PAY Spacecraft I/F
🚧 This document is still being actively worked on and is subject to change. 🚧
Scope​
This document outlines the Spacecraft interface connecting the Payload Subsystem with the rest of the sage spacecraft.
Electrical Interface​
The electrical interface utilizes a sealed D-Sub-Micro 15 connector from Comtronics. The company also provides the space grade custom cable assemblies. The cables end in Molex Micro-Lock Plus 505568-1581 connectors.
The pinout for the most recent version on the POBC side is: POBC version: 3.0.0 Updated: 21.02.2025
| Pin | Signal | Type | Voltage | Description |
|---|---|---|---|---|
| 1 | RST_N | Logic | 3.3V | MCU Reset |
| 2 | SWDIO | Logic | 3.3V | Programming / Debugging |
| 3 | SWCLK | Logic | 3.3V | Programming / Debugging |
| 4 | CS_N | Logic | 3.3V | OBC SPI CS |
| 5 | SCK | Logic | 3.3V | OBC SPI SCK |
| 6 | MOSI | Logic | 3.3V | OBC SPI MOSI |
| 7 | MISO | Logic | 3.3V | OBC SPI MISO |
| 8 | CAN_B_N | CAN | 5V | CAN_B_N |
| 9 | CAN_B_P | CAN | 5V | CAN_B_P |
| 10 | CAN_A_N | CAN | 5V | CAN_A_N |
| 11 | VCP_TX | Logic | 3.3V | UART Console Port |
| 12 | CAN_A_P | Logic | 5V | CAN_A_P |
| 13 | VCP_RX | Logic | 3.3V | UART Console Port |
| 14 | 5V | Power | 5V | Power Supply |
| 15 | GND | Power | GND | PC104 Ground |
Mechanical​
The payload pressure box is fastened on the four PC104 threaded rods and locked in place with 8 M3 nuts. We intend on using ceramic nuts, tough their stability during the launch environment has yet to be determined. If not possible, metal nuts with ceramic/polymer washers will be used to minimize heat flow. The through-holes in the container are slightly oversized as to minimize the contact area.
The 8 nuts only sustain the loading of the container mass and do not contribute to sealing the atmospheric pressure of the container lid onto the box.
The walls are thick enough that only negligible bulging occurs in vacuum.
The container is made from AW 6061 T6 Aluminium.