Stratospheric balloon 1 – May 2019

In cooperation with Vanguard Technologies and our partner the Institute of Space Science, we were involved in building and launching a stratospheric balloon. Our payload consisted of a picoAPRS v3 module, a 4k 360° video camera and an Arduino-based GPS logger. Our partner planned to add SSTV transmission of live pictures using a custom-made transceiver, but unfortunately this had to be removed due to insufficient available helium. We hope for a second flight in June!


Following the launch at 9:27 UTC, we received APRS packets up to 14.8 km altitude, when probably the internal GPS stopped providing valid data. The secondary GPS continued to work up to 26.4 km, when most likely the battery temperature reached approximately -25°C and stopped working.

Probably due to missing GPS lock, the picoAPRS started reporting the position once every 30 minutes (10:24, 10:54, 11:24, 11:54), when it (most likely) reported the last valid GPS data (34.6 km altitude). By synchronizing the video footage events and by extrapolating the data, we can conclude that the maximum altitude was reached between 11:24 and 11:54, and it was higher than 30 km. However, it is possible that the maximum altitude reported through APRS is valid, but it was reported late by the transceiver.

Special thanks go to the Romanian HAM radio community for operating and maintaining the APRS iGate transceivers!
We also want to thank Vanguard Technologies for building the payload housing, acquiring all the required parts and obtaining the launch authorization. Check out their Facebook post!

Some photos courtesy of Vanguard Technologies.


  • Raw APRS packets (via the balloon, chaser cars 1 and 2 (.kmz)
  • Processed data: GPS, APRS.
  • Flight paths (see picture above)
  • 360° flight video (raw, 360, edited – coming soon)


  • Most messages received by: YO9IPZ-11
  • Furthest message received by: LZ1JPT-10 (approx 400km)
  • Highest reported altitude received by: YO4FZV-10
  • Last (airborne) message received by: YO4ESB-12