PHAT-2 Subsystems Info

ADCS is responsible for developing a standard, modular interface between the command board and sensors. As of now, there has been substantial work done on the interface and its documentation, and drivers are being developed for a magnetometer, barometric altimeter, and thermometer following the specifications from the interface. There have also been boards designed upon which will be mounted the sensors and a terminal which will facilitate an I2C connection with the main board.

The CDH (Command and Data Handling) team is in charge of the centralized computing board on the mission. The board provides logic and signaling for all other electrical components, along with data processing and storage. In the spirit of the PHAT-2’s goal to provide infrastructure for future missions, the CDH team is putting a large additional focus on overhauling the current code libraries. With clarity and documentation in mind, our team has taken to rewriting core libraries in a reusable git submodule for both this mission and future use.

The Power Subsystem has been tremendously successful in accomplishing reach and target goals early in the project. Regulation and distribution of power on the subsystem level has been implemented, accommodating the variety of power consumption needs on PHAT-2. A nichrome wire “cut-down” circuit is in the works, giving the ability to detach the payload from the balloon at any time. It is likely that expertise from this subsystem will be called upon by other subsystems to assist in integration and the development of their own circuitry.

The Propulsion Subsystem is divided into two teams focused on development of a Pulsed Plasma Thruster (PPT) and a Langmuir Probe respectively. A PPT is a robust and well-studied Electric Propulsion system that the lab has extensive experience with, having flown one on Husky Sat-1. The PHAT-2 PPT will have a similar design and use a Teflon fuel source instead of a sulfur one. The Langmuir Probe team is working on building a probe to measure thruster performance in flight. If successful data on electron temperature and density in the plasma will be determined at various altitudes. Currently, the subsystem is focused on circuit design and ensuring that commands can be received, and data properly recorded during the mission.

The goal of the Structures subsystem is to develop a modular payload mounting system that can be adapted to specific payloads for future missions. The payload mounting system will be comprised of curved lengths of PVC connected by 3D-printed components upon which each payload component will be mounted. The payload mounting system is connected via fishing line to the electronics bus, constructed of insulating foam, which will house the circuit boards and battery packs from other subsystems.