ptfrd

joined 1 year ago
[–] ptfrd@sh.itjust.works 2 points 2 months ago* (last edited 2 months ago)

I still remember the press conference before the first F9 booster reuse. The customer CEO(?) was saying that his team was comfortable, and I think even that the insurance company was comfortable too. So I was fairly confident it would work.

In this case, there's no customer or insurance company giving any high level push-back on any concerns.

One possibility I wonder about is that Musk and/or other senior SpaceX ppl might be wanting to 'double down' on how this is a bold & risk-taking programme, for psychological reasons, in defiance of all the naysayers after the Flights 7 & 8 situation. And thus ignoring the 'critical path' argument, and the fact that the only good risks to take are calculated risks.

Do you think the cost of booster production could be a factor in their decision?

Unsure about this topic in general. My guess is that the raw materials and COTS components are relatively cheap, and that most of the costs are labour. So one uncertainty lies in whether the people would be employed at Starbase regardless of whether they had to build an extra booster or not. And just in general, when we hear dollar figures bandied around, what proportion of those are the true 'marginal'(?) cost.

But ultimately I think yes, now you mention it, cost would've been a significant factor in the decision.

Along with maybe production rate? Maybe they can easily shift existing people & factory space from boosters, to ships. And so the full 'critical path' argument needs to take into account how booster reuse could potentially increase the ship production rate.

[–] ptfrd@sh.itjust.works 2 points 2 months ago* (last edited 2 months ago) (1 children)

Well I certainly wouldn't want to launch on an F9 booster on its first flight![1] And NASA recently gave a clear sign that they share that logic to at least some extent.[2] So I'm definitely open to that possibility, for Super Heavy, and maybe SpaceX already believes it.

But as an outsider my guess is that, if nothing else, the 'unknown unknowns' should give us significant concern on the first attempt. I'm guessing a 20% probability that the booster reuse significantly hampers Flight 9.


[1] - Nor on its 2nd actually. My theory is that there could be manufacturing defects in/around the reusability hardware that don't get stressed until after the main stress of the first flight, which the second flight then uncovers. E.g. a landing leg attachment fitted imperfectly causes a crack in the rocket body during the 1st landing, and the crack causes a RUD at max Q during the 2nd flight.

In other words the first section of the bathtub curve might not be as steep as we'd like.

[2] - I think within the last year there was a problem during transport of a brand new F9 booster, and NASA said they were glad to subsequently give it a test flight on a Starlink mission before it was used for a NASA mission.

[–] ptfrd@sh.itjust.works 5 points 2 months ago (1 children)

When next launch? (Flight 8) NET April, “4 to 6 weeks” after Flight 8. (Elon)
When previous launch? (Flight 7)? Booster 15 and Ship 34 launched on 2025-03-06.

I think the numbers in the parentheses need incrementing.

[–] ptfrd@sh.itjust.works 4 points 2 months ago (8 children)

SpaceX has spent several weeks refurbishing, testing, and preparing Booster 14 for its next flight, which is planned to be on Starship’s next flight, Flight 9. The company also announced that 29 out of the 33 engines on the booster are flight-proven,

I wonder if this decision is a mistake. Seems like ship development is on the critical path, and booster development is very much not.

If the estimated increase in risk from the reusing Super Heavy for the first time is substantial, it might be better to delay that until some more progress has been made with Starship.

[–] ptfrd@sh.itjust.works 2 points 2 months ago (1 children)

target UK's first vertical orbital launch

And I think, more to the point, its first successful orbital launch.

And very plausibly (I think), depending on what else happens this year, they could be targeting Western Europe's first successful orbital launch.

[–] ptfrd@sh.itjust.works 3 points 2 months ago (1 children)

even Robert Zubrin

For those who don't know, Zubrin is the gentle & touchy-feely author of joyfully uplifting & empowering self-help books, who also talks about Mars sometimes.

[–] ptfrd@sh.itjust.works 2 points 2 months ago

That’s not how you Federation.

Depends whether the only other two countries to ever achieve human spaceflight are: a single-party state (proto-Borg?), and a gangster nation that occasionally tries to take over a neighbouring nation and steal its children (part Romulan?).

[–] ptfrd@sh.itjust.works 3 points 2 months ago (2 children)

But people keep calling Isaacman "Isaacson", so a more likely mix-up would be Elon Musk's biographer, Walter!

(People including, I think, multiple senators at the nomination hearing. And even Robert Zubrin recently.)

[–] ptfrd@sh.itjust.works 2 points 2 months ago

Hmm, now I'm sincerely hoping that Orlando has a curry restaurant called the Kennedy Spice Center

[–] ptfrd@sh.itjust.works 2 points 2 months ago

Atlas can carry 27 Kuiper satellites

Bit of a coincidence that 27 is also the number of Starlink satellites that Falcon 9 currently seems to be launching (out of Vandenberg) each time.

[–] ptfrd@sh.itjust.works 2 points 2 months ago* (last edited 2 months ago) (1 children)

Saw the headline, then it took me a couple of seconds to decide that this probably wasn't some kind of SpaceX collaboration.

The SpaceX hoppers were actually:

  • grasshopper for testing Falcon 9 landings
  • starhopper - what people call the first vehicle to fly with Raptor engine(s)
[–] ptfrd@sh.itjust.works 2 points 6 months ago* (last edited 6 months ago) (1 children)

Weird. I wonder if the possible CCP spying incident of 2024-11-30 is related.

If any of the late-starting webcasts happened prior to that date, perhaps Yinpiao Zhou noticed it and was innocently curious. Or perhaps he actually is a spy and his handlers noticed and ordered him to investigate. If not, perhaps some/all of the late-starting webcasts happened because of Zhou's drone flight.

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