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Starship's Twelfth Flight Test

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Re: Starship's Twelfth Flight Test

#61

Post by pmontra »

bediger4000 wrote: post #39
john_minsk wrote: post #35

Earlier quoted context omitted.

question: what will happen if orbit refuelling goes wrong? Won't it destroy everything in orbit?

Liquid handling in microgravity has always been weird. Big gas bubbles in the fluid, surface tension effects causing liquid to float in balls in the ullage, stuff like that. Turbopumps break if they ingest a larger bubble. There could be some odd failure modes I would think. Failure to pump the liquid, broken pumps, who really knows? My guess would be that a failure mode would be a big spill, a failure to pump, only…

A probably very naive question: why not pistons?

Re: Starship's Twelfth Flight Test

#63

Post by jvanderbot »

jasonwatkinspdx wrote: post #31
jvanderbot wrote: post #21

Earlier quoted context omitted.

Well, it's powered by bleeding exhaust from a very big rocket.

Nope, Raptor is full flow staged combustion, so both the fuel and oxidizer have dedicated preburners and turbopumps each.

Thanks for that correction!

Re: Starship's Twelfth Flight Test

#64

Post by hgoel »

bragr wrote: post #38
JumpCrisscross wrote: post #36

Earlier quoted context omitted.

> what will happen if orbit refuelling goes wrong? Won't it destroy everything in orbit? No. What is the mechanism through which you suspected this could happen?

Kessler syndrome presumably?

Keeping the orbits low enough, and/or intentionally going suborbital after docking/before starting the fuel transfer, will make the chances of that being possible very low.

It's also worth considering that they have demonstrated cryo propellant pumping between two tanks within a ship, so, AFAIK, transfer between two ships is more about testing the docking systems, than it is about the pumps. They could probably rig the system to first pump some inert gas to verify the quality of the docking, then try to pump propellants.

Re: Starship's Twelfth Flight Test

#65

Post by margalabargala »

bragr wrote: post #38
JumpCrisscross wrote: post #36

Earlier quoted context omitted.

> what will happen if orbit refuelling goes wrong? Won't it destroy everything in orbit? No. What is the mechanism through which you suspected this could happen?

Kessler syndrome presumably?

...caused by what?

Re: Starship's Twelfth Flight Test

#66

Post by rpmisms »

malfist wrote: post #47
rpmisms wrote: post #37

Earlier quoted context omitted.

Have you met hardware guys? This is not how they operate, in my experience.

Are you trying to say that "hardware guys" don't care if they're working to advance the agenda from a Nazi?

Historically, that has been true about rockets.

Re: Starship's Twelfth Flight Test

#67

Post by labcomputer »

pmontra wrote: post #61
bediger4000 wrote: post #39

Earlier quoted context omitted.

Liquid handling in microgravity has always been weird. Big gas bubbles in the fluid, surface tension effects causing liquid to float in balls in the ullage, stuff like that. Turbopumps break if they ingest a larger bubble. There could be some odd failure modes I would think. Failure to pump the liquid, broken pumps, who really knows? My guess would be that a failure mode would be a big spill, a failure to pump, only…

A probably very naive question: why not pistons?

Because there’s a much, much simpler and easier way:

1. Connect the two ships

2. Connect the liquid valves from both cryo tanks together.

3. Spin the ships about the short axis

4. Open the vent valve for the cryo tank to receive liquid.

5. Lock closed the vent valve for the cryo tank to supple liquid.

Steps 2, 4 and 5 are how you normally transfer cryo fluids between dewars on earth. You just to create pseudo gravity / acceleration in the body frame of the ships to make it work in space.

Re: Starship's Twelfth Flight Test

#69

Post by lysace »

Nevermark wrote: post #10

I am watching Elon give a long speech about the launch, scarily delivered at high speed, without pause. Including a Bitcoin marathon promotional informercial complete with an on-screen scan code. "That QR code is your boarding pass." He just repeated several paragraphs verbatim from a few minutes ago. He occasionally mentions the aspirational 100x reduction in launch costs. AI slop. Yuck, Youtube. Surely Google could…

Ignorant eyeballs are also eyeballs. One might argue - sometimes even more profitable eyeballs.

Silicon Valley built this machine. Many tens of thousands of software engineers worked on this.

Re: Starship's Twelfth Flight Test

#70

Post by stephc_int13 »

GMoromisato wrote: post #32

There is a lot riding on V3. SpaceX cannot afford to take too many launches to get V3 solid. If 2026 is another 2025 (3 V2 failures in a row followed by 2 V3 successes), then they can forget about landing on the moon before 2030. My hope is that Flight 12 goes nearly flawlessly (at least gets to soft splashdown) and they can start testing in-space refueling in July/August. If they can demonstrate in-space refueling b…

I am pretty sure that at least some SpaceX engineers are reading HackerNews.

But I don't think I ever seen any insiders comments here, even anonymously.

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