THREAD’S Milestone finalization: an experimental stress test plan for thermites to be used in-orbit for satellite demise
The THREAD project - Thermite Reactions Assisting Satellite Demise - funded under HORIZON-EIC-2024-PATHFINDER, offers an innovative solution to the challenge of the growing number of decommissioned satellites returning to Earth and surviving re-entry, which poses safety risks and environmental concerns on the ground. It is the first EU-funded initiative aiming to introduce the Thermite-for-Demise (T4D) concept directly into the satellite design and manufacturing process.
The idea is to exploit localized exothermic reactions to support the controlled destruction of satellites during reentry. The technology relies on small, non-explosive thermite charges composed of metal and metal oxide embedded at key structural points within the satellite. These charges are designed to ignite without any external input and generate intense localized heat that enhances the breakup of the structure, even when satellites are no longer active. Thus, this approach aims at greatly improving safety outcomes on the ground.
The project, coordinated by Politecnico di Milano, Italy, and led by Prof. Filippo Maggi, Aerospace Science and Technology Department, brings together a consortium of international partners, including Université Jean Monnet Saint-Etienne, whose Matteo Ferrari from the MOPERE team leads WP4. THREAD aims to validate T4D technology through material development, wind tunnel testing, and cost-benefit analysis, paving the way for safer and more sustainable satellite disposal within the emerging space economy. WP4 focuses on environmental stress tests and analyses the response of thermite solutions, their elementary building blocks, and the thermite-based concepts to life-long stresses suffered from launch to ignition at satellite re-entry.
The use of these thermite charges in space missions requires extensive testing to ensure their behavior in the challenging environment experienced throughout their lifetime. In particular, this includes thermomechanical stresses associated with launch and radiation stresses associated with in-orbit operation. It is especially important to verify that the experienced stresses do not induce premature ignition or significant modifications of the combustion characteristics that could compromise satellite safety or correct demise. An example of ignition in controlled laboratory conditions is provided in (Picture 1). Within WP4, THREAD recently identified the main environmental stresses, and successfully designed an experimental test matrix to deepen the understanding of thermite stability with respect to these environmental constraints.
The recent validation of the test plan marks the achievement of one of the four expected milestones of the THREAD project. The test plan is being implemented across the Consortium’s facilities and shared among four partners. In particular, the Casaccia facility at ENEA (Roma, Italy) and the PETRA platform of the Laboratoire Hubert Curien will carry out the irradiation tests using, respectively, 60-Co gamma radiation and X-rays. ReActive (Peschiera Borromeo, Italy) and Politecnico di Milano will be responsible for the mechanical vibration tests and the thermal characterization of the ignition process on stressed thermite samples, respectively.
The inclusion of ionizing radiation tests in the plan represents one of the innovative aspects of the project. In fact, no previous irradiation experiments on thermites have been reported in the open literature. Indeed, radiation fields are among the main sources of hazards in the space environment.
The first irradiations of thermites in the form of free-flowing powder (Picture 2, left) have recently been carried out using the X-rays irradiation facilities of the PETRA platform. This also marks the first irradiation of energetic materials in our laboratory, conducted in compliance with the safety handling and storage procedures specified by the thermite producer and put in place with the support of our safety officers.
The defined irradiation protocol foresees the use of a plexiglass box to protect the facilities and operators in the event of sample ignition, along with thermocouples and cameras to monitor possible real-time ignition events induced by radiation. The developed setup is shown in (Picture 2, left, and Picture 3, right).
Figure 1, below: Ignition of a thermite sample in laboratory conditions
Figure 2, above:
Left: Sample of thermite in the form of free-flowing powder, placed in an aluminum container.
Right: First setup used for thermite irradiation with X-rays at the PETRA platform. The sample is placed inside a thick plexiglass box for safety, and is monitored in real time using a thermocouple and a camera to detect any possible ignitions. (Pictures by Sayah El Hajji and Matteo Ferrari)
Figure 3, below: Additional photograph of the setup by Sayah El Hajji
Further information about the THREAD project can be found at the following links:
Funded by the European Union through the European Innovation Council (EIC) within the THREAD project (Grant Agreement ID: 101186901). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or European Innovation Council (EIC). Neither the European Union nor the granting authority can be held responsible for them.