From the dispenser to a public linear transponder

Mission phases

• 0 · Integration & test Pre-launch
  FlatSat with the LTM on the bench, powered from the USB umbilical (which forces LTM_VSYS on). AMSAT's LTM acceptance test procedure is run, followed by flight-software qualification of the ltm1 CAN driver and environmental tests (random vibration, thermal vacuum and thermal cycling). The spacecraft is delivered with its RBF pin and with the deployment switches holding it powered off.
• 1 · Launch L-0
  Integrated in a 1U slot of a rideshare dispenser on SpaceX Transporter-22. Deployment switches and inhibits keep the battery disconnected, so there is no RF and no power during ascent.
• 2 · Deployment & quiet period T+0 → T+30 min
  The deployment switches close and the RP2350 boots. It logs the boot count, starts the RTC and keeps the LTM rail OFF (R125 pull-down). No deployables fire and no RF is transmitted for 30 minutes. Magnetic B-dot detumble starts using the face coils.
• 3 · Antenna deployment T+30 min
  The burn wire is fired through the TPS4H160 DEPLOY channel (about 1–2 A for a few seconds). The deployment flag is set in non-volatile memory. If the first burn fails, the software retries on later orbits with a sunlit-battery check.
• 4 · LTM power-on & first beacon T+45 min
  Flight software enables LTM_VSYS through MCP23017 GPB6, which is allowed only once antennas are deployed. The LTM boots in safe mode and starts its 1200 bps BPSK telemetry beacon. The FC begins sending health data (temperatures, UTC) over CAN.
• 5 · Commissioning Week 1 – 4
  The AMSAT command station checks LTM and bus health. FoxTelem stations worldwide upload frames to the AMSAT telemetry server. Team members verify the power and thermal trends against this site's budgets, then run short scheduled transponder tests.
• 6 · Nominal operations Month 1 → EOL
  The beacon runs continuously. The transponder is power-limited to about 5–8 % duty (about 69 min/day at β = 0°). It is scheduled over high-demand regions (North America, Europe, Japan) and weekend events, with a battery-gated fallback (ON above 80 % state of charge, OFF below 70 %).
• 7 · Safe mode Any time
  Triggered by low state of charge, a watchdog reset, an over- or under-temperature condition or a ground command. The LTM drops to safe mode (40 mA), the FC slows its clock, and the battery heater is thermostatic. Recovery is by ground command once the battery has charged.
• 8 · End of mission & disposal ~7 yr at 525 km
  On ground command the LTM transmitter is permanently disabled (FCC requires the ability to cease emissions). The spacecraft decays passively, and DAS shows every component demises on reentry.

Operating modes

Mode transitions are owned by the FC flight software. The LTM's own mode is requested over CAN, and AMSAT ground commands to the LTM can override it. See the power budget for line-item loads.

Ground segment

Licensing & coordination

• IARU amateur-satellite frequency coordination (iaru.org, status).
• FCC Part 97 amateur space station notification, with an Orbital Debris Assessment Report built from DAS.
• The launch-provider ICD and dispenser compliance (CubeSat Design Specification rev 14.1).