Balloon and Helium

Over the next few posts, we will go through the detailed specifics of each area of our project. The first thing we’ll go over is the balloon and lifting gas we used.

By far the two most common lifting gases used in HABs are helium and hydrogen. Hydrogen is cheaper and has better lift, but unfortunately it is quite flammable. We found that the vast majority of HAB groups use helium since it is an inert gas and therefore is safer to handle.

Finding helium is tougher than you’d think. The large tanks from party stores cost a fortune (~$200) to rent, plus require a $150+ deposit to make sure you don’t take their tank. And, I was not aware that there was recently a nationwide helium shortage and that helium is now regulated by the government. From what I understand helium is a non-renewable resource, and since it is lighter than air once it escapes and rises into the atmosphere it is gone forever. Fortunately we were able to rent a 120 cu. ft. helium tank at Airgas for about $90. We will also attempt to rent it through our college which will save us the safety deposit.

It is recommended to have enough helium to generate 1.5x lift compared to the weight of the payload. Doing some quick math and the chart here we find:

120 cu. ft. of helium is equivalent to 7.5 lbs of lift, and 7.5/1.5 = 5 lb max payload

So we are going to try to stay below 5 lbs including: balloon, parachute, box with equipment. This sounds reasonable compared to other’s projects.

Make sure you buy a high quality weather balloon from a reputable dealer. We bought a 600g weather balloon from Amazon.

Here are some super helpful videos on preparing and filling a HAB:

Here are a couple of more helpful links related to filling a HAB:

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