Recent miniaturization of electronics in very small, low-cost and low-power configurations suitable for use in spacecraft have inspired innovative small-scale satellite concepts, such as ChipSats, centimeter-scale satellites with a mass of a few grams. These extremely small spacecraft have the potential to usher in a new age of space science accessibility. Due to their low ballistic coefficient, ChipSats can potentially be used in a swarm constellation for extended surveys of planetary atmospheres, providing large amounts of data with high reliability and redundancy. We present a preliminary feasibility analysis of a ChipSat planetary atmospheric entry mission with the purpose of searching for traces of microscopic lifeforms in the atmosphere of Venus. Indeed, the lower cloud layer of the Venusian atmosphere could be a good target for searching for microbial lifeforms, due to the favourable atmospheric conditions and the presence of micron-sized sulfuric acid aerosols. A numerical model simulating the planetary entry of a spacecraft of specified geometry, applicable to any atmosphere for which sufficient atmospheric data are available, is implemented and verified. The results are used to create a high-level design of a ChipSat mission cruising in the Venusian atmosphere at altitudes favorable for the existence of life. The paper discusses the ChipSat mission concept and considerations about the spacecraft preliminary design at system level, including the selection of a potential payload.