A Compact Drone-Based Instrument Sonde for Venus Balloon Missions

NASA is currently developing concepts for controlled variable-altitude balloons for study of the Venusian atmosphere at altitudes ranging from 52 to 62 km. A balloon mission could closely study the chemical composition of trace compounds in the upper atmosphere and resolve ongoing scientific debate regarding the presence of specific gases having biological origins on Earth. The moderate Earth-like pressures and temperatures at such high altitudes on Venus allow for long-term operation of scientific equipment, unlike the very the high surface temperature and pressure which severely limit survivability of exploration vehicles. Prior lander missions to Venus survived just over two hours on the surface before overheating, while high-altitude balloons have operated for days (limited by battery capacity). Future balloon-based missions could far exceed previous mission durations, but balloons have an inherently limited lifetime due to loss of lift. Balloon platforms also have limited altitude operating range and do not penetrate the lower atmosphere. To address these balloon system limitations, Creare proposes the Venus Sonde, a drone-based ballast sonde with a mass of 5 to 10 kg capable of flying multiple missions and returning to the balloon prior to a final one-way flight to the surface. During the initial high-altitude flights, the Venus Sonde launches from the balloon platform under fixed-wing flight to profile the atmosphere in the vicinity of the balloon up to 70 km in altitude and then returns to land on the platform under vertical flight. The final flight occurs when needed to reduce the ballast weight of the system, thereby increasing net lift. The drone sonde includes thermal management systems needed to survive surface conditions for several hours to conduct image surveys and then transmit data from the surface.