Zephyr is the payload gondola that has been developed to host all Strateole-2 instruments.

Zephyr gondolas
Zephyr gondolas in the preparation tent in Seychelles. Credits: J. Lenseigne, LMD.


The role of Zephyr is to ensure that all scientific instruments are able to perform nominally during the 3-month balloon flights in the stratosphere. Hence, Zephyr provides:

  • a thermal insulation between the instrument electronics and the atmosphere. Indeed, the air temperature at the balloon float altitude can be as low as -80°C, which would prevent any semi-conductor device to work as expected. Zephyr’s insulation is achieved with a 8-cm thick styrofoam box.
  • renewable power management. Solar panels are used to recharge batteries during day, while the batteries provide sufficient power to handle nighttime activities.
  • positioning and timing thanks to an onboard GPS receiver.
  • communication to the ground control center. Zephyr uses the Iridium space-borne communication system to both download scientific data collected onboard and upload tele-commands from the ground. Communications between the ground control center and Zephyr gondolas are performed every hour, so as to be able to download in near real-time the most recent observations.

Zephyr ground control center is the web-based interface that enable instrument principal investigators to download their data, and the Zephyr team to monitor onboard activities.


Zephyr has been developed under the lead of Éric d’Almeida (LATMOS), as a collaboration between: