Bubble wrap was one of the experiments on the first flight of NearSys in 1996. In that experiment, it was determined that bubble wrap could survive a Near space flight and provide cushioning. Bill Brown (WB8ELK) also reports he can use it for protection, including thermal protection.
In an effort to update the near space book written by NearSys, it was decided to repeat this experiment and collect some statistics. This included testing other forms of bubble wrap that did not exist in 1996.
Procedure
The BalloonSat for this experiment carried five patches of bubble wrap. They were, clear with 1/2" diameter bubbles, pink with 1/2" bubbles, clear with 1" bubbles, pink with 1" bubbles, and air pillows. The number of intact bubbles was recorded before flight and then compared to intact bubbles after recovery.
Results
Clear with 1/2" bubbles: 30.6% popped
Pink with 1/2" bubbles: 6.6% popped
Clear with 1"bubbles: 86.4% popped
Pink with 1" bubbles: 14.3% popped
Air Pillows: 100% popped.
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| One and 1/2 inch diameter bubble wrap patches after their near space flight. The popped 1/2" bubbles are marked in black. All of the 1" bubbles are popped. |
Discussion
It appears that in many cases, air is leaking from one bubble to another. So it seems that desalination of the bubble wrap is an issue. In addition, air may have leaks from bubbles without popping the bubble. One needs to do a better job accounting for the shape the bubble wrap is in prior to starting the experiment. This will prevent a low-fill bubble being treated as a popped bubble.
It's not surprising the Air Pillows failed. They were very full of air prior to launch. The fact that they burst shows that the plastic film used to create the pillows isn't very strong.
Recommendations
The experiment should be re-performed with newer bubble wrap that has not been previously used as packing material. NearSys will next assess the ability of a layer of bubble wrap to keep its interior warmer than ambient air temperature,
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