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01 High Altitude Ballooning

Balloon Flight Theory
Much of this page is taken from this is a great resource but is UK based so we need to take into account Australian conditions.

The general theory is:
      • a payload (an insulated box containing some electronics such as a GPS and a radio to allow you to follow progress) is attached to a balloon which is filled with helium (He). 
      • The balloon is released and, as helium is lighter than air, the balloon rises and pulls the payload with it. 
      • As the balloon rises the outside pressure decreases which leads to the helium inside the balloon expanding (imagine like its expanding to fill the gap as the outside pressure decreases), this causes the balloon to stretch.
      • The balloon is made of a form of latex and is incredibly stretchy however it gets to a point where it can't stretch any more and bursts.
      • Now that there isn't any upward pull from the balloon the payload begins to fall to earth pulled by gravity, as it falls the parachute opens up slowing its descent and it gently glides down to earth.

Throughout the flight the GPS module in the payload box is providing information on its position, this information is passed through an Arduino microcontroller which reads the info and converts it into another protocol and in most payloads transmits the data over a radio link to the ground station. As a backup sometimes there is also a mobile phone which sends the data as a SMS as well (however this will only work near to the ground as mobile phones don't get signal at high altitudes).

Therefore given we want to fly a HAB mission you need to construct a payload box with a tracking device (e.g. GPS module, microcontoller and then a radio/mobile phone). Additional components include for example cameras and temperature sensor. You also will need a parachute, a balloon and some helium and permission to launch. 

For this competition all you need to do is design the experiment that will fly on the balloon mission. We will work with the winners to design the payload box, choose the Balloon, organise the retrieval and organise permission to fly

Obviously we cannot just launch balloons loaded with electronics at random in Australia so we use the guidelines from the Australian Civil Aviation Safety Authority to guide the launch. The relevant regulations are the Civil Aviation Safety Regulations 1998 (CASR)  Part 101. It is included at the bottom of this page. 

The regulations are very technical but we will work with balloon providers to ensure our experiments work as required.

Getting a system that works is harder then it sounds, BUT DON'T WORRY we learn from our failures. HAB payloads are difficult to test in advance so there is a failure rate that unfortunately affects us all. The better planned a payload/flight the less chance of something going wrong. If something doesn't go to plan you just need to learn from the problem, fix it and try again - its happen to us all! 

Alan Ibbett,
Jul 26, 2016, 4:35 AM