what he wanted so the design became a complete fabrication of this guys mind. Nothing that would risk much damage to anything but also not exactly what was required. Our saying when this happened was 'Jerry checked it' and out it went. I need a meme with a pic of that debris flying through the air with Elon checked it over it. If I knew how to post photos anymore, I'd do it.

AWvsCBsteeeerike3 wrote: ↑

April 26 23, 11:33 pm

I'm surprised they were allowed to store their fuel (I imagine that is what is in those big white silos/tanks) that close to the launchpad.

Ran across this photo of the SLS launchpad. I guess placing your fuel tanks pretty close to the pad is standard.
Also, another essay on the Starship test now that we have more info:

https://lavieohana.medium.com/starship- ... 3585d9e39d

Couple things stand out. Confirmation that the Flight Termination System, the safety device that’s supposed to detonate the rocket when something goes wrong took at least 40 seconds to produce the required destruction, which seems completely outrageous and unacceptable if they launch this thing within hundreds of miles of people.

Confirms that there is no secret backup plan for lunar missions, and they really do need to do 16+ quick consecutive launches to complete a moon landing mission.

If it works someday, it would be a highly capable system, but it’s massively over designed and risky for a near term moon landing, and it seems that this has predictably led to the current situation where is seems like they are unlikely to succeed.

Thanks for sharing that article. Seems like things could have been a lot worse. Hadn't realized that the rocket drifted so much. And wow, the FAA getting sued!

ghostrunner wrote: ↑

May 3 23, 10:36 am

Thanks for sharing that article. Seems like things could have been a lot worse. Hadn't realized that the rocket drifted so much. And wow, the FAA getting sued!

NEPA and its associated lawsuits are some some of the most dysfunctional elements of US practice surrounding building things. This is the vague 1970 law, that requires you to make a detailed statement about every possible environmental impact of everything but doesn’t actually require you to take specific actions, only state the possible consequences through incredibly expensive multi-year studies. This is a major reason US infrastructure costs are wildly out of control compared to peer countries. Texas Republicans are quite aware of this, and as a way to fight the scourge of renewable power in Texas are this year trying to pass a state level NEPA that would only apply to renewable projects because of how effective it is at preventing developments you personally object to.

None of this is to say that environmental review isn’t important, just that NEPA is wildly dysfunctional. if you need to spends multiple years and extra billions of dollars on environmental review for your solar power plant, that’s bad for the environment not good.

Anyway, the SpaceX launch does seem like a genuinely bad environmental event that should have been prevented by forcing SpaceX to show good engineering data that their launchpad was going to survive. If that were the main outcome of a NEPA lawsuit, that would be great, but that is not the norm for such things.

Arthur Dent wrote: ↑

May 3 23, 10:15 am

AWvsCBsteeeerike3 wrote: ↑

April 26 23, 11:33 pm

I'm surprised they were allowed to store their fuel (I imagine that is what is in those big white silos/tanks) that close to the launchpad.

Ran across this photo of the SLS launchpad. I guess placing your fuel tanks pretty close to the pad is standard.

Also, another essay on the Starship test now that we have more info:

https://lavieohana.medium.com/starship- ... 3585d9e39d

Couple things stand out. Confirmation that the Flight Termination System, the safety device that’s supposed to detonate the rocket when something goes wrong took at least 40 seconds to produce the required destruction, which seems completely outrageous and unacceptable if they launch this thing within hundreds of miles of people.

Confirms that there is no secret backup plan for lunar missions, and they really do need to do 16+ quick consecutive launches to complete a moon landing mission.

If it works someday, it would be a highly capable system, but it’s massively over designed and risky for a near term moon landing, and it seems that this has predictably led to the current situation where is seems like they are unlikely to succeed.

Thanks for sharing.

Unrelated but noteworthy.

Not sure how early astronauts typically get in their seats, but being in one for 3+ hours prior to launch, not even knowing if you're going to launch, would make me go insane. Being on an airplane for 20 minutes prior to departure drives me nuts. Nerves of steel those guys/gals.

Would Ozzy Osbourne still be able to bark at the moon if we detonated a nuclear bomb up there?

The crazy plan to explode a nuclear bomb on the Moon

In the 1950s, with the USSR seemingly sprinting ahead in the space race, US scientists hatched a bizarre plan – nuking the surface of the Moon to frighten the Soviets.

https://www.bbc.com/future/article/2023 ... n-the-moon

Another attempt at launching Starship is scheduled for tomorrow morning if anyone wants to tune in.

Arthur Dent wrote: ↑

November 16 23, 11:40 am

Another attempt at launching Starship is scheduled for tomorrow morning if anyone wants to tune in.

Hey, if NASA is launching these guys into space, I'm in.

Arthur Dent wrote: ↑

November 16 23, 11:40 am

Another attempt at launching Starship is scheduled for tomorrow morning if anyone wants to tune in.

Now pushed to Saturday morning.

Good show. Got much further with successful stage separation, though it seemed like it happened late. Booster started to head back for landing but something went wrong, and they blew it up. Upper stage completed most its burn before they blew that up too.

Looks like the launch pad upgrades at least mostly worked as it didn’t detonate, so hopefully it won’t require as much time to make changes and try again.