totm nov 2023 SpaceX Discussion Thread

[Spaceception]

1 minute ago, JoeSchmuckatelli said:

I was looking at the Moon to Mars thing and it dawns on me. 

SX really needed the 'engines shatter concrete and blowback destroys engines' thing with the launch table. 

I mean, sure you can model stuff and game it out - but nothing proves that landing a ship on the main engines might need rethinking like just destroying them on takeoff. 

 

SpaceX have already addressed that to some extent. They're supposed to be using a cluster of engines mounted further up for landing and presumably takeoff for the Artemis lander. They might be adequate for Mars too, at least enough for the intial/final moments near the ground.

[mikegarrison]

Just now, Spaceception said:

SpaceX have already addressed that to some extent. They're supposed to be using a cluster of engines mounted further up for landing and presumably takeoff for the Artemis lander. They might be adequate for Mars too, at least enough for the intial/final moments near the ground.

Those engines are for landing, but I'm not sure about takeoff.

However, the lunar lander has non-aerodynamic features that a Starship intended for aerobraking/re-entry can't have.

[sevenperforce]

51 minutes ago, mikegarrison said:

Those engines are for landing, but I'm not sure about takeoff.

They are for both; there is no refuel on the lunar surface.

51 minutes ago, mikegarrison said:

However, the lunar lander has non-aerodynamic features that a Starship intended for aerobraking/re-entry can't have.

True. However, the first few star ships to Mars will be one way. The upper section could incorporate blow-off panels in the heat shield to allow for those canted landing engines.

[tater]

8 hours ago, mikegarrison said:

I am not trying to say that SpaceX is developing Starship entirely on NASA money, or that they were not going to develop it if they hadn't won that contract. But they are using that contract to help subsidize developing it. It's all quite reasonable, but it would be wrong to say there is no NASA money in Starship.

When they hit milestones, yes, certainly. The thing is, they'd be building it anyway—it was actually surprising they won the contract (probably credit to Shotwell, she's... just fantastic).

[Exoscientist]

 

[Nuke]

8k and they formatted it for phone screens. you wasted 3k of my 4k monitor, so i only saw it in 1k.

Edited April 23, 2023 by Nuke

[JoeSchmuckatelli]

I just watched a slowmo of the launch... and the Kraken actually smiled on SX.  Look at the video below - the sheer size of some of the chunks of stuff flying up in the dust plume.  It's literally a miracle that the ship flew at all.

 

Time set to just before the plume.

Manley says 'Big component is dust, and sand, and pulverized concrete' - but looking at the video?  There's BOULDER sized chunks flying straight up alongside the rocket.

[Exoscientist]

 

 Here’s a short clip of it:

 

[JoeSchmuckatelli]

23 minutes ago, Exoscientist said:

 

 Here’s a short clip of it:

 

Those are not small splashes 

[darthgently]

58 minutes ago, JoeSchmuckatelli said:

I just watched a slowmo of the launch... and the Kraken actually smiled on SX.  Look at the video below - the sheer size of some of the chunks of stuff flying up in the dust plume.  It's literally a miracle that the ship flew at all.

 

Time set to just before the plume.

Manley says 'Big component is dust, and sand, and pulverized concrete' - but looking at the video?  There's BOULDER sized chunks flying straight up alongside the rocket

There are several technical observers/commentators that watch every thing happening at Boca Chica that have expressed extreme doubt about the entire concrete pad issue many times and they have 100% rights to say "I told you so" at this point

[grawl]

9 minutes ago, darthgently said:

There are several technical observers/commentators that watch every thing happening at Boca Chica that have expressed extreme doubt about the entire concrete pad issue many times and they have 100% rights to say "I told you so" at this point

I guess they reached the point  where Best Part is No Part and Move Fast and Break Things cross their paths !

[JoeSchmuckatelli]

1 hour ago, grawl said:

I guess they reached the point  where Best Part is No Part and Move Fast and Break Things cross their paths !

Well played, sir.

[StrandedonEarth]

2 hours ago, grawl said:

I guess they reached the point  where Best Part is No Part and Move Fast and Break Things cross their paths !

"If you don't find yourself adding parts back in, then you haven't removed enough parts!"

[Nuke]

one of my more questionable life choices ended in the phrase: "dude! you're losing parts!"

[magnemoe]

3 hours ago, JoeSchmuckatelli said:

I just watched a slowmo of the launch... and the Kraken actually smiled on SX.  Look at the video below - the sheer size of some of the chunks of stuff flying up in the dust plume.  It's literally a miracle that the ship flew at all.

Time set to just before the plume.

Manley says 'Big component is dust, and sand, and pulverized concrete' - but looking at the video?  There's BOULDER sized chunks flying straight up alongside the rocket.

Agree, that plan did not worked well and it created serious damage to the pad as it got blasted hard, also damage to tank farm and probably the tower. 
But the rocket was defended by the rocket flame so its not that much going straight up. Enough to take out some engines I guess but not a lot. 
 

[FleshJeb]

I have some issues with the narrative that this was a wild success. Smells like marketing. Shifting the goalposts from aspirationally "crashing Starship in the Pacific" to "clearing the pad" is a pretty clear sign to me.

"Flying concrete is bad for rocket engines" is not novel or valuable data. "Well they figured out how NOT to build a pad!" Yeah, NASA figured that out over 50 years ago, and they have the papers and math freely available to study. This is still not a lesson that needed to be learned. It's a big rocket, but the parameters are not out of spec for what we already know how to do.

I sat down with my dad this afternoon, who has been a civil engineer for 45 years, and described the setup and end result to him. The first words out of his mouth were, "That is some amateur BS."

He asked me why they launched if they had a flame diverter almost ready to go, and I was only able to answer with "scheduling issues." His response was, "Of course schedule is always an integral factor, but if your 'profit margin' is [volume and quality of] test data, and you lose half to 3/4 of your opportunity to generate data [Starship not getting any meaningful testing in this event], then you've just cost yourself time and money for no good reason."

In terms of opportunity cost, I can only see this as a massive failure.

I will grant that erosion is a big problem in engineering, because it's a cascading failure--Any flaw in design or construction will be exploited. So the answer is always robust design and safety factors. At the very least, you should understand the failure modes and plan for where the blowout is going to occur. If anyone followed the Oroville Dam spillway failure, you might recognize that it was located well away from the main body of the dam, and that's why the undercutting wasn't completely catastrophic. It was still a massive design and maintenance screwup, but nobody died.

Sevenperforce did a really great analysis upthread showing that being only 18% above nominal in a bunch a factors leads to a 600% worse outcome. In isolation, that seems like a big number, but it also means that a very tiny 1.2 factor of safety on all their inputs would have solved the problem.

I've worked for engineering firms that specialize in doing challenging and innovative things. Unfortunately, that didn't include having robust standards, workflows, and competency in the basics. Because we're cool and innovative and that's just boring stuff. What that results in is failures, blown budgets, late nights, apologetic calls to clients, and construction change orders. The cool and innovative thing was rarely the primary challenge on the project.

So when I see an organization making very basic engineering errors and trying to handwave them by pointing at the cool and innovative part, I'm not too impressed. I just see a cultural and systemic problem in the organization.

[Gargamel]

5 hours ago, JoeSchmuckatelli said:

Those are not small splashes 

Splashes of unusual size 

[Pthigrivi]

Man maybe Im just a yankee but damn where is the common sense. Stage zero is the one thing you’re not trying to destroy. Take half a year and finish the deluge system. This is straight up dumb. When are people gonna take a second and realize Elon is just an obnoxious toolbag who offers zero value to this equation. 

Edited April 24, 2023 by Pthigrivi

[GuessingEveryDay]

58 minutes ago, Pthigrivi said:

When are people gonna take a second and realize Elon is just an obnoxious toolbag who offers zero value to this equation. 

Elon does help light fires under everyone and help them move faster.

Come on, which company is going to be at the front in 5 years? It's either SpaceX or Stoke, and SpaceX will still have the biggest rocket.

[Nothalogh]

2 hours ago, FleshJeb said:

I have some issues with the narrative that this was a wild success. Smells like marketing. Shifting the goalposts from aspirationally "crashing Starship in the Pacific" to "clearing the pad" is a pretty clear sign to me.

"Flying concrete is bad for rocket engines" is not novel or valuable data. "Well they figured out how NOT to build a pad!" Yeah, NASA figured that out over 50 years ago, and they have the papers and math freely available to study. This is still not a lesson that needed to be learned. It's a big rocket, but the parameters are not out of spec for what we already know how to do.

I sat down with my dad this afternoon, who has been a civil engineer for 45 years, and described the setup and end result to him. The first words out of his mouth were, "That is some amateur BS."

He asked me why they launched if they had a flame diverter almost ready to go, and I was only able to answer with "scheduling issues." His response was, "Of course schedule is always an integral factor, but if your 'profit margin' is [volume and quality of] test data, and you lose half to 3/4 of your opportunity to generate data [Starship not getting any meaningful testing in this event], then you've just cost yourself time and money for no good reason."

In terms of opportunity cost, I can only see this as a massive failure.

I will grant that erosion is a big problem in engineering, because it's a cascading failure--Any flaw in design or construction will be exploited. So the answer is always robust design and safety factors. At the very least, you should understand the failure modes and plan for where the blowout is going to occur. If anyone followed the Oroville Dam spillway failure, you might recognize that it was located well away from the main body of the dam, and that's why the undercutting wasn't completely catastrophic. It was still a massive design and maintenance screwup, but nobody died.

Sevenperforce did a really great analysis upthread showing that being only 18% above nominal in a bunch a factors leads to a 600% worse outcome. In isolation, that seems like a big number, but it also means that a very tiny 1.2 factor of safety on all their inputs would have solved the problem.

I've worked for engineering firms that specialize in doing challenging and innovative things. Unfortunately, that didn't include having robust standards, workflows, and competency in the basics. Because we're cool and innovative and that's just boring stuff. What that results in is failures, blown budgets, late nights, apologetic calls to clients, and construction change orders. The cool and innovative thing was rarely the primary challenge on the project.

So when I see an organization making very basic engineering errors and trying to handwave them by pointing at the cool and innovative part, I'm not too impressed. I just see a cultural and systemic problem in the organization.

Come on, now, you're a KSP player.

Anything downrange of the pad is some kind of success, when unmanned.

And any landing you walk away from is a good landing, when manned.

 

And all this wailing and gnashing of teeth is childish at best, the alternative is to do this the post-Apollo NASA way, which would add twenty years and ten times the budget for a quarter of the initially intended features.

Sorry, not sorry, I don't want another Space Shuttle, and neither should you.

[CatastrophicFailure]

People are really seeing what they want to see around all this. Elon said many times prior to the launch that he wanted to mute expectations, and yes that anything clearing the tower and sending telemetry really would be a success. We, as spectators, have been a bit spoiled the last few years. There was plenty of pre-launch handwringing before Falcon Heavy, and even then Musk said he only gave it 50/50. Then it went & turned out to be not only a success but an astounding success, no one was expecting Starman streaming mind-blowing views for six hours before heading off into the wild black yonder. Block 5 has had a perfect record, and even booster landing has become “normal” and rarely fails. 

I think it’s given the peanut gallery a false sense of security to a degree, we tend to forget that space is hard. Big Space is even harder. 

We are just a bunch of armchair Monday-morning rocket scientists and as I often say, we don’t have all the data. Some of the best minds in the world who do have all the data examined the situation and thought the pad could survive a single launch. Obviously they were wrong, but we outsiders don’t know how wrong. If, as it appears more and more, this thing was a hair’s breadth away from a RUD the entire time, then the fact that the facilities are still standing at all is nothing short of amazing. Maybe if one thing went a little differently we wouldn’t be having this discussion at all, cuz either the launch site would be completely boned or just barely scratched. Or maybe not. But all we have is pure speculation because, again, we don’t have all the data. 
 

1 hour ago, Pthigrivi said:

Elon is just an obnoxious toolbag who offers zero value to this equation. 

I’m not gonna get into this with you beyond this one sentence, but I need to say it. 

You are WRONG; purely, objectively, bitterly wrong. 
 

ok I’m done, /rant_off, that’s enough internet for tonight. 

[Pthigrivi]

46 minutes ago, GuessingEveryDay said:

Elon does help light fires under everyone and help them move faster.

Come on, which company is going to be at the front in 5 years? It's either SpaceX or Stoke, and SpaceX will still have the biggest rocket.

He’s doing basically one thing really, really well—convincing people who like him have as much money as they do an overinflated sense of their own genius to sign great big checks. And great! These idiots are financing some really cool engineering! They also have about as much genuine understanding as Elon does, which is to say about as much understanding as Elizabeth Holmes had in blood testing. Its all fine when they’re actually listening to the engineers. But at a certain point some of them decide money and ego and “fire” can purchase reality. What SpaceX has accomplished is incredible, and no one should take away from the tireless work all those folks have put into it. At the same time the dude wandering about taking credit for it all named his presumably human child an equation and followed up the model 3 by trying to sell workaday American contractors a cyberdelorean. Its possible, maybe, he's just an overinflated moron. 

[FleshJeb]

40 minutes ago, Nothalogh said:

Come on, now, you're a KSP player.

Anything downrange of the pad is some kind of success, when unmanned.

And any landing you walk away from is a good landing, when manned.

 

And all this wailing and gnashing of teeth is childish at best, the alternative is to do this the post-Apollo NASA way, which would add twenty years and ten times the budget for a quarter of the initially intended features.

Sorry, not sorry, I don't want another Space Shuttle, and neither should you.

I'm this kind of KSP player:

Spoiler

Don't pee on my head and tell me it's raining--I've been in the civil engineering industry for 30 years, I have close to 1000 projects under my belt, and I'm the guy they call to fix it when the project is FUBAR.

What, in your mind, would have constituted a failure for this mission? Not clearing the pad? They're very lucky it made it, for completely predictable and avoidable reasons. Luck is not in the engineering handbook.

Quote

the alternative is to do this the post-Apollo NASA way

This is a false dichotomy. The industry can be less risk averse AND dot their i's and cross their t's. That doesn't change the fact that with some better risk mitigation, this mission could have had a MUCH higher return on investment. That's objective fact. My subjective opinion is that I find it hard to believe that the value they got out of it was worth the investment, since an orbit-capable Starship got all blowed up before they lit the candle.

I want to see humanity have access to space as much as you do, that's why i think it's important to recognize and critique the failures.

Quote

For Want of a Nail

For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of a rider the message was lost.
For want of a message the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.

 

Quote

I don't want another Space Shuttle, and neither should you.

Yes, I 100% agree. The Shuttle was a waste and a boondoggle from first engineering principles, and I have nothing nice to say about it.

[tater]

Part of the cascading failure is deciding to go if they lost any engines on run up to liftoff for any reason, increasing dwell time on the area below the OLM.

I assume the reason they did not do a full power static fire is very much that they thought it would not do well. The short duration F9 static fires might well be because the pad is designed for full power (with margins) for the distance/time of a launch—moving meters away per second.

As a reality check up thread I pointed out that the distance from the bottom of the 39A/B flame trench to the bottom of Shuttle was ~18-21m depending on what height they left the crawler at (it can adjust between 20-26 feet tall). The OLM is ~17m from the ground. So 1-4m closer depending on the crawler. Split the difference and say 2m.

So in effect, they have the flame trench already, that's just XX meters of empty space under the booster. Once they get a actively cooled diverter they might be able to do a full static fire, or at least work their way up.

The con side of a full static fire on the pad is that there is a nonzero chance of a catastrophic failure—which would be worse all around than a failure of the concrete under the OLM.

We'll get to know what the real delay would have been if part of the repairs is installing the deluge/flame diverter they already have. If they manage to get it together in just a few months, then the damage looks less concerning—but it also means that the delay in getting it set up right the first time would have been if anything shorter than the repair time. We'll know soon enough.

Still if they get the pad up and running in 2 months (per Musk) then they could have pushed the launch until June and had the deluge/diverter installed anyway for the first flight.

Edited April 24, 2023 by tater

[Nothalogh]

25 minutes ago, FleshJeb said:

This is a false dichotomy.

It would be a false dichotomy if it weren't the de-facto standard operating procedure of all the parties heretofore involved, for the last fifty years.

They blew up five, if I remember correctly, Atlas SM-65s before they got one to fly.

THAT is the standard I want to see a return to.