warm lox

[gin455res]

Instead of sub-cooling propellants, could they be warmed up to delete pressurisation copv-s?

particularly for the booster. Then just scale up design to make up for worse mass fraction. (turbo pumps assumed). Like vapak only for pump fed tank pressures.

Is it easier to heat the bulk liquid with a hx than inject out of equilibrium vapour

[Hobbes-22]

This is called autogenous pressurization, and it's used in various rockets: Titan 34D, Space Shuttle, Space Launch System, Starship, Terran 1, and New Glenn.

[Jim]

Instead of sub-cooling propellants, could they be warmed up to delete pressurisation copv-s?

particularly for the booster. \.

It is.  See autogenous pressurization

Instead of sub-cooling propellants, could they be warmed up to delete pressurisation copv-s?

particularly for the booster. Then just scale up design to make up for worse mass fraction. (turbo pumps assumed). Like vapak only for pump fed tank pressures.

Is it easier to heat the bulk liquid with a hx than inject out of equilibrium vapour

too much bulk to warm up and it can't keep up with depletion.

The issue is for restart.

[gin455res]

Starship uses sub cooled lox and the hot pressurant  gas is constantly condensing (I assume); ie. Is not in equilibrium. Maybe slosh is more troublesome when there is a dis-equilibrium between vapour and liquid - producing a wildly fluctuating surface area for condensation?

if the quickreach was going full pressure fed (altitude enabled), they must have been warmer than this and felt it was viable.

I am suggesting, say, - 157 deg C lox (maybe 8bar vapour pressure? -grok deepsearch..)