Going to space for 1 minute, effectively.. but will be low atmosphere for 8 minutes or so.. I'm not going, but our project is. It's not a theoretical problem.
The problem with a polyswitch is it resets after the fault is cleared and power is removed. I need something that will reset automatically, the idea is a nut will rattle loose and short something, or similar event, and the circuit needs to get power restored so I'd imagine a device that would cycle it in an out often (but not RF often).
Imagine a can with some circuits in it, a battery, and some pocket change, a few washers, nuts, and. Between say three circuits, a minimum of two of them have to function to execute an event upon certain condition or time greater than Tx. As the can is rattled, wasker, nuts, screws, change, and a dash of fire and brimstone interact with the circuits occasionally only at the connectors to the boards. The electronics are put inside, the switch turned on, and the can is shaken vigorously for a minute, during that minute, the 'mains' have to be protected from total failure, and certain events have to take place irrespective of individual or temporary failures. We haven't worked short-proof into the scheme yet, and can't risk melting the mains while assuring that anything that can use power gets it. It's probably the most obsessive project I'll ever be involved in, it has to work on absolute terms, even though we aren't sending people up. If we don't have a clean power protection solution we have to go with hard wire and crossing fingers, and I don't want to go that way, though it merits consideration.
The specific heat of the chips is often adequate, but at any appreciable power (>100mW) potting or heat sinks will be used. There is another cooling idea.. we might bring along a gas cannister. The trick is running the transmitter in the vacuum, when it is needed most.. or highly desired.. at some 20 watts.. but that will be dealt with.
Thanks, Geoff