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Venus—Clouds—Life—Habitability—Aerial Biosphere—Sample Return
Abstract:
The recent and still controversial claim of phosphine detection in the venusian atmosphere has reignited consideration
of whether microbial life might reside in its cloud layers. If microbial life were to exist within Venus’
cloud deck, these microorganisms would have to be multi-extremophiles enclosed within the cloud aerosol
particles. The most straightforward approach for resolving the question of their existence is to obtain samples
of the cloud particles and analyze their interior. While developing technology has made sophisticated in situ
analysis possible, more detailed information could be obtained by examining samples with instrumentation in
dedicated ground-based facilities. Ultimately, therefore, Venus Cloud-level Sample Return Missions will likely
be required to resolve the question of whether living organisms exist in the clouds of Venus. Two multiphase
mission concepts are currently under development for combining in situ analyses with a sample return component.
The Venus Life Finder architecture proposes collection of cloud particles in a compartment suspended
from a balloon that floats for weeks at the desired altitude, while the Novel solUtion for Venus explOration
and Lunar Exploitation (NUVOLE) concept involves a glider that cruises within the cloud deck for 1200 km
collecting cloud aerosol particles through the key regions of interest. Both architectures propose a rocket-driven
ascent with the acquired samples transported to a high venusian orbit as a prelude to returning to Earth or the
Moon. Both future conceptual missions with their combined phases will contribute valuable information relative
to the habitability of the clouds at Venus, but their fulfillment is decades away. We suggest that, in the
meantime, a simplification of a glider cloud-level sample collection scenario could be accomplished in a shorter
development time at a lower cost. Even if the cloud particles are not organic and show no evidence of living
organisms, they would reveal critical insights about the natural history and evolution of Venus.
