I'm planning on making a weather balloon payload that will work as a ham radio repeater. I want to have a method to log temperature and altitude data , I was thinking this could be done with a DHT11 and some GPS receiver and SD module for the arduino , however when testing in a vacuum chamber, at -20 inHg the Arduino stopped working. It turned off and it will not power back on. Capacitors look fine and im sure it did not overheat. Why is this happened and how can I prevent it?