Open-source Designs Currently in Development
PROMETHEUS BATTERY BOARD
An in-house, open-source battery board undergoing development by AlbertaSat since 2017. Capable of both discharge and charge control; includes resistive battery-heating capabilities, as well as temperature and current sensors.
The Prometheus battery board is the sister board to the Atlas electronic power system, another system developed at AlbertaSat. Atlas controls the flow of power to and from Prometheus and interfaces with its sensing capabilities. Prometheus has four lithium-ion cells arranged in a 2S2P array, and its battery heaters are composed of four 1W metal film resistors.
The two-layer printed circuit board contains four connectors: two stack headers, one data header that exchanges information on battery and heater switching, and one ground charge header allowing for external ground charging capabilities. Prometheus fits the PC104 standard, and is easily configurable for different battery requirements.
Properties of the Prometheus battery board:
|Maximum voltage||8.4 V|
|Maximum current||13.6 A|
|Mass||300 g (including 194 g for all batteries)|
|Volume envelope||(87.63 x 93.35 x 34.72) mm³|
|Short circuit protection||Internal to cells|
|Charge temperature||0°C – 45°C|
|Operating temperature||0°C – 40°C|
|Storage temperature||0°C – 60°C|
APOLLO UHF TRANSCEIVER
The Apollo UHF transceiver, an in-house design that is powered by the TMS570LS1224 Hercules Mircocontroller and uses the ADF7021 transceiver, establishes communication between Ex-Alta2 and ground stations. It supports a variety of FSK modulations with a data rate of up to 32.8 kbps. It is also built with a 64GB NAND SLC SD Card for storage, and a SMB coax connector. Apollo is compliant under the PC/104 standard.
The transceiver board is thermally interfaced with the satellite housing via the through-hole connectors. The rod through holes consist of large vias with smaller vias within. This ensures good thermal conductivity between the rods and the board itself.
Proprieties of the Apollo UHF transceiver:
|Volume Envelope||93.34 mm x 87.63 mm x 12.65 mm|
|Modulation Scheme||2FSK, 3FSK, 4FSK. MSK|
|Supply Voltage||1.2V, 3.3V|
|Communication Interfaces||CAN, SPI, I2C|
|Output Power Range||≤4W|
|Frequency Range (Tx/Rx)||160 MHz to 650 Mhz|
|Baud Rate (Tx/Rx)||50 to 32800|
|Data Rate||0.05 kbps to 32.8 kbps|
|Operating Temperature||(-40 to 85)°C|
|Storage Temperature||(-40 to 150)°C|
By Jie Cheng, Joanne Cai, Bill Kung and Zack Dorward
This page was last updated March 2021