Author Topic: Scrappy or crappy? Critique by former SpaceX lead engineer  (Read 39387 times)

Offline alugobi

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #120 on: 05/17/2023 05:20 pm »
fixing the launch mount post-launch won't take any longer than fixing it pre-launch would have.
I don't think that that's right.

The mess made added days, if not weeks, to clean up that they wouldn't otherwise have had, if the surface was still intact and they could just start busting it out and digging for the substructure of the steel.  They're also replacing cladding that would still be serviceable.  Probably other stuff, too.

Offline Robotbeat

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #121 on: 05/17/2023 05:27 pm »
I’m not totally sure. The estimates pre-launch for how long it would take to get that flame plate installed are about the same it looks like that they’ll actually get it installed. I think the flight added urgency. The fight also eliminated uncertainty. They have solid data on what kind of loads and conditions to expect that they didn’t have before. Certainty allows expediency.

I mean, on a first principles basis and ignoring the epistemology aspect (ie hindsight, reduction in uncertainty, etc), you would expect it to take longer because there’s more work to do, but much of that work can and is being done in parallel and the epistemological aspects allow them to work faster now than they may otherwise have done.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline DanClemmensen

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #122 on: 05/17/2023 05:31 pm »
fixing the launch mount post-launch won't take any longer than fixing it pre-launch would have.
I don't think that that's right.

The mess made added days, if not weeks, to clean up that they wouldn't otherwise have had, if the surface was still intact and they could just start busting it out and digging for the substructure of the steel.  They're also replacing cladding that would still be serviceable.  Probably other stuff, too.
It appears to have been about 21 days, assuming that beginning the drilling for the new pilings is on the critical path and making some WAGs about the time needed prior to that drilling if the 4/20 damage had been minimal. To my uneducated eye, it appears that the other repair work is not on the critical path, so yes, it's extra work, but no, it does not affect the schedule unless those workers were needed on the critical path.

Offline Robotbeat

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #123 on: 05/17/2023 05:44 pm »
It is also quite possible they are reinforcing the pad more than they would have if they had waited for the flame trench.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline envy887

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #124 on: 05/17/2023 06:35 pm »
fixing the launch mount post-launch won't take any longer than fixing it pre-launch would have.
I don't think that that's right.

The mess made added days, if not weeks, to clean up that they wouldn't otherwise have had, if the surface was still intact and they could just start busting it out and digging for the substructure of the steel.  They're also replacing cladding that would still be serviceable.  Probably other stuff, too.

More work? Probably. But they have lots of people and can do more than one thing at a time, so I don't think it would have been significantly faster to do the upgrades before launching. Clean up and cladding repair is happening in parallel with the mount upgrades, so those don't contribute to the critical path timeline.

But in the meantime, the propulsion and structures teams now have real data to chew on, which lets them do their jobs faster, and they are definitely in the critical path to program success.

Offline john smith 19

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #125 on: 05/17/2023 08:14 pm »

Of NASA funded research
No.

Several of them include references to the Titan 1 and 2 structures and engines. None of this (AFAIK) had anything to do with NASA (but certainly through the USAF)

I'll certainly agree a lot of it was NASA funded, but not all of it.
« Last Edit: 05/17/2023 08:15 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #126 on: 05/17/2023 08:26 pm »

Wrong, it isn't.  It is energy expended and not distance.   Fly that 2 tones at 2,400 kph for that 200 km
"Frontiers of Space" reckoned the energy to orbit was about the round trip fuel for London/Sydney.

This process is affordable because a) The hardware is reusable for 1000s of flights b)It can be turned around and reused in hours, not weeks, months or years.

When you throw away all or a substantial fraction of the vehicle on every launch it should not be surprising the costs rise enourmously.

I'm amazed this myth still exists in the third decade of the 21st century.
« Last Edit: 05/17/2023 08:32 pm by zubenelgenubi »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline redneck

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #127 on: 05/17/2023 09:02 pm »

Wrong, it isn't.  It is energy expended and not distance.   Fly that 2 tones at 2,400 kph for that 200 km
"Frontiers of Space" reckoned the energy to orbit was about the round trip fuel for London/Sydney.

This process is affordable because a) The hardware is reusable for 1000s of flights b)It can be turned around and reused in hours, not weeks, months or years.

When you throw away all or a substantial fraction of the vehicle on every launch it should not be surprising the costs rise enourmously.

I'm amazed this myth still exists in the third decade of the 21st century.

Actually he threw a twist in there.  The 2,400 kph is over Mach 2    In atmosphere that can be a fuel guzzler. 

Offline john smith 19

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #128 on: 05/19/2023 05:50 am »
Actually he threw a twist in there.  The 2,400 kph is over Mach 2    In atmosphere that can be a fuel guzzler.
Good point. Bono & Gatland would have been talking about subsonic aircraft. Concorde was a super-cruise aircraft for decades (a fact few people noticed or mentioned) but its fuel burn was always going to be above subsonic aircraft (although designed to be competitve with the lever of contemporary aircraft) and the upgrade would have eliminated the afterburner.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline dondar

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #129 on: 05/19/2023 05:51 pm »
Everything you do costs time and money....Or in another words "path of innovation and access to resources"
Taking engineering resources to build something that's not needed dearly (as in nothing works without) is not only bad in terms of misusing precious engineering resources. There is nothing  worse for an engineer performance than waiting game....

I find it peculiar that a person who claims to be working in SpaceX as an executive during "20k$" times bothers comparing Starship program with SLS. Just basically all of his arguments.... What did he do in SpaceX really?

Ahhh some good ad-hominem to add to the pile.

I detailed in the OP what the person did during his time at SpaceX, which even if it were little (it wasn't) would be more than (most/all?) dismissive posters here put together: actually developing things that worked and continue to do so without so much destruction, rule-bending and hubris, plus admitting mistakes and showing the dangers of letting a certain philosophy get too far.
if he really participated in the projects which are practically define "SpaceX scrappingess" (the barges definitely ARE there) how could he write  what he writes now, especially if he claims he was executive? The difference between 7/20 and initial landing tests on barges is ZERO. Exactly the same major/minor filosophy (test target and minor tests if the major successful etc.), the same scrappinness (don't do the things which are not required for this test) etc.
Generally  just by observing the money flow it is obvious that SpaceX does what they do "on scraps", more of it Musk  clearly understands what industrial capacity does and what actual costs entail. So called "money burn" is very real thing. Designing what depends on the things unknown is extremely stupid double costly things etc.

Offline john smith 19

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #130 on: 05/23/2023 08:55 pm »
Designing what depends on the things unknown is extremely stupid double costly things etc.
You seem to think that SS is inside the known envelope for these sorts of mission.

It's actually a long way outside that envelope. Both in size and it's attempt to be as much like a conventional stg 2 as possible.

Everyone else whose proposed vehicles on this size (EG the NASA "Nova" concepts or the Bono SSTO's) have either been completely ELV's or squat, or low aspect ratio tapered inward vehicles coming in behind the plug nozzle as a heat shield. Maximum volume in minimum possible hot surface.

In fact SS depends on the design working OK under quite a lot of unknowns, primarily the air flow, and the heating caused by that airflow. BTW the uncertainty bars on lift and drag widen as the airspeed rises. So you have to make a much larger allowance for worst case values just when you need the best possible accuracy in your predictions.  :(

We'd all like the next flight to fly the full trajectory (especially the highly interesting stg 2 reentry around Hawaii) but to be honest I'd be impressed with them managing stage 2 separation and ignition. This would be (AFAIK) the first ignition at altitude of an engine cluster with a centralised gas generator ignitor.

If that sounds unambitous keep in mind all engine ignition has (AFAIK) never been an issue for F1, F9 or FH. That ignition system was certainly developed in the "scrappy" days of SX.
 OTOH ignition has been an issue for both Stg 1 all-engine ignition attempts with SS so far.

I'm certainly looking forward to their next attempt.
« Last Edit: 05/28/2023 06:32 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline thespacecow

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #131 on: 11/19/2023 06:25 am »
It turns out the Starship team is indeed scrappy and not crappy, who would have guessed...
« Last Edit: 11/19/2023 06:27 am by thespacecow »

Offline Elvis in Space

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #132 on: 11/19/2023 07:14 pm »
It turns out the Starship team is indeed scrappy and not crappy, who would have guessed...

Really. When I see people try to analyze Spacex it sort of implies that there is a better way to do this, that has never been done before, even faster and better. The closest analogue I can think of are the Apollo days of my youth. There was an abundance of scrappy and crappy there as well. And a lot more money. Is there anyone out there really disappointed with what's been accomplished thus far?
Cheeseburgers on Mars!

Offline steveleach

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #133 on: 11/19/2023 07:34 pm »
Is there anyone out there really disappointed with what's been accomplished thus far?
Yep, lots of people who be their corporate futures on SpaceX not being able to accomplish all this.

Offline rpapo

Is there anyone out there really disappointed with what's been accomplished thus far?
Yep, lots of people who bet their corporate futures on SpaceX not being able to accomplish all this.
Or those few who actually believe Elon Musk's extremely optimistic time projections.  But the thing is, even if it takes two or three times longer than he predicted, it is still much faster than the rest of the industry.  The only ones who come remotely close are Rocket Lab and the Chinese.
« Last Edit: 11/19/2023 09:12 pm by rpapo »
Following the space program since before Apollo 8.

Offline dolphin5588

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #135 on: 11/24/2023 06:49 pm »
When someone uses the verbiage at the end of this quote, there's a political tinge I want nothing to do with. I did not read.



Quote
DISCLAIMER: I want to make clear that I am not picking on SpaceX here. If you read it that way, take a deep breath, check yourself, and put down all the water you’ve been carrying for billionaires.

Offline DAA640

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #136 on: 11/24/2023 07:22 pm »
When someone uses the verbiage at the end of this quote, there's a political tinge I want nothing to do with. I did not read.



Quote
DISCLAIMER: I want to make clear that I am not picking on SpaceX here. If you read it that way, take a deep breath, check yourself, and put down all the water you’ve been carrying for billionaires.
Before I ever read the article I knew that any argument would be bad faith with that opening. By implying that people who might be upset at his unfair and untrue assertions about spacex are simply "billionaire stooges" he indicates his disdain for SpaceX fans right out the gate, as well as trying to insert a mechanism to shut down criticism of his biased musings ("well these guys are just mad because I attacked their favorite billionaire").

It was an incredibly bad faith article from the get go, made even more egregious by the writer being a competitior who builds launchpad equipment.

Offline Emmettvonbrown

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Re: Scrappy or crappy? Critique by former SpaceX lead engineer
« Reply #137 on: 11/25/2023 07:41 am »
Some posters on this thread should really have some cheese with their whinne, and cool down.
« Last Edit: 11/25/2023 07:52 am by Emmettvonbrown »

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