Few things needed to be tested on this flight: performance of solar panel at low temperatures (luckily it gets better,) LiPo charging regime during the day and performance deterioration during the night, GPS operation close to two sources of EMI on the same PCB.
Results:
Solar panels worked very well and kept battery at full charge.
Battery survived -28C temperatures and kept going all night.
Balloon floated at 8300m but started descending few hours after the sunset in what is thought to be a thermal runaway.
Landed, warmed up and after an hour rest broke loose and ascended again at original rate.
At 1600m got into the rain and has been forced to land again an hour later 30 miles South of the first landing spot - this time permanently.
Retrieved next day - just when countryside walkers have been taking it to their car.
Balloon still has original free lift which implies that there was no Helium loss at float altitude.
Brownie points:
Highest 36" foil baloon flight/float.
Lightest payload flown.
Payload weight - 10.7 grams.
Free lift - 1.8 grams.
Frequency - 434.510MHz USB
Downlink mode - DominoEX 16
Launch time 12:00 local time
Altitude in metres:
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