Demodulation demonstration using the LightCube CubeSat

TL;DR

This paper demonstrates the operation of the LightCube CubeSat, showcasing its communication capabilities, telemetry reporting, and tracking by amateurs, providing insights into its deployment, operation, and failure analysis.

Contribution

The paper presents the first demonstration of LightCube's communication system, telemetry decoding, and tracking, along with the development of educational radio decoding tools.

Findings

LightCube successfully transmitted a visible flash on command.

Amateur radio operators tracked and decoded signals from LightCube.

The team reconstructed the sequence of events leading to the satellite's battery failure.

Abstract

LightCube is a 1U educational CubeSat which had the goal of connecting the public with space by producing a flash visible to the naked eye on command by a public user. The spacecraft could be triggered via HAM radio communications by those with an amateur license. LightCube is commanded with a DTMF sequence, and reports telemetry using RTTY, an AFSK modulation scheme and is decoded with a custom GNURadio-companion flowgraph. Several radio applications were written, including a from-scratch decoder written for educational purposes and one optimized to be compatible with the SatNOGS environment. Lightcube deployed from the International Space Station on April 24th 2023 and operated for 24 hours before suffering a battery failure. During this time it was tracked by many amateurs around the world with observations reported to the SatNOGs database. Audio observations of the beacons were subsequently decoded by the student team and by amateurs. Having received many observations from around the world, the team has been able to reconstruct the sequence of events leading to loss of communications.