  Small, expendable drop probes are an attractive method for making
measurements in the lower atmosphere of Venus, \,augmenting the capabilities of
orbiters or aerial platforms that must remain in the benign temperature region
above 50 km altitude. However, probe miniaturization is impeded by the need to
provide thermal and pressure protection for conventional payloads. This paper
determines the minimum mass limits for an insulated pressure vessel probe that
operates all the way to the Venusian surface. Scaling laws for the probe
performance and mass of major system components are explicitly derived using a
simple model that captures the relevant physics. Streamlining the probe is
found to be a highly effective strategy for lowering the system mass, but it
also reduces the time available for data collection and transmission.
Tradeoffs, guidelines and design charts are presented for an array of
miniaturized probes. Total system masses on the order of 5 kilograms are
plausible with streamlined probes if the desired science measurements can be
performed faster than a standard Venus descent timeline.
