A Rozière balloon uses two distinct chambers to achieve buoyancy: a sealed upper cell filled with a lighter-than-air gas like helium, and a lower open envelope filled with heated air. Pilots control their altitude by firing burners to heat the air, which preserves the unheated lifting gas for long-duration flights. This design is the standard choice for extreme endurance records and around-the-world balloon attempts.
Heard on the job
We're prepping the Rozière balloon for a transpacific crossing, so double-check the burner fuel lines.