X-CubeSat was a microsatellite project developed by students at Ecole Polytechnique and was part of the larger QB50 project, an international network of CubeSats for multi-point, in-situ measurements in the lower thermosphere and re-entry research, managed by the von Karman Institute in Belgium.
Funded by Thalès and CNES (Project JANUS), the X-CubeSat project started in 2010 and each year a new batch of engineering students would take over and take it forward. A 2U nanosatellite unit, the project was managed by the late M. Gérard Auvray since its conception, and was part of the activities of Ecole Polytechnique's Centre Spatial Etudiant. More than 70 students have been involved in its development.
The main purpose of the QB50 project was to study the upper layers of the troposphere in the altitude range from 350 km down to 200 km. The QB50 project also had the objective of demonstrating the possibility of launching a network of about 50 CubeSats built by universities all over the world to perform first-class science in the largely unexplored lower thermosphere.
X-CubeSat contained the FIPEX (Flux-Φ-Probe Experiment) of TU Dresden as the primary payload for the QB50 project, which is able to distinguish and measure the time-resolved behaviour of atomic and molecular oxygen as a key parameter of the lower thermosphere. It also contained an amateur FM transponder. More information here.
The cubesat was launched from the International Space Station (ISS), carried there first by a Cygnus cargo spacecraft and deployed using the Japanese Kibo module and the station’s robotic arm equipped with the Small Satellite Orbital Deployer tool (SSOD). This system was specifically designed to extract satellites from the Kibo module’s airlock and launch them into space. It was placed in orbit on 17th May 2017.
Although initially planned for only a six-month mission, X-cubesat served for more than a year and half in space, sending back important data to help advance upper atmosphere science. It was finally destroyed during re-entry on 4th February 2019.