I spent some time considering the design of a PCB that can fly, having both a battery (separated from the drone system), a separate GPS receiver, sensors and a long range wireless serial modem. Then on my work desk I saw this:

It is the populated board of a #Portable environmental monitor , that in its last iteration has everything I need, and also a SDCARD slot as a bonus, should radio data links not be possible right from the start. Surely, the LND712 tube is not fit for drone flight due to it's mechanical fragility, so it will be replaced, and the ESP8266-ESP03 will be removed in favour of a long range serial wireless module, but the good think is I'll be able to share the VCC / GND / TX / RX pads already on the PCB. As for the sensors, I'll be able to fit additional sensors as permitted by weight.

So all in one these boards already do what I need, they don't have the right form factor, but that because a detail considering how much time I can save reusing them.

Here's an identical #Portable environmental monitor taking a flight from Sydney to Adelaide. The data shows the elevated radiation readings as expected, due to the increased cosmic radiation:

I plan to get very much the same but using the drone platform for 3D space access.