A balloon equipped with photovoltaic means exhibiting an active face intended to receive solar rays and comprising an envelope, characterized in that the envelope comprises at least: a first zone transparent to solar rays; a second reflecting zone for said solar rays; a third zone comprising said photovoltaic means, the active face of which is directed toward the inside of said envelope; the second and third zones being positioned and cooperating in such a way as to reflect the solar rays in the direction of said third zone.