The Smart Balloon concept was developed in the early 1990's by a collaboration between the National Oceanic and Atmospheric Administraion - Air Resources Laboratory and University of Hawaii  for use in Lagrangian field experiments (Johnson et al., 1998). The buoyancy of the balloon automatically adjusts through the pumping of air into or out of the ballast portion of the balloon when it travels vertically outside a set barometric pressure. Thus, the Smart Balloon is a constant volume adjustable density balloon that maintains equillibrium as the temperature and barometric pressure of the surrounding atmosphere changes. The design provides GPS location, combined with measurements of ambient barometric pressure, temperature, relative humidity and ozone levels. Smart Balloon technology in atmospheric research was used in several field campaigns such as the Second Aerosol Characterization Experiment (ACE-2) over the Atlantic (Johnson, et al., 2000). The balloon has the capability to conduct sustained flights of 5-10 days and withstand precipitaion rates of up to 7.5 cm/hour.