Larsen, what part of "Demand fed" did you not understand?
Demand fed, in simple english: No pressure until there is demand. IE, dry when not in use. Simple to do.
And no, not the radio telescope crowd, either... scouts often, according to canonical sources, need to operate dirstside in steath mode. (See WBH.) Essentially, electronics off.
Microwaves are readily monitored; they are common comm frequencies. Sure, they're not part of SETI's search, but MANY other groups use them, including TV, radio, newspaper, internet, and telephone companies. I don't know about your world, but I do know that when there is a sudden change in microwave noise, the local TV stations take note... if this coincides with a UFO, someone's bound to look. I know that my neighbor's microwave interferes with a lot more than just the microwave spectrum, too. I suspect mine does, but the items I notice being affected are not ones I'm using when i use my microwave. Things like TV, 2m radio, etc, all pick up the vast ammounts of noise from microwaves, computers, etc. IMTU, soutships are set for nearly all contingencies. Including short periods totally powered down and using hand fed steam for cooking.
Likewise, the military supply mind is not prone to safety concerns (otherwise you'd have had a wholly different specialty). It is prone to using the lowest tech solution to a need available. To wit, a demand fed steam system for cooking. The steam powered oven need not even be open cycle... and unlike terrestrial naval steam useage, you can often hav a pressure-drop vent which will vent to space... and WILL flush the system to space when open.
Steam is very dangerous stuff for a certain pressure range or in large quantity. In the dishwasher, absolutely. A few L of steam is going to do little to a scout craft, slightly more to the occupants, which will be most likely shielded against the excess watrer for a number of LS based reasons, not the least of which is that we combine carbon-hydrogen compounds with oxygen to make CO2 and H2O in our bodies.
Steam heating is, in fact, so safe, that many army and airforce bases use HP steam for central heating of housing. (Elmendorf AFB does....) 700° steam at that. and that's at the quarters supply transfer, in an earthquake prone area.
Besides, unlike a microwave, it's got few moving parts, is field repairable, low-tech (TL4+ rather than 7+,) replaceable, and the cooking and cleaning media are essentially free to a ship with life forms of our ilk aboard, so the cost of water for the steam line are nil, and thus comparable. Plus, the steam line can use residual heat in the radiator systems, and/or the Power Plant core, so the power need not be on to use it.
Yes, if a steam line ruptures, it can be ugly. Microwaves are deadly to pacemaker patients. Hot air can be just as dangerous. (and has been proposed in the past by others.)
