The bluedog_Skylab_VFB_entryProbe probe core part has both internal RCS and an internal solid rocket, but it only has a single propellant switch option, covering HTP, hydrazine, PSPC, PBAN and HTPB. The part always holds 160 Hydrazine, and then adds 160 of whichever propellant is selected on top of that. Switching the propellant type switches both the SRMs fuel type and the RCS fuel type, so you can create improper combinations such as draining PBAN for RCS or HTP for the SRM engine.
The
bluedog_Skylab_VFB_entryProbeprobe core part has both internal RCS and an internal solid rocket, but it only has a single propellant switch option, covering HTP, hydrazine, PSPC, PBAN and HTPB. The part always holds 160 Hydrazine, and then adds 160 of whichever propellant is selected on top of that. Switching the propellant type switches both the SRMs fuel type and the RCS fuel type, so you can create improper combinations such as draining PBAN for RCS or HTP for the SRM engine.