With the recent news of the possible discovery of the signs of possible life in the upper atmosphere of Venus, there is renewed interest in some quarters in the idea of atmospheric probes to sample the air and clouds directly. The most practical way to do this in something resembling a long term is with a balloon. With Venus’ carbon dioxide atmosphere, something usually useless as a lifting gas like nitrogen or oxygen could be used, but hydrogen or helium would work even better there than above Earth.
Such probes have been proposed for a *long* time. Here is art of Martin Marietta design for a Venus balloon from more than fifty years ago.
Martin studied a Buoyant Venus Station as far back as 1967. Included in the study were the instruments to be carried, including “drop sondes,” expendable instrument packages that would be dropped from the station to radio back data from lower down:
