totm nov 2023 SpaceX Discussion Thread

[magnemoe]

On 5/13/2023 at 6:21 PM, mikegarrison said:

Um ... there is nothing special about containing that kind of pressure in general. What makes it difficult in an aerospace engine is doing it with a light enough structure to fly with.

For rocket engines its high,  the pressure is not exceptional compared to hydraulic systems. The heat is the serious problem and it obviously increases with pressure. So you used film cooling combined with liquid cooling with cryogenic fuel. 

[RCgothic]

 

 

[tater]

I really like her... but I have to say I don't like the way the sausage is made (that literally anyone in government can move to a remunerative non-government job, like politicos to lobbyists, or NASA to industry (Gerst, too, smart as the pickup was for SpaceX).
 

But this is true for every big defense/science-related company out there (pharma, etc), revolving door with gov agencies.

Edited May 15, 2023 by tater

[CatastrophicFailure]

Possible FTS testing:

no, not that one. Look over to the left… 

Better view: 

 

[tater]

 

[mikegarrison]

20 hours ago, tater said:

I really like her... but I have to say I don't like the way the sausage is made (that literally anyone in government can move to a remunerative non-government job, like politicos to lobbyists, or NASA to industry (Gerst, too, smart as the pickup was for SpaceX).
 

But this is true for every big defense/science-related company out there (pharma, etc), revolving door with gov agencies.

Boeing is actually really sensitive to it, after getting so hugely burned by the Mike Sears / Darleen Druyun fiasco. Mike Sears was probably the heir apparent as CEO, and instead ended up in prison.

[tater]

 

[tater]

NSF has the full actual quote available from Cummings:

Quote

So to give you a sense of scale, I was just in our crew cabin, the starship lunar lander crew cabin mockup in California, I think it was last week. And the crew deck of the starship lunar lander is about twice the size of this stage. And there is room in starship for multiple crew decks, we only really need one for the Artemis III mission. Below that crew deck, there are two airlocks that are each about the pressurized volume of a Dragon Capsule. So each airlock has about the space of, you know, a human spaceflight vehicle that's flying people to space station now. And then those airlocks are inside a very large garage which is again about the size, or double the size of the stage. the idea is that we are starting with the capability that we need for Artemis III, and then we'll work towards being able to fly more people for longer durations, adding the ability to land on Mars with the Martian atmosphere which is a little bit different then landing on the moon where there is no atmosphere. And so that's how all of these things kind of work together to enable a day where we have ideally, hopefully in our vision, hundreds, thousands, maybe even one day one hundred thousand or more people living on Mars.

 

[Exoscientist]

“Angry Astronaut” is not so enthused on the upgraded Raptor 3 as are other SpaceX fans. He notes what SpaceX should be focused on is improving Raptor reliability and reusability. On the SH/SS  flight, a quarter of the engines failed with one and likely two actually exploding.

https://www.youtube.com/watch?v=0KYztCHTXaM

  Bob Clark

Edited May 16, 2023 by Exoscientist

[Lukaszenko]

18 minutes ago, Exoscientist said:

“Angry Astronaut” is not so enthused on the upgraded Raptor 3 as are other SpaceX fans. He notes what SpaceX should be focused on is improving Raptor reliability and reusability. On the SH/SS  fight, a quarter of the engines failed with one and likely two actually exploding.

https://www.youtube.com/watch?v=0KYztCHTXaM

  Bob Clark

I didn't watch the video, but on the surface it sounds cringefully close to the ol' "why are we spending money on space when we have problems on Earth" argument 

[tater]

2 hours ago, Exoscientist said:

“Angry Astronaut” is not so enthused on the upgraded Raptor 3 as are other SpaceX fans. He notes what SpaceX should be focused on is improving Raptor reliability and reusability. On the SH/SS  fight, a quarter of the engines failed with one and likely two actually exploding.

Yeah, not terribly interested in what that guy has to say about anything, tbh.

Edited May 16, 2023 by tater

[StrandedonEarth]

1 hour ago, Exoscientist said:

“Angry Astronaut” is not so enthused on the upgraded Raptor 3 as are other SpaceX fans. He notes what SpaceX should be focused on is improving Raptor reliability and reusability. On the SH/SS  fight, a quarter of the engines failed with one and likely two actually exploding.

https://www.youtube.com/watch?v=0KYztCHTXaM

  Bob Clark

I would think that part of Raptor 3 development is addressing those issues…

[Exoscientist]

1 hour ago, Lukaszenko said:

I didn't watch the video, but on the surface it sounds cringefully close to the ol' "why are we spending money on space when we have problems on Earth" argument 

Watch the video. He is a fan of SpaceX. He wants the SH/ST to be rapidly qualified for operational flight. That’s not going to happen when multiple engines RUD during test flights.

  Robert Clark

[tater]

I don't care what he's a fan of, I think I saw one of his videos a year or two ago and found him annoying to listen to (and not telling me anything I didn't already know).

[Meecrob]

3 hours ago, Exoscientist said:

“Angry Astronaut” is not so enthused on the upgraded Raptor 3 as are other SpaceX fans. He notes what SpaceX should be focused on is improving Raptor reliability and reusability. On the SH/SS  flight, a quarter of the engines failed with one and likely two actually exploding.

https://www.youtube.com/watch?v=0KYztCHTXaM

  Bob Clark

In a roundabout way, improving thrust/chamber pressure increases reliability because it allows them an equivalent TWR with less engines. Now, many might say that this sounds like a band aid solution, but if SpaceX knows it will take (hypothetically) two years to get raptor reliability to where they want it for testing, are they just going to shut flight test down until the engines are ready or start building flight data with imperfect engines? Also, I imagine flight data from engines will help narrow down the causes of the reliability issues.

[Elro2k]

2 hours ago, tater said:

I don't care what he's a fan of, I think I saw one of his videos a year or two ago and found him annoying to listen to (and not telling me anything I didn't already know).

Very true, most of his videos are op-ed style, and very opinionated. I mostly stick with Marcus House for weekly updates, and CSI Starbase whenever they decide to bless us with a video.

[sevenperforce]

On 5/14/2023 at 2:21 AM, Exoscientist said:

SpaceX might claim their per kilogram cost will make them preferred but the example of the bus companies and the airlines make that argument extremely dubious.

@tater already made many good points, but interjecting to note that this is the fatal error in your reasoning.

SpaceX isn't claiming that the per-kilogram cost of launching on Starship makes them the cheapest. SpaceX is claiming that the per-launch cost of launching Starship makes them the cheapest.

If I am out in the city on foot and need a ride home, and I pull up Lyft, and I see a Prius for $50 and a Cadillac Escalade for $22, and both of them have the same pickup and dropoff times, then I will take the Escalade, thank you very much. Even though I might not NEED that much room, I will choose the bigger vehicle if the bigger vehicle is cheaper. Even if I'm all by myself and don't have anybody riding with me.

I will take the cheapest option.

If it is cheaper to launch a single Cubesat on Starship than it is to get a dedicated launch with Electron or a rideshare launch with New Glenn, and Starship is available, then the Cubesat owner will launch it on Starship. Every time.

On 5/14/2023 at 2:21 AM, Exoscientist said:

Then consider: when pricing their launch vehicles the largest proportion of that price is not coming from the production cost, but in fact due to the amount added on to recoup the development cost over time.  SpaceX has spent $10 billion developing the SuperHeavy/Starship with more billions yet to be spent on the development. This is in the range of 100 times higher than the development cost for the companies with smaller launchers. Then the amount to be added on to the price due to development cost, which again makes up the largest bulk of the customer price, will be radically smaller. 

This is a lot of words and not enough numbers.

On 5/14/2023 at 2:21 AM, Exoscientist said:

Note that SpaceX won’t be superior in price reduction due to reusability either since all the New Space companies also are focusing on reusability.

Most of the New Space companies are not focusing on full reuse, and the ones that are don't yet have anything remotely resembling full-stack hardware.

If Stoke Space comes along and is able to launch smallsats cheaper (on a per-launch basis) than Starship through full reuse, then Stoke Space will capture the smallsat market, right up to the limit of its payload capacity, and Starship will have the rest of the market.

[Exoscientist]

7 hours ago, tater said:

I don't care what he's a fan of, I think I saw one of his videos a year or two ago and found him annoying to listen to (and not telling me anything I didn't already know).

 Perhaps because I’m a budding curmudgeon myself I like his “slaying the sacred cows” style. 
 Even if he is a supporter of SpaceX he makes criticism of them if he feels they are taking a wrong approach. Much more honest, and realistic, than serving as their cheerleader on every topic. 
 

  Bob Clark

[tater]

20 minutes ago, Exoscientist said:

 Perhaps because I’m a budding curmudgeon myself I like his “slaying the sacred cows” style. 
 Even if he is a supporter of SpaceX he makes criticism of them if he feels they are taking a wrong approach. Much more honest, and realistic, than serving as their cheerleader on every topic.

I'm totally fine with that, there are legitimate issues anyone can have with their design choices... I'm just not one to watch much youtube for this stuff, I generally prefer reading it (the exception might be actual press conferences, keynotes, or particularly interviews (on site, ideally like the good one Dodd did over at stoke).

(I'm also a curmudgeon, lol)

[magnemoe]

5 hours ago, tater said:

NSF has the full actual quote available from Cummings:

 

I said the official starship manned  layout is way overbuild for lunar spaceship.
I say the cargo deck should hold two moon  buggies, Tesla style . Second is an backup, also an drill rig because you want one. 
Primary air lock hold all crew as in 4, it might also be an lift, second one could be on second level. You could always pressurize the cargo hold and you probably do to repair stuff. 
Second level also hold labs, 3'rd level is living area, 4'rd is airlock and storage. 

 

 

[tater]

As to what you say is his point, that they should not be working on Raptor 3, and should instead be improving Raptor 2 reliability... I think that fails to understand the way SpaceX does things at all. They are not going to ignor other improvements they have decided they are needed to get to reliability. They will have found things that need fixing for reliability, AND other issues, and implement all of them. It could well be that in fact some reliability improvement led them to believe they could push the chamber pressure as well once they tested it. We simply don't know.

[Pthigrivi]

The issue is that it underscores the general mental/cognitive incompetence of the person running this. The galactic stupidity of corporate misadventures like cybertruck and blowing up the OLM for no conceivable reason are illustrated as part of a pattern. Hair plugs don't fix dumb. 

https://www.thedailybeast.com/elon-musk-gives-his-craziest-interview-yet-with-cnbcs-david-faber?ref=home?ref=home

[tater]

4 minutes ago, Pthigrivi said:

The issue is that it underscores the general mental/cognitive incompetence of the person running this. The galactic stupidity of corporate misadventures like cybertruck and blowing up the OLM for no conceivable reason are illustrated as part of a pattern. Hair plugs don't fix dumb. 

Cybertruck? LOL. It will be hugely popular. Tesla makes more money per car than... anyone I think. Not per EV, per V.

The OLM is damaged, but fine.

It still likely makes orbit before the BO rocket designed to compete with Falcon 9.

PS, the "daily beast" is not a credible source for anything and doesn't belong here, it's clearly a political opinion source.

[Pthigrivi]

20 minutes ago, tater said:

Cybertruck? LOL. It will be hugely popular. Tesla makes more money per car than... anyone I think. Not per EV, per V.

The OLM is damaged, but fine.

It still likely makes orbit before the BO rocket designed to compete with Falcon 9.

PS, the "daily beast" is not a credible source for anything and doesn't belong here, it's clearly a political opinion source.

Have you seen the Wire? I feel like you should sit down and watch the Wire. 

[tater]

10 minutes ago, Pthigrivi said:

Have you seen the Wire? I feel like you should sit down and watch the Wire. 

These days I'm reminded more of 1984—or the blend of that, Brave New World, and Harrison Bergeron.

I watched the Wire. I don't see any relationship whatsoever (and it wouldn't belong on a thread in this forum if I did).