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Special Feature

Research on Balloons to Float Over 50km Altitude
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Development of an adhesion machine for the balloon

In FY1991, we began the study and development of the thermal-adhesion machine. The fabrication of big balloons in Japan up to that time had been done by thermal-adhesion machine, an electromagnetic pressure bonding type of about 2m in length. The machine performs adhesive operation in meter units and is easy to handle, so it is suitable for operation in a limited space. However, it takes a long time to fabricate a balloon due to intermittent adhesion, and the machine is not suitable for large-volume balloons over 100m in length. Therefore, we developed a new self-driven belt sealer adhesion machine. The new machine offers continuous adhesion and can even stop/restart at desired positions during operation. It can also be used regardless of operation space and fabricate large balloons efficiently under high quality control. The newly developed machine allows us to set adhesive temperature in the range of 92 to 250 deg C and adopts the proportional control method for temperature accuracy of less than ±1 deg C. The adhesive pressure can be set in the range of 0 to 2 kg/m2, enabling adhesion of a wide range of film thicknesses from 20 to 3 µm. The machine can perform continuous thermal adhesion at speeds of 0 to 6m/min. Figure 1 shows the new, patented, belt sealer adhesion machine for balloons.

Figure 1 New Belt Sealer
Figure 1 New Belt Sealer

Development of thin-film balloon holding equipment

As the volume of the balloon increases, total buoyancy increases proportionally. As a result, it is impossible to hold the balloon’s head in the hands. It was imperative to develop new equipment similar to the palms of the hand to hold the balloon’s head, and we developed new equipment using an airbag. As shown in Figure 2, the equipment consists of an airbag to hold the balloon, a cylindrical plate to fix the airbag, an electromagnet to release the cylindrical plate, etc. The balloon is gripped by filling the airbag with air, and raising the pressure to a level comparable to total buoyancy. The equipment can grip the balloon, even one constructed of 3.4 µm thickness film, and yet protects the thin film from damage.

Figure 2 Balloon Holding Equipment
Figure 2 Balloon Holding Equipment

Development of a large floating platform

The newly developed large floating platform is fixed on a 6m-diameter turntable, and by turning the table we can release the balloon corresponding to the direction of the ground wind. The 4m x 3m board for placing observation instruments can lift the instruments up to 5m by elevator so that we can float the balloon in wind velocity up to 5m/s. Completion of the large floating platform shown in Figure 3 allows us to release the balloon at full inflation. This method is almost the same as dynamic floating. The launcher to release the observation instruments, however, is fixed. Thus, we completed the Japanese original floating method suitable for a narrow floating field. We call this method the “semi-dynamic floating method.”

Weight reduction of basic onboard instruments

We succeeded in reducing the weight of the basic onboard instruments to less than 10kg by the development of: a PCM encoder circuit using serial output type ADC for the telemeter; a PCM encoder and decoder using multiple code coincidence method for the command; a permanent magnet with solenoid movement mechanism for the ballast valve; etc.

Figure 3 Large Floating Platform
Figure 3 Large Floating Platform


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