Japanese polar patrol balloon experiments from 2002 to 2004

Polar patrol balloon experiments were carried out at Syowa Station in Antarctica from 2002 to 2004. Two balloons were launched for the purpose of observing phenomena in the polar atmosphere and one was done for the observation of high energy cosmic electrons. We developed a new housekeeping system including communication device using the Iridium satellite network, an auto-level controller driven by a new program for keeping the flight altitude, and a power management system for solar cells combined with secondary batteries.Two balloons for studying phenomena in the Antarctic atmosphere launched on January 13, 2003 made flights for 18 days and 25 days, respectively. All the housekeeping system worked well during the flights as we expected. Based on these experiments, we adjusted parameters for the altitude control system and the power management system. We launched a balloon for the cosmic electron observation on January 4, 2004. It flew 13 days around the Antarctica with the perfect operation of the onboard housekeeping system. We hope that fruitful scientific results will be obtained from these long-duration flights.