totm nov 2023 SpaceX Discussion Thread

[Minmus Taster]

10 minutes ago, darthgently said:

To keep things science-based, it is plausible that SpaceX isn’t failing enough to optimize iterative learning according to experts in learning

 

An interesting proposition, but rocketry is expensive and even SpaceX can't afford to expend so many vehicles on failed flights. Sooner or later you need to see a return on investment, though for them that day seems to be relatively far off.

[darthgently]

3 minutes ago, Minmus Taster said:

An interesting proposition, but rocketry is expensive and even SpaceX can't afford to expend so many vehicles on failed flights. Sooner or later you need to see a return on investment, though for them that day seems to be relatively far off.

Exactly.  There is likely an optimization of a cost and learning function that minimizes cost while maximizing iterative learning and I wouldn’t be shocked if SpaceX was in that ballpark.

[Minmus Taster]

[Nuke]

5 hours ago, SunlitZelkova said:

I think the only reason the N1 didn’t work was because of lack of resources and political support, two things SpaceX now has (the latter in the form of internal backing + HLS contract). The N1 nearly made it to orbit on the 4th flight and probably would have succeeded on the 5th.

But yes, stuff like the Nedelin disaster had no benefit and was pretty easily avoidable.

I was planning to say this in response to the hubbub about lack of regulations and accusations of negligence but I didn’t: SpaceX has no incentive to build an unsafe rocket. They’re a business that doesn’t have a lot of leeway in terms of fatalities or injuries. A carmaker can build something that kills 1,000 people a year and people think it’s normal, but a rocket maker gets one guy killed for the first time in seven years and accusations the company is pure evil go flying.

This is extreme, but even without the FAA (or with a reduced FAA) I would trust SpaceX to at least do some due diligence to make sure people are out of harms way before launching. I also trust them to figure out what went wrong and try to fix it before the next flight.

They’re just not building a minivan where 1,000 out of a million can fail and people won’t care. Space is high profile stuff and they have enormous incentive to improve safety even without having regulators looking over their shoulders all the time.

I think that’s saying a lot considering I’m a person who on the other hand didn’t, and still doesn’t trust SpaceX to do due diligence to protect the environment around Starbase (although as much as I lack that trust I don’t bring it up anymore because I’ve just accepted Starbase is a critical national security facility now and nothing can realistically be done).

proportionality needs to be observed. a thousand people dying a year in auto accidents sounds bad, but then again how many cars are there? also with cars when there is an accident, you can usually blame one driver or the other, and the car maker gets a pass. usually also the people who designed the highway system and i am convinced some intersections are defacto death camps. if a million people fly in rockets then a couple deaths dont look so bad. every time a plane crashes the body count is usually near or in the hundreds, yet its the safest way to travel because of the shear volume of air traffic. idk how it lapped trains and steamers in terms of safety, perhaps that statistic is just airline marketing. probibly because there is a history of shipping going back to the age of sail that was not always as safe as it is now. seems train wrecks never happen either, ive heard about a dozen aircraft incidents to one train incident. trains being close to the ground are somewhat more survivable and you dont usually drown or catch fire when they derail. what is the lethality of those? 

maybe im wrong to bring up the lethality of the shuttle too often. seems everything we humans do comes with an element of risk, and its not really my place to cover everyone in bubble wrap, take away their sharp objects and tell them not to have fun to make myself feel better. society likes to drive cars, live in cities, work dangerous jobs, climb mountains, and go to mars (crossing the street belongs somewhere in that list). now that i think about it safetyism probibly does  more harm than good. we can play it safe until the sun explodes or the biosphere becomes uninhabitable either by our own hand or external forces out of our control. that's not how you build a galactic empire.

Edited 9 hours ago by Nuke

[RCgothic]

Trains are safer in terms of fatalities per trip. 

Planes are safer in fatalities per mile. 

The difference is that planes traverse vastly larger distances on each trip than the typical train journey.

If you could make the same trip by either mode of transport, trains would be the safer option.

[magnemoe]

8 hours ago, Minmus Taster said:

An interesting proposition, but rocketry is expensive and even SpaceX can't afford to expend so many vehicles on failed flights. Sooner or later you need to see a return on investment, though for them that day seems to be relatively far off.

Who is true, but things was going very well at flight 5 and 6, they was able to catch the booster and do soft touchdown with ship after reentry. 
Had flight 7 went as well as 6  they probably tried to put it up into orbit on flight 8 or 9. 

Now something I find troubling is how ship started spinning wildly once one vacuum engine went out rater than reducing trust on the other engines and compensating with of the sea level engines. 

[Lisias]

2 hours ago, magnemoe said:

Now something I find troubling is how ship started spinning wildly once one vacuum engine went out rater than reducing trust on the other engines and compensating with of the sea level engines. 

Because nobody configure the Abort button on KSP, I mean, SpaceX!

[tomf]

4 hours ago, RCgothic said:

Trains are safer in terms of fatalities per trip. 

Planes are safer in fatalities per mile. 

The difference is that planes traverse vastly larger distances on each trip than the typical train journey.

If you could make the same trip by either mode of transport, trains would be the safer option.

I expect it would be interestingly more complicated than that. My guess is that the risk of train accident on a given journey is proportional to the length of the journey, mostly due to signalling problems, poorly maintained track etc. The air travel risk however is pretty concentrated in takeoff and landing.

I expect there is a theoretical journey length where the per trip safety of aircraft overtakes trains again.

[darthgently]

3 hours ago, magnemoe said:

is how ship started spinning wildly once one vacuum engine went out rater than reducing trust on the other engines and compensating with of the sea level engines. 

This is interesting.  There was a deeper side effect that trashed sensors or code.  Or maybe valves just stuck open.  The RCS seemed to be trying to correct the spin so the software seemed to be getting some attitude data but I wonder if data that the fact that several engines were kaput at that point was available.  It is like it still considered things being under balanced thrust or something.  Maybe a secondary  thrust balance calculation based on attitude changes is needed if not there