The following article is part of Diogo Peralta Cordeiro's Logbook.

Porto Space Team - Rocket

Published in 2022-08-12 by Diogo Peralta Cordeiro.

Last update: 2022-08-13

This is a weekly updated document with brief sitreps of the E-42 SoftEng Dept. of the Porto Space Team.

SitRep 1 (2022-08-12)

Requirements for the Main Flight Computer

Hardware

The Electrical Eng. Dep. has decided on the following specification:

Redundant COTS Recovery Electronics

TRS

Total Recovery System - It triggers two parachutes to bring the rocket safely to the ground, records flight statistics and allows to download the flight profile to a computer, for graphing purposes.

It commonly uses a GPS module, and a transmitter to broadcast the rocket’s location in real-time to the ground station.

Reports Elapsed Flight Time, Altitude @ Time, Raw Velocity @ Time, and filtered Altitude and Velocity @ Time

Flight memory is non-volatile, so all settings and flight data are retained with the battery disconnected, and interrupted flights can still produce a data graph up to the point of failure (or impact…)

COTS

Commercial Off-The-Shelf

Requirements for the TRS:

According to “EuRoC DTEG 3.5.2. TRS Flight Computer Frequencies”:

EuRoC will make specific frequencies available for tracking system use, without the need for specific radio amateur licenses. Eggtimer Ham-frequency equipment can thus legally be used during EuRoC without a license. This means that all mandatory TRS Flight Computers must be purchased in the US “Ham” frequency range. While the “EU” license free version of the TRS sounds like a compelling option, there is a major drawback in the fact, that the EU license free band contains only three separate channels/frequencies, and TRS systems cannot share the same frequency.

Furthermore, according to “EuRoC DTEG 3.5.4. TRS Flight Computer Firmware Update”:

Teams must ensure that the TRS Flight Computer is running a custom version of the firmware for the 70 cm Ham frequency band, having a channel selection resolution of 25 kHz. This is necessary in order to be able to select the frequencies allotted to EuRoC. Please note that firmware updates can be done at any time by participating teams, as long as the hardware has been procured.

Execution

Questions for E-20 (Electrical Eng. Dept.)

Feedback from E-20