Overpressurized balloon

The overpressurized balloon, which was proposed by J.M. Simpson in 1990, is supposed to be a new system for a long duration flight. The overpressurized balloon is quite useful to extend the duration of the flight. However, one must solve the problem to control the gas pressure automatically; that is, the gas pressure inside the balloon must be kept to the desired level. Here, we propose a simple device, which utilizes the normal horse tail duct to exhaust the excess pressure. The duct is normally closed by the valve system of rubber magnets. This system is adjusted to open the duct by the strength of the rubber magnet when the gas pressure exceeds the desired pressure. This pressure control mechanism is very simple and reliable, since it does not include any active elements. A simulation experiment has been performed in the room, and several features of this system were observed. The overpressurized balloon with this system was launched from the Sanriku Balloon Center (SBC) in 1997. We will describe some details of this system, its characteristics and the results of the test flights in this paper.