Hi Dave,
The short high altitude flights we have normally seen use a latex weather balloon for flight. You put enough gas in it to get it off the ground. It will rise in altitude until the balloon has expanded enough to burst and then the balloon comes down usually on a parachute.
The around the world balloon flights use a different type of balloon called a zero pressure envelope. The material is usually mylar and the envelope is much bigger. This design allows the gas to expand to fill the envelope as the balloon rises in altitude while never bursting like a weather balloon would. This allows the balloon to stay at whatever altitude it stabilizes at and just float along with the winds traveling long distances at various speeds following the global wind patterns. Very cool!
The same type of zero pressure envelope has been used to lift science payloads as well as humans to very high altitudes for extended rides. You can come down at will just by releasing the gas, you won't go back up though so you have to pick a good location to bring them down to.
Jeff Moore -- KE7ACY
On Fri, Dec 23, 2016 at 10:01 AM, Dave Marthouse dmarthouse@gmail.com wrote:
I have seen posts from time to time on the BB about balloons with amateur radio payloads on them.
I've got a question regarding the missions that carry payloads around the world. What stops the balloons from going up until they explode do to the high altitude. How are the packages kept from doing this to achieve such long distance flights?
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Dave Marthouse N2AAM dmarthouse@gmail.com
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