SLS Skylab-II/EUS deployed pressurized with Argon/Xenon after a chemical burn SEP variant

Con ops

EUS Skylab-II performs burn to(based on system mass) to

(A) GTO( a heavy variant)

(B) Highly elliptical Lunar orbit crossing and flyby trajectory

(C) Direct to L-2

EUS LH2/LO2 is pressurized with Argon/Xenon ullage gasses after chemical stage burnout a IVF system utilizes any remaining propellent however the Argon/Xenon system retains the ullage gas bottle and lines(formerly Helium)

If the propellent tanks can handle a known PSI of chemical fuel then the same PSI of the Argon/Xenon pressurize gas using the ideal gas law should tell us how many moles of Argon/Xenon gas are available to an ion powered engines

The hybrid nature of this chemical/ion powered SLS EUS greatly enables the capability of the SLS launch system as the mass of the propellent tanks are performing a repurposed double duty and the mass of the noble gasses and the tank and line system should make for good ratio or gears in with the  ion powered engines

We have however imagined a yet another more powerful idea that extends this system even further,The habitat itself the proposed skylab-II that is it self repurposed EUS tankage would also be pressurized with Argon/Xenon to feed the EUS ion engines, perhaps the Argon/Xenon in the Skylab-II is expended first so that the habitat can be pressurized with a breathable atmosphere and the EUS now has a maximized fuel load for extended missions after deploying the habitat

The Argon/Xenon EUS is in fact a very large version of the proposed ARM mission and would benefit from ARM mission design.The EUS in the mars system depleted of noble gases could be refueled by some future chemical fuel depot so it would require the EUS to have long-lived deep space avionics.Future fuel depots should also have cryogenic Argon/Xenon on hand.This would require the knowledge of the gear ratios of cryogenic ion engine propellants stockpiled from an Earth based source

We think this makes sense only in the case of self ferry of the EUS back to earth from Mars orbit under ion engine power to pick up another cargo.Fuel depots that have some boil off of LH2/LO2 and perhaps LCH4 could keep Noble gases cryogenic to refuel the EUS ion engines.

In nuclear reactors Noble gasses are neutron poisons, would a noble gas upper/in space stage provide some protection against deep space radiation?( see our previous posts on this topic)

Parallel development of the ARM and Ion powered hybrid EUS might make for synergys,ion powered EUS is much to big for most ARM proposed missions( very large cargo missions) yet a ion powered EUS could enable beyond Mars cargo missions very large asteroid as resource missions

Future versions of this hybrid engine could have in space removable chemical engines(for reuse?) or refuel with cryogenic propellants back in cislunar space

It is hoped this would lead to incorporation into any future EELV in space stage such as the proposed ACES

Edit

The ARM ion propulsion system could inform us as to whether a much larger EUS SEP could be scaled up, we might need for example a space based air liquefier to remove Argon/Xenon for Oxygen/Nitrogen in the skylab-II or remove Oxygen/Hydrogen from the EUS (remove the noble gasses and vent remaining H and O to the ULA IVF)