Abstract

This project sought to develop an inline flight termination system capable of surviving in damp, intermittently submerged conditions with and without the balloon line still attached. Firstly the unit must allow for a line to pass through its housing. This is achieved using compression fittings tapped into the enclosure to retain two silicone disks with healing properties. These disks allow the line to pass through their center and remain waterproof. Additionally, a wax line is used so that when pulled free, the silicone membranes collapse, and the wax helps fill the hole, ensuring the fittings remain watertight. Two sides of the housing are removable to allow for the resetting of the cutdown device. Silicone o-rings are used to keep the removable sides watertight alongside 4 bolts in each corner. The housing was 3D printed out of ABS with thick wall layers to ensure strength and temperature resistance. The main housing body also includes a location for securing to the top of the parachute such that the device is not lost upon cutdown. The device cuts the line using a nichrome wire bridging a gap between two terminals, where the line is held taught against the nichrome. To facilitate cutdown, a specific radio signal is sent to the cutdown device from the dispatcher connected to the satellite antenna. Upon reception of this signal, a 1.5 V difference between the terminals results in several hundred milliamps flowing through the nichrome wire, making it red hot and cutting the taught line, thus allowing it to come out of the housing.

Keywords: Ocean, Waterproof, Cutdown

How to Cite:

Nichols, L. D., Schmidt, I. H. & Uhlenbruck, T. T., (2022) “Waterproof Inline Flight Termination System for Ocean Bound High Altitude Balloons”, Academic High Altitude Conference 2020(1). doi: https://doi.org/10.31274/ahac.11640