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🚧 This document is still being actively worked on and is subject to change. 🚧
| Responsible |
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| Last Updated | 10/12/2025, 12:48:54 PM |
| Last Author | Kai Berszin |
OBC Software
This section describes the software of the OBC. It gives details on the architecture, overall design and interfaces with other systems. It is further structured in the following subsections:
- Architecture: Gives details on the SW architecture on a higher level.
- Implementation: Provides additional documentation to the code. From code quality to interfaces and the logic.
Constraints​
The flight software is subject to multiple constraints given by substystem requirements and hardware limits.
Memory Budget​
These numbers are rought estimations which should be in future more rigorously defined using information from the individual subsystems.
Data generated by Experiments​
| Experiment | Scenario | Duration | Rate | Data |
|---|---|---|---|---|
| PAY | Nominal | 100 days | 8 MB/h | 19200 MB |
| GNSS | Precise orbit determination 1 | 3 Months | 259 B/s | 1920 MB |
| GNSS | Attitude determination 1 | 100 Minutes | 5168 B/s | 30 MB |
| Trikarenos | Reduced Test 1 | - | - | 1 MB |
| Trikarenos | Full Test 1 | - | - | 16 MB |
| Earth Camera | Daily images | 3 years | 8 MB/day | 8700 MB |
| Total | 38000 MB |
[1]
Status data generated over lifetime of mission​
Where the data is stored during flight is noted in the Data allocation Table.
| Source | Min rate 2 | Max rate 3 | Min data | Max data |
|---|---|---|---|---|
| PAY | 1 B/s | 4 B/s | 95 MB | 380 MB |
| ADCS | 1 B/s | 4 B/s | 95 MB | 380 MB |
| OBC | 4 B/s | 128 B/s | 480 MB | 12110 MB |
| GNSS | 18 B/min | 18 B/s | 28 MB | 1710 MB |
| TC | 32 B/min | 32 B/s | 50 MB | 3030 MB |
| EPS | 1 B/s | 32 B/s | 95 MB | 3030 MB |
| COM | 1 B/s | 32 B/s | 95 MB | 3030 MB |
[1]
Data allocation​
| Memory Unit | Capacity | Protection | Data |
|---|---|---|---|
| MCU SRAM | 1 MBytes | ECC, FDIR | Runtime Data |
| MCU Flash | 2 MBytes | ECC, CRC | Firmware |
| OBC NAND flash (shared) | 4x8 Gbits | ECC, littlefs | Telemetry, status data, experiment data, logs |
| OBC MRAM (private) | 2x 64 Mbits | ECC, CRC | Firmware images (backup, current, up-date) |
| OBC MRAM (shared) | 4 Mbits | ECC, CRC | Runtime data, cryptographic keys, critical logs |
| OBC SD Card | 1x >16 GBytes | ECC, littlefs | Experiments: PAY, GNSS, Trikarenos, camera images, artificial gravity data, extended telemetry data |
[1]
References​
[1] O. Tl and G. Ielpo, ‘SAGE-SYS-SW’, Mar. 2024.