From July 16 to 20, 2025, the "SOURCE CubeSat" team from the University of Stuttgart conducted environmental testing at the European Space Agency's CubeSat Support Facility at ESEC-Galaxia in Libin, Belgium. The objective was to verify the satellite's autonomously designed solar panel deployment system, marking a critical step in the satellite's journey to space.

The SOURCE team is currently in Phase D of CubeSat development, focusing on final design, integration, and testing. Their satellite is a 3U CubeSat equipped with a custom solar panel deployment device, a feature crucial for power generation after entering orbit and for the overall success of the mission.

This testing activity was conducted under the ESA Academy's "Fly Your Satellite!" programme, providing student teams with a professional-level testing environment within one week. The testing consisted of two parts: vibration testing, simulating the mechanical stresses during launch to evaluate the structural integrity and deployment reliability of the solar panel deployment system; and thermal vacuum testing (TVAC), exposing the deployment system to extreme temperatures and space vacuum to ensure its performance in orbit.

After four thermal cycles simulating drastic temperature fluctuations in space, the internal deployment system successfully activated during the fourth hot-cold plateau, verifying its functionality under mission-representative conditions.

This successful deployment is an important milestone for the SOURCE project. Confirming that the system can deploy in a simulated space environment gives the team confidence in its performance after launch. At the same time, this experience provided students with practical opportunities to participate in full-cycle environmental qualification testing, covering aspects such as cleanroom preparation, safety protocols, data recording, troubleshooting, and analysis.

SOURCE team members stated: "The successful deployment after the fourth thermal cycle is not only a technical achievement but also a great boost to confidence, clearing the way for advancing satellite integration work."

With the environmental testing activities completed, the SOURCE team is preparing for the next step: satellite integration. This phase will integrate all CubeSat subsystems, forming a fully assembled, flight-ready spacecraft.

ESA Academy congratulates the SOURCE team on their achievements and will continue to support student teams in pioneering sustainable, technically advanced space solutions.