PHAT-2

The Platform for High Altitude Technology 2 (PHAT-2) was a balloon mission developed by the Husky Satellite Lab, and it was the first project that I was assigned after joining the club. Unfortunately, a number of factors meant that the structure and software aspects of the balloon were never finished, but I was able to build and test all of the electronics. The photos below show the cutdown detector, a langmuir probe controller, the power distribution board, and the ADCS/IMU board. The coolest part of the driver electronics is the Pulsed Plasma Thruster (PPT) charger and igniter. The Advanced Propulsion Laboratory at the University of Washington had a design for the charger and igniter circuits that required a 4 layer PCB, it required two separate high voltage flyback converters and it would produce huge surges when it fired. These surges killed the control electronics for PHAT-1, so I redesigned the charger to provide complete galvanic isolation between the PPT and the electrical subsystem during firing. I was also able to eliminate one of the flyback converters and use a 2 layer PCB. It could charge a 100uF bank of capacitors to 800V in a few hundred milliseconds, and generate 26kV arcs for ignition. For this project, I also build a langmuir probe controller and frontend, a power distribution board, and a very simple system for detecting when the flight was terminated by a nichrome wire cutdown using a single limit switch.