This afternoon, the styrofoam boxes, which we ordered, arrived at our institute. We plan to place our experiment CHAOS inside one of these boxes for thermal control during the flight on the stratospheric BEXUS balloon. This approach was successully used by other BEXUS experiments from our Department before.
These boxes were designed to transport and cool food and drinks, not to be flown on a stratospheric balloon. To test wether the styrofoam withstands the expected low pressure environments, we spontaneously decided to put it into our vacuum chamber and start a test. The styrofoam encapsulates tiny bubbles of air. In a low pressure environment this air wants to expand and can become critical if the syrofoam loses its structural integrity because of this expansions. Unfortunately, we could only place the lid of a box inside the chamber because of the size of the box.
The results of our test can be seen below. The plot shows the pressure of the backing pump (p2) and within the chamber (p1). We can see that we reached pressures of less than 0.01 mbar. This is three orders of magnitude below the expected pressure environment during the BEXUS flight. In the last picture we see the comparison of the tested styrofoam (top) with an untested lid (bottom). The tested lid shows some open pores, but the styrofoam kept its structural integrity. Therefore, we conclude that the styrofoam boxes are ready for flight.
