Long duration flight systems in ISAS

Abstract

The balloon group in the Institute of Space and Astronomical Science (ISAS) has been spending many efforts to study the systems of long duration balloon flights for scientific observations. Among these, an earlier achievement was the Boomerang Balloon Systems. The Polar Patrol Balloon at Antarctica have been established already the circumpolar flights at level altitude taking almost 3 weeks. The National Institute of Polar Research and ISAS have been conducting this program. One of the recent feasibility studies is the balloons with new films of EVAR. The film has specific IR absorption band, and is expect to be useful to save the ballast for the long duration flights. A ground test for a small balloon also exhibited good structural performances compared with the polyethylene balloons. Another study is the possible use of the Pumpkin Shaped Overpressurized Balloons (OPS) with a simple auto-control of overpressure. OPS seems to be preferable to OZP on the mechanical stress point of view. As for the long range flights, ISAS is now also exploring the possibility to launch balloons from Northern part of Hokkaido to fly over the northern part of China. The payloads are to be recovered in Mongolia or the Central Asia.