4 ms·
> I'll defer to people who know more about rocket design about why you couldn't have a huge stretchy bladder holding RP-1 (for example) in a rocket stage. Do y
by jessriedel 2y ago
> I'll defer to people who know more about rocket design about why you couldn't have a huge stretchy bladder holding RP-1 (for example) in a rocket stage.
Do you mean you have a cite to this claim? Would love to read.
> You either need to accelerate the docked rockets (so the liquids pool at one end)
Right, this is what I was referring to as “ullage”.
> Engines never have to worry about the microgravity case, there are always ullage motors
My point was that standard ullage motors can and will be used by SpaceX for the transfer. Why do you think this is harder than the fairly standard case of starting an engine in microgravity?
- idlewords 2y ago> Do you mean you have a cite to this claim? Would love to read. No, I mean that I have a handwavy explanation for why you can't put 500 tons of kerosene in a big stretchy bladder inside your rocket, but I'm hoping that someone who knows more about rocket design than I do will comment here. > My point was that standard ullage motors can and will be used by SpaceX for the transfer. Why do you think this is harder than the fairly standard case of starting an engine in microgravity? Because the motors have to run for much longer (many minutes instead of a few seconds) and the mass distribution of the docked system is rapidly changing during that entire time.
- jessriedel 2y agoI agree they have to run longer.