Solar unmanned balloon launch
July 22, 2015
On July 22, 2015, faculty and students from the Computer Science department
launched a solar balloon. This balloon was a 16' diameter tetroon, made from
36 black plastic trash bags of 30 gallon capacity and 0.5 mil thickness, bound together with
masking tape.
The balloon carried a payload weighing just short of 1 pound, consisting of a Raspberry Pi,
Pi cam camera, Arduino Uno, and SainSonic AP510 APRS tracker. The Pi was programmed to run
the camera and take images of the ground through the Pi cam. The Arduino was used to
power the Pi system and to run a servo, which controlled the cutdown mechanism. Cutdown
was set for one hour and 15 minutes after launch.
The balloon was filled and launched in slightly windy weather conditions, from
next to Streibel Hall on the campus of UND. The cutdown time came and went, and it became
apparent the cutdown system had malfunctioned and the balloon was still going up.
The last packet received by the chase teams indicated an altitude of 39,800 feet.
After that, no decodeable packets were received. The payload had been labeled with
business cards from the PI of the project. It is hoped that the balloon and payload
will be eventually found and returned to the school, but as of 7-24-2015 no one has
contacted the group.
The failure of the release system may be due to a number of different factors: a part of
the system was lost the day before and replaced with a part that was not identical to
the original 3D-printed part, the Arduino may have suffered a brown/black out and
reset the mission clock, the servo arm may have been tangled in the lift line, or
the balloon nozzle may have stuck shut for some unknown reason. Additional ground testing
will be done on future flights to try to avoid a repeat of this issue.
The AP510 tracker sent APRS packets that did not I-gate properly, though they were logged by
a local I-gate system (text file, KML file).
The flight track is the one on the right:
