In this post is a graph of internal and external temperature (all in Kelvin) against time. The graph we see is very much expected and we are fortunate it was like this as the batteries would not have worked terribly well if it dropped too much.
The external temperature reading themselves aren’t what I’d expect. Temperatures go down below zero in some parts of the atmosphere. I put this down to the fact the temperature sensor is mostly enclosed in some Areldite (glue) to reduce chance of shorting of leads in ‘wet’ environment. We are also going very quickly through the various zones of the atmosphere which means we might not have enough time for the temperature to settle.
What is interesting is the lag between internal temperature and external temperature. The Internal temperature was recorded inside a Polycarbonate box, which inside was generating some heat itself – majority from the RFD900 radio and other electrical components.